Macroscale abundance patterns of hydromedusae in the temperate Southwestern Atlantic (27°-56° S).

María Sofía Dutto,Carolina Soledad Rodriguez,Agustín Schiariti,Carlo Javier Chazarreta,Luciana Mabel Diaz Briz,Gabriel Néstor Genzano,Maura (Gee) Geraldine Chapman

doi:10.1371/journal.pone.0217628

Abstract

Gelatinous organisms are crucial components of marine ecosystems and some species imply social and economic consequences. However, certain geographic areas, such as the temperate Southwestern Atlantic (SWA, 27° - 56° S), remain understudied in terms of jellyfish ecological data. We analyzed 3,727 plankton samples collected along ~6.7 million km2 over a 31-year period (1983–2014) to determine the occurrence, abundance, and diversity patterns of hydromedusae in the SWA. Analyses were made at both community and species levels. Two abundance hot spots of hydromedusae were identified, where values up to 2,480 ind. m-3 were recorded between 2003 and 2014. Liriope tetraphylla and Obelia spp. were the main responsible for recurrent peaks. Diversity indexes were in the range of those published for temperate areas worldwide, and some coastal zones showed values that can be considered moderate to high for a temperate neritic region. The community analysis yielded 10 groups following previously determined biogeographic schemes throughout the study area. This work enhances the knowledge of hydromedusae in the SWA and provides essential information about the current global warming context and the gelatinous zooplankton data necessity.

Highlights

Gelatinous zooplankton are critical components of marine ecosystems because they can shape food webs [1,2]
One of the ocean regions most poorly studied in terms of jellyfish ecological data is the Southwestern Atlantic (SWA) [12,13]
The two abundance hot spots of hydromedusae identified in our study include two large estuarine fronts of particular hydrographic and topographic features within a zone defined by high biological production [21,22]

Summary

Introduction

Gelatinous zooplankton (i.e., mostly medusae and ctenophores, commonly grouped as “jellyfish”) are critical components of marine ecosystems because they can shape food webs [1,2]. They are ubiquitous and voracious on a wide range of prey including fish [2], and they typically display events of massive occurrences over a variety of spatial and temporal scales, which. Abundance patterns of hydromedusae in the temperate Southwestern Atlantic. Nacional de Promocion Cientıfica y Tecnologica (ANCyT, https://www.argentina.gob.ar/ciencia/ agencia, PICT 2015-1151 to MSD). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

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Discussion

Conclusion