Seasonal succession of zooplankton in coastal waters of the Argentine Sea (Southwest Atlantic Ocean): prevalence of classical or microbial food webs

The demographic characteristics of marine zooplankton make it especially suitable for examining the variability of marine ecosystems. The zooplankton annual succession was studied at a permanent coastal station in the Argentine Sea (38°28′S, 57°41′W) in relation to physical conditions and phytoplank...

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Bibliographic Details
Authors: Viñas, Maria Delia; Negri, Ruben Mario; Cepeda, Georgina Daniela; Hernández, Daniel; Silva, Ricardo; Daponte, María Cristina; Capitanio, Fabiana Lia
Format: Article
Status:Published version
Publication date:2013
Country:Argentina
Institution:Consejo Nacional de Investigaciones Científicas y Técnicas
Repository:CONICET Digital (CONICET)
Language:English
OAI Identifier:oai:ri.conicet.gov.ar:11336/25109
Online Access:http://hdl.handle.net/11336/25109
Access Level:Open access
Keyword:Mesozooplankton Succession
Small Copepods
Larvaceans
Phytoplankton Fractions
Epea Station
Argentine Sea
Southwest Atlantic Ocean
https://purl.org/becyt/ford/1.5
https://purl.org/becyt/ford/1
Description
Summary:The demographic characteristics of marine zooplankton make it especially suitable for examining the variability of marine ecosystems. The zooplankton annual succession was studied at a permanent coastal station in the Argentine Sea (38°28′S, 57°41′W) in relation to physical conditions and phytoplankton size fractions. Small copepods (<1 mm total length), mainly represented by Oithona nana (Cyclopoida) and adults and copepodites of Calanoida, numerically dominated the metazooplankton throughout the year. In summer, small copepods also exceeded large copepods in biomass. Larvaceans (mostly <1 mm total length) were the second most important metazooplankton group, with strong dominance of Oikopleura dioica. The zooplankton succession exhibited two main periods throughout the year: (1) a cold winter–spring period characterized by a dominant classical herbivore food web in which the large copepod Calanoides carinatus and lamellibranch larvae were associated with the lowest temperatures and highest Chl-a and microphytoplankton, and (2) a warm summer period dominated by a microbial food web in which microbial filter-feeders such as Oithona nana, Paracalanus spp., Oikopleura dioica and Penilia avirostris predominated and the highest density of picophytoplankton and lowest concentrations of Chl-a were recorded. The implications of the present findings for the growth and survival of fish larvae distributed in the study area are discussed.