Title

Trophic Structure Over the Northern Mid-Atlantic Ridge: The Bathypelagic Zone Really Matters

Event Name/Location

ASLO Ocean Sciences Meeting, Portland, Oregon, February 22-26, 2010

Document Type

Poster

Publication Date

2-2010

Abstract

We present preliminary results and ongoing efforts to characterize the trophic structure and energy flow of the pelagic ecosystems of the northern Mid-Atlantic Ridge (MAR), from Iceland to the Azores. This study is one component of the international CoML field project MAR-ECO (www.mar-eco.no). We found a diverse deep-pelagic fish fauna (205 spp.), with unexpectedly high bathypelagic fish biomass and spatial complexity. Based on literature reports of species present, crustacean planktivory is the dominant trophic guild (79% of individuals 47% of species), primarily within the mesopelagial. “Gelativory” was second (12% ind., 4% spp.), primarily within the bathypelagial. Omnivory (3%, 13%), “shrimpivory” (2%, 4%), and piscivory (1%, 21%) were the remaining major feeding guilds. The diets of 22 spp., primarily bathypelagic, are unknown. A spatially explicit food web model revealed that of 12 fish assemblages discriminated by multivariate analysis, only three accounted for more than 4% of total fish consumption. The most striking finding was that along much of the MAR, fish consumption in the bathypelagic equals or exceeds the epi- and mesopelagic. Further, “alternate” trophic pathways (gelatinous zooplankton and shrimp consumption) appear to me major energy vectors in the deep North Atlantic.

Comments

Eos Trans. AGU, 91(26), Ocean Sci. Meet. Suppl.

Additional Comments

Identifier: BO25E-07