CMCC Lectures
9 January 2026, 12:00 CET | Online and Lecce, CMCC Foundation
To join the lecture, register here

Seasonal upwelling in the Northern California Current System supports abundant plankton, fish, and other marine life, but over the past 30 years has also contributed to growing hypoxia and ocean acidification. In this lecture, CMCC Bassi Fellow Samantha Siedlecki associate professor at the University of Connecticut, whose prominent research is informing coastal resilience strategies and helping communities adapt to changing ocean conditions, will shed light on multi-decadal changes in these stressors and how they are influenced by coastal modification of upwelling, contributing to improved projections of future ecosystem health.

The Northern California Current System (nCCS) is known for its high productivity, supporting diverse fisheries through seasonal upwelling – the rise of cold, nutrient-rich waters from the deep ocean to the surface. However, this process also brings environmental challenges for the continental shelf, including hypoxia (low oxygen) and ocean acidification, conditions that have become more frequent and severe over the past 30 years.

In this CMCC Lecture, Samantha Siedlecki, associate professor at the Department of Marine Sciences, University of Connecticut, and Bassi Fellow at CMCC Foundation, will present new findings on the historical multi-decadal evolution of compound ocean change in the northern California Current system. Dr. Siedlecki’s results highlight that coastal modification of the upwelling signal appears to amplify rates of deoxygenation and acidification in this system, emphasizing that this process is important to monitor and consider in future ecosystem projections.

The Lecture will explore how both seasonal and long-term changes in upwelling influence oxygen levels and acidity on the continental shelf, and how these changes have been captured using the LiveOcean forecast system to simulate ocean conditions from 1993 to 2022, and key metrics such as the Coastal Upwelling Transport Index (CUTI) and the Biological Effective Upwelling Transport Index (BEUTI).

Finally, the talk will highlight the implications of these findings for marine resource management and for projecting the future health of coastal ecosystems.

Join us to learn how natural processes and climate-driven changes interact to shape coastal ocean health and the challenges faced by marine ecosystems and human communities.

Speaker: Samantha Siedlecki, Associate Professor at the Department of Marine Sciences, University of Connecticut

Moderator: Nadia Pinardi, CMCC and University of Bologna
Discussant: Silvia Torresan, CMCC

As an oceanographer, Dr. Siedlecki focuses on coastal regions, implementing numerical simulations to identify processes responsible for biogeochemical dynamics in modern and future oceans. She earned her PhD from the University of Chicago, focusing on theoretical ocean systems. As a postdoctoral fellow at JISAO, University of Washington, she began simulating Washington and Oregon water responses using realistic ocean acidification and hypoxia variables, developed by the Coastal Modeling Group. At JISAO, she extended that work to include seasonal (J-SCOPE) and short-term (LiveOcean) forecasts. Now as associate professor at the University of Connecticut, she explores regional climate projections of ocean conditions on both U.S. coasts. Through collaborations in NCAR’s Early Career Faculty Innovators Program and several funded projects, she partners with social scientists to incorporate these tools into climate resilience decisions for marine resources. She is a member of the Integrated Ocean Carbon Research programme (IOC-R), the Carbon and Climate section for PICES, co-champion of OARS Outcome 5 (Prediction), and the UN Decade Programme CoastPredict.

The event is part of the CMCC Lectures webinar series, which presents frontier topics and solutions in climate sciences and action, through the insights of leading experts. The series provides a platform for prominent scientists to showcase their cutting-edge research and engage in dialogue with peers and stakeholders.