Status of macrobenthic communities in the hypersaline waters of the Gulf of Salwa, Arabian Gulf

The spatial extent of hypersaline marine ecosystems is very limited and therefore they have received only little scientific study. Here, we present the status of macrobenthic communities in a hypersaline water body, the Gulf of Salwa (Saudi Arabia part), in the Arabian Gulf and assess the natural stress, if any, in the communities. The Gulf of Salwa is nearly isolated from the main water body of the Arabian Gulf and shows a progressive southward increases in salinity (up to 63 during summer) and temperature (up to 40 degrees C during summer) due to the southward decrease in tidal flushing. The study reveals that the benthic communities in the southern region (south of 25 degrees 10' N) of the Gulf of Salwa are under natural stress, while the deeper, the northern, and the inner bay regions have healthier benthic communities than the south. In the southern region, there were 87 to 93% reduction in polychaete species, 49 to 57% reduction in species diversity of polychaetes and 70 to 71% in non-polychaete taxa compared to the northern region. The present study identified some opportunistic taxa such as Fabricia sp., Heteromastus filiformis, Platynereis insolita and Nereis sp. 1 and non-polychaetes such as chironomid larvae, podocops and cumaceans capable of adapting to the hypersaline environment in the Gulf of Salwa when salinity exceeded 60 and temperature exceeded 35 degrees C during summer. (C) 2015 Elsevier B.V. All rights reserved.