[PAST EVENT] Dynamics of coastal meta-ecosystems

April 19, 2013
VIMS - Watermen's Hall, McHugh Auditorium
1375 Greate Road
Gloucester Point, VA 23062Map this location
Presenter: Professor Bruce Menge of Oregon State University

Reception at 3:00 p.m. in the lobby of Watermen's Hall
Seminar from 3:30 p.m. to 4:30 p.m. in McHugh Auditorium

Dynamics of coastal meta-ecosystems: the intermittent upwelling hypothesis and a test in rocky intertidal regions

The intermittent upwelling hypothesis (IUH) predicts that the strength of ecological subsidies, organismal growth responses, and species interactions will vary unimodally along a gradient of upwelling from persistent downwelling to persistent upwelling, with maximal levels at an intermediate or "intermittent" state of upwelling. To test this model, we employed the comparative-experimental method to investigate these processes at 16-44 wave-exposed rocky intertidal sites in Oregon, California, and New Zealand varying in average upwelling and/or downwelling during spring-summer. As predicted by the IUH, ecological subsidies (phytoplankton abundance, prey recruitment rates), prey responses (barnacle colonization, mussel growth), and species interactions (competition rate, predation rate and effects) were unimodally related to upwelling. On average, unimodal relationships with upwelling magnitude explained ~50% of the variance in the various processes, and unimodal and monotonic positive relationships against an index of intermittency explained ~37% of the variance. Regressions among the ecological subsidies and species interactions were used to infer potential ecological linkages that underpinned these patterns. Abundance of phytoplankton was associated with increases in rates of barnacle colonization, intensity of competition and predation, and with predation effects, and rates of barnacle recruitment were associated with increases in mussel growth, barnacle colonization, and species interactions. Positive effects on interactions were also seen for rates of colonization, competition, predation, and predation effects. Several responses were saturating or exponential, suggestive of threshold effects. These results suggest the IUH has geographic generality, and are also consistent with earlier arguments that bottom-up effects and propagule subsidies are strongly linked to the dynamics of higher trophic levels, or top-down effects, as well as to non-trophic interactions. The ~50% of the variance not explained by upwelling is likely due to more regional to local influences on the processes examined, and future efforts should focus on incorporating such effects into the IUH.

Bruce A. Menge is a Distinguished Professor of Zoology and the Wayne and Gladys Valley Endowed Professor of Marine Biology in the Department of Zoology at Oregon State University. He also served as Chair of the Department from 2008-2011. His major research areas are marine community and meta-ecosystem ecology, physiological ecology, and he is currently focused on the impacts of climate change, including ocean acidification, on coastal marine ecosystems. He received a BA in Zoology at the University of Minnesota in 1965 and a Ph.D. in Zoology at the University of Washington in 1970. He is the lead PI in PISCO, the Partnership for Interdisciplinary Studies of Coastal Oceans, and in OMEGAS, the Ocean Margin Ecosystem Group for Acidification Studies. He is a member and Fellow of the American Association for the Advancement of Science, and a member of the Ecological Society of America, the American Society of Naturalists, and the Society of Limnology and Oceanography. Professor Menge has authored or co-authored >125 refereed research papers. Honors include the George Mercer Award (1979) for the Best Paper in Ecology during the previous year, a John Simon Guggenheim Fellowship (1994-95), an Honorary Doctor of Science degree at Southampton College of Long Island University (1999), recognition as one of the 0.5% of the most cited ecologists over the past two decades (ISI Highly Cited.com, 2002), and the Western Society of Naturalists' Lifetime Achievement Award (2010).

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