About this Research Topic
This Research Topic will include a variety of article types (see below) resulting from a symposium held at the Institute for Advanced Research (Hanse-Wissenschaftskolleg) in Delmenhorst, Germany on April 27-30, 2019. This meeting stimulated discussion about molecular marine organic biogeochemical research among scientists working on multiple aspects of biogeochemistry. Complex and incompletely understood chemical, biological and physical processes affect the delivery, transport and storage of organic matter (OM) in the ocean. Atmospheric and climate-relevant gases, primarily carbon dioxide, are closely linked to the production and flux of organic matter from continental systems to the ocean (including the sediments) and within the ocean via the biological pump. OM is transformed in the water column, released to the atmosphere, or transported to the sediments where some fraction is stored over geological time. These functions are intimately linked to global nutrient cycles and ecosystem processes. Marine organic biogeochemistry provides a molecular-level window onto the functioning and scale of processes that control the behavior of OM in the ocean. Marine OM covers a wide size continuum that includes particulate, colloidal, and dissolved phases that are largely operationally defined:
Particulate organic matter (POM): Processes that regulate the vertical flux of POM involve particle sinking velocity, aggregation and disaggregation, biological particle consumption and transformation, and potential mineral interaction. Are large particles preferentially remineralized over small particles? How can organic biogeochemistry improve our understanding of the dynamics of the biological pump that links surface processes with the deep ocean? Since POM is the dominant source of OM to the sediments, what insight into early diagenesis in near-surface sediments and into paleoenvironments can we gain from organic biomarker proxies in the sediments?
Colloidal and gel organic matter (COM): Marine colloids and gels represent an interface between particulate and dissolved organic carbon phases. Though they originate from macromolecular colloidal material, gels are three-dimensional hydropolymers that are cross-linked with Ca or Mg ions. Gels link biological productivity and microbial degradation as they may be metabolic hotspots for the microbial loop. How common are gels in the ocean? Are all gels alike in physical, chemical, and biological attributes? How important are gels to particle aggregation and POM flux?
Dissolved organic matter (DOM): DOM is released by zooplankton, by microbial decomposition of POM, and by diagenesis in sediments. It is exported from the upper water column, but there are additional sources within the ocean’s interior. What controls the size of the marine DOM reservoir, and how well do we understand DOM sources and sinks? What are the best approaches to characterizing the physical properties and molecular complexity of DOM?
Analytical and computational advancements, opportunities, and challenges: A new understanding of the functioning of the oceanic organic carbon cycle requires new sampling and experimental protocols, analytical instrumentation and methods, computational tools for handling large datasets, and modeling that integrates organic results at the molecular level into larger scale ocean biogeochemical cycles. What are the most promising new analytical trends? How do we handle the new computational and data storage needs so that these new data sets can best be used? How can molecular-level organic data be incorporated into conceptual models that better describe the behavior of marine organic matter?
Expected article types to be submitted by workshop participants: Speakers are invited to contribute papers on their talks. These would most likely fall in the categories of Original Research, Systematic Review, Review, Mini Review, or Hypothesis and Theory. All attendees will be encouraged to submit shorter papers in the categories of Methods, Technology Reports, Brief Research Report, or Hypothesis and Theory. The discussion during the meetings will lead to jointly authored papers in the categories of Perspective, General Commentary, or Opinion.
Keywords: Dissolved organic matter, Particulate organic matter, Analytical and computational advances, Production and flux of marine organic matter, Transport and storage of marine organic matter
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.