Plenary 3: attribution of coastal processes to Ω, pH, & carbon variability – a modeling study (text & video)

OA Week 2021, Plenary Session 3 GOA-ON Goal #3 – Acquire and exchange data and knowledge necessary to optimize modeling for OA and its impacts

Dr. Samantha Siedlecki, Department of Marine Sciences, University of Connecticut, USA


Corrosive and hypoxic events in coastal waters are of increasing concern to local fisheries. Many important species (oysters, crabs, phytoplankton, zooplankton) in Washington and Oregon coastal waters are currently experiencing or are expected to feel effects of ocean acidification. Direct effects have been observed on the $100 million shellfish industry, and additional indirect economic impacts could impact the finfish industry through loss of prey species. Recent findings from the West Coast Ocean Acidification and Hypoxia Panel and the Washington Blue Ribbon Panel Addendum emphasize the need to use models to assess probable future conditions at local and regional scales. It is now possible to simulate important processes for regional Ω, pH, and hypoxia variability due to the higher spatial and temporal resolution of models combined with more comprehensive observations. The ability to predict the intensity of hypoxic and corrosive conditions, spatial variability of these conditions, and changes in their duration could be of considerable benefit to managers. These abilities require models to forecast and project variability with accurate representations of processes important to determining that variability. A suite of forecast and projections have been in development for the Pacific Northwest coast including a short-term forecast (LiveOcean, 72 hour) and some high-emissions scenario projections out to 2100. These simulations enable us to attribute regional variability to important processes like regional freshwater influence, water column metabolism, and changes in buffer capacity. The simulations also allow us to explore impacts of future emission scenarios on the regional expression of those processes within the context of Ω and pH variability on a range scales. In this work, we discuss methods for evaluating model forecasts and projections to ensure they achieve well-simulated conditions for the right reasons, showcase results of simulating important processes attributed to determining variability in the region, and determine the implications for these processes in a future scenario. Our results will shed light on the extent and timing of the risks to local ecosystems and provide critical guidance to those concerned with mitigation of and adaptation to the threat of ocean acidification.

Ocean Acidification Week 2021 was sponsored by the following organizations:

(1) GOA-ON, the Global Ocean Acidification Observing Network,

(2) NOAA, the United States National Oceanic & Atmospheric Administration,

(3) IAEA OA-ICC, the International Atomic Energy Agency – Ocean Acidification International Coordination Centre, and

(4) IOC-UNESCO – the Intergovernmental Oceanographic Commission of the United Nations Educational, Scientific and Cultural Organization

For more information, please visit

GOA-ON, YouTube, 24 september 2021. Text and video.

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