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With leadership from the Ocean Atmosphere Interaction Committee (OAIC), OCB convened a community workshop Ocean-Atmosphere Interactions: Scoping directions for new research October 1-3, 2019 at The Woodlands at Algonkian in Sterling, VA. The goal of this workshop was to bring together members of the U.S. air-sea research community to facilitate new collaborations and identify knowledge gaps and high-priority science questions to motivate innovative research and contribute to international SOLAS efforts. The workshop included 59 members of the air-sea research community and representation from NSF, NASA, and the US Carbon Cycle Science Program. Keynote speakers gave presentations on each of the five core themes of the 2015-2025 SOLAS Science Plan:
After each presentation, participants broke up into small groups for in-depth discussions to identify knowledge gaps and priorities for future research within each theme. After the theme discussions, the workshop participants identified crosscutting (across themes) questions of interest and convened small group discussions to assess relevance and importance to SOLAS, associated unknowns, and potential implementation mechanisms (experiments, measurements or field campaigns, models, parameterizations, remote sensing products, etc.). The workshop also included a panel discussion on previous SOLAS process studies and field campaigns featuring agency managers and scientific leadership from GasEx, Southern Ocean GasEx, the North Atlantic Aerosols and Marine Ecosystems Study (NAAMES), and several Arctic campaigns. Panelists shared their insights on the scientific outcomes, logistical challenges, community coordination needs, and funding mechanisms for these large-scale efforts.
From the participant discussions at the workshop, the OAIC will assemble a grassroots document to help coalesce the U.S. air-sea interaction research community around a common set of science goals and research priorities. The workshop and its outcomes are expected to strengthen ties between the ocean and atmosphere research communities and foster a more cohesive U.S. contribution to international SOLAS. For more information and to view the presentations from the workshop, please visit the workshop website.
Plankton in the surface ocean convert CO2 into organic biomass thereby fueling marine food webs. Part of this organic biomass sinks down into the deep ocean, where the surface-derived organic carbon, or respired CO2, is locked in for decades to millennia. Without the biological carbon pump, atmospheric CO2 would be ~200 ppm higher than it is today. We know that ecological processes in the surface ocean plankton communities have a paramount importance on the efficiency of the biological carbon pump. Unfortunately, however, the mechanisms how ecology determines sinking fluxes are poorly understood.
A recent study in Global Biogeochemical Cycles used large-scale in situ mesocosms to explore how the ecological interplay within plankton communities affects the downward flux of organic material. Organic biomass tends to sink faster when produced by smaller organisms because the sinking material they generate forms dense aggregates. Conversely, larger organisms produce relatively porous particles that sink more slowly.
Figure: Flow chart illustrating how plankton community structure affects the properties of sinking organic particles and ultimately the strength and efficiency of the biological carbon pump. The thick arrows at the bottom indicate that flux attenuation depends on the properties of particulate matter formed in the surface ocean. For example, slow-sinking porous aggregates containing large amounts of easily degradable organic substances will decay faster (right side) than dense aggregates of more refractory organic matter (left side).
The key finding of this study was the unexpectedly large influence that plankton community composition has on the degradation rate of sinking organic biomass. In fact, degradation rates changed maximally 15-fold over the course of the study while sinking speed changed only 3-fold. Degradation rate of sinking material, measured in oxygen consumption assays, was quite variable and tended to be higher for more easily degradable fresh organic matter. The rate was lower during harmful algal blooms, which produce toxic substances that inhibit organisms that feed on aggregates thereby reducing degradation rates. These findings are an important step forward as they show that our predictive understanding of the biological carbon pump could be improved substantially when linking degradation rates of sinking material with ecological processes in surface ocean plankton communities.
Authors:
L. T. Bach (University of Tasmania)
P. Stange, J. Taucher, E. P. Achterberg, M. Esposito, U. Riebesell (GEOMAR)
M. Algueró‐Muñiz (Alfred-Wegener-Institut Helmholtz)
H. Horn (NIOZ and Utrecht University)
Although chlorophyll fluorescence is widely-used as a proxy for chlorophyll concentration, sunlight exposure makes fluorescence measurements inaccurate through a process called non-photochemical quenching, limiting its proxy accuracy during daylight hours. In the open ocean, where time and space scales are large relative to variability in phytoplankton concentration, daytime chlorophyll fluorescence—necessary for satellite algorithm validation and for understanding diurnal variability in phytoplankton abundance—can be estimated by averaging across successive nighttime, unquenched values. In coastal waters, where semidiurnal tidal advection drives small scale patchiness and short temporal variability, successive nighttime observations do not accurately represent the intervening daytime. Thus, it is necessary to apply a non-photochemical quenching correction that accounts for the additional effect of tidal advection.
In a recent study in L&O Methods, authors developed a model that uses measurements of tidal velocity to correct daytime chlorophyll fluorescence for non-photochemical quenching and tidal advection. The model identifies high tide and low tide endmember populations of phytoplankton from tidal velocity, and estimates daytime chlorophyll fluorescence as a conservative interpolation between endmember fluorescence at those tidal maxima and minima (Figure 1). Rather than removing nearly 12 hours’ worth of hourly chlorophyll fluorescence observations (i.e., all of the daytime observations) as was previously necessary, this model recovers them. The model output performs more accurately as a proxy for chlorophyll concentration than raw daytime chlorophyll fluorescence measurements by a factor of two, and enables tracking of phytoplankton populations with chlorophyll fluorescence in a Lagrangian sense from Eulerian measurements. Finally, because the model assumes conservation, periods of non-conservative variability are revealed by comparison between model and measurements, helping to elucidate controls on variability in phytoplankton abundance in coastal waters.
Figure 1: Model (light blue line) is a tidal interpolation between high tide (blue points) and low tide (red points) phytoplankton endmembers. The model represents nighttime, unquenched chlorophyll fluorescence measurements well (black points), while daytime, quenched measurements are visibly reduced (gray points).
This result is a critical achievement, as it enables the use of daytime chlorophyll fluorescence, which increases the temporal resolution of coastal chlorophyll fluorescence measurements, and also provides a mechanism for satellite validation of the ocean color chlorophyll data product in coastal waters. The model’s capacity to accurately simulate the pervasive effect of non-photochemical quenching makes it a vital tool for any researcher or coastal water manager measuring chlorophyll fluorescence. This model will help to provide new insights on the movement of and controls on phytoplankton populations across the land-ocean continuum.
Authors:
Luke Carberry (University of California, Santa Barbara)
Collin Roesler (Bowdoin College)
Susan Drapeau (Bowdoin College)
Four new research projects are giving a boost to NOAA’s ability to measure, track and forecast ocean acidification, warming and other important ocean health indicators.
NOAA Research’s Ocean Observing and Monitoring Division has awarded $3 million in funding for projects that will expand the ability of the global Argo Program to measure ocean chemistry.
Two of the selected projects will partner with ocean observation technology companies Sea Bird Scientific and MRV to refine biogeochemical (BGC) Argo float designs and test new sensors through the release of about 20 floats in the Tropical Pacific, an important region for understanding the ocean’s role in the global carbon cycle. Two additional projects will support selected NOAA Research Laboratories and Cooperative Institutes in developing and deploying BGC Argo floats and using the resulting information to describe ocean chemistry changes in the California Current Large Marine Ecosystem and northwest Atlantic ocean — both significant areas for fisheries.
September 13-15, 2019 (C-MORE Hale Center, Honolulu, HI)
Prior to OO19, the OCB Project Office planned and hosted an NSF EarthCube Workshop focused on shipboard ocean time series data. Data synthesis and modeling efforts across ocean time series represents an important and necessary step forward in broadening our view of a changing ocean and maximizing the return on our continued investment in these programs. Despite the scientific insights and technology advances of the past couple of decades, significant barriers remain that hinder important synthesis work across time series. Participants of this workshop sought to address key ocean time series data challenges related to access and discoverability, metadata reporting, interoperability across databases, and broadening users. The workshop was founded on the FAIR (Findable, Accessible, Interoperable, Reusable) data paradigm and included presentations on existing data models and use of controlled vocabularies, guidelines and frameworks for conducting data synthesis and establishing community best practices, and existing and planned ocean time series data products. The following seven small group discussions provided opportunities for participants to prioritize key issues and brainstorm to identify potential short- and long-term solutions:
Actionable outcomes emerging from the workshop include developing a pilot data model test case with well-established time series programs and a limited set of variables; pursuing a longer-term focused community activity (e.g., NSF RCN, SCOR or National Center for Ecological Analysis and Synthesis (NCEAS) Working Group, etc.) that builds on the recommendations of workshop participants (e.g., vocabularies, data citation guidelines, metadata reporting, data interface design, etc.) to increase data discoverability and interoperability and enable synthesis and broader applications; forming a centralized international coordination body for shipboard ocean time series to facilitate development of community best practices and increased recognition as a key component of the Global Ocean Observing System (GOOS); and writing a series of high-profile briefs and visualizations that highlight the role of sustained ocean time series in capturing important climate (e.g., expansion of “the Blob”) and marine ecosystem events and changes (HABs, coastal acidification, coral bleaching events, hypoxic events, etc.). A full workshop report is in preparation and will be shared broadly. In the meantime, please contact Heather Benway (hbenway@whoi.edu) or visit the workshop website for more information.
OceanObs19 Side Meeting Enhancing biological observing capacity of ocean programs and platforms – September 18, 2019 (Honolulu, HI)
During the OceanObs19 Meeting, OCB planned and hosted a side meeting to bring together members of the oceanographic community to identify biological and ecological observing technology that could be deployed on current sus
tained observational programs. In order for the measurements to be accommodated in programs such as GO-SHIP they should be at the appropriate readiness level for large-scale deployment. Participants also touched upon opportunities for short-term, cost-effective deployments via other existing shipboard and autonomous programs and platforms (Argo, OOI, OceanSITES, LTER, GEOTRACES, etc.). The oceanographic community has made great strides over the past couple of decades in developing physical and biogeochemical observing capacity and this can serve as a foundation for biological and ecological measurements. A more holistic understanding of marine ecosystem function and change will require more large-scale and sustained ocean biological and ecological observations. The time for such an integrated approach is now. In particular, rapid advances in imaging, acoustics, and genomic sensing as applied to biological and ecological system functioning have made it feasible to incorporate these measurements into current sustained observing efforts with minimal impact on the established operations.
This side meeting convened 35-40 participants across disciplines, agencies, and observing networks and programs. Meeting presenters highlighted the current GO-SHIP operations and criteria for incorporation of new measurements. Participants discussed the scientific justification and urgency of a more globally expansive marine ecological observing network to document changes in biodiversity, biogeography, food webs, etc.. An overview of biological and ecological observing technology status was presented. Presenters emphasized the importance of incorporating existing technologies to measure biology now, and new technologies as they mature. Program representatives shared status updates and near-term plans for GO-SHIP and Biogeochemical-Argo (BGC-Argo). Participants engaged in Q&A and discussed strategies and logistical feasibility of integrating biological observations into these and other programs. Recent proposals to federal funding agencies offer the potential for a greatly expanded array of BGC-Argo floats. As a starting point for GO-SHIP, an ad hoc committee of scientists will develop recommendations for incorporation of biological and ecological measurements into the next phase of US GO-SHIP. These recommendations will build upon the Integration of Plankton-Observing Sensor Systems to Existing Global Sampling Programs (P-OBS) SCOR WG-154 report that will be available for community comment in October.
Please contact Heather Benway in the OCB Project Office (hbenway@whoi.edu) for more information.
Applications are now being accepted to participate in the upcoming workshop: Ocean nucleic acids ‘omics intercalibration and standardization funded by the US Ocean Carbon Biogeochemistry (OCB) program. The goal of this workshop is to develop a focused marine microbial nucleic acid (na) ‘omics intercomparison and intercalibration effort to enhance future field programs that integrate methods such as molecular barcoding, metagenomics and transcriptomics to understand the functioning of prokaryotic and eukaryotic microbes in the ocean. Initial efforts are guided, in part, by the success of the marine geochemistry community in implementing programs like GEOTRACES.
The workshop will take place from January 8-11 2020 (arrival on Jan 8, full workshop days Jan 9-11) at the University of North Carolina Chapel Hill. A limited number of participants (approximately 5-10 people) will be selected through an application process with the remainder being invited participants based on their expertise and leadership in being at the forefront of developing one or more of the methods considered for intercalibration in marine systems and beyond. All participants will have their travel costs and accommodation covered by OCB. We encourage applications from all experience levels ranging from senior graduate studies to well-established researchers in all related fields. Overall participation in this workshop will be limited to approximately 30 people. Applications are due by 11:59pm (EST) on October 18, 2019.
For more information and to apply, please visit the activity home page.
The 2020 OCB ‘omics intercalibration workshop organizing committee (Andrew Allen, Paul Berube, Scott Gifford, Bethany Jenkins, Adrian Marchetti, and Alyson Santoro).
When will we see significant changes in the ocean due to climate change? A new study in Nature Climate Change confirms that outcomes tied directly to the escalation of atmospheric carbon dioxide have already emerged in the existing 30-year observational record. These include sea surface warming, acidification, and increases in the rate at which the ocean removes carbon dioxide from the atmosphere.
In contrast, processes tied indirectly to the ramp-up of atmospheric carbon dioxide through the gradual modification of climate and ocean circulation will take longer, from three decades to more than a century. These include changes in upper-ocean mixing, nutrient supply, and the cycling of carbon through marine plants and animals.
The researchers performed model simulations of potential future climate states that could result from a combination of human-made climate change and random chance (figure 1). These experiments were performed with an Earth System Model, a climate model that has an interactive carbon cycle such that changes in the climate and carbon cycle can be considered in tandem.
Figure 1: Percentage of ocean with emergent anthropogenic trends in ocean biogeochemical and physical variables. A time series of the percentage of the global ocean area with locally emergent anthropogenic trends illustrates the disparity of emergence timescales for anthropogenic changes in the ocean carbon cycle. Emergence is defined as the point in time when the LE’s signal-to-noise ratio for a linear trend referenced to the year 1990 first exceeds a magnitude of two, which represents a 95% confidence in the identification of an anthropogenic trend in the LE Ω applies to the saturation state of both the aragonite and calcite forms of calcium carbonate (CaCO3), for which the emergence times are approximately equivalent. The CaCO3 and soft-tissue pumps were calculated as the export flux at 100 m depth of CaCO3 and particulate organic carbon, respectively. The heat content was calculated as an integral over 0–700 m, whereas the oxygen (O2) inventories consider the integral 200–600 m, and chlorophyll inventories were considered over 0–500 m. NPP represents an integral over 0–100 m. All the other variables represent sea surface properties.
The finding of a 30- to 100-year delay in the emergence of effects suggests that ocean observation programs should be maintained for many decades into the future to effectively monitor the changes occurring in the ocean. The study also indicates that the detectability of some changes in the ocean would benefit from improvements to the current observational sampling strategy. These include looking deeper into the ocean for changes in phytoplankton and capturing changes in both summer and winter ocean-atmosphere exchange of carbon dioxide rather than just the annual mean.
Figure 2. Venn Diagram schematic of sources of uncertainty in simulation (using Earth-System Modeling approach) and observation of changes in the Earth system. For emergence, detection or attribution of an observed or simulated signal to occur, the signal must overcome the sources of uncertainty in their respective brackets.
Many types of observational efforts, including time-series or permanent locations of continuous measurement, as well as regional sampling programs and global remote sensing platforms are critical for understanding our changing planet and improving our capacity to detect change.
Authors:
Sarah Schlunegger (Princeton University)
Keith B. Rodgers (Institute for Basic Science and Busan National University, South Korea)
Jorge L. Sarmiento (Princeton University)
Thomas L. Frölicher (University of Bern)
John P. Dunne (NOAA Geophysical Fluid Dynamics Laboratory)
Masao Ishii (Japan Meteorological Agency)
Richard Slater (Princeton University)
Phytoplankton respond directly to climate forcing, and due to their central role in global oxygen production and atmospheric carbon sequestration, they are critical components of the Earth’s climate system. There are however few observations detailing past variability in marine primary productivity, particularly over multi-decadal to centennial timescales. This limits our understanding of the long-term impact of climatic forcing on both past and future marine productivity.
Multi-century decline of subarctic Atlantic productivity. From top: standardized (z-score units relative to ad 1958-2016) indices of Continuous Plankton Recorder (CPR)-based diatom, dinoflagellate and coccolithophore relative-abundances; North Atlantic [chlorophyll-α] reconstruction from Boyce et al. (2010, Nature); ice core-based [MSA] PC1 productivity index. The “Industrial Onset” range shows the estimated initiation of declining subarctic Atlantic productivity; reconstructed (Rahmstorf et al., 2015, Nat. Clim. Change) and observed sea-surface temperature-based Atlantic Meridional Overturning Circulation (i.e., AMOC) index, alongside 5-year averaged subarctic Atlantic freshwater storage anomalies (relative to A.D. 1955) from Curry and Mauritzen (2005; Science).
Future atmospheric warming is predicted to contribute to accelerating Greenland Ice Sheet runoff, ocean-surface freshening, and AMOC slowdown, suggesting the potential for continued declines in productivity across this dynamic and climatically important region. Such declines will, in turn, have important implications for future maritime economies, global food security, and drawdown of atmospheric carbon dioxide.
Authors:
Matthew Osman (Massachusetts Institute of Technology)
Sarah Das (Woods Hole Oceanographic Institution)
Luke Trusel (Rowan University)
Matthew Evans (Wheaton College)
Hubertus Fischer (University of Bern)
Mackenzie Griemann (University of California, Irvine)
Sepp Kipfstuhl (Alfred-Wegener-Institute)
Joseph McConnell (Desert Research Institute)
Eric Saltzman (University of California, Irvine)
Figure references:
Boyce, D. G., Lewis, M. R. & Worm, B. (2010) Global phytoplankton decline over the past century. Nature 466, 591–596.
Curry, R. & Mauritzen, C. (2005) Dilution of the northern North Atlantic Ocean in recent decades. Science 308, 1772–1774.
Rahmstorf, S. et al. (2015) Exceptional twentieth-century slowdown in Atlantic Ocean overturning circulation. Nat. Clim. Change 5, 475–480.
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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.