Distribution of phytoplankton along an environmental gradient off Kakinada, East Coast of India

357-364In the present study phytoplankton distribution and species composition was examined on a salinity gradient from River (R), River Mouth (RM) and coastal water (RF) at surface and subsurface layers along the coast off Kakinada, East Coast of India. Average numerical abundance of phytoplankton at R, RM and RF are 336 nos.mL-1, 150 nos.mL-1 and 169 nos.mL-1 respectively. <span style="font-size: 9.0pt;mso-fareast-font-family:Calibri;mso-bidi-language:GU;mso-bidi-font-weight: bold" lang="EN-GB">Percentage contribution of each group of phytoplankton was in the order: Pinnate diatoms <span style="font-size:9.0pt;mso-fareast-font-family: Calibri;mso-bidi-language:GU;mso-bidi-font-weight:bold" lang="EN-GB">> Cyanophyceans<span style="font-size:9.0pt;mso-fareast-font-family:Calibri;mso-bidi-language:GU; mso-bidi-font-weight:bold" lang="EN-GB"> > Centrales <span style="font-size:9.0pt;mso-fareast-font-family:Calibri; mso-bidi-language:GU;mso-bidi-font-weight:bold" lang="EN-GB">> Prasinophyceans<span style="font-size:9.0pt;mso-fareast-font-family:Calibri;mso-bidi-language:GU; mso-bidi-font-weight:bold" lang="EN-GB">. However, total phytoplankton species at surface and subsurface water at all the stations showed presence of 52 and 24 species respectively. At the group level, cyanophyceans were significant at RF locations. Pennate diatoms were more at the remaining locations. Species <i style="mso-bidi-font-style: normal">Oscillatoria limosa was found to be abundant at both the surface and subsurface water with 340 filaments.ml-1 and 488 filaments.mL-1 recpectively. Thalassiothrix longissima was found to be maximum at surface water but absent in subsurface water. Wide variation in evenness values (0.16-0.910) suggests uneven distribution of species along the environmental gradient. </span

Distribution, abundance and diversity of phytoplankton in the inshore waters of Nizampatnam, South East coast of India

348-356Distribution, abundance and species assemblages of Phytoplankton were studied from inshore waters of Nizampatnam, South East coast of India in March 2007. <span style="mso-fareast-font-family:Calibri;mso-ansi-language:EN-US;mso-bidi-language: GU;mso-bidi-font-weight:bold" lang="EN-US">Significant spatial variations in temperature, pH, salinity, dissolved oxygen (DO), nitrites (NO2) –N)<span style="mso-fareast-font-family:Calibri;mso-ansi-language:EN-US;mso-bidi-language: GU;mso-bidi-font-weight:bold" lang="EN-US">, nitrates (NO3) – N)<span style="mso-fareast-font-family:Calibri;mso-ansi-language: EN-US;mso-bidi-language:GU;mso-bidi-font-weight:bold" lang="EN-US">, phosphate (PO4) –P),<span style="mso-fareast-font-family:Calibri;mso-ansi-language:EN-US;mso-bidi-language: GU;mso-bidi-font-weight:bold" lang="EN-US"> silicate (SiO4) – (Si)<span style="mso-fareast-font-family:Calibri; mso-ansi-language:EN-US;mso-bidi-language:GU;mso-bidi-font-weight:bold" lang="EN-US"> were monitored. A total of 90 species of phytoplankton (net hauls) represented by 5 groups were identified at nine stations, collected along three transects during low tide.<span style="mso-fareast-font-family: Calibri;mso-ansi-language:EN-US;mso-bidi-language:GU;mso-bidi-font-weight:bold" lang="EN-US"> Percentage contribution of each group of phytoplankton was in the order: Bacillariophyceans <span style="mso-fareast-font-family: Calibri;mso-ansi-language:EN-US;mso-bidi-language:GU;mso-bidi-font-weight:bold" lang="EN-US">> Dinophyceans <span style="mso-fareast-font-family: Calibri;mso-ansi-language:EN-US;mso-bidi-language:GU;mso-bidi-font-weight:bold" lang="EN-US">> Cyanophyceans <span style="mso-fareast-font-family: Calibri;mso-ansi-language:EN-US;mso-bidi-language:GU;mso-bidi-font-weight:bold" lang="EN-US">> Euglenophyceans<span style="mso-fareast-font-family:Calibri;mso-ansi-language:EN-US;mso-bidi-language: GU;mso-bidi-font-weight:bold" lang="EN-US">. Pleurosigma angulatum, Navicula sp. were dominant species in the study area. Bray - Curtis similarity and group average clustering, recommended identifying two assemblages of phytoplankton in the study area. High diversity of phytoplankton in the present area suggests stable environmental conditions. </span