Welcome to the GO-BGC Webinar Series!
Hundreds of Biogeochemical (BGC) profiling floats have been deployed worldwide, and the number of floats is expected to continue to increase in the coming years. Specifically, the Global Ocean Biogeochemistry Array (GO-BGC) is a NSF Mid-Scale Research Infrastructure project that is funded to deploy 500 BGC floats globally over the next 5 years. We expect additional significant contributions from other US and international institutions, which will build towards a sustained global array of BGC-Argo floats.
The quality-controlled, freely available data from these floats are transforming our capacity to observe, quantify, and understand ocean biogeochemical processes and how they are responding to anthropogenic pressures (e.g., acidification and deoxygenation). With improved constraints on the biological carbon pump and air-sea CO2 exchange, these data sets will also inform marine ecosystem management and decision making.
This quarterly webinar series, hosted by GO-BGC and the OCB Project Office, aims to build and support a growing community of biogeochemical float data users. As the BGC-Argo array matures and expands its global coverage, so will the potential for scientific discovery. We hope that the applications and research findings highlighted in this webinar series will demonstrate the potential for these globally distributed datasets and inspire the community to explore novel applications, scientific questions, and new collaborations in the use of BGC-Argo data.
Watch the whole series on YouTube or via the links below.
| Webinar Title & Link | Date | Speakers & Topics | Description |
|---|---|---|---|
| BGC Argo Webinar #9 Leveraging BGC-Argo and machine learning https://youtu.be/4JtfFKbsXqc | 2024 December 18 10am Pacific/1pm Eastern | Yui Takeshita (Monterey Bay Aquarium Research Institute, U.S.) An update on the GO-BGC Program Jonathan Sharp 4-D BGC-Argo data products seminar announcement Colette Kelly (Woods Hole Oceanographic Institution) - Low-pressure storms drive nitrous oxide emissions in the Southern Ocean Guillaume Liniger (Monterey Bay Aquarium Research Institute) - Two decades of increase in Southern Ocean net community production revealed by BGC-Argo floats | Kelly abstract: The Southern Ocean is net source of the potent greenhouse gas nitrous oxide to the atmosphere. Marine nitrous oxide emissions are difficult to constrain, however, due to their sharp gradients and small scales of variability in both space and time. In the Southern Ocean, where extratropical cyclones create conditions conducive to high air-sea gas flux, traditional shipboard sampling is unlikely to capture the full extent of nitrous oxide emissions due to the inability to sample in the centers of such storms. Here, we propose that the Southern Ocean nitrous oxide source is almost double the magnitude of previous estimates, based on machine learning-derived nitrous oxide observations from biogeochemical Argo floats. Our results suggest that the low-pressure centers inside extratropical cyclones amplify air-sea nitrous oxide disequilibria and create brief, intense pulses of nitrous oxide to the atmosphere. We demonstrate further that taking these low-pressure centers into account, instead of assuming a barometric pressure of 1 atmosphere, increases the overall magnitude of the Southern Ocean nitrous oxide source by a significant margin, explaining the discrepancy between previous work and our higher, more comprehensive estimate. Our results imply that the Southern Ocean plays a significant role in the global nitrous oxide cycle and may be a weaker net sink of greenhouse gases than previously thought. Liniger abstract: Nitrate is an essential nutrient for phytoplankton growth that is closely coupled to carbon cycling. Understanding the spatial and temporal variability of surface ocean nitrate is important for primary productivity and carbon export to the deep ocean. In this study, we developed a neural network constrained by the high spatial and temporal coverage of BGC-Argo floats to predict nitrate in a consistent way throughout space and time in the Southern Ocean, a key area for ocean carbon uptake and controlling global ocean nutrient distributions. Here, we show that annual net community production (ANCP), calculated from seasonal nitrate drawdown, reveals the greatest production around the 40-50°S meridional band. After correcting for physical and sampling biases, basin-wide ANCP averages 3.49 ± 0.11 PgC y-1, with a significant increase of 0.63% y-1 from 2004 to 2022. Our results demonstrate the potential of using machine learning constrained by BGC-Argo observations to study long term changes of biogeochemical processes in the ocean. |
| BGC Argo Webinar #8 Comparing BGC-Argo observations with models https://youtu.be/6XclbUk2DAs | 2024 October 16 | Yui Takeshita (Monterey Bay Aquarium Research Institute, USA) An update on the GO-BGC program Camila Serra-Pompei (Technical University of Denmark) Assessing the potential of backscattering as a proxy for phytoplankton carbon biomass Martí Galí Tàpias (Institute of Marine Sciences [ICM-CSIC], Spain) | Serra-Pompei: 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. Galí Tàpias: 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. |
| GO-BGC Webinar #7: High-Latitude Biogeochemistry https://youtu.be/6rWOkrW7b4w | 2024 May 9 | Yui Takeshita - An update on the GO-BGC program Daniel Koestner (University of Bergen, Norway) - Biogeochemical properties of the Lofoten Basin Eddy from 14 years of BGC-Argo float data Sophie Shapiro (University of California San Diego, USA) - Lessons and opportunities from the Southern Ocean Sea Ice team at the 2023 GO-BGC Float Data Workshop Discussion | Abstracts Koestner: Oceanic eddies are typically short lived but are a crucial physical phenomenon supporting heat and nutrient exchanges across water bodies. The Lofoten Basin Eddy (LBE) is a seemingly permanent topographically constrained anti-cyclonic eddy situated in the northern Norwegian Sea containing relatively cool surface waters and consistently warmer subsurface waters. As such, the conditions in the LBE may drive significantly different biogeochemical processes than the surrounding waters. Here we examine the unique biogeochemical signatures of the LBE with the 14-year timeseries of BGC-Argo float observations. We describe methodology for float-eddy colocation and examine differences in key biogeochemical parameters inside and outside of the eddy, including organic carbon export. Shapiro: In the winter of 2023, the Southern Ocean reached a record low sea ice extent anomaly. This unprecedented low sea ice coverage coincided with the August convening of the GO-BGC float data workshop. What insights could a cohort of motivated researchers uncover with two working days and the BGC Argo dataset? In this talk, we present preliminary data from BGC floats deployed in the Southern Ocean marginal sea ice zone. We illustrate the potential of the observational network to investigate further questions about the dynamics and impacts of changing sea ice. Finally, we highlight insights and challenges from the GO-BGC workshop to demonstrate the further potential of collaborative data working groups. |
| Carbon Export Dynamics https://youtu.be/Cx8mjEWGrlg | 2024 January 31 | Ellen Park (Woods Hole Oceanographic Institution) Quantifying biological carbon pump parameters from the global Biogeochemical Argo float array Adam Stoer (Dalhousie University) Estimating marine phytoplankton biomass and productivity from Biogeochemical-Argo floats | Abstracts Park: The ocean is a large sink for carbon dioxide and thus plays an important role in regulating the Earth’s climate. This uptake occurs at the air-sea interface through a combination of physical and biological processes, which are commonly referred to as carbon pumps. The biological carbon pump (BCP) transfers carbon against its concentration gradient via the sinking and transport of particulate organic matter that is produced in the surface ocean. In the modern ocean, the BCP is thought to remove an estimated 6-12 Pg C from the surface ocean annually, which is approximately equivalent to total annual anthropogenic carbon dioxide emissions. The magnitude and variability of the BCP’s drawdown of atmospheric carbon dioxide have large uncertainties due to limited measurements across both space and time and the fact that the ocean has varying ecosystem compositions and physical dynamics. Here, we leverage floats with optical backscatter sensors from the global Biogeochemical Argo float array to quantify BCP metrics across different biomes in the global ocean. The particulate backscatter signals can be decomposed into a large, fast sinking particle signal and small, slower sinking particle one. These values are used to estimate BCP metrics such as particulate matter attenuation coefficients and transfer efficiencies. Quantifying these metrics across time and biomes is important for reducing uncertainties in the BCP, improving model parameterizations, and ultimately better constraining the global carbon cycle. Stoer: Knowledge on the biomass and productivity of ocean phytoplankton is fundamental to our understanding of life on Earth. Phytoplankton are autotrophic microbes at the base of the marine food web, that, through photosynthesis, produce organic matter that sustains higher trophic organisms. In this talk, I estimate the biomass and productivity of phytoplankton by using the fleet of Biogeochemical-Argo floats. In the first part of my talk, I describe a method for estimating net primary productivity using daily cycles of particulate carbon constructed from float profiles distributed across the ocean. This method provides depth-resolved estimates of productivity that are representative of large swathes of ocean, and which are comparable to satellite models. In the second part of this talk, I use the global array of floats to estimate Earth’s stock of phytoplankton biomass, as well as their seasonal and geographic distribution. I also compare the seasonal cycles between carbon biomass stocks and chlorophyll-a concentrations at the surface, a metric commonly-used as a proxy for biomass, and show how surface chlorophyll-a cannot accurately identify the timing of the peak annual bloom in three-quarters of the ocean. Using these observations, I demonstrate how the Biogeochemical-Argo array can provide a more accurate, holistic view of ocean phytoplankton ecology. |
| New tools for BGC-Argo data access and visualization https://youtu.be/neTx8u_kze8 | 2023 June 20 | Yui Takeshita: Updates on GO-BGC (10 min) Reiner Schlitzer: Online analysis and visualization of BGC-Argo data with webODV (20 min) Hartmut Frenzel: OneArgo toolbox for accessing and analyzing Argo data - overview and new features (20 min) Q&A: 10 minutes | This webinar will have 2 presentations on new tools for BGC-Argo data access and visualization. Dr. Reiner Schlitzer will present on webODV, a new online tool based on Ocean Data View that can be used to visualize, explore, and export BGC-Argo data through a GUI interface. Dr. Hartmut Frenzel will present on the One-Argo toolbox, an open source toolbox designed to efficiently access, process, and visualize BGC, Core, and Deep Argo data. Float data can be searched using a variety of criteria including sensor type, location, and date. Recordings will be available on the OCB and GO-BGC website. |
| Observing Mesoscale and Sub-Mesoscale Processes with BGC Argo https://youtu.be/bV_3z3KtqEA | 2023 February 15 | Yui Takeshita (Monterey Bay Aquarium Research Institute, USA) yui@mbari.org An update on the GO-BGC program Lily Dove (California Institute of Technology, USA) dove@caltech.edu Investigating Ventilation at the Submesoscale in the Southern Ocean Shuangling Chen (Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China) slchen@sio.org.cn Episodic oxygen injections observed from BGC-Argo | This webinar focused on using BGC-Argo float data to investigate chemical and biological processes in the ocean that are influenced by eddies, meanders, and other mesoscale and sub-mesoscale processes. |
| Using BGC floats for the study of extreme events https://youtu.be/UttSHhBvnms | 2022 October 5 | Yui Takeshita (Monterey Bay Aquarium Research Institute, USA) - An update on the GO-BGC program Jakob Weis (Institute for Marine and Antarctic Studies, Australia) - Using BGC-Argo floats to study phytoplankton blooms stimulated by the 2019-2020 Australian bushfires Magdalena Carranza (Monterey Bay Aquarium Research Institute, USA) - The role of storms on air-sea CO2 flux in the Southern Ocean Discussion | The first of two consecutive webinars focused on using BGC-Argo float data to investigate chemical and biological processes in the ocean that are influenced by weather and extreme events. |
| Understanding ecological dynamics using BGC-Argo data https://youtu.be/eUcJsBi7x2Y | 2022 June 29 | Yui Takeshita (Monterey Bay Aquarium Research Institute): An update for GO-BGC program Nicholas Bock (Columbia University): Biogeographical classification of the global ocean from BGC-Argo Floats Marin Cornec (NOAA Pacific Environmental Laboratory): Dynamics of the deep chlorophyll maxima at a global scale based on bio-optical measurements of BGC-Argo floats Mariana Bif (Monterey Bay Aquarium Research Institute): The impact of heatwaves on the northeast Pacific ecosystem | GO-BGC Webinar #2 (29 June 2022) focused on investigations of phytoplankton phenology and variability at regional to global scales using a range of chemical and bio-optical sensors on the BGC-Argo floats. Three short presentations about exciting new work in this area, followed by a community discussion about best practices, challenges, and future perspectives of using BGC-Argo data to advance our understanding of ecological dynamics and the footprint of progressive climate change on the ocean. |
| GO-BGC Science Webinar kickoff https://youtu.be/xBgj05ZiNbU | 2022 March 30 | Introduction to the GO-BGC webinar series (Yui Takeshita, MBARI) Introduction to BGC-Argo and GO-BGC (Alison Gray, University of Washington) Upcoming float deployment plans (Yui Takeshita, MBARI) How to use BGC-Argo data? (Jonathan Sharp and Hartmut Frenzel, NOAA PMEL) What is the quality of BGC-Argo data? (Yui Takeshita, MBARI) Discussion and community Q&A | GO-BGC will host quarterly webinars about emerging science using GO-BGC or BGC-Argo float data, focusing on early career researchers. The webinar series is hosted by the US Ocean Carbon and Biogeochemistry program. The kickoff webinar is focused on updating the status of GO-BGC and BGC-Argo, projected float deployment locations over the next year, followed by community Q&A. |
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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.