Effects of a tropical cyclone on a pelagic ecosystem from the physical environment to top predators

TitleEffects of a tropical cyclone on a pelagic ecosystem from the physical environment to top predators
Publication TypeJournal Article
Year of Publication2013
AuthorsFiedler PC, Redfern JV, Van Noord J., Hall C., Pitman R.L, Ballance LT
JournalMarine Ecology Progress Series
Date Published2013/06
Type of ArticleArticle
ISBN Number0171-8630
Accession NumberWOS:000320321300001
KeywordsBottom-up forcing; climate-change; disturbance; dynamics; eastern tropical pacific; ecology; hurricane; movements; pacific-ocean; Pelagic ecosystem; populations; risk; seabirds; Storm; Top predator

Tropical cyclones are environmental disturbances that may have important effects on open-ocean ecosystem structure and function, but their overall impact has rarely been assessed. The Stenella Abundance Research Line Transect and Ecosystem (STARLITE) survey, in August-November 2007, investigated spatial and temporal ecosystem variability in the eastern tropical Pacific Ocean off southwestern Mexico. Oceanographic, plankton, flyingfish, seabird, and cetacean sampling was conducted along eight 170 km transect lines, each of which were surveyed on 2 consecutive days at similar to 3 wk intervals. Tropical storm Kiko passed though the study area on 15-17 October and forced changes in the physical environment and in the ecosystem, from plankton to top predators. Kiko mixed water from beneath the strong, shallow thermocline to the surface. As a result, surface temperature decreased by 0.6 degrees C, the thermocline and chlorophyll maximum layer shoaled by 10-20 m, stratification decreased by 27%, and chlorophyll increased by 33% at the surface and 35% over the euphotic zone. These changes persisted for at least 4 wk. Zooplankton biomass increased by 59% about 3 wk after the phyto plankton increase. Changes in the stomach fullness and diet composition of planktivorous flyingfish were consistent with the increase in zooplankton biomass. Among top predators, the sighting rate of dolphins declined, while the response of seabirds varied by species and was confounded by seasonal migration patterns. Tropical cyclones are a recurrent disturbance in this region. They initiate a bottom-up forcing of the ecosystem, creating persistent patches of higher primary and secondary production, and may be regarded as a disturbance regime.

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