Extremes and predictability of ocean biogeochemical ecosystem stressors

Samuel Mogen

University of Colorado Boulder

Tuesday, Feb 11, 2025, 2:00 pm MT
DSRC Room 2A305

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Abstract

Anthropogenic climate change is driving ocean warming, acidification, and deoxygenation with ramifications for marine organisms and ecosystems. Alongside the impacts of these long-term changes on marine ecosystems, there is growing interest in the short-term variability of these stressors, which can lead to extreme events that rapidly alter marine conditions, including marine heatwaves (MHW) and ocean acidification extremes (OAX). Relatively limited biogeochemical observations make these short-term changes hard to study, leading to the use of Earth System Models (ESMs), which provide valuable insights into biogeochemical changes and predictability. Here we focus on three research questions: (1) How do MHW affect regional biogeochemistry? (2) Can ESMs forecast surface and subsurface marine stressors? (3) Can ESMs forecast marine extreme events (MHW, OAX)? We first focus on the regional biogeochemical impacts of two notable MHWs in the Northeast Pacific: the Blob (2013-2017) and the Blob2 (2019), using a combination of in-situ observations, observation-based products, and ESM reconstructions. We then use model output to estimate the dynamical drivers of biogeochemical changes associated with these MHWs. Next, we assess the ability of the Community Earth System Model (CESM) Seasonal-to-Multiyear Large Ensemble (SMYLE) to predict anomalies of surface and subsurface marine ecosystem stressors. Finally, we assess the ability of CESM SMYLE to forecast global MHW and OAX over the historical period and determine drivers of skillful forecasts.

Bio: Samuel Mogen is a PhD candidate at the University of Colorado Boulder Department of Atmospheric and Oceanic Sciences working with Dr. Nicole Lovenduski. He previously obtained a B.S. in Environmental Sciences from the University of Virginia.