Jan Marcin Węsławski1*
Jacek Urbański1
Joanna Piwowarczyk1
Lech Kotwicki1
Jacek Piskozub1
Karol Kuliński1
Ksenia Pazdro1Józef Wiktor1
Sławomir Sagan1Iwona Psuty2Waldemar Walczowski1Aleksandra Koroza1- 1Institute of Oceanology Polish Academy of Sciences (PAN), Sopot, Poland
- 2Sea Fisheries Institute, Govermental Research Institute (GRI), Gdynia, Poland
The Gulf of Gdańsk belongs to the best-known marine areas in the Baltic, with regular environmental observations since mid-20th century. It covers the widest array of marine habitats in Polish Maritime areas (from large river mouth to Gdańsk Deep), shallow vegetated lagoon and stony reefs and the highest resources of species diversity (about 400 Metazoa and over 300 Protista species). The area was also important as a fishing ground as well as a key site for the marine industry, shipping and tourism. The review of the changes in the Gulf of Gdańsk over last 40 years shows that it follows some of the global trends (increase in temperature, storminess, sea level rise, decrease in ice and oxygen), while the specific local phenomena like eutrophication and contamination are more difficult to assess (e.g., strong reduction in nutrient discharge did not change the levels of P and N in the system). After recovery from the environmental crisis in the 1980s, the toxic compounds in sediment and seawater are below the accepted thresholds. The reduction in some toxins resulting from better management (e.g., Mercury or chlorinated compounds) is blurred by the negative effects of climate warming (expansion of anoxic sediments) and contamination connected with its biogeochemical activity. Formerly degraded coastal habitats are recovering (especially seagrass), while the commercial fish catch collapsed, likely caused by the large-scale phenomena (climate warming), not directly connected with the local conditions of the Gulf. The societal use of the Gulf changed from industrial/fishery to largescale tourism and service, with fast growing pressure for coastline urbanization. The key phenomena (drivers of events) of the area include eutrophication, industrialization and biodiversity recovery.
Introduction
The Gulf of Gdańsk at the Southern Baltic belongs to the best-known marine areas in the region, as large harbour and metropolis of Gdańsk-Sopot-Gdynia, several high schools and universities, research institutes and fishery centre are situated at its coast (Figure 1). We have the records of the changes in the Gulf since the beginning of the 20th century – Lakowitz 1907; Demel 1935; Pliński and Wiktor 1987). This very area has been suppressed between 1970 and 1990 with extreme environmental stress due to the industrial, agricultural and household contaminants. The original habitats and communities of the Gulf have been heavily disturbed, mainly by oxygen deficit connected with heavy eutrophication (Żmudziński and Osowiecki, 1991; Ciszewski et al., 1991; Szaniawska et al., 1999) or physically destroyed (like exploitation of drifting fucoids and red algae (Andrulewicz, 2021; Kotwicki et al., 2024). The untreated wastewater from the area resulted in closing the coastline for bathing and even water sports almost every summer, with record count of Escherichia coli index of a few thousand cells per ml (Sobol and Szumilas, 1992). Massive investments in the water treatment facilities started in 1994, after adopting the EU regulations, and the pollution issue has largely been controlled since (Pastuszak et al., 2018). At the same time, global warming started to be recorded in the area, as the whole Baltic Sea belongs to the fast-warming areas of the globe (IPCC, 2014; Meier et al., 2022; Dutheil et al., 2022). Those two independent processes – better care of the environment from the level of the state and the global warming, drive the changes of marine ecosystem in different ways, causing confusion in the public debate about the state of coastal environment.
Figure 1. Gulf of Gdansk with density of population on the coast and main bathymetric features.
The biogeochemical structure and variability of the water column in the Gulf of Gdańsk are driven mostly by the large-scale biogeochemical processes and hydrological circulation occurring in the entire Baltic Proper and the inflow of the Vistula River waters (the second largest river entering the Baltic Sea with an average water flow of 1055 m3 s−1, IMGW, 2024).
The Gulf of Gdańsk is monitored by the Polish Institute of Meteorology and Water Management (IMGW), with monitoring cruises conducted 4–12 times per year since 1989. The Institute of Oceanology Polish Academy of Sciences (IOPAN) also conducts systematic studies in the Southern Baltic, conducting four expeditions annually (Rak and Wieczorek, 2012). The SatBaltyk program (www.satbaltyk.iopan.gda.pl) provides SST and other sea surface properties, while the Argo-Poland program (www//Argo Poland//iopan.pl) supplies CTD and dissolved oxygen (DO) data from Argo floats operating in the Southern Baltic (Walczowski et al., 2020).
Thanks to the activity of HELCOM, the updated reports on the state of the Baltic are available, from the ecosystem health parameters (HELCOM, 2023) to the detailed study of benthic fauna and its habitats (e.g., Gogina et al., 2016). However, small yet important areas such as the Gulf of Gdańsk may have its own dynamics, and hence we want to present a review of the recent marine environmental changes in this very area with a special focus on the marine biodiversity and the corresponding societal response of local inhabitants within the recent decades.
Materials and methods
The majority of material presented comes from cited literature. The methods used to reanalyse the data on sea ice change are presented below.
To analyse the ice variability in the last 40 years in the Gulf of Gdańsk, the daily raster data of sea ice fraction with a spatial resolution of 0.02° × 0.02° and temporal extent from 1 January 1982, to 30 September 2023, were used. The data were obtained from the Copernicus Marine Service (https://doi.org/10.48670/moi-00156) for the Gulf of Gdańsk area. They include high-resolution sea ice concentration data from SMHI for the period between 1982 and 2011 and the Copernicus SI-TAC product from 2012. Ice thickness was not considered due to the lack of reliable data. See the appendix for details about the methods.
Results
Atmosphere – wind and storminess
In the Baltic Sea region, the winds, especially in winter when most extreme storms occur, are strongly correlated with the North Atlantic Oscillation (NAO) index of zonal circulation (Rutgersson et al., 2015). The results of studies suggesting the increasing storminess in the recent decades (cf. Różyński, 2010; Wolski and Wiśniewski, 2021) may be biased by starting the time series with the negative NAO and low storminess of the 1970s and ending it with the predominantly positive NAO and high storminess period in the 1990s or the recent series of nine winters with positive NAO (2014–2022).
The Gulf of Gdańsk geographical position makes it susceptible mostly to storm waves and surges with northerly winds, from NW to NE, while being mostly protected with more prevalent storm winds from SW and W directions (Różyński et al., 2006). This protection causes significant wave height being on average about twice smaller in the Gulf than in the open Baltic coast of Poland (Różyński, 2010), resulting in historic extreme storm surges lower than elsewhere on the Polish coast (Zeidler et al., 1995), even though the number of hours with surges greater than 70 cm are higher in the Gulf compared to other areas (Wolski and Wiśniewski, 2020; Wolski and Wiśniewski, 2021).
That said, the highest storm surge in the Gulf of Gdańsk in recent decades was recorded on 2 January 2019 (storm Zeetje with 161 cm surge recorded in the Gdańsk Port Północny). There are reasons to believe that the winter NAO index (and therefore also the Baltic storminess) may be related to the ongoing global warming (Blackport and Fyfe, 2022), implying anthropogenic influence of the recent storminess trends. That would match the existing consensus amongst studies regarding a projected increase in the mean significant wave height in the Baltic Sea in the 21st century (Morim et al., 2018), as well as the recent projections of increase in average and extreme wind speeds in Poland (Gąska, 2023). The risk of future storm surges in the Gulf of Gdańsk is exacerbated by the increasing sea level, the long-term trend of which in the Baltic Sea is close to the global one (Hünicke et al., 2015).
Water transparency
From the start of Secchi disc depth (ZSD) observations in the Gulf of Gdańsk in the late 1950s the declining trend was observed, and for the period between 1980–90 the mean values of 4.5 m were reported (Sagan, 1991; Trzosińska, 1992). Since 2003, the regular observations of ZSD were carried out in the Gulf on evenly distributed grid of several stations in spring (months M, A, M) and autumn (months S, O, N). As a result, a weak trend of the increase in water transparency ZSD, of 0.012 m/yr., is observed, (Figure 2).
Figure 2. Increase of water transparency in the Gulf of Gdansk in last decades. Secchi depth observed in the Gulf of Gdansk, years 2003–2015 n = 463, thick line shows trend of 0.012 m/year. Original unpublished data from IOPAN archive.
In 2015, the average value of ZSD exceeded 5 m. In terms of the depth of euphotic zone, Zeu, the decadal change ranges from ∼16 m to ∼18 m. The increase in mean transparency may be attributed to the reported decrease in pollution load from the terrestrial sources, and it corresponds with the observed trend of decreasing the chlorophyll content in the Gulf of Gdańsk in the last 20 years (Stoń-Egiert and Ostrowska, 2022). Also, analysis of long-term trends of ZSD in the open Baltic areas show its increase in the southernmost sub-basins, opposite to the decrease in the central and northern part of the Baltic (Fleming-Lehtinen and Laamanen, 2012).
Salinity and temperature
Estimates of the average SST increase in the Baltic vary, but within the same order of magnitude. Stramska and Białogrodzka (2016) estimated the SST increase of 0.05°C/year for the period between 19822013, and Liblik and Lips (2019) determined an average SST increase of 0.05°C/year between 19822016. Generally, over the last 30 years, the average SST increase ranges from 0.04°C to 0.06°C/year (Meier et al., 2022). The SST increase is seasonal, with the highest warming occurring in the summer months (May to September) and lower trends in winter (Stramska, Białogrodzka, 2016; Kniebusch et al., 2019; Liblik and Lips, 2019). The SST increase is not uniform across the entire Baltic Sea (Stramska and Białogrodzka, 2016), with the Bay of Bothnia and Gulf of Finland experiencing the strongest growth. The temperature trend in the Baltic Sea is not constant and is correlated with atmospheric temperature. In 2018, Europe experienced the warmest summer in the instrumental measurement period, including the warmest summer in the Southern Baltic in the last 30 years (Naumann et al., 2019).
The Cold Intermediate Layer (CIL), also referred to as the “dicothermal layer” forms during spring when the upper layer warms from the surface, contrasting with the cold winter waters below, and persists throughout the summer, usually disappearing during autumn convection (Lepparanta and Myrberg, 2009). In the Gdańsk Deep, CIL reaches a depth of 40–70 m and can last at this depth until the next cold season.
Over decades, surface salinity in the Baltic Sea has been decreasing (Stockmayer and Lehmann, 2023). The salinity increases with depth, reaching its highest values near the bottom (up to 14 PSU). The salinity variability is influenced by inflows from the North Sea, especially major Baltic inflows (MBI) (Figure 3).
Figure 3. Vertical profiles of temperature and salinity in the Bay, original unpublished data from IOPAN archive.
The sea surface temperature (SST) time series from between 2009–2020 provided by SatBaltyk (Figure 4), alongside strong seasonal variability, indicates that during this period, the average annual SST increase was significantly higher than previously reported for the entire Baltic Sea, amounting to 0.12°C/year. The notion of a greater SST increase in summer is not confirmed. On the contrary, the trend was highest in winter (January-March) at 0.25°C/year, while in summer (July-September), it was close to 0°C/year. The highest summer temperatures were recorded in 2010, 2014, with a record-setting 2018.
Figure 4. Sea surface temperature in the Gulf of Gdansk in the last decades (unpublished original data from IOPAN archive).
There is considerably less information on the interannual changes in the water column structure, thermocline depth, and halocline depth. Rak and Wieczorek (2012) analysed the water structure, temperature variability, and salinity changes for selected areas of the Southern Baltic from between 1994–2010. From in situ data collected during 68 voyages of r/v Oceania, the temperature trend for the surface layer (0–10 m) for the period between 1994–2010 was 0.11°C/year for the Gulf of Gdańsk. The salinity changes in the layer up to 50 m were approximately 0.038 PSU/year, and at a depth of 90 m, they reached up to 0.07 PSU/year.
Sea ice
During the winter between 2005–2006, ranging from strong to mild severity, ice in the inner part of the Gulf persisted for 70–80 days, while in the outer part, it lasted for 10–20 days (Urbanski and Kryla, 2006). In the remaining part of the Gulf of Gdańsk, ice phenomena occurred for about a month only during severe winters, and in milder winters, it failed to occur at all (Schmelzer et al., 2008).
The variability of ice phenomena over a 40-year period in the Gulf of Gdańsk is shown in Figure 5. Multi-year periods of extensive or moderate ice cover, lasting from two to 5 years, are interrupted by periods with low or no ice. Up to 2003, there were two such periods lasting approximately 4-5 years. However, after 2003, winters with low ice cover in the Gulf of Gdańsk occurred individually, with the majority of winters characterized by moderate ice cover. Average values were calculated from the time series presented as 30-year climatological normals for the periods between 1982–2011 and 1992–2021 to determine whether they differ from each other. Due to the non-normal distribution of the analysed data, the non-parametric Mann-Whitney U test was employed. The calculated U statistics was 432.5, with a p-value of 0.8, indicating that there is no significant difference in means.
Figure 5. The percent of maximum accumulated sea ice in the Gulf of Gdansk for years 1982–2023, data from IMGW data repository (IMGW, 2024).
A more detailed analysis was conducted separately for the two previously discussed areas of the Gulf. The histograms (Figure 6) illustrate the variability in the number of ice days, with the cover above 10% of the maximum cover in a given area, for two consecutive two-decade intervals: between 1982–2001 and 2002–2021.
Figure 6. The number of ice days during the periods 1982–2001 and 2002–2021.
Without analysing the statistical significance of the conclusions, several characteristic features of these distributions can be noted. In the Puck Bay, the duration of ice cover exceeded 50 days in 5 years between 1982–2001 and in 3 years between 2002–2021. A higher number of milder winters between 1982–2001 resulted in more frequent occurrences of no ice in the Puck Bay during that time. In the coastal waters of the Gulf of Gdańsk, ice occurred only three times throughout the entire 40-year period analysed.
Coastal change and erosion
Coastal change over the years is connected mainly with the technical measures against the erosion of soft sediment shores (Subotowicz, 1982; Pruszak and Zawadzka, 2008). The increase in technical infrastructure prevailed in the outer part of the Polish Baltic Sea coast, while in the inner part mainly beach nourishment was used almost every year (Łabuz, 2015). There was no considerable expansion of hard infrastructure on the shores of the Gulf except for the prolonged concrete walls at the Vistula River mouth, and the new (2020) artificial opening between the Gulf and Vistula Lagoon. The massive loss of reed in the inner part of the Gulf between 1980–90, was caused by the uncontrolled expansion of recreational infrastructure (camping owners) and was recently stopped by law, and active protection – reed planting was successfully applied (Zostera, 2024).
Biogeochemical change in water column
Depending on the wind speed and direction as well as the freshwater discharge, the river water plume may extend from 9 to 27 km horizontally from the river mouth and from 0.5 to 12 m vertically in the water column. Due to the predominance of westerly winds, the Vistula River waters are mostly directed eastward and then spread to the northeast being introduced into the anticyclonic circulation of the surface waters in the Baltic Proper (Matciak and Nowacki, 1995). The Vistula River, draining large and highly agriculturally transformed catchment, is a great source of nutrients to the Gulf of Gdańsk. This triggers primary production in the region, which between 1993 and 2018 was on average 6%–17% higher and started about 1 month earlier than in the open waters of the southern Baltic Sea (Zdun et al., 2021). As a consequence, during the productive season, the surface waters of the Gulf of Gdańsk are often oversaturated with O2 and undersaturated with CO2 (Stokowski et al., 2021) thus performing important environmental functions, namely, being a source of O2 to the atmosphere and a sink for atmospheric CO2. By contrast, during winter Stokowski et al. (2021) found the surface waters in the Vistula River plume to be close to saturation or slightly undersaturated with O2 and oversaturated, sometimes significantly, with CO2 as a result of high CO2 levels in the Vistula waters accumulated in the course of terrestrial organic matter remineralization.
The measures taken in recent decades, mostly within the HELCOM framework, resulted in a substantial reduction in riverine nutrient loads to the Baltic Sea (Kuliński et al., 2022). For the Vistula River, the flow normalised loads of total phosphorus decreased from 7,700 tons P/year in 1993 to ca. 5,000 tons P/year between 2013 and 2014. An even larger drop was found for phosphates, for which loads decreased by at least 50%, from 4,000 to 4,900 tons P/year in the 1990s to ca. 2,000 tons P/year between 2013 and 2014. A substantial reduction has been also observed for total nitrogen, for which the flow normalized loads declined from 125,000 tons N/year in 1988 to ca. 74,000 tons N/year between 2013–2014 (Pastuszak et al., 2018). This small response in productivity of the Gulf of Gdańsk to the reduction in nutrient loads is not a region-specific phenomenon but is a consequence of the biogeochemical changes occurring in the entire Baltic Proper. In short, eutrophication of the Baltic waters, triggered in the second half of the 21st century by the high nutrient input (with its maximum in the 1980s), caused the expansion of hypoxic and anoxic bottom waters in the Baltic. Such conditions favoured nitrogen removal from the system through denitrification and hampered phosphorus burial in sediments (higher P recycling in the system and additional P release from sediments that turned to anoxic). This led to the shift in N:P ratio and, consequently, a higher P availability for the after-spring-bloom period, which was beneficial for N2-fixing cyanobacteria additionally stimulated by the rising temperatures. In that way, the Baltic Proper, including the Gulf of Gdańsk, has been pushed into “a vicious circle” – a mechanism of self-sustaining eutrophication (Vahtera et al., 2007; Kuliński et al., 2022).
Oxygen conditions above the oxycline are good, with an average DO value of 12 mg/L, characterized by significant seasonal variability, with two maxima in March/April and November (Rak et al., 2020). The oxycline begins at a depth of 60 m, with a permanent oxygen deficit (below 4 mg/L) reached at a depth of 85 m. In the bottom layer, the average DO drops below 2 mg/L. Similarly to salinity and temperature, oxygen conditions below the oxycline are shaped by MBI inflows from the North Sea. In contrast to upstream basins (Bornholm Basin), the increase in DO due to inflows is short-lived (Rak et al., 2020). Argo float profiling, conducted at a high frequency (1-2 days), reveals that even small baroclinic inflows reach the Gdańsk Basin and may influence both oxygen and halocline conditions in this area (Walczowski et al., 2020).
The oxygen deficits in the bottom waters exist mostly in the central and northern parts of the Gulf Gdańsk, the so-called Gdańsk Deep region, where the water column is permanently stratified, and sediments are rich in organic matter. The stratification of the water column with a halocline occurring at a depth of approx. 50–70 m hampers the vertical mixing and is the root cause of the hypoxia and anoxia occurring in the deep waters (Rak et al., 2020). Although the occurrence of oxygen deficits was known for the Gdańsk Deep already from the 1960s; their extent and frequency have increased ever since, just as it was observed for the entire Baltic Sea (Hansson and Viktorsson, 2023). On the other hand, the shallow parts of the Gulf of Gdańsk are generally free from hypoxia and anoxia as the water column is well-mixed to the bottom. This also refers to the inner part of the Gulf of Gdańsk that is well-oxygenated, although partially separated from the open sea circulation by the Hel Peninsula (Pryputniewicz-Flis et al., 2022). Still, several short-lasting (<4 days) episodic hypoxic events have been identified off the southwestern coast of the Gulf of Gdańsk at a depth of 7-8 m (Brzana et al., 2020). These events have been recorded in the vicinity of the manmade concrete foundations (part of the torpedo testing complex from World War II) that likely influence the natural water circulation and organic matter sedimentation in the region. Still, along with the climate warming and thus an increasing potential for the seasonal occurrence of sharp thermal stratification, the coastal episodic hypoxia may start to occur more often in the Gulf of Gdańsk in the future, as it has already been observed for the Stockholm Archipelago and the Finnish Archipelago Sea (Conley et al., 2011).
Sediment alterations – biogeochemical, industrial, and natural sedimentation
The Gulf of Gdańsk is impacted by numerous anthropogenic stressors related to the industrial, traffic, municipal, and agriculture activities (Zaborska et al., 2019; HELCOM, 2023); thus, the anthropogenic influence on the chemical composition of its sediments seems to be evident. The sedimentary material in the Gulf of Gdańsk originate from moraine cliff erosion, riverine transport and human activity. The rate of sediment accumulation and distribution of sediments on the seabed is dependent on a number of factors such as the sources of sediments, intensity of biological processes, depth of seabed with its geological composition, and local hydrodynamic regimes (Szmytkiewicz and Zalewska, 2014). The most dynamic areas are the shallow coastal zones with a dominance of sandy sediments. The organic matter in sediments of the study area shows stabilization in the transect from shallow areas to depositional ones, as a result of biochemical stability of the terrestrial fraction (Winogradow and Pempkowiak, 2018). Fine grained silt-clays, rich in OM are deposited in the central and northern (deepest) part of the Gulf of Gdańsk and occur also in front of the Vistula outlet (Uścinowicz, 2011). The data presented by Winogradow and Pempkowiak in 2018 show that the organic carbon burial rate in the Gdańsk Deep represents 49% of the carbon deposited into the sediments of the entire Gulf.
Hazardous substance spatial distribution in the Gulf is highly variable and is substance-, location- and/or environmental conditions/sediment properties dependent. The most polluted sediments are identified in the Vistula estuary, receiving large inputs of riverine transported pollutants, and in the Puck Bay semi-closed area with numerous pollution sources and little water exchange and in Gdańsk Deep - a depositional area (Staniszewska et al., 2016; Filipkowska et al., 2018; Zaborska et al., 2019). The elevated level of contamination in coastal areas is also observed in the vicinity of shipwrecks and munition dumpsites (Rogowska et al., 2015). The general picture is that hazardous substance levels are near background values or slightly elevated (thus posing no or low risk to wildlife), except for the above-mentioned specific areas, where high values have been periodically observed (Zaborska et al., 2019; Rogowska et al., 2015; Staniszewska et al., 2016). The social, political and economic system initiated in the 1990s in Poland combined with international restrictions or even prohibitions on using the so-called legacy pollutants resulted in the decrease in contaminant emissions followed by the downward trends in atmospheric deposition and partially, in waterborne input (HELCOM, 2023). Despite this, based on the results obtained for undisturbed sediment cores from the depositional area- Gdańsk Deep, common pattern in the temporal trends of individual contaminant concentration is hard to observe. Moreover, the reliable assessment of certain pollutant changes over time is difficult due to the uncertainty and scarcity of the results (HELCOM, 2023). According to the latest findings the decrease in Hg concentrations after the 1990s (close to 40%) seems to be apparent (Jędruch et al., 2023). The concentrations of other metals (Pb, Cd, and Zn) are not always decreasing (e.g., Zalewska et al., 2015), fluctuating since the 1990s without showing any clear trend, which might be related directly to the considerable amounts of heavy metals discharged to the Gulf by the Vistula River, but also to the secondary sources like surface run-off and/or sediment resuspension. Despite the ban on persistent chlorinated hydrocarbons (e.g., organochlorine pesticides, PCBs) these compounds can still be detected in the entire Gulf; however, a general decline of chlorinated substances is obvious (Zaborska et al., 2019; Pazikowska-Sapota et al., 2020). A declining trend in the deposition of some other organic contaminants (nonyl phenols and tributyltin) in the Gulf of Gdańsk sediments has also been observed by Kot-Wasik et al. (2004), Filipkowska et al. (2018). However, harbours, shipping routes and anoxic sediments may still be significantly contaminated with organotin compounds. On the other hand, Staniszewska et al. (2016) reported sharp increase in phenolic compounds in the youngest deposits (from about the last 10–15 years) in the Gdańsk Deep, which could be associated with the increase in the areal extent and volume of hypoxia and anoxia. There was no such distinct temporal variation in the polycyclic aromatic hydrocarbons (PAHs) concentrations over the last 100 years. Similar patterns were also reported for other areas of the Baltic Sea (Lubecki et al., 2019). This phenomenon may be explained by the predominant number of PAHs originating from pyrogenic sources such as domestic burning of coal and/or wood for heating purposes. As described above, brief overview of the available literature data shows that although restrictions or prohibitions on using all legacy pollutants resulted in the decrease in contaminant emission, their concentrations are not always decreasing. For example, reemission and remobilization of contaminants accumulated over the years on land and at sea bottom is expected (Szefer and Szefer, 1991; Zaborska et al., 2019; Jędruch et al., 2023). Such phenomena were already observed for mercury (Saniewska et al., 2018). The enhanced remobilization of pollutants may result in accelerated accumulation in the trophic chain. The climate-driven changes may also influence the eutrophication and/or organic matter preservation in a greater extent than the direct anthropogenic impact, which was suggested by Szymczak-Żyła and Kowalewska (2009) based on pigment analyses (used as proxies of eutrophication) in sediment cores taken from the Gdańsk Basin.
Pelagic life diversity, primary production
The number of microplankton (below 200 mkm size) species found in the water column of the Gulf of Gdańsk (Baltic Proper) area exceeds 739 (Hallfors, 2004) taxa. This number refers to the southern Baltic Sea as defined by HELCOM. For the Gulf of Gdańsk alone, this number is lowered to 245 taxa (GIOŚ database), among those only two alien or invasive taxa are reported (Olenina et al., 2010). Twenty years of the observations of chlorophyll concentration in the waters of the Gulf of Gdańsk showed a slight downward trend (−0.206 mkg Chl a/dm3/year (Stoń-Egiert and Ostrowska, 2022). The number of taxa is variable and depends on a season and year. However, the high reduction in nutrient loads (Pastuszak et al., 2018) has not resulted in a substantial change in primary production so far. The level of primary production in southern Baltic slightly lowered since the 1990s (Renk et al., 2000) ranging between 32 and 2297 (mean 1210 mgC/m−2 /day) while slightly higher values 3820 mgC/m−2/day were also reported (Witek et al., 1997; Janecki et al., 2023). According to the review by (Zdun et al., 2021), unlike in the open Baltic Sea, where a decline in primary production is observed, the Gulf of Gdańsk production remains unchanged, with a slight upward trend in spring and a downward trend in summer and autumn.
Benthic life – habitats, and species
The seabed habitats remained stable over the last 40 years, as the Gulf of Gdańsk is dominated by just three main types of habitats – vegetated sand in shallow and sheltered part, sand, muddy sand and mud in open and deeper parts of the area (Figure 1). The small area habitats (e.g., small stony reefs or reeds belts at the coast) were not marked in the map and are presented in Table 1. Over the last decades, some habitats expanded (seagrass beds, reeds belt, perennial algae on the stones) and some shrank e.g., toxic muddy bottom below halocline (Warzocha, 1995; Warzocha et al., 2001; 2018; Sokołowski et al., 2015; Sokołowski et al., 2021; Błeńska and Osowiecki, 2015; Brzana and Janas, 2016; Gic-Grusza et al., 2009). Consequently, the important bioturbator Scoloplos armiger and some other oxygen demanding and cold-water species (Astarte bivalves) are practically absent in the area (Osowiecki et al., 2008; Warzocha et al., 2018). In general, a set of macrobenthic and nectobenthic species increased – with twelve species that settled in the area during the last 40 years (Table 2) and no species lost except one - the bladderwrack – Fucus vesiculosus; however, the drifting form of this algae apparently reappeared (Kotwicki et al., 2024; Bałazy et al., 2024) along with the reappearance of rare perennial rhodophycean – Coccotylus brodiei (Zgrundo and Złoch, 2022). Interesting is the increase in the abundance of big crustaceans (two species of shrimps and American crab – Palaemon elegans, Palaemonetes varians, Rhitropanopaeus harrisi), that were very rare in the 1980s. Small isopods associated with mixed and hard bottom are less frequent than in the 1980s. The lack of records of some species that are difficult to identify for non-taxonomists might be the cause of the absence of species reported as rare in the 1980s (Gammarus locusta, G. inaequicauda) Jęczmień and Szaniawska (2000). Generally, the local biota belongs to the very resilient to the environmental alterations (Włodarska- Kowalczuk et al., 2010).
Table 1. Habitat types in the Gulf of Gdansk, with the score of three types of values associated.
Table 2. Selected benthic species from the Gulf of Gdansk, with the score of three types of values associated.
Fishes and fishery
The fish assemblage of the Gulf of Gdańsk ecosystem is spatially variable. The greatest diversity of species occurs in the shallow water part of the Puck Bay and the Vistula River estuary (Draganik, 1996; Draganik et al., 2005). The most significant negative impact on the fish assemblage refers to anadromous species (Atlantic salmon Salmo salar, sea trout Salmo trutta, European whitefish Coregonus lavaretus) - hydrotechnical construction on rivers, for freshwater spawning species (northern pike Esox lucius, roach Rutilus rutilus) - drainage of coastal areas (Bartel et al., 2016). For species associated with submerged meadow habitat (broadnosed pipefish Syngnathus typhle, straightnose pipefish Nerophis ophidion) – the loss of habitat area (Margoński, 1994; Andrulewicz and Witek, 2002; Bartel et al., 2007; Psuty, 2022; Psuty et al., 2023). These conditions together with the environmental pollution facilitated the expansion of eurytopic species not affected by the fishing pressure - three-spined stickleback Gasterosteus aculeatus and ninespine stickleback Pungitius pungitius. As early as in the late 1980s, they began to dominate the coastal pelagic zone (Sapota and Skóra, 1996; Sapota, 2001). In the 1990s, the roundhead goby Neogobius melanostomus colonised the entire coastal zone over the course of about 20 years (Sapota and Skóra, 2005). The species is now a permanent component of the ecosystem of the coastal zone of the Gulf of Gdańsk and serves as important food for piscivorous birds and predatory fish but is not present in numbers sufficient for profitable fishery exploitation. At about the same time, the previously sizeable population of the eelpout Zoarces viviparus declined (Psuty-Lipska, 2000).
In the last two decades, two distinct processes were observed in the fish assemblage of the Gulf of Gdańsk: the recovery of fish populations associated with submerged meadows and a further decline in commercial fish stocks. Broadnosed pipefish and straightnose pipefish have become numerous, despite the persistent dominance of stickleback. This was connected not only with the restoration of submerged meadows, but also with the fish reproduction strategy, which protects the fry during their most vulnerable period of life, thus reducing the predation pressure of stickleback fish. The habitat degradation is the main barrier to the recovery of pike and perch populations spawning in the Puck Bay as it was observed in other Baltic areas (Nilsson, 2006).
Climate change and excessive fishing pressure have contributed to the decline of the most important species to the Gulf of Gdańsk fishery - Eastern Baltic cod Gadus morhua (Voss et al., 2019). Its fishing has been suspended in the Baltic since 2019 and, for the time being, there are no signs of the population recovery. No other fish predator has taken its place. Turbot Scophthalmus maximus, which would have had a chance to occupy this niche in the coastal zone, is an increasingly rare species. Fishermen no longer target this species, but undersized turbot are a by-catch in flounder fisheries (Draganik et al., 2005). The pike population of the Puck Bay has not yet recovered, despite intensive stocking in the last decade (Psuty et al., 2023). However, access to freshwater spawning grounds has not been provided. Despite many years of efforts under the Polish Marine Stocking programme, salmonid populations have declined (Dębowski, 2018). In the coastal zone of the Gulf of Gdańsk, sea trout are caught in particular, but traditional fishing methods have become unprofitable due to the pressure from the increasing grey seal population. The Atlantic mackerel Scomber scombrus enter the Gulf of Gdańsk sporadically and garfish Belone belone migrate to the Puck Bay only for a short spring spawning season (Sea Fishery Institute unpublished data).
Out of the remaining commercial species, the drastic decrease in the European eel (Anguilla anguilla) availability is caused by the stocking only. The prospect of a fishing ban on this once most valuable species for fishermen is imminent (Moriarty and Dekker, 1997; Hanel et al., 2019). The availability of herring Clupea harengus and perch Perca fluviatilis for fishing is strongly dependent on the fecundity of single generations, which means that these stocks are also showing signs of overfishing. Only flounder Platichthys flesus stocks remain relatively stable, although according to fishermen the size of their population is lower than 20 years ago (Rakowski et al., 2020).
Charismatic species
Seabirds (both nesting and wintering) and sea mammals (all seasonal migrants) in the area are almost all under strict protection, and a set of species known from the1980s increased with no species loss (Table 3). The extensive Baltic monitoring for the common porpoise (Phocaena phocaenat) does not indicate a change in the abundance of this rare species in the Central Baltic (SAMBAH, 2024). Grey seal (migrants) and black cormorant (nesting) are more abundant in 2020s compared to the previous time. The abundance of wintering seabirds (diving ducks) decreased in southern Baltic, which might result from milder winters and shorter migration moves (Gedas, 2001; Skov et al., 2011); however, substantial mortality in fishing nets was also reported (Stempniewicz, 1994; Marchowski, 2021). The monitoring of wintering birds in Southern Baltic (including the Gulf of Gdańsk) shows a decrease in two species (Clangula hyemalis and Larus argentatus) and increase in three (Melanitta nigra, Uria aalge, Gavia stellata) – between 2012 and 2018 (Chylarecki et al., 2018).
Table 3. Charismatic species in the Gulf of Gdansk with the score of three types of values associated.
Public health
From June to the end of August, the Gulf coastal waters are key touristic areas, and hence are being monitored by the state sanitary authorities, for the safety of bathing waters. At the beginning of 1980s, there were regular summer beach closure decisions due to the high level of bacterial contamination (coli index) – Sobol and Szumilas (1989), Sobol and Szumilas (1992), Sobol and Szumilas (1998). In the 1990s, 50% of the 37 monitored coastal bathing sites was closed to the public (IMMT, 1995). After the introduction of water cleaning facilities, the coli index is very rarely high, with no closure decisions after 2000 (Szumilas et al., 2004). On the other hand, the beach closure due to potentially toxic bluegreen algae blooms happens every summer (Sanepid, 2024). Although currently it is not considered a significant threat to the public health in the Gulf of Gdańsk, there are already indications that climate change will increase the abundance of pathogenic Vibrio bacteria in the Gulf shallow waters. This may cause infections in humans either through direct contact with marine water (i.e., through swimming or bathing) or the consumption of raw food (Bartelt et al., 1982; Amato et al., 2018; Riedinger et al., 2024). In the long run, these might become a potential issue not only for the local healthcare system but also for the tourism sector; although at present it is overridden by other environmental and economic issues, the possible implications of pathogenic bacteria growing communities are already acknowledged by the representatives of the local tourism sector (Wolska et al., 2022; Rakowski et al., 2023).
Tourism and economic development
The waters of the Gulf of Gdańsk and the adjacent land have always been popular among tourists and visitors, and they continue to be so (Kozak, 2006; Nędza and Matlingiewicz, 2022). Its most sheltered part (the Puck Bay) is not only popular for “3s” mass tourism but is also one of the largest sites for water sports in the South Baltic (Węsławski et al., 2010). With the increasing wealth of society (Borkowski, 2019) accompanied by a constant increase in active tourism (Szwichtenberg, 2019), there is an increasing pressure for further development of the tourism-related services and coastal infrastructure. Indeed, during the summer season, some coastal municipalities receive several times more visitors than the number of their permanent residents (Borkowski, 2019). These large numbers overwhelm the local tourism infrastructure (Węsławski et al., 2011) and have negative consequences on the real estate market. The prices of housing in the coastal areas, and especially around the Tri-City, are among the highest in Poland, and continue to grow (as cited in: rankomat.pl). Many apartments are bought as high-return investment for short-term rentals, which results in conflicts with local residents (Jasińska, 2019).
On the other hand, many small coastal towns and villages are, effectively, economically dependent on tourism (Krzymiński, 2014). This tourism benefits from the coastal landscapes and marine seascapes (DS, 2012; Sagan and Masik, 2018; DS, 2021). However, the SWOT analysis performed for the Pomeranian province of Poland indicates that the state of natural environment and the increased pressures towards the marine and coastal ecosystems can limit the regional ability to develop and impact negatively the health and wellbeing of the regional residents (DS, 2012; DS, 2021).
This pressure from the tourism sector has two consequences. First, it results in a rapid development of new forms of tourism, including wellness and spa, yachting, diving, biking and nature and cultural tourism (Wendt and Wiskulski, 2017; Szwichtenberg, 2019; Piwowarczyk and Zaucha, 2021). Their availability extends the tourism season beyond the short summer but nonetheless does not prevent the local businesses from maximizing profits in summer at the expense of nature and society (Wendt and Wiskulski, 2017; Piwowarczyk and Zaucha, 2021). Second, the development of tourism infrastructure permanently alters the coastal landscapes and seascapes (e.g., Andrulewicz, 2021). Examples include improving beach access through nourishments, construction of breakwaters, new roads, parking lots, hotels and other facilities such as beach bars and restaurants (Węsławski et al., 2010; Węsławski et al., 2011; Szwichtenberg, 2019; Andrulewicz, 2021). These investments not only alter natural habitats but also threaten the cultural landscape. For instance, old fishery harbours are replaced with concrete constructions of sometimes undefined use, leading to the coastal municipalities losing their specific character (Andrulewicz, 2021). Such pressures are not always properly addressed by the local municipalities (Borkowski, 2019; Andrulewicz, 2021). Oftentimes, the local municipalities lack the tools to fight unauthorized activities of local entrepreneurs, for instance, the extension of camping sites in the Puck Bay or coastline modifications, including beach widening (Wendt and Wiskulski, 2017), and the maritime administration is not always efficient (Wendt and Wiskulski, 2017; Pikner et al., 2022). Sometimes, the municipalities themselves apply for national or European funding for misguided investments (Borkowski, 2019).
Other threats from tourism include excessive noise, boats and vessels not matching the environmental standards, changes in hydrological conditions and mechanical destruction of habitats, including reeds and underwater meadows (Wendt and Wiskulski, 2017; Borkowski, 2019). Indeed, the demands of the tourism sector are the focal point of the human vs ecosystems conflict in the Gulf of Gdańsk, and the carrying capacity of the coastal areas has already been exceeded in many places (Kistowski, 2005).
The current managerial solutions are inadequate partially because of the ambiguity of laws and unclear responsibilities of governmental actors (Wendt and Wiskulski, 2017; Szwichtenberg, 2019; Pikner et al., 2022). Local residents, especially those who depend economically on tourism, recognize the need for a shift from mass tourism to more active, culture- or nature-oriented tourism, especially in the most crowded areas of the Gulf of Gdańsk. They postulate providing more tools and more support for local entrepreneurs and introducing limitations for the “big and rich” investors coming from outside the region (Piwowarczyk and Zaucha, 2021).
While the tourism industry plays the most important role in smaller towns, in bigger towns and large cities there are additional pressures coming from the maritime industry. The Pomeranian province strives to become an international transportation hub, aiming to promote the development of shipping, logistics and shipbuilding, also in the context of future off-shore investments (DS, 2021). Two ports of national importance and a number of smaller ports are located on the shores of the Gulf of Gdańsk (Krzymiński, 2014), and maritime and related logistic sectors constitute about 7% and 6%, respectively, of the regional economy (Sagan and Masik, 2014; 2018). Off-shore wind farms promise to provide additional source of revenue and jobs, but this sector is not developing so smoothly and still faces important legal barriers (DS, 2021). Even though none have yet been constructed, the farms already raise concerns, especially among the residents of coastal towns that will be most directly impacted (Laskowicz, 2021).
Since the 1990s, there were attempts to create universal index that will illustrate the health or the quality of marine ecosystem. There were numerous papers on this subject, some dealing specifically with the Baltic Sea (e.g., Tett et al., 2013; Blenckner et al., 2020; HELCOM, 2016; HELCOM, 2023; HELCOM, 2023a). There is an inherited problem for the assessment system that was designed for open ocean and its transfer to the specific brackish, coastal sea. The same is true when the scale is changed from the whole Baltic to the specific area – the Gulf of Gdańsk. That is why, we have summarized our knowledge on the present Gulf of Gdańsk area in the scale of 5 × 5 km squares, addressing each square with four types of phenomena – socio cultural value, socioeconomic value, human disturbance level and ecological value (Table 4). Each of these phenomena was scaled from 0- none to 4 very high value and consisted of several descriptors – see Table 4. In the case of human disturbance (impact), we have used only those effects that are directly dependent on human management. That is why we are not considering global warming that results in stronger water column stratification and resulting oxygen depletion below halocline as well as the freshening of the surface of Baltic waters (Meier et al., 2022). The results shown in a map in Figure 7B, present the current level of anthropogenic impact in the scale of the observed area. The main difference between the cumulative impact presented by HELCOM (2023) and our map (Figure 7B) involves considering tourism and shipping as the stressors. The most changed/impacted are the areas in the vicinity of harbours and large cities as well as main shipping routes and areas of fishery pressure (Figure 7B). The biological–ecological values (EVA – ecological values assessment, inherit biological value not related to the human use) were modified and updated from paper and are presented in Figure 7A. Here, important observation might be drawn – the low disturbance is not necessarily linked to the high ecological value and vice versa – areas of high ecological value are not always free from human impact (see the sectors near Gdynia harbour – 80, 91, 102–115) in Figure 7. Two additional characteristics of the area include socio economic values (those directly transferred to market economy) – Figure 7C and sociocultural values (representing public perception of the area) –Figure 7D. The criteria for such evaluation are listed in Table 4. Clearly, the economically important areas are those next to harbours, fishing grounds and most visited tourist resorts; to some extent those areas correspond to the places most valued by visitors. The Pearson correlation calculated in R programme shows the relatively strong correlation between socio-economic and socio-cultural values (mainly because of tourism and recreation that links the two areas) and weak correlation between ecological value and socio-cultural value. Interestingly the human disturbance does not correlate with any of the other factors analysed (Figure 8).
Table 4. Four summary characteristics of the Gulf of Gdansk.
Figure 7. Four characteristics of the Gulf of Gdansk as of decade 2014–2024, (A) Ecological valuation of seabed from Weslawski et al., 2009 with update, (B) human impact/disturbance, (C) socio-cultural valuation, (D) socioeconomic valuation – criteria taken from Table 4, values after authors expert judgement.
Figure 8. Pearson Correlation among characteristics – values presented on Figure 7, values considered listed in Table 4.
Conclusion
Due to very incomplete data, it is impossible to provide a complete image of other, the so-called emerging pollutants (e.g., pharmaceutical residues, plastic components), both in terms of time trends and even spatial distribution in the Gulf of Gdańsk. The projected climate-driven changes is another important factor which should be taken into account. The increase in strength and frequency of extreme weather phenomena, changes in water dynamics, decrease in oxygen conditions in the near-bottom zone, intensified coastal erosion) (Meier et al., 2022; Reckermann et al., 2020) are expected to have a major impact on hazardous substance cycles, including transfer along the trophic chain in the Baltic Sea.
Following Cormier et al. (2019) concept of “bow–tie” analysis, the chain of causes and consequences and key drivers of environmental change in the Gulf of Gdańsk include:
1) Eutrophication - land induced excessive transport of nutrients and phosphorus
Known from the 1970s as the main driver of the Baltic Sea ecosystem deterioration, eutrophication is being driven by surface runoff from agriculture and single outflows of Vistula and local minor rivers. The loads of nutrients were monitored, and after 1994, diminished from top 14 kilotons of phosphorus to the current 7 kilotons. Eutrophication drives the filamentous algae growth in coastal waters (estimated at a peak as 30 kilotons per year and now down to less than 10 kilotons) and pelagic primary production (from peak of 240 g C/m2/year to the current 150 g C/m2/year-co). The ungrazed algae are transported to seabed and cause oxygen deficit - this process continues with anoxic areas expansion to the depth of 50 m locally. Harmful algal blooms (bluegreen algae) are mainly based on phosphorus transport as the nitrogen can be obtained from the atmosphere, the blue green blooms are more common, due to the extreme heat waves in summer and windless weather. Unlike previous years, the blooms start in the central Baltic, not in the coastal waters. The further reduction in phosphorus transport from land is very difficult to obtain in Poland, as the Vistula watershed is very large and covers rich agricultural land. Per capita, the Polish farmer uses less nutrients that the Scandinavian one - who is cultivating much smaller arable area with much higher nutrient load (Pastuszak et al., 2018).
2) Industrialisation and infrastructure expansion - that started to increase after 1994 in the area, mainly as the tourist coastal infrastructure, and to a minor degree the pipelines, cables and other industrial installations in the Gulf. The ports of Gdynia and Gdańsk are constantly expanding with planned area change for the offshore installations (30% expansion of the existing area). Wind turbines and gas platforms are planned, but on the edge of the BBT area. In terms of biodiversity, the coastal infrastructure seems to be most destructive as it impacts the species-rich shallow water habitats, often leading to their complete destruction. On the other hand, some of the installations are beneficial for seabirds and sea mammals as resting areas with no disturbance from tourists.
3) Seagrass and coastal reeds vegetation change - prior to 1970, the shallow areas of the BBT were covered in 80% with seagrass and in coastal belt with rich reeds margin. Due to the environmental crisis in the 1980s, the seagrass shrank to less than 10% of the area and tourist expansion caused the reduction in reed belts by 30%. Now, seagrass is spontaneously expanding again - to 50% of its original occurrence as the protection of reeds belt caused its regeneration. Following these changes in the “vegetated shallow seabed” habitat, there are the changes in biodiversity - more species of crustaceans and other invertebrates are common in vegetated areas. So far, this is not having any effect on the fishery (except for the increased population of protected non-commercial fish). There were no observations of the adverse effects of new species (non natives) arrival, contrary to the common reports (Leppäkoski, 2002).
In summary, the Gulf of Gdańsk is, on the one hand, better managed and shows general improvement of ecosystem health because of the state nature protection policy, and natural recovery of species and habitats, while on the other, global warming brings some negative effects (alterations of oxygenation, stratification, cold water species retreat) that can cover the positive changes of the area. Similar dual development is observed in the societal and economic use of the area. On the one hand, the decrease in fishery and increase in soft sector of tourism and recreation, on the other, the increase in heavy industrial development of harbours and shipping and offshore business. All these observations lead to the somewhat unseen phenomenon of cohabitation between natural values, societal and economic interests.
Author contributions
JW: Conceptualization, Funding acquisition, Visualization, Writing – original draft, Writing – review and editing. JU: Formal Analysis, Investigation, Visualization, Writing – original draft, Writing – review and editing. JoP: Investigation, Writing – original draft, Writing – review and editing. LK: Conceptualization, Investigation, Writing – original draft, Writing – review and editing. JaP: Conceptualization, Investigation, Writing – original draft, Writing – review and editing. KK: Conceptualization, Investigation, Writing – original draft, Writing – review and editing. KP: Conceptualization, Investigation, Writing – original draft, Writing – review and editing. JW: Conceptualization, Investigation, Writing – original draft, Writing – review and editing. SS: Conceptualization, Investigation, Writing – original draft, Writing – review and editing. IP: Investigation, Writing – original draft, Writing – review and editing. WW: Conceptualization, Investigation, Writing – original draft, Writing – review and editing. AK: Investigation, Visualization, Writing – original draft, Writing – review and editing
Funding
The author(s) declare that financial support was received for the research and/or publication of this article. This review paper was partly funded by: MARBEFES–MARine Biodiversity and Ecosystem Functioning leading to Ecosystem Services, European Union’s Horizon Europe research and innovation programme under Grant Agreement no 101060937. – SK, JC, JW, JP, and JU. Contribution of KK to this study was supported by Polish National Science Centre, grant no. 2023/49/B/ST10/02690. Contribution of KP to this study was supported by Polish National Science Centre, grant no. 2022/04/Y/NZ8/00099.
Conflict of interest
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Generative AI statement
The authors declare that no Generative AI was used in the creation of this manuscript.
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References
Amato, E., Riess, M., Thomas-Lopez, D., Linkevicius, M., Pitkänen, T., Wołkowicz, T., et al. (2018). Epidemiological and microbiological investigation of a large increase in vibriosis, northern Europe. Euro Surveill. 27 (28), 2101088. doi:10.2807/1560-7917.es.2022.27.28.2101088
Andrulewicz, E. (2021). Minione krajobrazy zatoki puckiej. Warsztaty z Geogr. Turyzmu 11, 215–227. in Polish.
Andrulewicz, E., and Witek, Z. (2002). Anthropogenic pressure and environmental effects on the Gulf of Gdansk: recent management efforts. Baltic coastal ecosystems: structure, function and coastal zone management. G. Schernewski and U. Schiewer. Berlin, Heidelberg: Springer Berlin Heidelberg, 119–139.
Bałazy, P., Wiktor, J., Tatarek, A., and Węsławski, J. M. (2024). Apparent return of free living Fucus vesiculosus to the Polish Baltic waters. Oceanologia. doi:10.1016/j.oceano.2024.02.004
Bartel, R., Pelczarski, W., Kardela, J., Nadolna-Ałtyn, K., and Lejk, A. (2016). “Restitution of salmon and sea trout in Polish waters: a review and a chronology of activities,” in 95th anniversary of the sea fisheries institute: current research topics. T.1 I – fish stocks and fisheries. Gdynia. Editor I. Psuty (Gdynia: Morski Instytut Rybacki-PIB), 69–80.
Bartel, R., Wiśniewolski, W., and Prus, P. (2007). Impact of the wloclawek dam on migratory fish in the Vistula River [Poland] archiwum rybactwa polskiego 15 (2): 141–156.
Bartelt, W., Heinrich, U., Pohl, U., and Albrecht, K. (1982). Untersuchungen zu einer im Jahr 1976 in einer Küstenstadt aufgetretenen ECHO-Virus 30 Meningitisepidemie. Author(s) Z. fur gesamte Hyg. ihre Grenzgeb. 28 (8), 542–545.
Blackport, R., and Fyfe, J. C. (2022). Climate models fail to capture strengthening wintertime North Atlantic jet and impacts on Europe. Sci. Adv. 8, eabn3112. doi:10.1126/sciadv.abn3112
Blenckner, T., Mollmann, Chr., Lowndes, J. S., Griffiths, J. R., Campbell, E., De Cervo, A., et al. (2020). The baltic health index (BHI): assessing the social – ecological status of the Baltic Sea. People Nat. 3, 359–375.
Błeńska, M., and Osowiecki, A. (2015). Biotic typology of polish marine arreas based on bottom macrofauna communities. Bull. Mar.Inst. Gdansk, BMI 30, 167–173. doi:10.5604/12307424.1186449
Borkowski, R. (2019). Wyzwania i zagrożenia dla turystyki na Półwyspie Helskim w XXI wieku. Bezpieczeństwo Teor. i Prakt. 2, 129–146. in Polish.
Brzana, R., and Janas, U. (2016). Artificial hard substrate as a habitat for hard bottom benthic assemblages in the southern part of the Baltic Sea – a preliminary study. Oceanol. Hydrobiol. Stud. 45, 121–130. doi:10.1515/ohs-2016-0012
Brzana, R., Janas, U., and Tykarska, M. B. (2020). Effects of a 70-year old artificial offshore structure on oxygen concentration and macrobenthos in the Gulf of Gdańsk (Baltic Sea). Estuar. Coast. Shelf Sci. 235, 106563. doi:10.1016/j.ecss.2019.106563
Chylarecki, P., Chodkiewicz, T., Neubauer, G., Sikora, A., Meissner, W., Woźniak, B., et al. (2018). Trendy liczebności ptaków w Polsce. Warszawa: Główny Inspektorat Ochrony Środowiska, 471.
Ciszewski, P., Kruk-Dowgiałło, L., and Andrulewicz, E. (1991). A study of pollution of the Puck Bay Lagoon and possibility of restoring the lagoon's original ecological state. Acta Ichtyologica Piscatoria 21 (Suppl. l.), 29–37. Available online at: https://www.aiep.pl/volumes/1990/1_S/pd-
Conley, D. J., Carstensen, J., Aigars, J., Axe, P., Bonsdorff, E., Eremina, T., et al. (2011). Hypoxia is increasing in the coastal zone of the Baltic Sea. Environ. Sci. Technol. 45, 6777–6783. doi:10.1021/es201212r
Cormier, R., Elliot, M., and Rice, J. (2019). Putting on a bow-tie to sort out who does what and why in the complex arena of marine policy and management. Sci. Total Environ. 648, 293–305. doi:10.1016/j.scitotenv.2018.08.168
Dębowski, P. (2018). The largest Baltic population of sea trout (Salmo trutta L.): its decline, restoration attempts, and current status. Archives Pol. Fish. 26 (2), 81–100. doi:10.2478/aopf-2018-0010
Demel, K. (1935). Studja nad fauną denną i jej rozsiedleniem w polskich wodach bałtyku. Arch. Hydrobiol. i Rybactwa 9, 239. In Polish.
Draganik, B., Maksimov, Y., Ivanov, S., and Psuty-Lipska, I. (2005). The status of the turbot Psetta maxima (L.) stock supporting the Baltic fishery. Bull. Sea Fish. Inst. 1, 23–53.
Draganik, B., Naguszewski, A., Wesołowska, A., Maksimov, Y., and Psuty, I. (1996). The ichthyofauna associated with the shallow waters off Poland and Lithuania. ICES C.M. 1996/J:32.
DS (2012). Strategia rozwoju województwa pomorskiego 2020. Gdańsk: Sejmik Województwa Pomorskiego, 70.
DS (2021). Strategia rozwoju województwa pomorskiego 2030. Gdańsk: Sejmik Województwa Pomorskiego, 133pp.
Dutheil, C., Meier, H. E. M., Gröger, M., and Börgel, F. (2022). Understanding past and future sea surface temperature trends in the Baltic Sea. Clim. Dyn. 58 (9-10), 3021–3039. doi:10.1007/s00382-021-06084-1
Filipkowska, A., Ludwik, L. L., Szymczak-Żyła, M., Ciesielski, T. M., Jenssen, B. M., Ardeland, M. v., et al. (2018). Anthropogenic impact on marine ecosystem health: a comparative multi-proxy investigation of recent sediments in coastal waters. Mar. Pollut. Bull. 133, 328–335. doi:10.1016/j.marpolbul.2018.05.058
Fleming-Lehtinen, V., and Laamanen, M. (2012). Long-term changes in Secchi depth and the role of phytoplankton in explaining light attenuation in the Baltic Sea. Estuar. Coast. Shelf Sci. 102–103, 1–10. doi:10.1016/j.ecss.2012.02.015
Gąska, J. (2023). Climate change and windstorm losses in Poland in the twenty-first century. Environ. Hazards 22 (2), 99–115. doi:10.1080/17477891.2022.2076646
Gedas, V. G. (2001). Ecological adaptations of seabirds to the gradient of winter climatic conditions in the Baltic Sea region. Acta Zool. Litu. 11 (3), 280–287. doi:10.1080/13921657.2001.10512461
Gic-Grusza, G., Kryla-Straszewska, L., Urbański, J., Warzocha, J., and Węsławski, J. M. (2009). Atlas of Polish marine area bottom habitats: environmental valorization of marine habitats. Gdansk, 179.
Gogina, M., Nygard, H., Blomqvist, M., Daunys, D., Josefson, A. B., Kotta, J., et al. (2016). The Baltic Sea scale inventory of benthic faunal communities. ICES J. Mar. Sci. 73, 1196–1213. doi:10.1093/icesjms/fsv265
Hallfors, G. (2004). Checklist of Baltic Sea phytoplankton species (including some heterotrophic protistan groups). Balt. Sea Environ. Proc. 95, 208pp.
Hanel, R., Briand, C., Diaz, E., Döring, R., Sapounidis, R., Warmerdam, W., et al. (2019). Research for PECH Committee – environmental, social and economic sustainability of European eel management. Brussels: European Parliament, Policy Department for Structural and Cohesion Policies.
Hansson, M., and Viktorsson, L. (2023). Oxygen survey in the Baltic Sea 2022 -extent of anoxia and hypoxia, 1960-2022. (Göteborg, Sweden: Report Oceanography No. 74, Swedish Meteorological and Hydrological Institute – SMHI Oceanographic Unit), 92.
HELCOM (2023a). Cumulative impact from physical pressure on benthic biotopes. Helcom indicator report online. ISSN 2343- 2543
HELCOM (2023). State of the Baltic Sea. Third HELCOM holistic assessment 2016-2021. Balt. Sea Environ. Proc. n°194.
Hünicke, B., Zorita, E., Soomere, T., Madsen, K. S., Johansson, M., and Suursaar, Ü. (2015). “Recent change—sea Level and wind waves,” in The BACC II author team, second assessment of climate change for the Baltic Sea basin, regional climate studies (Cham: Springer), 69–97. doi:10.1007/978-3-319-16006-1_9
IMGW (2024). Report from the workshop meeting Rzeszów, April 2, 2025 Podkarpackie Voivodeship Office in Rzeszów. Available online at: https://hydro.imgw.pl/#/.
IPCC (2014). AR5 Synthesis Report: Climate Change 2014. Available online at: https://www.ipcc.ch/report/ar5/syr/.
Janecki, M., Dybowski, D., and Dzierzbicka-Głowacka, L. (2023). The influence of biochemical parameters on primary production in the Gulf of Gdańsk region: a model study. Oceanologia 65 (4), 517–533. doi:10.1016/j.oceano.2023.05.001
Jasińska, E. (2019). Impact of environmental and climate conditions on the investment potential of real estate in the belt of the Gulf of Gdansk Coast. E3S Web Conf. 86, 00013–00017. doi:10.1051/e3sconf/20198600013
Jęczmień, W. ., and Szaniawska, A. (2000). Changes in species composition oft he genus Gammarus Fabr. in Puck Bay. Oceanologia 42 (1), 71–87.
Jędruch, A., Falkowska, L., Saniewska, D., Grajewska, a., Bełdowska, M., Meissner, W., et al. (2023). Mercury in the Polish part of the Baltic Sea: a response to decreased atmospheric deposition and changing environment. Mar. Pollut. Bull. 186, 114426. doi:10.1016/j.marpolbul.2022.114426
Kistowski, M. (2005). Próby typologii sytuacji konfliktowych w relacjach “zagospodarowanie przestrzenne – środowisko przyrodnicze” na obszarze parków krajobrazowych nad Zatoką Gdańską. In: (eds.) A. Hibszer, and J. Partyka Między ochroną przyrody a gospodarką – bliżej ochrony: konflikty człowiek-przyroda na obszarach prawnie chronionych w Polsce. Polskie Towarzystwo Geograficzne Oddział Katowicki – ojcowski Park Narodowy. Sosnowiec: Sosnowiec – Ojców, 18–31. in Polish.
Kniebusch, M., Meier, H. E. M., Neumann, T., and Börgel, F. (2019). Temperature variability of the Baltic Sea since 1850 and attribution to atmospheric forcing variables. J. Geophys. Res.-Oceans 124, 4168–4187. doi:10.1029/2018jc013948
Kot-Wasik, A., Dębska, J., and Namieśnik, J. (2004). Monitoring of organic pollutants in coastal waters of the southern baltic gulf of Gdansk. Mar. Pollut. Bull. 49, 76–264.
Kotwicki, L., Herman, A., Kijewski, T., Wiktor, J., Tatarek, A., Torn, K., et al. (2024). Perspectives for the recovery of Fucus spp. Population in the southern Baltic Sea.combination of citizen science and drift modelling approach. Res. Gate. doi:10.2139/ssrn.4627007
Kozak, M. W. (2006). Konkurencyjność turystyczna polskich regionów. Stud. Reg. i Lokal. 3 (25), 49–65. In Polish.
W. Krzymiński (2014). (Warszawa: Raport do Komisji Europejskiej. Główny Inspektorat Ochrony Środowiska), 450.Wstępna ocena stanu środowiska wód morskich polskiej strefy Morza Bałtyckiego.
Kuliński, K., Rehder, G., Asmala, E., Bartosova, A., Carstensen, J., Gustafsson, B., et al. (2022). Biogeochemical functioning of the Baltic Sea. Earth Syst. Dynam. 13, 633–685. doi:10.5194/esd-13-633-2022
Łabuz, T. A. (2015). “Environmental impacts—coastal erosion and coastline changes,” in Second assessment of climate change for the Baltic Sea basin. Regional climate studies. Editor The BACC II Author Team (Cham: Springer). doi:10.1007/978-3-319-16006-1_20
Lakowitz, C. W. (1907). Die algenflora der Danziger bucht. Ein beitrag zur kenntnis der Ostseeflora. Danzig: Kessinger Publishing reprint 2010, 154.
Laskowicz, T. (2021). The perception of polish business stakeholders of the local economic impact of maritime spatial planning promoting the development of offshore wind energy. Sustainability 13 (12), 6755. doi:10.3390/su13126755
Leppäkoski, E. (2002). “Harmful non-native species in the Baltic Sea — an ignored problem,” in Baltic coastal ecosystems. Central and eastern European development studies. Editors G. Schernewski, and U. Schiewer (Berlin, Heidelberg: Springer). doi:10.1007/978-3-662-04769-9_20
Lepparanta, M., and Myrberg, K. (2009). Physical oceanography of the Baltic Sea. doi:10.1007/978-3-540-79703-6
Liblik, T., and Lips, U. (2019). Stratification has strengthened in the Baltic Sea – an analysis of 35 Years of observational data. Front. Earth Sci. 7, 174. doi:10.3389/feart.2019.00174
Lubecki, L., Oen, A. M. P., Breedveld, G. D., and Zamojska, A. (2019). Vertical profiles of sedimentary polycyclic aromatic hydrocarbons and black carbon in the Gulf of Gdańsk (Poland) and Oslofjord/Drammensfjord (Norway), and their relation to regional energy transitions. Sci. Total Environ. 646, 336–346. doi:10.1016/j.scitotenv.2018.07.300
Marchowski, D. (2021). Bycatch of seabirds in the Polish part of the southern Baltic Sea in 1970–2018: a review. Acta Ornithol. 56, 139–158. doi:10.3161/00016454AO2021.56.2.001
Margoński, P. (1994). Some aspects of straight-nosed (Nerophis ohidion L.) and broad-nosed (Syngnathus typhle L.) pipefishes` biology in the Gulf of Gdańsk. Zesz.Nauk.UG Oceanogr. 13, 40–59.
Matciak, M., and Nowacki, J. (1995). The Vistula river discharge front-surface observations Plume front Surface water properties River Vistula. Oceanologia 37, 75.
Meier, H. E. M., Kniebusch, M., Dieterich, C., Gröger, M., Zorita, E., Elmgren, R., et al. (2022). Climate change in the Baltic Sea region: a summary. Earth Syst. Dynam. 13, 457–593. doi:10.5194/esd-13-457-2022
Moriarty, C., and Dekker, W. (1997). Management of the European eel. Fish. Bull. (Dublin) 15, 1–110.
Morim, J., Hemer, M., Cartwright, N., Strauss, D., and Andutta, F. (2018). On the concordance of 21st century wind-wave climate projections. Glob. Planet. Change 167, 160–171. doi:10.1016/j.gloplacha.2018.05.005
Naumann, M., Gräwe, U., Mohrholz, V., Kuss, J., Siegel, H., Waniek, J. J., et al. (2019). Hydrographichydrochemical assessment of the Baltic Sea 2018, meereswiss. Ber., warnemünde, 110. doi:10.12754/msr-2019-0110
Nędza, A., and Matlingiewicz, S. (2022). Ocena atrakcyjności turystycznej wybranych miejscowości nadmorskich w Polsce. Ann. Univ. Paedagog. Cracoviensis Stud. Geogr. 18, 155–170. doi:10.24917/20845456.18.10
Nilsson, J. (2006). Predation of northern pike (Esox lucius L.) eggs: a possible cause of regionally poor recruitment in the Baltic Sea. Hydrobiologia 553 (1), 161–169. doi:10.1007/s10750-005-1949-8
Olenina, I., Wasmund, N., Hajdu, S., Jurgensone, I., Gromisz, S., Kownacka, J., et al. (2010). Assessing impacts of invasive phytoplankton: the Baltic Sea case. Mar. Pollut. Bull. 60 (10), 1691–1700. doi:10.1016/j.marpolbul.2010.06.046
Osowiecki, A., Łysiak-Pastuszak, E., and Piątkowska, Z. (2008). Testing biotic indices for marine zoobenthos quality assessment in the Polish sector of the Baltic Sea. J. Mar. Syst. 74, 124–132. doi:10.1016/j.jmarsys.2008.03.025
Pastuszak, M., Bryhn, A. C., Håkanson, L., Stålnacke, P., Zalewski, M., and Wodzinowski, T. (2018). Reduction of nutrient emission from Polish territory into the Baltic Sea (1988–2014) confronted with real environmental needs and international requirements. Oceanol. Hydrobiological Stud. 47 (2), 140–166. doi:10.1515/ohs-2018-0015
Pazikowska-Sapota, G., Galer-Tatarowicz, K., Dembska, G., Wojtkiewicz, M., Duljas, E., Pietrzak, S., et al. (2020). The impact of pesticides used at the agricultural land of the Puck commune on the environment of the Puck Bay. PeerJ 2020, 1–21. doi:10.7717/peerj.8789
Pikner, T., Piwowarczyk, J., Ruskule, A., Printsmann, A., Veidemane, K., Zaucha, J., et al. (2022). Sociocultural dimension of land–sea interactions in maritime spatial planning: three case studies in the Baltic Sea region. Sustainability 14, 2194. doi:10.3390/su14042194
Piwowarczyk, J., and Zaucha, J. (2021). Integrating cultural values in marine spatial planning and the blue growth. Output of activity 2.3 of the interreg Baltic Sea region programme funded project land-sea-act (R098) “land-sea interactions advancing blue growth in Baltic Sea coastal areas”. Available online at: https://land-sea.eu/wp-content/uploads/2022/01/LSA_Case_Study_Poland.pdf (Accessed: June 23, 2024).
Pliński, M., and Wiktor, K. (1987). Contemporary changes in coastal biocenoses of the Gulf of Gdansk(south Baltic). A review. Pol. Arch. Hydrobiol. 34, 81–90.
Pruszak, Z., and Zawadzka, E. (2008). Potential implications of sea level rise for Poland. J. Coast Res. 24, 410–422. doi:10.2112/07a-0014.1
Pryputniewicz-Flis, D., Burska, D., and Bolałek, J. (2022). “Warunki tlenowe w wodach Zatoki Puckiej,” in Zatoka pucka. Editors J. Bolałek, and D. Burska (Gdansk: Wydawnictwo Uniwersytetu Gdańskiego), 18–30.
Psuty, I. (2022). Are we ready to implement resist–accept–direct framework thinking? A case study of fish stocks and small-scale fisheries in the Puck Bay (Southern Baltic). Fish. Manag. Ecol. 29, 423–438. (n/a). doi:10.1111/fme.12543
Psuty, I., Zaporowski, R., and Gaweł, W. (2023). Goodbye to northern pike (Esox lucius) in the Polish southern Baltic? Fish. Res. 258, 106549. doi:10.1016/j.fishres.2022.106549
Psuty-Lipska, I. (2000). Eelpout as an index of changes, in the fish community in the Gulf of Gdansk from 1985 to 1999. ICES CM. 2000/Z:05.
Rak, D., Walczowski, W., Dzierzbicka-Głowacka, L., and Shchuka, S. (2020). Dissolved oxygen variability in the southern Baltic Sea in 2013–2018. Oceanologia 62 (4), 525–537. doi:10.1016/j.oceano.2020.08.005
Rak, D., and Wieczorek, P. (2012). Variability of temperature and salinity over the last decade in selected regions of the southern Baltic Sea. Oceanologia 54 (3), 339–354. doi:10.5697/oc.54-3.339
Rakowski, M., Mytlewski, A., and Piwowarczyk, J. (2023). Recognition of the vibriosis risk in Polish coastal waters of the Baltic Sea and public engagement in its mitigation. J. Water Lad Dev. 59 (X–XII), 291–297.
Rakowski, M., Mytlewski, A., and Psuty, I. (2020). “Small-Scale Fisheries in Poland,” in Small-Scale Fisheries in Europe: Status, Resilience and Governance. Editors: J., Pascual-Fernández, C. Pita, and M., Bavinck. MARE Publication Series. (Cham: Springer), 23. doi:10.1007/978-3-030-37371-9_24
Reckermann, M., Meier, H. E. M., and Stendel, M. (2020). Editorial: the Baltic Sea region in transition. Front. Earth Sci. 8, 589252. doi:10.3389/feart.2020.589252
Renk, H., Ochocki, S., and Kurzyk, S. (2000). In situ and simulated in situ primary production in the Gulf of Gdańsk. Oceanologia 42, 2.
Riedinger, D. J., Fernández-Juárez, V., Delgado, L. F., Sperlea, T., Hassenrück, C., Herlemann, D. P. R., et al. (2024). Control of Vibrio vulnificus proliferation in the Baltic Sea through eutrophication and algal bloom management. Commun. Earth Environ. 5, 246. doi:10.1038/s43247-024-01410-x
Rogowska, J., Kudłak, B., Tsakovski, S., Gałuszka, A., Bajger-Nowak, G., Simeonov, V., et al. (2015). Surface sediments pollution due to shipwreck s/s Stuttgart: a multidisciplinary approach. Stoch. Environ. Res. Risk Assess. 29, 1797–1807. doi:10.1007/s00477-015-1054-0
Różyński, G. (2010). Wave climate in the gulf of Gdańsk vs. Open Baltic Sea near lubiatowo, Poland. Archives Hydro-Engineering Environ. Mech. 57 (2), 167–176.
Różyński, G., Ostrowski, R., Pruszak, Z., Szmytkiewicz, M., and Skaja, M. (2006). Data-driven analysis of joint coastal extremes near a large non-tidal estuary in North Europe, Estuarine. Coast. Shelf Sci. 68, 317–327.
Rutgersson, A., Jaagus, J., Schenk, F., Stendel, M., Bärring, L., Briede, A., et al. (2015). “Recent change -atmosphere,” in The BACC II author team, second assessment of climate change for the Baltic Sea basin, regional climate studies. Cham: Springer, 69–97.
Sagan, I., and Masik, G. (2014). Economic resilience. The case study of Pomorskie Region. Raumforsch. Und Raumordn. 72, 153–164. doi:10.1007/s13147-013-0266-3
Sagan, I., and Masik, G. (2018). The economic crisis and the Pomorkie region in Poland: a case study of resistance,” in Economic crisis and the resilience of regions: a European case study. (eds.) G. Bristow, and A. Healy (Cheltenham: Edward Elgar). 25–40.
Sagan, S. (1991). “Transmisja światła w wodach południowego bałtyku,” in Rozprawy i monografie 2/1991. Sopot: Instytut Oceanologii PAN, Sopot.
SAMBAH (2024). SAMBAH. Available online at: https://www.sambah.org/.
SANEPID (2024). Bathing areas. Available online at: https://sk.gis.gov.pl/kapieliska/mapa.
Saniewska, D., Bełdowska, M., Bełdowski, J., Saniewski, M., Gębka, K., Szubska, M., et al. (2018). Impact of intense rains and flooding on mercury riverine input to the coastal zone. Mar. Pollut. Bull. 127, 593–602. doi:10.1016/j.marpolbul.2017.12.058
Sapota, M. (2001). Spatial (depth dependent) and temporal distribution of fish in sandy eulittoral of the tip of the Hel Peninsula (the gulf of Gdańsk – Baltic). Oceanol. Stud. 30, 77–89.
Sapota, M., and Skóra, K. E. (1996). “Fish abundance in shallow inshore waters of the Gulf of Gdańsk,” in Proceedings of polish-Swedish symposium on baltic coastal fisheries resources and management. Gdynia, Poland, morski instytut rybacki, 215–224.
Sapota, M., and Skóra, K. E. (2005). Spread of alien (non-indigenous) fish species Neogobius melanostomus in the Gulf of Gdansk (south Baltic). Biol. Invasions 7, 157–164. doi:10.1007/s10530-004-9035-0
Schmelzer, N., Seina, A., Lundqvist, J. E., and Sztobryn, M. (2008). “Ice,” in State and evolution of the Baltic Sea, 1952-2005. Wiley & Sons, 199–240.
Skov, H., Heinanen, S., Zydelis, R., Bellenbaum, J., Bzoma, S., Dagys, M., et al. (2011). Waterbird population and pressurres in the Baltic Sea. Thema nord 2011:550. Copenhagen: Nordic Council of Ministers, 208pp.
Sobol, Z., and Szumilas, T. (1989). Sanitary state of the sea coastal waters on the basis of bacteriological and physical-chemical examinations carried out in 1986 and 1987. Bull. Inst. Marit. Trop. Med. Gdynia N. R. 40.
Sobol, Z., and Szumilas, T. (1992). Sanitary state of coastal waters in the Gulf of Gdańsk. IMMiT, Gdyn. (In Polish). Inz. Mor., ISSN 0138-0540. 10 (6). 244–247.
Sobol, Z., and Szumilas, T. (1998). Ocena stanu sanitarnego wod przybrzeznych Morza Baltyckiego w latach 1995-1997 na podstawie wynikow badan Instytutu Medycyny Morskiej i Tropikalnej w Gdyni oraz wojewodztw nadmorskich. Med. srodowiska 1.
Sokołowski, A., Jankowska, E., Bałazy, P., and Agnieszka, J. (2021). Distribution and extent of benthic habitats in Puck Bay (gulf of Gdańsk, southern Baltic Sea). Oceanologia 63, 301–320. doi:10.1016/j.oceano.2021.03.001
Sokołowski, A., Ziółkowska, M., and Zgrundo, A. (2015). Habitat-related patterns of soft-bottom macrofaunal assemblages in a brackish, low-diversity system (southern Baltic Sea). J. Sea Res. 103, 93–102. doi:10.1016/j.seares.2015.06.017
Staniszewska, M., Koniecko, I., Falkowska, L., Burska, D., and Kiełczewska, J. (2016). The relationship between the black carbon and bisphenol a in sea and river sediments (Southern Baltic). J. Environ. Sci. 41, 24–32. doi:10.1016/j.jes.2015.04.009
Stempniewicz, L. (1994). Marine birds drowning in fishing nets in the Gulf of Gdansk (southern Baltic), 2. Lund: Ornis Svecica.
Stockmayer, V., and Lehmann, A. (2023). Variations of temperature, salinity and oxygen of the Baltic Sea for the period 1950 to 2020. Oceanologia 65, 466–483. doi:10.1016/j.oceano.2023.02.002
Stokowski, M., Winogradow, A., Szymczycha, B., Carstensen, J., and Kulinski, K. (2021). The CO2 system dynamics in the vicinity of the Vistula River Mouth (the southern Baltic Sea): a baseline investigation. Estuar. Coast. Shelf. Sci. 258, 107444. doi:10.1016/j.ecss.2021.107444
Stoń-Egiert, J., and Ostrowska, M. (2022). Long-term changes in phytoplankton pigment contents in the Baltic Sea: trends and spatial variability during 20 years of investigations. Cont. Shelf Res. 236, 104666. doi:10.1016/j.csr.2022.104666
Stramska, M., and Białogrodzka, J. (2016). Satellite observations of seasonal and regional variability of particulate organic carbon concentration in the Barent Sea. Oceanologia 58, 249–263.
Szaniawska, A., Janas, U., and Normant, M. (1999). “Changes in macrozoobenthos communities induced by anthropogenic eutrophication of the gulf of Gdansk,”. In: Changes in macrozoobenthos communities induced by anthropogenic eutrophication of the Gulf of Gdansk. Editors J. S. Gray, W. Ambrose, and A. Szaniawska (Dordrecht: Springer), 59, 147–152. doi:10.1007/978-94-011-4649-4_8
Szefer, P., and Szefer, K. (1991). Concentration and discrimination factors for Cd, Pb, Zn and Cu in benthos of Puck Bay, Baltic Sea. Sci. Total Environ. 105, 127–133. doi:10.1016/0048-9697(91)90335-c
Szmytkiewicz, A., and Zalewska, T. (2014). Sediment deposition and accumulation rates determined by sediment trap and 210Pb isotope methods in the Outer Puck Bay (Baltic Sea). Oceanologia 56 (1), 85–106. doi:10.5697/oc.56-1.085
Szumilas, T., Michalska, M., and Bartoszewicz, M. (2004). Changes of sanitary conditions of coastal waters near Gdansk in years 1993–2002. Inzynieria Morska i Geotech 3, 131–138.
Szwichtenberg, A. (2019). Gospodarka turystyczna na polskim wybrzeżu w drugiej połowie XX w. i na początku XXI w. In: Polska geografia morza: przyrodnicze i społeczno-ekonomiczne badania morza i obszarów nadmorskich. Editors A. Cedro (Szczecin: Wydawnictwo volumina.pl.). 7–28.
Szymczak-Żyła, M., and Kowalewska, G. (2009). Chloropigments-a in sediments of the Gulf of Gdansk deposited during the last 4000 years as indicators of eutrophication and climate change. Palaeogeogr. Palaeoclimatol. Palaeocology 284 (3-4), 283–294. doi:10.1016/j.palaeo.2009.10.007
Tett, P., Gowen, R. J., Painting, S. J., Elliott, M., Forster, R., Mills, D., et al. (2013). Framework for understanding marine ecosystem health. Mar. Ecol. Prog. Ser. 494, 1–27. doi:10.3354/meps10539
Trzosińska, A. (1992). Water transparency in the polish zone of the Baltic Sea. Oceanologia 33, 203–209.
Urbanski, J., and Kryla, L. (2006). Mapping sea ice distribution in the Puck Bay from MODIS satellite data, Oceanol. Hydrobiological Stud. 35, 4.
S. Uścinowicz (2011). Geochemia osadów powierzchniowych morza bałtyckiego (Warszawa: Państwowy Instytut Geologiczny-Państwowy Instytut Badawczy), 356.
Vahtera, C. D. J., Gustafsson, B. G., Kuosa, H., Pitkänen, H., Savchuk, O. P., Tamminen, T., et al. (2007). Internal ecosystem feedbacks enhance nitrogen-fixing cyanobaceria blooms and complicate management in the Baltic Sea. Ambio 36, 186–194.
Voss, R., Quaas, M. F., Stiasny, M. H., Hänsel, M., Stecher Justiniano Pinto, G. A., Lehmann, A., et al. (2019). Ecological-economic sustainability of the Baltic cod fisheries under ocean warming and acidification. J. Environ. Manag. 238, 110–118. doi:10.1016/j.jenvman.2019.02.105
Walczowski, W., Merchel, M., Rak, D., Wieczorek, P., and Goszczko, I. (2020). Argo floats in the southern Baltic Sea. Oceanologia 62 (4), 478–488. doi:10.1016/j.oceano.2020.07.001
Warzocha, J. (1995). Classification and structure of macrofauna communities in the southern Baltic. Arch. Fish. Mar. Res. 42, 225–237.
Warzocha, J., Grelowski, A., m Bolałek, J., and Białkowska, I. (2001). The response of soft bottom benthic macrofauna to environmental changes in the Gulf of Gdansk in 200-2001. #rd Symposium on functioning of coastal ecosystems Gdynia. 19–21.
Warzocha, J., Gromisz, S., Wodzinowski, T., and Szymanek, L. (2018). The structure of macrozoobenthic communities as an environmental status indicator in the Gulf of Gdańsk (the Outer Puck Bay). Oceanologia 60, 553–559. doi:10.1016/j.oceano.2018.05.002
Wendt, J. A., and Wiskulski, T. (2017). Problems of development of tourism and yachting on the coast of Gdansk Pomerania (Poland). Études caribéennes 36.
Węsławski, J. M., Kotwicki, L., Grzelak, K., Piwowarczyk, J., Sagan, I., Nowicka, K., et al. (2011). Przemysł Turystyczny i przyroda morska na Półwyspie Helskim. Gdańsk: WWF Polska.
Węsławski, J. M., Urbański, J., Kryla-Straszewska, L., Andrulewicz, E., Linkowski, T., Kuzebski, E., et al. (2010). The different uses of sea space in Polish Marine Areas: is conflict inevitable? Oceanologia 52 (3), 513–530. doi:10.5697/oc.52-3.513
Winogradow, A., and Pempkowiak, J. (2018). Characteristics of sedimentary organic matter in coastal and depositional areas in the Baltic Sea. Estuar. Coast. Shelf Sci. 204, 66–75. doi:10.1016/j.ecss.2018.02.011
Witek, Z., Ochocki, S., Maciejowska, M., Pastuszak, M., Nakonieczny, J., Podgórska, B., et al. (1997). Phytoplankton primary production and its utilization by the pelagic community in the coastal zone of the Gulf of Gdansk (southern Baltic). Mar. Ecol. Prog. Ser. 148, 169–186. doi:10.3354/meps148169
Włodarska-Kowalczuk, M., Węsławski, J. M., Warzocha, J., and Janas, U. (2010). Habitat loss and possible effects on local species richness in a species-poor system: a case study of southern Baltic Sea macrofauna. Biodivers. Conserv. 19, 3991–4002. doi:10.1007/s10531-010-9942-6
Wolska, L., Kowalewski, M., Potrykus, M., Redko, V., and Rybak, B. (2022). Difficulties in the modeling of E. coli spreading from various sources in a coastal marine area. Molecules. 27, 4353. doi:10.3390/molecules27144353
Wolski, T., and Wiśniewski, B. (2020). Geographical diversity in the occurrence of extreme sea levels on the coasts of the Baltic Sea. J. Sea Res. 159, 101890. doi:10.1016/j.seares.2020.101890
Wolski, T., and Wiśniewski, B. (2021). Characteristics and long-term variability of occurrences of storm surges in the Baltic Sea. Atmosphere 12, 1679. doi:10.3390/atmos12121679
Zaborska, A., Siedlewicz, G., Szymczycha, B., Dzierzbicka-Głowacka, L., and Pazdro, K. (2019). Legacy and emerging pollutants in the Gulf of Gdańsk (southern Baltic Sea) – loads and distribution revisited. Mar. Pollut. Bull. 139, 238–255. doi:10.1016/j.marpolbul.2018.11.060
Zalewska, T., Woroń, J., Danowska, B., and Suplińska, M. (2015). Temporal changes in Hg, Pb, Cd and Zn environmental concentrations in the southern Baltic Sea sedimentsdated with 210Pb method. Oceanologia 57, 32–43pp. doi:10.1016/j.oceano.2014.06.003
Zdun, A., Stoń-Egiert, J., Ficek, D., and Ostrowska, M. (2021). Seasonal and spatial changes of primary production in the Baltic Sea (Europe) based on in situ measurements in the period of 1993–2018. Front. Mar. Sci. 7. doi:10.3389/fmars.2020.604532
Zeidler, R. B., Wróblewski, A., Miętus, M., Dziadziuszko, Z., and Cyberski, J. (1995). Wind, wave, and storm surge regime at the polish baltic coast. J. Coast. Res., 33–55.
Zgrundo, A., and Złoch, I. (2022). Gone and back—the AnthropogenicHistory of Coccotylus brodiei (Turner)Kützing and Furcellaria lumbricalis(hudson) J.V. Lamouroux in the gulfof Gda´nsk (southern Baltic Sea).Water. 14, 2181. doi:10.3390/w14142181
Żmudzinski, L., and Osowiecki, A. (1991). Long-term changes in the bottom macrofauna of the Puck Lagoon. Acta Ichtiologica Piscatoria 21 (S).
Zostera (2024). Project on restoration and monitoring of sea grass beds in Puck Bay, Southern Baltic, Polish EEZ. Available online at: https://old.iopan.pl/projects/Zostera/index.html.
Keywords: baltic, climate change, societal change, biodiversity, Gulf of Gdańsk
Citation: Węsławski JM, Urbański J, Piwowarczyk J, Kotwicki L, Piskozub J, Kuliński K, Pazdro K, Wiktor J, Sagan S, Psuty I, Walczowski W and Koroza A (2025) Environmental change between 1980 and 2020 followed by societal change in the Gulf of Gdańsk, Southern Baltic, a review. Front. Earth Sci. 13:1557993. doi: 10.3389/feart.2025.1557993
Received: 09 January 2025; Accepted: 21 April 2025;
Published: 16 May 2025.
Edited by:
Juris Aigars, Latvian Institute of Aquatic Ecology, LatviaReviewed by:
Taavi Liblik, Tallinn University of Technology, EstoniaAndris Andrusaitis, Latvian Institute of Aquatic Ecology, Latvia
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*Correspondence: Jan Marcin Węsławski, d2VzbGF3QGlvcGFuLmdkYS5wbA==