Author Archive for mmaheigan – Page 4

Gulf of Mexico node

Posted by mmaheigan 
· Wednesday, December 4th, 2024 

On the evening of February 19, 2024 members of the Gulf of Mexico (GMx) Regional Node Working Group on Marine Carbon Dioxide Removal (mCDR) met for the first time. They kicked off the first night of the Ocean Sciences Meeting in New Orleans, a week for oceanographers across all disciplines to share their work. The evening began with a networking hour co-hosted by Carbon to Sea, Exploring Ocean Iron Solutions (ExOIS), [C]Worthy, and Ocean Visions. Leaders from the mCDR industry gathered amid the bluish glow of the tarpon exhibit at the Audubon Aquarium for a night of meaningful conversation and shared connections. After networking, members of the GMx node group moved to a breakout room for their own meeting.

This launched a new effort to address climate challenges in the Gulf Coast's unique ecological landscape. Framed by its vital connection to the Caribbean Sea through the dynamic Gulf Stream, GMx is nourished and challenged by the substantial discharge from the Mississippi River. This area is a nexus of environmental contrasts, grappling with coastal hazards such as hurricanes, escalating sea level rise, and the distressing phenomenon of coral reef bleaching.

Marine carbon dioxide removal has the potential to shape the future of the Gulf. Members sharing this belief attended the meeting to connect through local knowledge and goal setting. Nineteen participants from the Gulf region and beyond, including Louisiana, Texas, Florida, Georgia, and the Bahamas, participated in a series of interactive activities (Figure 1). After introductions, they clustered into groups according to these regions of origin and were asked to highlight several challenges and opportunities unique to their area. A few of these opportunities are:

  • High nutrient and carbon input from the Mississippi River, enhancing primary productivity.
  • The river’s buoyancy extends the residence time of coastal waters, facilitating sediment settling and potentially enhancing mCDR.
  • Integrating wetlands, estuarine, and marine environments supports diverse mCDR strategies.
  • Existing oil and gas infrastructure could support new mCDR initiatives, with significant interest from the private sector.

These challenges and opportunities then became the center of discussion. While consensus on specific actions was not reached, the group found a common interest in the environmental and socio-economic impacts of mCDR. Members closed the session by sharing two personal or professional goals for the upcoming year.

Moving forward, the group strategy involves seeking co-production opportunities with industry and non-profit partners. Possible projects include the development of an MRV (Monitoring, Reporting, and Verification) toolbox and a foundational study outlining regional mCDR opportunities. Highlighting these opportunities is essential to attract government and private investment and unite stakeholders around shared objectives. The newly formed GMx node left their kickoff meeting feeling energized to develop these plans further and launch them into action.

 

 

California Current mCDR Node

Posted by mmaheigan 
· Sunday, December 1st, 2024 

The California Current mCDR Node convened a workshop on October 7-8, 2024 in California (in partnership with California Ocean Science Trust and Southern California Coastal Water Research Project). The workshop will address topics related to the environmental effects, both positive and negative, of mCDR. Attendees represent federal, state, and local agencies, NGOs, industry, and scientists. The goal of the workshop is to foster dialogue among these California sectors and advance on a framework for assessing environmental effects of mCDR.

 

New Ocean Metaproteomics paper

Posted by mmaheigan 
· Friday, November 8th, 2024 

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.

Capacity Building in Physical Chemistry for Oceanography

Posted by mmaheigan 
· Friday, October 25th, 2024 

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:

  1. Expertise, applications, and professional roles
  2. Opinions concerning skills gaps in physical chemistry for different areas of oceanography and needs for capacity building

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).

Swirling Currents: How Ocean Mesoscale Affects Air-Sea CO2 Exchange

Posted by mmaheigan 
· Friday, October 25th, 2024 

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)

How tiny teeth and their prey shape ocean ecosystems

Posted by mmaheigan 
· Friday, October 25th, 2024 

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)

OAIC gathering at AGU Fall Meeting 2024

Posted by mmaheigan 
· Tuesday, October 22nd, 2024 
People interested in ocean-atmosphere interactions and SOLAS are meeting up for drinks at AGU –  please come if you can. Everyone is welcome. The meetup will be on Thurs. Dec. 12 at 6:00 PM in Dacha Beer Garden. 1600 7th St NW, Washington DC 20001

Hawaii Ocean Time-series (HOT) can now be accessed using webODV!

Posted by mmaheigan 
· Thursday, October 10th, 2024 

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.

 

BGC Argo Webinar #8, Oct 16 Comparing BGC-Argo observations with models

Posted by mmaheigan 
· Tuesday, September 24th, 2024 

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.

REGISTER

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

Fast-sinking salp and fish detritus impacts OMZ size and ocean biogeochemical cycles

Posted by mmaheigan 
· Thursday, September 12th, 2024 

Marine fishes and filter-feeding gelatinous zooplankton such as salps and pyrosomes generate detritus in the form of poop and dead carcasses, which sink ~10 times faster than other oceanic detritus. This detritus is hypothesized to have a disproportionally large impact on the marine biological pump as it sequesters carbon and nutrients deeper in the water column. Until now, global models had not considered these fluxes, thus, their impacts on ocean biogeochemical cycles were not well understood.

A recent study in Geophysical Research Letters investigated the sensitivity of deep ocean carbon, oxygen, and nutrient cycles to fast-sinking detritus from filter-feeding gelatinous zooplankton (pelagic tunicates) and fishes, using a modified version of the NOAA-GFDL ocean biogeochemical model COBALT (“GZ-COBALT”). We found the fast-sinking detritus decreased surface productivity and export, while increasing transfer efficiency and sequestration at depth. Ocean oxygen minimum zones (OMZs) also decreased in size: fast-sinking detritus triggered less remineralization, particularly in the mid-depths, resulting in less oxygen consumption and a reduced expansion of OMZs.

Figure caption: Flux of detrital carbon at various depths (A, B, C), shows that incorporating fast-sinking detritus counter-intuitively decreases carbon export from the surface while increasing sequestration at depth. Particulate organic carbon (POC) export flux at (A) 100 m, (B) 1,000 m and (C) seafloor (mgC/m2/d), shows (left) the control simulation with no fast-sinking detritus, (center) the experiment with fast-sinking fish and gelatinous zooplankton detritus, and (right) the differences between the control and fast-sinking detritus simulation. (D) Total ocean volume over the 300-year simulation at the suboxic (O2 ≤ 5 mmol/m3) level, shows the simulation with fast-sinking particulate organic carbon (red) had lower suboxia than the control (black). Large hypoxic and suboxic zones are a common model bias; these results suggest that fast-sinking detritus may be one biogeochemical mechanism to reduce the expansion of these low oxygen zones.

Past observations have shown that fast-sinking, highly reactive detritus reaching the seafloor can fuel significant benthic consumption and respiration. On a global scale, we suggest that the increased fluxes to the seafloor in the model can be supported by observational constraints of seafloor oxygen consumption, suggesting that these processes could be realistically incorporated into future generations of Earth System Models.

 

Authors
Jessica Y. Luo (NOAA GFDL)
Charles A. Stock (NOAA GFDL)
John P. Dunne (NOAA GFDL)
Grace K. Saba (Rutgers University)
Lauren Cook (Rutgers University)

« Previous Page
Next Page »

Filter by Keyword

abundance acidification additionality advection africa air-sea air-sea interactions algae alkalinity allometry ammonium AMO AMOC anoxic Antarctic Antarctica anthro impacts anthropogenic carbon anthropogenic impacts appendicularia aquaculture aquatic continuum aragonite saturation arctic Argo argon arsenic artificial seawater AT Atlantic atmospheric CO2 atmospheric nitrogen deposition authigenic carbonates autonomous platforms AUVs bacteria bathypelagic BATS BCG Argo benthic bgc argo bio-go-ship bio-optical bioavailability biogeochemical cycles biogeochemical models biogeochemistry Biological Essential Ocean Variables biological pump biophysics bloom blue carbon bottom water boundary layer buffer capacity C14 CaCO3 calcification calcite carbon carbon-climate feedback carbon-sulfur coupling carbonate carbonate system carbon budget carbon cycle carbon dioxide carbon export carbon fluxes carbon sequestration carbon storage Caribbean CCA CCS changing marine chemistry changing marine ecosystems changing marine environments changing ocean chemistry chemical oceanographic data chemical speciation chemoautotroph chesapeake bay chl a chlorophyll circulation clouds CO2 CO3 coastal and estuarine coastal darkening coastal ocean cobalt Coccolithophores commercial community composition competition conservation cooling effect copepod copepods coral reefs CTD currents cyclone daily cycles data data access data assimilation database data management data product Data standards DCM dead zone decadal trends decomposers decomposition deep convection deep ocean deep sea coral denitrification deoxygenation depth diatoms DIC diel migration diffusion dimethylsulfide dinoflagellate dinoflagellates discrete measurements distribution DOC DOM domoic acid DOP dust DVM ecology economics ecosystem management ecosystems eddy Education EEZ Ekman transport emissions ENSO enzyme equatorial current equatorial regions ESM estuarine and coastal carbon fluxes estuary euphotic zone eutrophication evolution export export fluxes export production extreme events faecal pellets fecal pellets filter feeders filtration rates fire fish Fish carbon fisheries fishing floats fluid dynamics fluorescence food webs forage fish forams freshening freshwater frontal zone functional role future oceans gelatinous zooplankton geochemistry geoengineering geologic time GEOTRACES glaciers gliders global carbon budget global ocean global warming go-ship grazing greenhouse gas greenhouse gases Greenland ground truthing groundwater Gulf of Maine Gulf of Mexico Gulf Stream gyre harmful algal bloom high latitude human food human impact human well-being hurricane hydrogen hydrothermal hypoxia ice age ice cores ice cover industrial onset inland waters in situ inverse circulation ions iron iron fertilization iron limitation isotopes jellies katabatic winds kelvin waves krill kuroshio lab vs field land-ocean continuum larvaceans lateral transport LGM lidar ligands light light attenuation lipids low nutrient machine learning mangroves marine carbon cycle marine heatwave marine particles marine snowfall marshes mCDR mechanisms Mediterranean meltwater mesopelagic mesoscale mesoscale processes metagenome metals methane methods microbes microlayer microorganisms microplankton microscale microzooplankton midwater mitigation mixed layer mixed layers mixing mixotrophs mixotrophy model modeling model validation mode water molecular diffusion MPT MRV multi-decade n2o NAAMES NCP nearshore net community production net primary productivity new ocean state new technology Niskin bottle nitrate nitrogen nitrogen cycle nitrogen fixation nitrous oxide north atlantic north pacific North Sea NPP nuclear war nutricline nutrient budget nutrient cycles nutrient cycling nutrient limitation nutrients OA observations ocean-atmosphere ocean acidification ocean acidification data ocean alkalinity enhancement ocean carbon storage and uptake ocean carbon uptake and storage ocean color ocean modeling ocean observatories ocean warming ODZ oligotrophic omics OMZ open ocean optics organic particles oscillation outwelling overturning circulation oxygen pacific paleoceanography PAR parameter optimization parasite particle flux particles partnerships pCO2 PDO peat pelagic PETM pH phenology phosphate phosphorus photosynthesis physical processes physiology phytoplankton PIC piezophilic piezotolerant plankton POC polar polar regions policy pollutants precipitation predation predator-prey prediction pressure primary productivity Prochlorococcus productivity prokaryotes proteins pteropods pycnocline radioisotopes remineralization remote sensing repeat hydrography residence time resource management respiration resuspension rivers rocky shore Rossby waves Ross Sea ROV salinity salt marsh satellite scale seafloor seagrass sea ice sea level rise seasonal seasonality seasonal patterns seasonal trends sea spray seawater collection seaweed secchi sediments sensors sequestration shelf ocean shelf system shells ship-based observations shorelines siderophore silica silicate silicon cycle sinking sinking particles size SOCCOM soil carbon southern ocean south pacific spatial covariations speciation SST state estimation stoichiometry subduction submesoscale subpolar subtropical sulfate surf surface surface ocean Synechococcus technology teleconnections temperate temperature temporal covariations thermocline thermodynamics thermohaline thorium tidal time-series time of emergence titration top predators total alkalinity trace elements trace metals trait-based transfer efficiency transient features trawling Tris trophic transfer tropical turbulence twilight zone upper ocean upper water column upwelling US CLIVAR validation velocity gradient ventilation vertical flux vertical migration vertical transport warming water clarity water mass water quality waves weathering western boundary currents wetlands winter mixing zooplankton

Copyright © 2025 - OCB Project Office, Woods Hole Oceanographic Institution, 266 Woods Hole Rd, MS #25, Woods Hole, MA 02543 USA Phone: 508-289-2838  •  Fax: 508-457-2193  •  Email: ocb_news@us-ocb.org

link to nsflink to noaalink to WHOI

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.