ZEN at the 2012 Benthic Ecology Meeting

March 26th, 20122011 Experiment, Blog4 comments

The Zostera Experimental Network (ZEN) team formally emerged into public view for the first time at the Benthic Ecology Meeting this past week in Norfolk, Virginia. ZEN coordinator Dr. Pamela Reynolds (top center in the photo, in red) presented a first look at the results of our 2011 experiment evaluating the relative importance of grazing, nutrient loading, and abiotic forcing on dynamics of eelgrass (Zostera marina) communities across the Northern Hemisphere.

ZEN had representation from several of our 15 global sites, and a diverse group of PIs, grad students and undergrads, at BEM this year. These included teams from northern Japan (PI Massa Nakaoka and grad student Kyosuke Momota), Quebec (graduate students Julie Lemieux and Laetitia Joseph), Massachusetts (PI James Douglass), North Carolina (PI Erik Sotka, grad students Rachel Gittman and Nicole Kollars, technicians Danielle Abbey and Alyssa Popowich), and Virginia (Emmett Duffy, Pamela Reynolds, Paul Richardson).

The abstract of Pamela’s presentation:

A comparative-experimental approach reveals complex forcing among bottom-up and top-down processes in seagrass communities across the Northern Hemisphere

Pamela L. Reynolds (1); Emmett Duffy (1); Christoffer Boström (2); James Coyer (3); Mathieu Cusson (4); James Douglass (5); Johan Eklöf (6); Aschwin Engelen (7); Klemens Eriksson (3); Stein Fredriksen (8); Lars Gamfeldt (6); Masakazu Hori (9); Kevin Hovel (10); Katrin Iken (11); Per-Olav Moksnes (6); Masahiro Nakaoka (12); Mary O’Connor (13); Jeanine Olsen (3); Paul Richardson (1); Jennifer Ruesink (14); Erik Sotka (15); Jay Stachowicz (16); Jonas Thormar (8)

 

(1) Virginia Institute of Marine Science, (2) Åbo Akademi University, (3) University of Gronigen, (4) Université du Québec à Chicoutimi, (5) Northeastern University, (6) University of Gothenburg, (7) Universidade do Algarve, (8) University of Oslo, (9) Fisheries Research Agency, Japan, (10) San Diego State University, (11) University of Alaska Fairbanks, (12) Hokkaido University, (13) University of British Columbia, (14) University of Washington, (15) College of Charleston, (16) University of California Davis

 

Two fundamental challenges to prediction in ecology are complexity and idiosyncrasy. How do we evaluate the importance and generality of multiple, interacting factors in mediating ecological structure and processes? One promising way forward is the comparative-experimental approach, integrating standardized experiments with observational data. In summer 2011 the Zostera Experimental Network (ZEN), a collaboration among ecologists across 15 Northern Hemisphere sites, initiated parallel field experiments exploring bottom-up and top-down control in eelgrass (Zostera marina) communities. Eelgrass is among the most widespread marine plants, forming ecologically and economically important but threatened coastal habitats. We factorially added nutrients and excluded small crustaceans (mesograzers) using a degradable chemical deterrent for four weeks, and measured responses of associated plant and animal communities. As expected, results varied strongly across the global range. Our cage-free deterrent strongly reduced crustacean grazers; at several sites grazer exclusion released blooms of epiphytic algae and/or sessile invertebrates. In Chesapeake Bay, these blooms reduced eelgrass biomass after eight weeks, demonstrating mutualistic dependence between eelgrass and mesograzers. Surprisingly, nutrient addition had little effect on epiphytes, except in Massachusetts and Sweden where grazers are suppressed by mesopredators. Ongoing research is analyzing the relative influence of grazer diversity and environmental forcing in mediating these processes.

Analysis of the 2011 experiments is still under way–even as we swing into high gear for planning the 2012 experiment. We will be presenting the complete results of the 2011 experiment at the Ecological Society of America meeting in Portland (August 2012) and the 47th European Marine Biology Symposium in Arendal, Norway (September 2012). We hope to see you at one or another of these events!