LATITUDINAL VARIABILITY AND LONG-TERM RESPONSES OF PELAGIC COMMUNITY STRUCTURE TO CLIMATE FORCING ACROSS FOUR MARINE LTER SITES

Pelagic marine ecosystems exhibit varied responses to both stochastic and long-term environmental changes, but the mechanisms driving these responses are not fully understood. Long-Term Ecological Research (LTER) sites provide invaluable long-term data across a latitudinal gradient. Here, we analyze pelagic populations across four marine LTER sites—Northeast U.S. Shelf, California Current Ecosystem (CCE), Northern Gulf of Alaska, and Palmer Antarctica—to investigate how zooplankton respond to climate forcing. We tested whether mechanisms observed in the CCE, in particular the Double-Integration Hypothesis, apply to other marine ecosystems and help explain distinct patterns in community composition and structure across varying timescales. This hypothesis suggests that cumulative integrations of noisy atmospheric forcing drive long-term population variability. Using time-series data spanning 25-75 year duration for taxa encompassing copepods, euphausiids, and pteropods, we find varying degrees of support for the Double-Integration Hypothesis across sites, considering indices such as the Pacific Decadal Oscillation, the El Niño-Southern Oscillation, and the Gulf Stream Index. This work reveals both similarities and unique responses, highlighting the importance of a cross-system perspective in understanding marine ecosystem responses to physical climate forcing. Understanding how pelagic populations respond to changing conditions and the drivers of long-term variability is crucial for effective ecosystem management due to the central role of plankton in marine ecosystems.

Presentation Preference: Oral

Primary Presenter: Alexandra Cabanelas, Woods Hole Oceanographic Institution (acabanelas@whoi.edu)

Authors:

Alexandra Cabanelas, Woods Hole Oceanographic Institution  (acabanelas@whoi.edu)

Jack Conroy, University of California Santa Cruz  (jaconroy@ucsc.edu)

Moira Décima, Scripps Oceanography  (mdecima@ucsd.edu)

Bia Dias, University of Washington  (biadsdias@gmail.com)

Gwenn Hennon, University of Alaska  (gmhennon@alaska.edu)

Russell Hopcroft, University of Alaska  (rrhopcroft@alaska.edu)

Thomas Kelly, University of Alaska  (tbkelly@alaska.edu)

Mark Ohman, Scripps Oceanography  (mohman@ucsd.edu)

Oscar Schofield, Rutgers  (oscar@marine.rutgers.edu)

Deborah Steinberg, Virginia Institute of Marine Science  (debbies@vims.edu)

Michael Stukel, Florida State University  (mstukel@fsu.edu)

Heidi Sosik, Woods Hole Oceanographic Institution  (hsosik@whoi.edu)