Kalender

Abstract Measurements of changes in atmospheric O2, CO2, and CO2 isotopes now span many decades. These measurements reveal a rich spectrum of variability including long-term trends, seasonal cycles, and interannual variations. In parallel, we now also have decades of measurements of dissolved oxygen and carbon in the ocean. This talk will highlight the application of these data to quantify impacts of climate changes and rising CO2 on global biogeochemistry, from tracking global land and ocean carbon sinks, to tracking changing water-use efficiency of land plants. The talk will also discuss two emergent applications under development, one using carbon isotopes to track recent changes in ocean circulation, and the second using atmospheric O2-measurements to track changes in the biogeochemistry of the Arctic ocean. Speaker information Ralph’s work centers on long-term measurements of the major constituents in air. He has been on the faculty at the Scripps Institution of Oceanography, UC San Diego, since 1993. He was the first to demonstrate that the O2 content of air is decreasing due to the burning of fossil-fuels and has directed a program to track this decrease since 1989. Since 2005 he has also directed the Scripps CO2 program which sustains the iconic record of carbon dioxide at Mauna Loa and other sites, begun by his father, Charles D. Keeling. He is engaged in ongoing research to refine estimates of sources and sinks of carbon dioxide using atmospheric measurements. Keeling has received the Rosenstiel Award in marine and atmospheric chemistry, the Humboldt Research Award, and is a Union Fellow of the American Geophysical Union.

Abstract Seagrass meadows are coastal marine ecosystems that store autochthonous and allochthonous carbon in sediments. Despite their importance as “blue carbon” ecosystems along European coastlines, seagrasses are rarely included in national climate plans, partly due to difficulties in mapping carbon stocks at scale. The MARCO-BOLO Horizon EU project aims to strengthen coastal, marine, and freshwater biodiversity observing in support of decision making. As part of this project, we examined how remote sensing can support European needs for blue carbon mapping. Here we test whether oceanographic data products, including remote-sensing-derived variables, can predict seagrass sediment organic carbon stocks. Environmental drivers of carbon storage were identified, and datasets from NASA and Copernicus were spatially matched with seagrass sediment carbon measurements from the EURO-CARBON database. A suite of machine learning models were trained to predict carbon density in seagrass sediment cores. Incorporating oceanographic data products substantially increased model performance, with the top 15 variables explaining up to 65% of the variance (R2) of measured carbon density. Carbonate chemistry, nutrient, and hydrodynamic energy variables emerged as key predictors for all models. The highest performing model, a Gaussian Process Regressor (GPR) was used to predict carbon stocks across all European seagrass beds based on known seagrass extent from the seagrass Essential Ocean Variable. Beyond the project scientific results, I will also discuss how a co-design process with stakeholders was implemented throughout the process to align the scientific approach with policy and management needs. The outcome resulted in a virtual research environment which allows users to estimate carbon stocks by providing seagrass bed coordinates and species identity. This tool addresses growing needs for scalable blue carbon mapping in Europe and demonstrates how global data products can support these efforts. Speaker information Natalya Gallo is a marine ecologist and biological oceanographer. She is a senior researcher at the Norwegian Research Centre (NORCE) in Bergen, Norway, working in the Ocean Observing Group, and is an affiliate of the Bjerknes Centre for Climate Research. Her overarching interests are in how climate change impacts marine ecosystems and fisheries, the role of the ocean in climate change mitigation and adaptation (including blue carbon and mCDR), and how scientific research can support sustainable ocean management and development. Prior to coming to NORCE, she worked at the University of Bergen and the Scripps Institution of Oceanography UCSD.