Macrobenthic abundance in the vicinity of spreading ridge environment in Central Indian Ocean

Abstract

Macrofaunal communities of the Central Indian Ocean were evaluated for their composition, distribution, abundance and biomass. The fauna comprised of 24 major groups belonging to 15 phyla. The density of macrofauna varied from 30 to 1430 ind.m–2 (mean = 376.39 ± 345.97 SD; n = 56) and biomass varied from 0.11 to 12.75 g wet wt m–2 (mean = 1.02 ± 1.85 SD; n = 56). The results indicate that faunal density was negatively correlated with water depth (Y = – 0.204x + 1204.5; r = – 0.601; n = 56; P < 0.001). Exponential increase in benthic standing stock (density and biomass) from eastern to western region (Y = 2.3328x2 – 328.8x + 11640; r = – 0.712; n = 56; P < 0.001; n = 56) suggests the direct relationship between the mid-ocean ridge environment and macrobenthic abundance. The recent discovery of hydrothermal activity in the Indian Ocean strongly suggests the possibility of many more such activities in the region and hence the mid-ocean ridge systems in the Indian Ocean make them a very attractive environment for benthic biological studies.