2020 Ocean Sciences Meeting
Dates: 16-21 February 2020
Location: San Diego, California, USA.
For more information: https://www2.agu.org/ocean-sciences-meeting
GEOTRACES and GEOTRACES related sessions:
Revealing Biogeochemical Processes on Basin Scales through Ocean Transects
Session ID#: CT008
Biogeochemical processes that affect the cycling of trace elements and their isotopes, as well as carbon, macronutrients and other constituents, are studied using two basic field strategies: sampling at a fixed station or regime to measure rates and examine specific processes, or transects on up to basin scales. Each has its strengths and weaknesses, but transects can gather a broad sweep of information on a relatively short time scale that can then be used to develop a more specific process-oriented approach. Indeed, the GEOSECS program of the 1970’s used the transect approach, and currently the GO-SHIP/Repeat Hydrography and international GEOTRACES programs feature long ocean transects. This session will highlight biogeochemical processes revealed on basin transects that affect trace constituents such as trace elements and isotopes, as well as organic constituents, including carbon and macronutrients. It will also focus on sampling and data analysis methods applied to sampling across basins, and biogeochemical modeling studies that integrate data from long transects into their analyses.
Primary Chair: Gregory A Cutter, Old Dominion University.
Co-chairs: Phoebe J Lam, University of California Santa Cruz; Karen L Casciotti, Stanford University; Rob Middag, Royal Netherlands Institute for Sea Research.
Linking the biology, geochemistry, and circulation of the Gulf of Mexico
Session ID#: OB015
The Gulf of Mexico is a small, dynamic marginal sea that supports a broad range of oceanographic environments, including eutrophic coastal systems, oligotrophic open ocean waters, hydrocarbon-impacted waters and sediments, and shelf waters that are susceptible to frequent harmful algal blooms. Large atmospheric, riverine, and submarine groundwater fluxes strongly influence the biogeochemistry of near-shore and open ocean waters, yielding a high degree of spatial and temporal variability. Several recent studies have focused on characterizing the biogeochemistry of the Gulf of Mexico using a range of interdisciplinary approaches. Following on a successful 2018 OSM Town Hall led by GEOTRACES and OCB, this session will bring together interested investigators to highlight new results from the Gulf and identify potential areas of common interest and collaborative opportunities to help inform future planning in GEOTRACES, OCB, and other relevant programs. We invite contributions that characterize the variability in the biology, geochemistry, and/or physical oceanography of the Gulf of Mexico, and especially the linkages between them. Suggested contributions may include, but are not limited to descriptions of water column and benthic geochemical distributions, biogeochemical rate measurements, characterizations of molecular ecology, geochemical fluxes, and descriptions of circulation that impact Gulf biogeochemical dynamics.
Primary Chair: Angela N Knapp, Florida State University.
Co-chairs: Alan M Shiller, University of Southern Mississippi; Heather M Benway, Woods Hole Oceanographic Inst.; Juan Carlos Herguera, Center for Scientific Research and Higher Education at Ensenada.
Controls on trace metal biogeochemistry and physicochemical speciation in seawater
Session ID#: CT004
Trace metals function as essential micronutrients and pollutants in the ocean. Organic complexation, size partitioning, and redox changes of trace elements can be mediated by biological processes including uptake, regeneration, cell lysis, and organic ligand production. Additional processes influencing the production, degradation, and composition of organic matter also play an important role in controlling trace metal distributions, and both vary across environments (e.g. estuaries, open ocean, air-sea-sediment interfaces, hydrothermal systems). In turn, resulting changes in bioavailability and cycling of trace elements governs the function and composition of marine phytoplankton communities. Recent efforts, particularly within GEOTRACES, have expanded the database of trace metal concentrations and physicochemical speciation. This session seeks to link our understanding of biology, organic matter, and trace metal chemistry from molecular to basin-wide scales, from studies related to biologically-mediated transformations of trace elements to the wider processes controlling metal distributions, size partitioning, and fluxes. We welcome submissions highlighting how marine organisms influence the physicochemical speciation of trace elements in seawater, and how changes in trace element chemistry impact the structure and function of marine ecosystems. In addition to observational, experimental and modelling studies, we also invite contributions on the production, degradation, and characterization of metal-binding compounds and colloids.
Primary Chair: Hannah Whitby, IUEM Institut Universitaire Européen de la Mer.
Co-chairs: Randelle M Bundy, University of Washington; Jessica N Fitzsimmons, Texas A & M University College Station; Andrea Koschinsky, Jacobs University Bremen.
Biogeochemical cycles in oxygen minimum zones: mechanisms, drivers, and change
Session ID#: CT001
Oxygen minimum zones in the coastal and open ocean are spatially expanding and intensifying, with model projections showing continued O2 loss in the future. These regions play a fundamental role in the biogeochemical cycles of elements such as carbon, nitrogen and sulfur as well as trace elements, host microbial communities with diverse metabolic pathways, and act as significant sources and sinks of nutrients and climatically relevant (greenhouse) gases. Yet, significant questions on the nature, drivers and variability of these processes remain. This session aims to build a comprehensive view of oxygen minimum zone biogeochemistry, by inviting researchers who apply a variety of approaches to these problems, from field and laboratory measurements, to -omics based studies, to observational synthesis and numerical models. Specifically, we invite submissions investigating: (1) the distribution, speciation and transformation of macronutrients (N, P, Si), trace metals (e.g. Mn, Fe, Co, Ni, Cu, Zn, Cd), redox-active elements (e.g. S, Cr, Mo, I) and their isotopes; (2) microbial interactions and their impacts on biogeochemical cycles; (3) processes occurring in and around particle-associated microenvironments, and (4) the physical drivers and variability of these processes. Studies assessing regional or global impacts with large/new datasets, e.g. from international programs such as GEOTRACES, and integrative approaches combining modeling, field/laboratory measurements, and/or microbial and molecular approaches are especially encouraged.
Primary Chair: David Janssen, University of Bern.
Co-chairs: Daniele Bianchi, University of California Los Angeles; Thomas S Weber, University of Rochester.
CT003 - Chemical Speciation and Biogeochemistry in a Changing Ocean
Session ID#: CT003
How is seawater chemistry responding to global change processes, and what are the consequences for marine ecosystems? How do advances in our understanding of chemical speciation give new mechanistic insight into biogeochemical processes? The thermodynamics of solution chemistry in addition to the distribution of trace metals and organic complexes along a gradient of particle sizes and ephemeral clusters are the focus of our session. Although solution thermodynamics is a relatively mature field, there is an upsurge of research on both measurement and modelling of chemical speciation and an increasing focus on the assessment of uncertainties. This session will also explore interactions between solid and soluble species, focusing on how recent developments examining the continuum between solid and dissolved (colloids, nanoparticles, etc.) alter our paradigm view of element cycling. The transport and reactivity of these ‘in-between’ species may differ from their fully dissolved or solid counterparts, yet they are the most difficult to sample and observe. We invite submissions pertaining to the measurement and modelling of chemical speciation; assessment of modelling uncertainties; abiotic and biotic transformations from the solid to soluble phase and back again; reactions at the solid-solution interface; trace metal binding environments; sediment-seawater relationships; and interpretation of paleo records.
Primary Chair: David R Turner, University of Gothenburg.
Co-chairs: Veronique Oldham, University of Delaware; Sylvia Sander, IAEA; Emily R Estes, WHOI.
Autonomous observing systems for macronutrients and bioactive trace metals in coastal and open ocean settings: present status, challenges and emerging technologies
Session ID#: IS003
Progress and discovery in the understanding and modeling of biological productivity and species composition in the marine environment is limited by our ability to make macronutrient and bioactive trace metal measurements at relevant spatial and temporal scales. While significant progress has been made with the advent of UV and microfluidic nitrate sensors, there are still few analytical systems for other important macronutrient species (P, Si, NH3) and virtually none for bioactive trace metals that can be deployed on the expanding array of platforms dedicated to long term unattended data gathering (i.e., moorings, gliders, profilers), particularly in oligotrophic surface ocean settings.
This session aims to: (1) highlight the latest developments in macronutrient and bioactive trace metal analytical methodologies with strong potential or demonstrated capabilities for unattended operation in coastal and open ocean settings and, (2) serve as a forum to nurture collaborations among sensor developers and oceanographers with an engineering and analytical chemistry inclination. Contributions from all stages of development are encouraged including: remote samplers, passive samplers, reagent-based microfluidic analyzers including the use of novel chemical probes, electrochemical methods, optical sensors, as well as the optimization, calibration, and field validation of emerging in situ technologies.
Primary Chair: Maxime Grand, Moss Landing Marine Laboratories.
Co-chairs: Andrew R Bowie, University of Tasmania; Agathe Laes-Huon, IFREMER; Alexander Beaton, National Oceanography Center, Soton.
Towards BioGeoSCAPES: Exploring molecular drivers of ocean metabolism and biogeochemistry
Session ID#: OB030
BioGeoSCAPES has been proposed as an idea for a new international coordinated research program to integrate knowledge on organism identity and physiology within frameworks of community ecology and global ocean biogeochemistry. It is envisioned that an improved, predictive, and quantitative understanding of ocean metabolism can be developed by combining detailed information on cell status, biochemical processes, and species interactions with intercalibrated measurements of nutrient fluxes and concentrations. We invite contributions describing research that can serve as inspiration for this nascent program. Appropriate abstracts could include: studies that integrate molecular and biogeochemical measurements, including fluxes; research that places ‘omics observations (e.g., genomic, transcriptomic, proteomic, metabolomic, metallomic, lipidomic, etc.) within quantitative numerical modeling frameworks; or studies that scale from the cellular to the ecosystem level through integrated field measurements or mechanistic models of interactions. The aim of this session is to highlight research that combines informatics, modeling, and biogeochemical measurements across scales of time and space, to test, integrate, connect, and expand upon studies of ocean ecology and metabolism.
Primary Chair: Benjamin S Twining, Bigelow Lab for Ocean Sciences.
Co-chairs: Erin Marie Bertrand, Dalhousie University; Martha Gledhill, GEOMAR Helmholtz Centre for Ocean Research; Naomi Marcil Levine, University of Southern California.
The role of micronutrient cycles in global-scale dynamics
Session ID#: CT24D
Via their fundamental control on ocean productivity and the biological carbon pump, the cycling of nutrients plays an integral role in the dynamics of atmospheric CO2 and climate. In contrast to the ‘big three’- nitrogen, phosphorus and silicon, with their well characterised modern distributions and relatively stable inventories, micronutrients, such as iron, remain relatively poorly observed and have the potential for rapid and profound changes in their inventories and biological availability in response to a host of poorly constrained processes. Micronutrients are currently the ‘wild card’ in both past and future carbon cycle and climate change, prompting the need for improved understanding of their role in Earth system dynamics. We invite a broad range of submissions to provide insights into the pieces of the puzzle, addressing boundary inputs and sinks, exchanges between dissolved and solid phases, interactions with organic compounds, and their reciprocal interactions with microbial ecosystems. Submissions may include observations, data synthesis or models, and may address ocean nutrient cycling over a range of time-scales, from past (paleo) through contemporary, and/or in response to future global change. We particularly encourage new insights into the role of feedbacks and the role micronutrient cycles play in shaping global-scale dynamics.
Primary Chair: Andy Ridgwell, University of California Riverside.
Co-Chair: Alessandro Tagliabue, University of Liverpool
Understanding Rare Earth Element (REE) distributions and isotopic ratios and the mechanisms behind their use as tracers of (paleo)oceanic processes
Session ID#: CT24E
Analytical advances have enabled a significant increase of environmental REE abundance and isotopic (e.g. Nd, Ce) data. These elements are increasingly recognized as promising tracers for elucidating past and present natural and man-made processes in a variety of aquatic environments. However, in spite of this growth in observations, our understanding of the mechanisms, capabilities and limitations of geochemical proxies based on REE abundances and isotopic ratios remains incomplete. We therefore invite presentations of field, laboratory, or modeling studies of REEs and related isotope systems aimed specifically at exploring mechanistic connections between their geochemical behavior and observed distributions in marine and terrestrial waters and sediments. Of particular interest are investigations linking REE abundance distributions to Nd or Ce isotopic ratios; validating the use of REEs as proxies of paleoceanographic processes; and addressing REE fractionation and source-to-sink transport on a global scale and at "geochemical hotspots" like estuaries, hydrothermal vents, nepheloid layers etc. Presentations that merely contribute TEI distribution data will be given lower priority. We especially encourage submissions from students and early-career scientists.
Primary Chair: Brian A Haley, Oregon State University
Co-chairs: Torben Stichel, Alfred Wegener Institute Helmholtz-Center for Polar and Marine Research Bremerhaven; Johan Schijf, University of Maryland Center for Environmental Science; Vanessa Hatje, Universidade Federal da Bahia.