Vertical distribution of Eucalanoid copepods within the Costa Rica Dome area of the Eastern Tropical Pacific.
A variety of ecological strategies for tolerance of low-oxygen conditions within the Costa Rica Dome (CRD) area of the Eastern Tropical Pacific are documented for the copepod family Eucalanidae. During the summer of 2010, we compared the ecological strategies used by the Eucalanidae inside and outside the central CRD region. We compared the vertical and horizontal distributions of five species,Eucalanus inermis,Subeucalanus subtenuis,Subeucalanus subcrassus,Subeucalanus pileatusandPareucalanus attenuatustogether withRhincalanusspecies, in the epipelagic (upper 200 m) among four locations, which we grouped into a section roughly crossing the core CRD area (inside-outside core CRD). The coastal area outside the CRD supported the most diverse assemblage, whereas overall abundance of Eucalanidae in the central CRD was 2-fold greater than outside and dominated byE. inermis(>60%). Eucalanidae in the central CRD had a shallow depth distribution, closely associated with the shallow thermocline (10-20 m). There was no evidence of daily vertical migration in the central CRD, butE. inermisdemonstrated vertical migration outside the CRD. The vertical abundance patterns of Eucalanidae in the CRD region reflect complex interactions between subtle physical-chemical differences and food resources.
University of Maryland Center for Environmental Science, Horn Point Laboratory , Cambridge, MD 21613 , USA.
Melanie L
ML
Jackson
Rosenstiel School of Marine and Atmospheric Science , 4600 Rickenbacker Causeway, Miami, FL 33149 , USA.
Sharon L
SL
Smith
Eucalanidae; Eucalanus inermis; oxygen minimum zone; zooplankton biomass