Impact of torrential rain on coastal ecosystem at kalpakkam, southeast coast of India

1609-1615The present study focuses on the drastic changes observed in the coastal ecosystem at Kalpakkam during flooding event due to huge rainfall that occurred in and around northern Tamil Nadu during December 2015. A significant increase in hydrological parameters (nitrate, phosphate, silicate, total nitrogen and phosphorous) was recorded as compared to previous years (2006-2014). In the present instance, the coastal water salinity which was about 19 psu was the lowest as compared to the data available since 1979. The phytoplankton population density was severely affected by the runoff. The present observed density 1.4 x 104 cells l-1 was the lowest among the available data at this coast. Availability of green algae species in the coastal waters was significantly high (10 species, 17 % of total species) as compared to previous reports. One of the most interesting features of this study was the observation of epibiosis on zooplankton in massive numbers. A comparison of previous occurrences of epibiotic relationship in plankton community with the present observation showed a staggering increase in epibiosis to 38 % of zooplankton species as compared to 5-13 % during 2008-2014

Assessment of temporal variation in coastal water characteristics through multivariate statistics- A case study at southwestern Bay of Bengal, India

1718-1731A study was carried out in the coastal waters of Kalpakkam, southeast coast of India, in order to find out the prevalence of different water masses in a spatio-temporal scale. This region of southwestern Bay of Bengal is influenced by both southwest and northeast monsoon. However, in absence of any major perennial freshwater input into the coastal water, the water mass characteristics in this region mainly depends upon the coastal current pattern. Statistical analysis showed two temporally distinct water mass; one during the monsoon period and the other during the pre- & post-monsoon periods. Cluster analysis also depicted existence of a well marked spatial heterogeneity in the study area.  Five principal components developed showed distinct environmental states of coastal waters such as nitrogen enrichment, phytoplankton growth, phosphate enrichment, low dissolved oxygen & high temperature condition and nitrite enrichment which might have existed at this location on a temporal scale.

Textural characteristics of beach sediments along Kalpakkam, south east coast of India

1562-1574Samples collected from foreshore region showed more variations in grain size as compared to mid-shore region samples. Median values varied from -0.08ø to 2.19 ø with an average of 1.04 ø (Std ± 0.65 ø). Mean value showed that samples were fine to coarse sand, whereas, only 1.8% of total samples were found as very coarse sand. During southwest monsoon the average mean size of the beach sediment was 0.98 ø, which is coarse sand in contrast to the medium sand observed during other seasons. Present study showed that, 81.7% of the samples were unimodal and 17.8% samples were bimodal. Sediment samples were very well sorted (0.18 ø) to poorly sorted (1.18 ø) and sorting characteristics decreased with increased wave energy. Skewness value indicated that 41% & 11% of the samples were positively skewed and negative skewed respectively, whereas, rest of the samples were symmetrical. All the beaches were dominated by mesokurtic sediment. Dominance of positively skewed sediment in the study area indicated the prevalence of low wave activity and longshore current. Presence of relatively high fraction of mesokurtic sediment indicated that the beaches along Kalpakkam by and large have uniform energy environment

New record of an epizoic diatom, Pseudohimantidium pacificum on two species of copepods from the Indian Ocean

1331-1334Pseudohimantidium pacificum Hustedt and Krasske, 1941, an epizoic diatom was found on the copepod genera Corycaeus Dana and Euterpina acutifrons Dana from the coastal waters of Southwestern Bay of Bengal. The present report forms the first record of the epibiont Pseudohimantidium pacificum from the Indian coast and the Indian Ocean

Geochemical distribution of forms of phosphorus in marine sediment of Bay of Bengal, southeast coast of India

1132-1141Sediment samples were collected from three transects in the continental shelf region (up to 30km offshore) between Chennai to Marakkanam. Sedimentary parameters such as sand, silt, clay and organic carbon percentage were analyzed in order to find out their relation with various phosphorus fractions.  Sediment was found to be predominantly sandy in nature with low silt and clay content. Among all the fractions (loosely bound- Lo-P, calcium bound- Ca-P, iron bound- Fe-P, aluminum bound- Al-P and organically bound- OP), Ca-P fraction constituted the largest portion (71.38%) followed by OP (16.16%). Bioavailable fractions of phosphorus ranged from 9.3 to 36.2% (avg. 20.9%) of the total phosphorus (TP) during the present study. Total phosphorus content in the offshore sediments ranged between 469.35 and 1219.34 mg/kg with an average of 824.66 mg/kg. The abundance of the major forms of P in the surface sediments of Kalpakkam coast followed the order: Ca-P > OP > Al-P > Lo-P > Fe-P. Cluster analysis clearly showed that all the three transects were different from each other as they formed three different clusters