Environment vs. Ecology: Decoding the Decline of a Kelp Forest Ecosystem in Northern California

Meredith McPherson,

Ph.D. Department of Ocean Sciences, UC Santa Cruz

Bull kelp forests experienced unprecedented losses along 220 miles of coastline in Northern California beginning in 2014 after the onset of a large marine heatwave and the local extinction of sunflower sea stars (sea urchins primary predator). These losses have had devastating consequences to the region’s communities, economies, and fisheries. Similar to the nature versus nurture debate in psychology, it can be equally challenging to tease apart environmental and ecological drivers (also known as "top down versus bottom up”) in ecosystem dynamics.

Using a suite of diver and satellite-derived data, join Meredith as she describes historical patterns of kelp canopy coverage in Northern California, decodes how and why this event occurred, and provides perspective on the future of these iconic marine ecosystems.


Register in advance for the online Science Sunday webinar (required): Please register at least one hour prior to event start time. Registration closes at 12:30 PM PST on Sunday, November 21, 2021.


Science Sunday is for everyone interested in the world around them. Join us on the third Sunday of every month (except December) for a public lecture from a marine scientist, who presents current research and topics in an entertaining and easy-to-understand format, with up-to-date photos, video, and discussion.

-Time: 1:30 PM; lectures are one hour long and include time for a few questions at the end.

-Location: Online; webinar preregistration is required.

-Recommended for ages 10 and older.

Virtual Science Sundays are free for Seymour Center members, and $10 per household for non-members. Please consider supporting the Seymour Center, and gaining free access to programs like Science Sunday, by becoming a member today.

Dial-In Information


Sunday, November 21, 2021 at 1:30pm to 2:30pm

Virtual Event

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