Study of diversity and distribution of ‎Polychaetes (Annelida: Polychaeta) in ‎Qeshm Island and the effect of ‎desalination plant effluent on them

The present study was carried out to investigate the diversity and distribution of the Polychaeta species in the Qeshm Island and the effect of desalination plants on their communities. The desalination plants provide a large portion of Qeshm Island drinking water. So, their waste waters could effect on environment especially benthic animals near the coastline. Substrate sampling was carried out in summer and winter 2014 from 9 stations. Station 1 was situated near (desalination site) with the highest temperature and salinity in both summer and winter season, which shows the effects of drainage waste water on environment condition. The substrates of the most stations were silt-clay. At the stations 4 and 5, which sediments included more silt and clay, organic matters were higher than other stations. In this study 49 genera and species were identified. There was a significant negative correlation between the polychaetes abundances and sediment content of silt and clay observed. The higher abundances of polychaetes were found in the stations with lower content of organic matters and greater grain size sediments. The genera Cossura sp. and Scoloplos simplex which related to Cossuridae and Orbiniidae families respectively were dominant specimens. The lowest level of diversity was estimated in station 1. Diversity and dominance indices at stations near the wastewater outlet showed significant differ in both seasons (P<0.05). Finally, it seems that desalination plant may affects adversely on species diversity by increasing of temperature and salinity in short distances.