Join us for a mCDR community gathering at ARTECHOUSE DC during AGU24!
Connect with fellow members of the mCDR Community in an inspiring setting – share ideas, network, and enjoy a night of small bites, drinks and immersive art!
New Ocean Metaproteomics paper published (web link and pdf link) to help promote proteomics in environmental settings. The study is open access. This paper is a product of OCB’s Intercomparison of Ocean Metaproteomic Analyses.
Earlier this year, we conducted an online survey and consultation with the broader ocean science community to assess what we perceive as emerging skills gaps in basic physical chemistry training and expertise in several areas of chemical oceanography, especially (but not exclusively) including the ocean carbonate system. In the survey, we asked just for this information:
We received well over 100 responses, with very many insightful observations and answers to our questions. We invite you to read the brief summary report describing the skill gap survey results and associated community feedback on recommended paths forward. Read the report.
Join us for a virtual community discussion at OA Week in November
To follow up on this survey, we are convening an online community discussion on Tuesday 19 November at 1600-1730 GMT/1100-1230 ET as part of the Global Ocean Acidification Observing Network (GOA-ON)’s Ocean Acidification (OA) Week 2024. The purpose of this discussion will be to discuss next steps for a community activity (most likely a workshop), including its focus, content, participants, and outcomes to help address the emerging skills gap identified in the survey. Register to participate in this community discussion HERE. If you would like further information, or you represent an organization that would like to participate in this effort, please get in touch with either Heather Benway (hbenway@whoi.edu) or Simon Clegg (s.clegg@uea.ac.uk).
Due to a sparsity of in‐situ observations and the computational burden of eddy‐resolving global simulations, there has been little analysis on how mesoscale processes (e.g., eddies, meanders—lateral scales of 10s to 100s km) influence air‐sea CO2 fluxes from a global perspective. Recently, it became computationally feasible to implement global eddy‐resolving [O (10) km] ocean biogeochemical models. Many questions related to the influence of mesoscale motions on CO2 fluxes remain open, including whether ocean eddies serve as hotspots for CO2 sink or source in specific dynamic regions.
A recent study in Geophysical Research Letters investigated the contribution of ocean mesoscale variability to air-sea CO2 fluxes by analyzing the CO2 flux anomaly within the mesoscale band using a coarse-graining approach in a global eddy-resolving biogeochemical simulation. We found that in eddy-rich mid-latitude regions, ocean mesoscale variability can contribute to over 30% of the total CO2 flux variability. The cumulative net CO2 flux associated with mesoscale motions is on the order of 105 tC per year. The global pattern of cumulative mesoscale-related CO2 flux exhibits significant spatial heterogeneity, with the highest values in western boundary currents, the Antarctic Circumpolar Current, and the equatorial Pacific. The local distribution of cumulative mesoscale-related CO2 flux displays zonal bands alternate between positive (a net source) and negative (a net sink) due to the meandering nature of ocean mesoscale currents, which is related to local relative vorticity and the background cross-stream pCO2 gradient.
Figure caption. Mesoscale (<nominal 2 degree) contribution to air‐sea CO2 flux (F<2°CO2)in the model. (a)–(d) Monthly time series of F<2°CO2 (black lines) and cumulative F<2°CO2 (green/red solid lines) in four locations marked in (e). Dashed lines are the least squares regression of cumulative flux for the period 1982–2000; slopes are indicated in the bottom left; (e) Blue colors imply a CO₂ sink, and red colors represent a source. The figure shows the global distribution of the regressed slopes of cumulative F<2°CO2. Units are converted from mol m-2 per year to kg of CO2 per year using the atomic mass of CO2. This figure shows significant spatial heterogeneity of mesoscale-modulated CO2 flux, showing contributions to both CO₂ sources and sinks across different regions of the ocean, with a magnitude on the order of 105 tC per year.
Authors
Yiming Guo (Yale University; now at Woods Hole Oceanographic Institution)
Mary-Louise Timmermans (Yale University)
It has long been suggested that diatoms, microscopic algae enclosed in silica-shells, developed these structures to defend against predators like copepods, small crustaceans that graze diatoms. Copepods evolved silica-lined teeth presumably to counteract this. But actual evidence for how this predator-prey relationship may drive natural selection and evolutionary change has been lacking.
Figure caption: Left: Copepod teeth may suffer damage when feeding on thick-shelled diatoms. The red arrows indicate damage to the copepod tooth, cracks or missing setae. When fed a large diatom, the row of spinose cusps was damaged in all analyzed teeth. Scale bar = 10 µm. Right: A Temora longicornis (ca. 750 µm) copepod tethered to a human hair using super glue, allowing for the capture of high-speed videography to quantify the fraction of cells that eaten or discarded by the copepod. The hair was kindly provided by the first author’s wife.
A recent publication in Proceedings of the National Academy of Sciences U.S.A. revealed a fascinating dynamic: Copepods that feed on diatoms may suffer significant damage to their teeth, causing them to become more selective eaters. The wear and tear on the copepod teeth were particularly pronounced when copepods consumed thick-shelled diatoms compared to “softer” prey like a dinoflagellate. By glueing copepods to human hair and filming them with a high-speed video camera, the authors found that copepods with damaged teeth were more likely to reject diatoms with thick shells than those with thin shells as prey. Shell thickness varies among and within diatom species and some can respond to copepod presence by increasing shell thickness. A thicker shell, however, may come at a cost to the cell in terms of reduced growth rate or increased sinking speed. This suggests that the evolutionary “arms race” between diatoms and copepods plays a crucial role in shaping and sustaining the diversity of these species.
Diatoms and copepods are important organisms in global biogeochemical cycles and hence understanding this microscopic interaction can help predict shifts in marine ecosystems, potentially affecting nutrient cycles and food webs that support fisheries.
Authors
Fredrik Ryderheim (Technical University of Denmark/University of Copenhagen)
Jørgen Olesen (University of Copenhagen)
Thomas Kiørboe (Technical University of Denmark)
Twitter
@fryderheim (Fredrik Ryderheim)
@OlesenCrust (Jørgen Olesen)
@Thomaskiorboe (Thomas Kiørboe)
@OceanLifeCentre (FR, TK group at DTU)
@NHM_Denmark (Natural History Museum of Denmark, JO employer)
One of the longest running open ocean time-series on our planet, the Hawaii Ocean Time-series (HOT) can now be accessed using webODV at https://hot.webodv.awi.de.
webODV [Mieruch and Schlitzer, 2023]) is the online version of the Ocean Data View (ODV) software. It is developed at the Alfred Wegener Institute, Bremerhaven, Germany with the aim to provide clients with user-friendly interfaces in their web-browser and access datasets that are centrally maintained and administered on a server using the full capacity of ODV.
This platform has recently been adapted to serve physical, biochemical, and ecological data from the HOT program. Dr. Sebastian Mieruch has generated an automated processing chain to aggregate, harmonize, and convert HOT data to the ODV format. Video tutorials for use of webODV to access, plot, and download HOT data can be found at https://hot.webodv.awi.de/docs.
Join us October 24 at 10am Eastern for a Leaky Deltas series webinar with:
Biogeochemical Patterns During Ecological Succession of Coastal Deltaic Floodplains - Robert Twilley, Vice President of Research, Louisiana State University.
Validation of hydrodynamic models: NASA’s Delta-X airborne mission in coastal Louisiana going global with SWOT and NISAR - Marc Simard, Senior Research Scientist, Jet Propulsion Laboratory.
A lead up activity to the March 2025 Leaky Deltas workshop
Webinar theme: Biogeomorphology and Arctic deltas
September 26, 2024 at 10am Eastern
Muriel Bruckner (LSU) - Modeling ecogeomorphic feedbacks in deltas to quantify the role of abiotic and biotic processes
Anastasia Pillouras (PSU) - The role of Arctic deltas in modulating land-ocean fluxes"
BGC Argo Webinar #8: Comparing BGC-Argo observations with models
October 16, 2024, 11am Pacific/2pm Eastern
Please join us for the quarterly GO-BGC webinar, hosted by the US Ocean Carbon and Biogeochemistry Project Office. This webinar will be focused on comparisons between BGC-Argo observations and ocean model simulations focusing on bbp and particulate forms of carbon. The webinar will begin with an update on the status of the GO-BGC float array, followed by two short presentations. We’ll then close with a community discussion and Q&A session. Recordings will be available on the OCB and GO-BGC websites.
1) Yui Takeshita (Monterey Bay Aquarium Research Institute, USA, yui@mbari.org): An update on the GO-BGC program
2) Camila Serra-Pompei (Technical University of Denmark): Assessing the potential of backscattering as a proxy for phytoplankton carbon biomass
The particulate backscattering coefficient (bbp) has often been used as an optical proxy to estimate phytoplankton carbon biomass (Cphy). However, total observed bbp is impacted by phytoplankton size, cell composition, and non-algal particles. The scarcity of phytoplankton carbon field data has prevented the quantification of uncertainties driven by these factors. Here, we first review and discuss existing bbp algorithms by applying them to bbp data from the BGC-Argo array in surface waters (<10m) and show that errors can be large when the bbp signal is low. Next, we use a global ocean circulation model (the MITgcm Biogeochemical and Optical model) that simulates plankton dynamics and associated inherent optical properties to quantify and understand uncertainties from bbp-based algorithms in surface waters. In an ideal world where field data has no methodological uncertainties, the model shows that bbp algorithms could estimate phytoplankton carbon biomass with an absolute error close to 20% in most regions.
3) Martí Galí Tàpias (Institute of Marine Sciences [ICM-CSIC], Spain): Constraining stocks and fluxes of Particulate Organic Carbon (POC) through the comparison between particulate backscattering measurements and the PISCESv2 model
BGC-Argo data offers a great opportunity for model evaluation, optimization, and the development of improved parameterizations, ultimately furthering our mechanistic understanding. However, comparison between BGC-Argo observations and models requires careful consideration of the spatiotemporal scales that each of them can resolve. When using particulate backscattering (bbp) as a proxy for particulate organic carbon (POC), additional attention must be paid to the variability in the POC/bbp ratio, its uncertainty, and its underpinning biogeochemical drivers. In this talk I will present comparisons between bbp from BGC-Argo and simulated POC based on both 3D (Eulerian) and 1D (pseudo-Lagrangian) frameworks. I will discuss the potential and limitations of model parameter optimization using BGC-Argo bbp as the observational reference. Finally, I will explore the impacts of optimized model parameters on mesopelagic POC budgets and vertical fluxes in the PISCESv2 model.
4) Discussion
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Funding for the Ocean Carbon & Biogeochemistry Project Office is provided by the National Science Foundation (NSF) and the National Aeronautics and Space Administration (NASA). The OCB Project Office is housed at the Woods Hole Oceanographic Institution.