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
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: 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
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)
Both climate change and the efforts to abate have the potential to reshape phytoplankton community composition, globally. Shallower mixed layers in a warming ocean and many marine CO2 removal (CDR) technologies will shift the balance of light, nutrients, and carbonate chemistry, benefiting certain species over others. We must understand how such shifts could ripple through the marine carbon cycle and modify the ocean carbon reservoir. Two new publications in Geophysical Research Letters and Global Biogeochemical Cycles highlight an often over looked pathway in this response: The appetite of zooplankton.
We have long known that the appetite of zooplankton—i.e. the half-saturation concertation for grazing—varies dramatically. This variability is largely based on laboratory incubations of specific species. An open-ocean perspective has been much more elusive. Using two independent inverse modelling approaches, both studies reached the same conclusion: Even at the community level, the appetite of zooplankton in the open-ocean is incredibly diverse.
Moreover, variability in zooplankton appetites maps well onto the biogeography of phytoplankton species. As these phytoplankton niches evolve, the composition of the zooplankton will likely follow. To help understand the impact of this response on the biological pump, we compared two models, one with only two types of zooplankton, and another with an unlimited amount, each with different appetites, all individually tuned to their unique environment. Including more realistic diversity reduced the strength of the biological pump by 1 PgC yr-1.
Figure Caption. A) Variability in the abundance and characteristic composition of phytoplankton drives B) large differences in the associated appetite and characteristic composition of zooplankton in two independent inverse modelling studies. C) When more realistic diversity in the appetite of zooplankton is simulated in models, the strength of biological pump is dramatically reduced.
That is the same order as the most optimistic scenarios for ocean iron fertilization. This means that when simulating the efficacy of many CDR scenarios, the bias introduced by insufficiently resolved zooplankton diversity could be just as large as the signal. Moving forward, it is imperative to improve the representation of zooplankton in Earth System Models to understand how the marine carbon sink will respond to inadvertent and deliberate perturbations.
Related article in The Conversation: https://theconversation.com/marine-co-removal-technologies-could-depend-on-the-appetite-of-the-oceans-tiniest-animals-227156
Authors (GRL):
Tyler Rohr (The University of Tasmania; Australian Antarctic Program Partnership)
Anthony Richardson (The University of Queensland; CSIRO)
Andrew Lenton (CSIRO)
Matthew Chamberlain (CSIRO)
Elizabeth Shadwick (Australian Antarctic Program Partnership; CSIRO)
Authors (GBC):
Sophie Meyjes (Cambridge)
Colleen Petrick (Scripps Institute of Oceanography)
Tyler Rohr (The University of Tasmania; Australian Antarctic Program Partnership)
B.B. Cael (NOC)
Ali Mashayek (Cambridge)
Introduction to Plankton, Aerosol, Cloud, Ocean Ecosystem (PACE) Hyperspectral Observations for Water Quality Monitoring
This online, introductory course will be cost-free and have three, 1.5-hour parts:
Part 1: Introduction to the PACE Mission for Water Quality Monitoring (September 25th)
Part 2: Overview, Access, and Analysis of PACE Ocean Color Data Products (October 2nd)
Part 3: Access and Visualization of PACE-OCI Data using Python/Jupyter Notebook Software (October 9th)
Registration is now open – course will be offered in English AND Spanish!
For more information and to register visit:
NASA’s ARSET program offers free, online training on using Earth Observations for decision making that are open to the public. Courses are designed for a broad audience, ranging from introductory to advanced. For more on ARSET and to see their wealth of upcoming and previous trainings, please visit their website.
OCB Scoping Workshop Leaky Deltas: Sources or sinks in the global carbon cycle?
March 17-20, 2025 at Louisiana State Univ. (Baton Rouge, LA)
River deltas and the adjacent coastal ocean are critical interfaces between terrestrial and oceanic environments. Deltas are the entry point of ~50% of the fresh water and 40% of all global particulate matter entering the ocean. They are major centers for particulate and dissolved organic carbon transfer between (i.e., to and from) land to ocean.
Recent evidence suggests that coastal oceans have become net sinks for atmospheric CO2 during post-industrial times and continued human pressures in coastal zones. Alterations to deltas will likely have an important impact on the future evolution of the coastal ocean’s carbon budget.
NOTE This workshop has multiple deadline options: early (if you need a visa to attend), mid (if you want to apply for travel support), and a final deadline for all applications.
Apply to attend Leaky Deltas workshop
Learn more on the workshop webpage.
Applications for a workshop on ethics and governance for (all forms of) climate interventions have just opened:
https://apply.knowinnovation.com/climateintervention/
NSF OCE will be sending out a “KandyGram” with this information soon.
The application deadline is August 23rd and we’d like to see good representation for mCDR.
Phytoplankton are the main primary producers in the ocean and fuel marine food webs. Long-term shifts in phytoplankton biomass are useful for understanding the context of short-term changes and for examining the relationships between climate indices and phytoplankton dynamics. However, current monitoring programs often offer too short a time frame to disentangle these relationships.
In a recent publication in the Proceedings of the National Academy of Sciences, data from the Narragansett Bay, RI Long-Term Plankton Time Series, were used to examine long-term trends in Chlorophyll a, a proxy for phytoplankton biomass. The magnitude of the winter-spring bloom and of annual phytoplankton biomass declined by about half from 1968 to 2019 (Figure 1). The winter–spring bloom, which fuels coastal ecosystems, occurred about five days earlier each decade. The authors found these changes were associated with multiple environmental factors impacted by climate change, including warming surface seawater temperatures and reduced nutrient concentrations.
Figure 1: In addition to long-term trends, the authors observed that phytoplankton biomass in Narragansett Bay was highly variable similar to other coastal and open ocean time series they analyzed. A high degree of variation in phytoplankton biomass means that it can take decades to identify a trend from the noise in a dataset. This highlights the need to sustain ecosystem monitoring of phytoplankton and other environmental factors for the long term globally. These results provide the first step to understanding the effect of climate change and anthropogenic inputs at the base of the food web, which will inform future research to determine how this change implicates the rest of the ecosystem.
A major secondary component of this study was the digitization of much of the historical dataset from 1959-1999, which required the lead author to obtain, organize, and digitally record 30 years of physical data from a storage closet and harmonize it with digitized data from 2000-2019. All biological and environmental data from this time series are now publicly available at BCO-DMO for scientists, managers, and educators to explore and utilize.
Authors:
Patricia S. Thibodeau (University of New England) @PattyPlankton
Gavino Puggioni (University of Rhode Island)
Jacob Strock (University of Rhode Island)
David G. Borkman (Rhode Island Department of Environmental Management, Office of Water Resources–Shellfish)
Tatiana A. Rynearson (University of Rhode Island) @RynearsonLab
How does the microbial carbon pump (MCP) redefine our understanding of oceanic carbon sequestration and climate change mitigation?
A recent study published in Nature Reviews Microbiology reviews the pivotal role of the microbial carbon pump (MCP) a novel concept differing from the known mechanisms for carbon sequestration in the ocean, the Biological Carbon Pump (BCP), the Carbonate Counter Pump (CCP), and the Solubility Carbon Pump (SCP) (Figure 1).
Figure 1 Illustration of the microbial carbon pump (MCP) and other carbon pumps, outlining their relationships and modes of carbon transformation and sequestration in the ocean.
Unlike the others, the MCP operates independently of physical processes like vertical transportation and sedimentation; it is driven by microbial processes at every depth in the water column, and functions as a two-way pump of carbon cycle, thus playing a unique role in regulation of climate change. The MCP’s role in transforming dissolved organic carbon (DOC) from labile states into refractory states, reveals the “enigma” of how the oceanic refractory DOC (RDOC) reservoir is formed. This paper also illustrates the dual functions of the MCP-regulated oceanic carbon reservoir over geological timescales, which may help explain the “eccentricity puzzle” in the Milankovitch climate theory.
The spatial and temporal distribution of RDOC is influenced by various microbial processes and the paper details how the MCP responds to environmental changes across environmental gradients and the entire water column. We also revealed the impacts of climate change on microbial activities and carbon sequestration efficiency, which in turn affect carbon cycles across different oceanic regions and depths. We explored the synergistic effects of the MCP with BCP, CCP, and SCP (BCMS), which could have great potentials in geoengineering. Applications of BCMS approach make it possible for international program on Ocean Negative Carbon Emissions (ONCE) practice for both of carbon sink enhancement and ecosystem sustainable development, such as scenarios of sea-farming areas and wastewater treatment plants, avoiding the potential risks of traditional geoengineering approaches.
Understanding the MCP processes and effects is essential for accurate assessment of the ocean’s capacity to mitigate climate change, and how the MCP can support potential modes of geoengineering. The findings and implications are of profound reference for policymakers, environmental stakeholders, and funding agencies for strategies to fight climate changes, leverage more effective preservation and restoration of ecosystems.
Authors:
Nianzhi Jiao (Xiamen University)
Tingwei Luo (Xiamen University)
Quanrui Chen (Xiamen University)
Zhao Zhao (Xiamen University)
Xilin Xiao (Xiamen University)
Jihua Liu (Shandong University)
Zhimin Jian (Tongji University)
Shucheng Xie (China University of Geosciences)
Helmuth Thomas (Helmholtz-Zentrum Hereon)
Gerhard J. Herndl (University of Vienna)
Ronald Benner (University of South Carolina)
Micheal Gonsior (University of Maryland)
Feng Chen (University of Maryland)
Wei-Jun Cai (University of Delaware)
Carol Robinson (University of East Anglia)
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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.