Sediment sampling and analysis of physico-chemical
parameters
Pterson’s grab (0.256 m2) was used to collect sediment samples.
The soil temperature was measured using a standard centigrade
thermometer by directly inserting in the sediment. The soil pH was
determined by adopting the method of Jackson ML [14]. Water was
added to air-dried samples in the ratio of 1:1 and stirred in a mechanical
shaker for an hour, and pH was measured in this solution. A known
amount of sediment samples was moisturized with double distilled
water up to the moisture saturation of the sediment. Then double the
volume of saturation level of water was added, mechanically shaken for
15 min, and the water with salt was filtered through a Whatman No. 1
filter paper and the salinity was measured using a hand refractometer.
Soil samples were brought to the laboratory in clean polythene bags,
air dried, and stored for further analysis. The percentage composition
of sand, silt, and clay in the sediment samples were determined by the
sieving method of Krumbein WC [15].
Macrofauna sampling and identification
The samplings covered all the tidal levels and were done by
using a line transect method. Pterson’s grab (0.256 m2) was used for
unit sampling. Six replicates for each station were maintained. Soon
after retrieval, samples were gently sieved through a 0.5-mm sieve.
The organisms retained by the sieve were preserved in 5% formalin
and brought to the laboratory for further identification. The sorted
organisms were first segregated into different groups and then identified
to specific, genetic or other higher levels to the greatest extent possible
with the help of standard taxonomic references viz. Polychaeta [16,17]
and Mollusca [18]. The organisms were counted under a stereoscopic
microscope, and abundance was expressed as individuals per square
meter. In the present study, the qualitative and quantitative assessments
of benthic macrofauna were noted only to polychaetes, bivalves, and
gastropods (molluscs), and isopods and amphipods (crustaceans).