Mesozooplankton assemblages in two bays in the Beagle Channel (Argentina) during January, 2001

This paper describes the composition and abundance of mesozooplankton of Bahía Ushuaia and Bahía Golondrina. These small bays are located in the northern Beagle Channel. Sampling was carried out from January 20 to 23, 2001 and samples were collected from the upper layer at nine stations. This study...

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Bibliographic Details
Published in:Scientia Marina
Main Authors: Fernández-Severini, Melisa Daiana, Hoffmeyer, Monica Susana
Format: Article in Journal/Newspaper
Language:English
Published: Consejo Superior de Investigaciones Científicas 2005
Subjects:
Online Access:https://scientiamarina.revistas.csic.es/index.php/scientiamarina/article/view/309
https://doi.org/10.3989/scimar.2005.69s227
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Summary:This paper describes the composition and abundance of mesozooplankton of Bahía Ushuaia and Bahía Golondrina. These small bays are located in the northern Beagle Channel. Sampling was carried out from January 20 to 23, 2001 and samples were collected from the upper layer at nine stations. This study is the first research on mesozooplankton in this part of the Beagle Channel. Due to their dominance in the mesozooplankton community, we compared our Copepoda data with those reported by other authors from Antarctic coastal environments. By applying cluster analysis, we found two station groups in both bays: one in slightly polluted zones and the other in undisturbed external zones. Four assemblages in Bahía Ushuaia and two in Bahía Golondrina were determined by using non-metric multidimensional scaling (MDS) and cluster analysis. Mesozooplanktonic assemblages showed a certain resemblance in zones with and without anthropogenic influence. Most of the copepod species in our samples are typical of the sub-Antarctic region. Oithona similis (=O. helgolandica sensu Ramírez, 1966), Oncaea curvata, and Ctenocalanus citer show either similar or higher abundances at Antarctic coastal sites, including the upper layer in oceanic areas, in comparison with sub-Antarctic coastal localities. This suggests that, in agreement with other findings, the Polar Front is probably not a major geographic boundary for the distribution of these species. Se describe la composición y abundancia mesozooplanctónica en Bahía Ushuaia y Bahía Golondrina, pequeñas bahías ubicadas al norte del Canal Beagle. El muestreo se realizó del 20 al 23 de enero de 2001 y las muestras se colectaron en el estrato superficial en nueve estaciones. Este estudio constituye la primera investigación realizada sobre el mesozooplankton, en las dos bahías del Canal Beagle. Debido a su dominancia en la comunidad mesozooplanctónica, los datos de copépodos fueron comparados con datos de otros autores para ambientes costeros de la Antártida. Los análisis de cluster y MDS revelaron dos grupos de estaciones en ambas bahías, uno en zonas levemente contaminadas y el otro en zonas más externas no perturbadas. Los mismos análisis permitieron determinar cuatro asociaciones de especies en Bahía Ushuaia y dos en Bahía Golondrina. Las asociaciones encontradas en ambas bahías presentaron una cierta semejanza en zonas con y sin influencia antrópica. La comparación del grupo Copepoda mostró que la mayoría de las especies de nuestras muestras son típicas de la región subantártica. Los copépodos Oithona similis (=O. helgolandica sensu Ramírez, 1966), Oncaea curvata y Ctenocalanus citer presentan similar o mayor abundancia en los ambientes costeros de la Antártida, incluyendo el estrato superficial de áreas oceánicas, que en los sitios costeros subantárticos. En coincidencia con otros hallazgos, el Frente Polar no parece ser una importante barrera geográfica para la distribución de dichas especies