Human Activities and Coastal Biogenic Element Cycles: Linkages, Drivers, and Mechanistic Insights

Coastal zones, although covering less than 10% of the marine area, are hot spots for ocean productivity, supporting over 90% of global fisheries and facilitating the sequestration of up to 80% of the ocean’s carbon stock. However, these dynamic ecosystems are increasingly subjected to multiple anthropogenic pressures—driven by intensive urbanization, aquaculture, agricultural runoff, and industrial effluents—due to more than half of the world’s population residing within 100 km of the coast. These cumulative activities dramatically alter the cycling and fate of essential biogenic elements, such as carbon (C), nitrogen (N), phosphorus (P), silicon (Si), sulfur (S), and iron (Fe), leading to cascading impacts: eutrophication, deoxygenation, harmful algal blooms, blue carbon loss, and new contaminant emergence. Despite advances in understanding individual stressors, major knowledge gaps remain in our ability to quantify interactive and synergistic effects of multiple anthropogenic influences on coastal ocean biogeochemistry. Addressing these gaps is essential for predicting, managing, and ultimately mitigating the impacts of global environmental change on coastal marine systems.



This Research Topic seeks to advance understanding of how human activities affect coastal biogenic element cycles, emphasizing integrated observational, experimental, and modeling perspectives. The aim is to provide a holistic platform exploring the mechanisms and feedbacks that govern land-sea element transfers and transformations under anthropogenic influence. We welcome contributions that address (but are not limited to):

• Interfacial Biogeochemical Fluxes: Quantifying riverine, groundwater, and atmospheric pathways of nutrient and contaminant delivery to coastal waters; elucidating the role of estuarine and coastal filter systems.

• Microbial and Ecophysiological Mechanisms: Investigating how altered element stoichiometry or emerging contaminants (e.g., microplastics, pharmaceuticals) affect microbial-mediated processes and elemental cycling.

• Anthropogenic Carbon and Nutrient Transformations: Assessing how management practices, urbanization, eutrophication, and acidification influence blue carbon sequestration, DOM cycling, and greenhouse gas emissions.

• Human-Altered System Feedbacks: Exploring how engineered structures (e.g., seawalls, aquaculture facilities) or habitat modifications impact sediment-water exchange, redox cycling, and diagenetic processes.

• Multi-Stressor Interactions: Examining the synergistic effects of warming, deoxygenation, and pollutant mixtures on element fluxes, with special attention to trace metal speciation and availability.

• Mitigation, Restoration, and Management: Evaluating the effectiveness of nature-based solutions (e.g., living shorelines, oyster reefs, constructed wetlands) in restoring and enhancing coastal element cycling under anthropogenic stress.



Through synthesizing research across disciplines—including biogeochemistry, ecology, pollution science, and coastal management—this Research Topic aims to foster a mechanistic and solution-oriented understanding relevant to both scientific inquiry and policy formulation.



We invite original research articles, reviews, mini-reviews, perspectives, and methods papers that contribute to any of the following themes:

• Key bioactive elements and their importance to coastal productivity: Studies focusing on C, N, P, Si, Fe cycles in coastal and nearshore waters.

• Anthropogenic pressures on coastal element cycling: Research on urban, agricultural, or industrial stressors unique to the land-sea interface.

• Mechanistic and microbial perspectives: Elucidation of pathways, stoichiometry imbalances, microbial mediation, and new biogeochemical models.

• Emerging and interactive stressors: Analyses that incorporate compounds/pollutants of emerging concern, hypoxia, acidification, or multi-stressor feedbacks.

• Solutions and management strategies: Assessments of restoration measures, blue carbon strategies, and nature-based interventions for improving coastal resilience.

This Research Topic provides a unique platform to integrate mechanistic science with applied solutions, advancing our collective understanding of how human activity is re-shaping the elemental foundation of coastal oceans.