Response of sediment-dwelling annelida community in relation to geochemical parameters in the Gorgan Bay, Caspian Sea

Abstract

This study aimed to investigate the population of annelida communities in relation to environmental factors and heavy metals accumulated in sediments of the Gorgan Bay. The pollution load index and potential ecological risk (PER) were calculated. The results indicated mean concentrations (ppm) of heavy metals were (mean ± SD) Pb: 11.5 ± 4.88, Cu: 18 ± 8.83, Zn: 42 ± 22.15, Ni: 29.20 ± 14.68, Co: 10.56 ± 14.68, As: 7.77 ± 2.12, Sr: 1,449 ± 902.59 and V: 26.64 ± 10.25. Considering PER, sediments of the Gorgan Bay had low ecological risk. Based on abundance data, dominant species were Streblospio gynobranchiata, Nereis diversicolor, Tubificoides fraseri and Tubificidae unknown, respectively. Results of redundancy analysis displayed that T. fraseri and N. diversicolor were associated with high values of Sr. All the species were negatively correlated with As. There were positive correlation between S. gynobranchiata and N. diversicolor with values of clay, salinity, depth and silt. The present study provided the relative importance of heavy metals and environmental variables which partly assist in structuring assemblages of annelida in a transitional area.

Multi-proxy indicators in a Pontocaspian system: a depth transect of surface sediment in the SE Caspian Sea

“…A longshore current from the West to the East has been detected in the same region (Zaker et al, 2011). Measurements made in August 2010 in the Gorgan Bay itself (maximum 4 m depth) show salinities between 5 and 13 psu and temperatures around 26 ºC (Bastami et al, 2014). Using the Zaker et al (2007) data, one may surmise what the conditions are for the Gorgan transect in summer taking into account the proximity to a coastal semi-desert.…”