Macrobenthos And Its Relation To Ecosystem Dynamics In The Cochin Estuary

Cochin estuary is a shallow brackish water body situated on the south west coast of India. It is a tropical positive estuary extending between 90 40’ and 100 12’ N and 760 10’and 760 30’ E with its northern boundary at Azhikode and southern boundary at Thannermukkom bund.The abundance of benthic fauna in an ecosystem shows the close relationship to its environment and reflects the characteristics of an ecological niche. Seasonal and monthly variations in the distribution of macrobenthos in relation to sediment characteristics were conducted in Cochin estuary from 2009-10 periods. Oxidation-reduction potential showed reducing trends that affected the distribution and diversity of fauna. Seasonal variations in water quality and river discharge pattern affected the faunal composition in the different stations. Sewage mixing was the principal source of organic pollution in the Cochin estuary. The sediment pH was generally on the alkaline side ranging from 4.99 at St.9 and 8.33 at St.1.The Eh ranged from -11mV at St.3 to -625mV at St.2.The temperature varied from 260C to 320C in the estuary. The moisture content ranged from 1.63 to 12.155%, that of organic carbon from 0 09 at St. 6 to 4.29% at St.9 and that of organic matter from 0.16 to 7.39%. Seasonally, the average of Eh was highest during the monsoon (156.22 mV) and in the pre monsoon (140.94 mV). The average pH for the 9 study stations was 7.68 during monsoon period and 7.08 during post monsoon. Based on group wise seasonal analysis, the average mean abundance was maximum for polychaetes (43.47) followed by nematodes (33.62), crustaceans (21.62), molluscs (11.94) and Pisces (0.05) in the estuary. Monsoon season was most favourable for benthic faunal abundance followed by the post monsoon period in the study. The series of human interventions like dredging, discharge of industrial effluents, urbanisation and related aspects had a strong influence on the distribution, abundance of benthic macrofauna in the wetland.

Effect of industrial pollution on the benthic communities of a tropical estuary

Cochin backwaters, a tropical barbuilt estuary is well known for its prawn, molluscan and demersal fisheries. Also it formed the dumping area for sewage,235 retting of husks and discharge of effluents from industries located on either side of it. As a result the fishery is being gradually dwindled year after year due to the lowering of the water quality. The effect of industrial polution on the benthic community of this tropical estuary was worked out. An area extending over 21 km from the mouth of the estuary to upstream of industrial belt was selected. Temporal and spatial variations of 16 environmental parameters at 9 stations along the area were monitored monthly during 1981. Benthic fauna of these 9 stations consisted of amphipods , polychaetes, isopods, tanaidaceans, molluscs and other crustaceans (Decapods, Acetes, Alpheids, Balanus, insect larvae, chironomid larvae, cumacea and some fresh water forms ). Apart from these, sea anemone, flat worms, nematodes, sipunculoids, echinoderms and fishes were also encountered. 75 species belonging to 31 faunal groups were identified. Of these 31 groups, amphipods, polychaedes, isopods, tanaidaceans and molluscs were numerically abundant. Rest of the 26 groups (including 13 riverine forms) were found less significant due to their rare occurrence/low numerical abundance. Polychaetes and molluscs were the only major groups present at all the stations.

Distribution of Benthic In fauna in the Cochin Backwaters In Relation To Environmental Parameters

The study revealed stress and localized impact of industrial waste on the biota, predominance of stress tolerant species and low diversity in the vicinity of the effluent discharge point. These studies on impact of environmental parameters on the distribution of macrobenthos thus indicate the quantum of endurance warranted by the infauna to tide over the wide range of environmental stress. Low diversity and lower number of benthic fauna near discharge site can be attributed to the stress caused by cumulative toxic effects of effluents. The results of the physico-chemical parameters highlight the effects of pollution. The results of the study indicated the changes due to the large-scale movements of the estuarine water under the influence of tide, monsoon and land runoff coupled with its heterogenous nature owing to the effluent discharge from the industries

A new species of Pseudostomella (Gastrotricha: Macrodasyida: Thaumastodermatidae) from a sandy beach of Kerala, India

During an interstitial faunal survey along the south-west coast of Kerala, India, gastrotrich fauna were found in abundance. Together with species of the genera Xenotrichula, Halichaetonotus and Tetranchyroderma, were present several undescribed thaumastodermatid gastrotrichs belonging to the buccal palp bearing genus Pseudostomella. Adults of the new species are characterized by the following traits: total body length of about 300 μm; cuticular armature made up of medium sized pentancres covering the entire dorsolateral surface; pre-buccal, grasping palps bearing five, large papillae dorsally and 4-6 smaller papillae ventrally; adhesive apparatus made up of six anterior, 22-24 ventrolateral, two dorsolateral and six posterior adhesive tubes; caudal organ pear-shaped; frontal organ spherical. Pseudostomella cheraensis sp. nov. is the fourth taxon of the genus known from India; however, all the previous species reported hitherto from India have tetrancres instead of pentancres.

Characterization of polyhydroxyalkanoates accumulating vibrios from marine benthic environments and production studies of polyhydroxyalkanoates by Vibrio sp. BTKB33

The present work deals with the characterization of polyhydroxyalkanoates accumulating vibrios from marine benthic environments and production studies of polyhydroxyalkanoates by vibrio sp.BTKB33. Vibrios are a group of (iram negative, curved or straight motile rods that normally inhabit the aquatic environments.The present study therefore aimed at evaluating the occurrence of PHA accumulating vibrios inhabiting marine benthic environments; characterizing the potential PHA accumulators employing phenotypic and genotypic approaches and molecular characterization of the PHA synthase gene. The study also evaluated the PHA production in V:'hri0 sp. strain BTKB33, through submerged fennentation using statistical optimization and characterized the purified biopolymer. Screening for PHA producing vibrios from marine benthic environments. Characterization of PHA producers employing phenotypic and genotypic approaches.The incidence of PHA accumulation in Vibrio sp. isolated from marine sediments was observed to be high, indicating that the natural habitat of these bacteria are stressful. Considering their ubiquitous nature, the ecological role played by vibrios in maintaining the delicate balance of the benthic ecosystem besides returning potential strains, with the ability to elaborate a plethora of extracellular enzymes for industrial application, is significant. The elaboration of several hydrolytic enzymes by individuals also emphasize the crucial role of vibrios in the mineralization process in the marine environment. This study throws light on the extracellular hydrolytic enzyme profile exhibited by vibrios. It was concluded that apart from the PHA accumulation, presence of exoenzyme production and higher MAR index also aids in their survival in the highly challenging benthic enviromnents. The phylogenetic analysis of the strains and studies on intra species variation within PHA accumulating strains reveal their diversity. The isolate selected for production in this study was Vibrio sp. strain BTKB33, identified as V.azureus by 16S rDNA sequencing and phenotypic characterization. The bioprocess variables for PHA production utilising submerged fermentation was optimized employing one-factor-at-a-time-method, PB design and RSM studies. The statistical optimization of bioprocess variables revealed that NaCl concentration, temperature and incubation period are the major bioprocess variables influencing PHA production and PHA content. The presence of Class I PHA synthase genes in BTKB33 was also unveiled. The characterization of phaC genes by PCR and of the extracted polymer employing FTIR and NMR analysis revealed the presence of polyhydroxybutyrate, smallest known PI-IAs, having wider domestic, industrial and medical application. The strain BTKB33 bearing a significant exoenzyme profile, can thus be manipulatedin future for utilization of diverse substrates as C- source for PHA production. In addition to BTKB33, several fast growing Vibrio sp. having PHA accumulating ability were also isolated, revealing the prospects of this environment as a mine for novel PHA accumulating microbes. The findings of this study will provide a reference for further research in industrial production of PHAs from marine microorganisms .

Macrobenthos of a tropical estuary

In this thesis a detailed sampling is conducted using grabs and dredges to access the qualitative and quantitative nature of the macrobenthos. A11 the animal contributing to the fauna are identified and their pattern of distribution and seasonal abundance are discussed. Affinity and diversity of polychaete fauna have also been studied. Importance of different benthic forms and their contribution to the standing crop are studied in detail. Trophic relationship between macrofauna and botton feeding commercially important fishes and prawns are also given attention. The physico-chemical aspects or the environment have been studied and their relation to the distribution and abundance of bottom fauna has been discussed. Environmental parameters such as temperature. salinity and dissolved oxygen. both in bottom and in the overlying waters. and rainfall were studied along with the benthos investigations. The physico-chemical nature of the sediments was also subjected to investigation. Influence of all those ecological parameters on the bottom fauna is discussed. A detailed quantitative faunal list of maorobenthio species and a brief systematic account of the polychaeta are also given.

Survey of coral lagoons of Laksbadweep Atolls using line intercept transect (LIT) technique

The present study aims at surveying the coral lagoons of four islands viz. Kavarathi, Kalpeni, Kadmat and Agathi, which include quantitative survey of the major benthic forms using Line Intercept Transect (LIT) technique and hydrographical study of these lagoon waters The distribution of PHC in the lagoons has also been followed to understand, the effects of introduction of flat bottomed ferry boats to the islands.From a biological monitoring stand point for the assessment of manmade disturbance of the coral reefs, it IS highly essential to identify faunal assemblages which will contain 'flag-stones' specIes as indicators of such disturbances. Among the known faunal assemblages In coral reefs the most diverse groups of sensitive species belongs to bryozoan assemblage. Therefore, the most common species of bryozoans distributed along the atolls and reef flats were collected and described in this work Along with this, bryozoans associated with coral from other parts of Indian ocean have also been added so as to provide a comprehensive picture of the distribution of bryozoans in the coral reefs.