Foraminíferos Bentónicos recolectados durante la expedición CIMAR 14 Fiordos, Patagonia Chilena

Abstract

In 2008, the National Oceanographic Committee (CONA) of Chile, organised the CIMAR14 Fiords Expedition to the Chilean channels and fiords, located between 47° and 50° S. One of the groups studied was the benthic foraminifera. Information on the community structure of the group is reported and results are compared with those obtained in previous cruises. The material studied comes from samples of superficial sea sediments, collected at 27 stations with a Box Corer. The samples were washed, dried and the microfauna extracted under a binocular microscope. Subsequently the species were identified and counted, assigning univariate and multivariate statistical indexes. Overall, 2,569 shells of benthic foraminifera were obtained belonging to the following suborders: Rotaliina (60,8 %; 39 species); Textulariina (26,9 %; 19 species), Miliolina (6,4 % ; 11 species), Lagenina (5,77%), Involutinina (1,97%), Spirillinina (0,69%) and Robertinina (0,42%) with one species each. Uvigerina bifurcata (13, 6 %), Recurvoides scitullum (8,7 %), Melonis affinis (6,8%), Cassidulinoides parkerianus (5,2%), Recurvoides contortus (5,2 %), Globobulimina notovata and Oridorsalis tener (4,3 %) were the most abundant. The species with a wider geographic distribution were G. notovata, Recurvoides contortus and U. bifurcata. A conglomerate analysis allowed splitting the stations into four groups: 1) without defined geographic distribution, 2) coastal area, 3) southern area and 4) northern area. Compared to the results obtained in previous surveys, there was an increase in the number of sand-foraminifera, and some species- mostly marine- were replaced by more euryhaline ones.