Interdisciplinary Seminar: Laura Fisch

An interdisciplinary seminar presented by UNC-CH Department of Marine Sciences graduate student, Laura Fisch.

Seminar Title: ENSO’s far reaching effects cascade through the trophic levels of the U.S. west coast

Abstract: The El Niño Southern Oscillation is a regular cycle that occurs every 3 to 8 years starting with an El Niño event. Warmer than usual sea surface temperature anomalies in the Equatorial Pacific Ocean mark the beginning of an El Niño event that can have far reaching effects all around the globe. In 1997/98, one of the strongest observed El Niño events ever recorded occurred. This event had catastrophic consequences for many regions around the globe including here in the United States. Along the U.S. west coast, dramatic changes in seasonal upwelling were observed. The upwelling along the U.S. west coast brings essential nutrients that sustain the phytoplankton required to maintain a diverse and productive ecosystem. During this El Niño, the U.S. west coast saw dramatic changes in marine ecosystem primary productivity which is a cause for concern for U.S. Pacific fishing industries. While sea surface temperatures and chlorophyll concentrations commonly show anomalies during ENSO events, it is unclear how swift and dramatic ecosystem changes alters higher trophic levels such as fish populations. El Niño events usually span less than 2 years and after the events primary productivity recovers. Thus dramatic effects on larger marine animals such as fish are not observed. El Niño events offer an opportunity to learn about how many different species respond to dramatic swift changes. Additionally, they offer a chance to see marine ecosystem resilience to years of low food and warmer waters.