Copepod distribution and production in a Mid-Atlantic Ridge archipelago.

Sigrid Neumann-Leitão,Silvio J De Macêdo,Mauro De Melo Júnior,Moacyr Araujo,Pedro A.M.C Melo

doi:10.1590/0001-3765201420130395

Abstract

The Saint Peter and Saint Paul Archipelago (SPSPA) are located close to the Equator in the Atlantic Ocean. The aim of this study was to assess the spatial variations in the copepod community abundance, and the biomass and production patterns of the three most abundant calanoid species in the SPSPA. Plankton samples were collected with a 300 µm mesh size net along four transects (north, east, south and west of the SPSPA), with four stations plotted in each transect. All transects exhibited a tendency toward a decrease in copepod density with increasing distance from the SPSPA, statistically proved in the North. Density varied from 3.33 to 182.18 ind.m-3, and differences were also found between the first perimeter (first circular distance band) and the others. The total biomass varied from 15.25 to 524.50 10-3 mg C m-3 and production from 1.19 to 22.04 10-3 mg C m-3d-1. The biomass and production of Undinula vulgaris (Dana, 1849), Acrocalanus longicornis Giesbrecht, 1888 and Calocalanus pavo (Dana, 1849) showed differences between some transects. A trend of declining biodiversity and production with increasing distance from archipelago was observed, suggesting that even small features like the SPSPA can affect the copepod community in tropical oligotrophic oceanic areas.

Highlights

The tropical ocean region is made up of oligotrophic waters characterized by low primary productivity and a low secondary productivity (Boltovskoy 1981)
The copepod community in the Saint Peter and Saint Paul Archipelago (SPSPA) was com posed of 38 taxa, of which 22 were Calanoida, 12 Cyclopoida and four were Harpacticoida
Typical epipelagic copepod assemblages charac terized the waters around the SPSPA, dominated

Summary

Introduction

The tropical ocean region is made up of oligotrophic waters characterized by low primary productivity and a low secondary productivity (Boltovskoy 1981). Tropical zooplanktonic communities have as their primary characteristic a high species richness, which in turn results in a large network of trophic interactions in Within this complex network of interactions, copepods play a significant role in the transfer of energy and organic material from primary producers to the higher trophic levels in pelagic ecosystems (Verity and Smetacek 1996, Satapoomin et al 2004) accounting for as much as 80% of the biomass of planktonic metazoans in the marine environment (Kiørboe 1998). The copepods are considered the most abundant and diverse components of mesozooplankton in marine environments and the most important secondary producers in marine food webs (Shimode et al 2006, Gallienne and Robins 2001). The presence of islands and seamounts is responsible for modifications in the hydrodynamics of the environments where these features occur, generating a diversity of physical and ecological processes, influencing the structure of several local communities (Boehlert and Genin 1987, Genin 2004, Rogers 1994) and promoting the creation of unique habitats for many species (De Forest and Drazen 2009)

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