Diversity and Composition of Phytoplankton Around Jaitapur Coast, Maharashtra, India
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Indian Journal of Geo Marine Sciences Vol. 47 (12), December 2018, pp. 2429-2441 Diversity and composition of phytoplankton around Jaitapur coast, Maharashtra, India Mayura Khot1, P. Sivaperumal1, Neeta Jadhav1, S.K. Chakraborty1, Anil Pawase2&A.K. Jaiswar1* 1ICAR-Central Institute of Fisheries Education, Panch Marg, Off Yari Road, Versova, Andheri (W), Mumbai - 400061, India 2Colleges of Fisheries, Shirgaon, Ratnagiri - 415602, India *[Email: [email protected]] Received 07 April 2017; revised 02 June 2017 The average phytoplankton density was observed to be highest during post-monsoon at inshore as well as offshore stations. Overall phytoplankton was comprised of Bacillariophyceae (81.4%), Dinophyceae (12%), Chrysophyceae (3%), Cyanophyceae (1.8%), Desmophyceae (2.9%) and Chlorophyceae (3.9%). A total of 86 species of phytoplankton belonging to 56 genera and 6 classes were recorded from offshore and inshore stations. A massive bloom of cyanobacteria Trichodesmium erythraeum was also sighted during the winter season. Dinoflagellates showed a peak during monsoon at inshore stations. Maximum values of diversity indices were recorded during winter at offshore and during pre-monsoon at inshore stations. [Keywords: Jaitapur, proposed nuclear power plant, phytoplankton, bloom, Trichodesmium erythraeum] Introduction other power plants hasshown temperature as an Coastal NPP sites usually consuming seawater for important factor in increasing biomass, primary coolant system and discharge warm water into the sea, productivity and changes in species dominance of thereby raising the temperature of sea water1-3. phytoplankton around the vicinity of cooling water Generally,water temperature plays an important role outlet19,20.Outcomes from Kaiga nuclear power plant ininfluencing the survival rate, growth ability, and revealed negative impact of evaluated temperature on reproduction of aquatic organisms4,5. The primary plankton up to 500m from discharge point on Kadra producer in the aquatic ecosystem, phytoplankton reservoir16.In view of the role of phytoplankton in fish plays a major role in the aquatic environment and production, many investigators have studied support to the food web. About 95% of the primary different aspects of phytoplankton from Indian production is contributed mainly by phytoplankton6. waters21-25.However, some reports are available on These primary producers form the base of food webs phytoplankton studies from the west coast of that support marketable fisheries in marine Ratnagiri district prior to establishment26-29. In order environment7. to fulfill these requirements, investigations on the Long-term studies have been carried out on phytoplankton community structure and water quality plankton since the 1930s with numerous research prior to pre-installationare important to compare the projects continuing today8.The outcome of research status after the plant has been commenced. Hence, the showed that thermal loading influences micro algal present study is to create a baseline data of population by altering the composition of phytoplankton phytoplankton diversity & abundance from the coastal community & affecting the photosynthetic rate9-11. and offshore areas around the proposed nuclear power Studies on the effects of thermal discharge on plant site in Jaitapur. phytoplankton have been carried out by some authors2, 12-15.Studies on the impact of thermal Material & Methods discharges on phytoplankton revealed that chlorine Jaitapur is situated (160 34’ 38” N - 16036’ 29” N, was major stress factor rather than the elevated 730 19’ 02” E - 730 20’ 48” E) along the west coast of temperatures in declining phytoplankton standing Maharashtra. The site for Jaitapur Nuclear Power stock around MAPS of Kalpakkam and coastal waters Plant (JNPP) is situated in the area between Rajapur of Taiwan16-18. However, thermal discharge from creek and Vijaydurg creek, about 40 km south of 2430 INDIAN J. MAR. SCI., VOL. 47, NO. 12, DECEMBER 2018 Ratnagiri town. The nearest village to the site is CSW5km. Thus, sixteen stations falling under Madban. For the present study, the lighthouse at the Ratnagiri and Sindhudurg district were selected. Jaitapur NPP site was considered as the reference Water samples were collected during March 2012 point. Along the coast area, seven stations were to February 2014 during pre-monsoon (March-May), selected on the northwest and south-west from the monsoon (June-August), post-monsoon (September- reference point such as Ganeshgule (NSW30kms), November) and winter (December-February) from the Vetye (NSW15kms), Ambolgad (NSW10kms), fixed coastal as well as offshore stations around Vijaydurg (SSW5kms), Girye (SSW10kms), Jaitapur. Samples could not be collected from Padavane (SSW15kms) and Devgad (SSW30kms) offshore stations during monsoon season due to strong (fig. 1).For offshore areas, nine stations from the southwest monsoon winds. Water parameters such reference point to southwest, northwest and towards as pH, salinity, dissolved oxygen, temperature; center were selected viz. SSW1km, SSW3km, alkalinity, ammonia,and nutrients were estimated SSW5km for south-west, NSW1km, NSW3km, by following standard methods30-32. Phytoplankton NSW5km for north-west and CSW1km, CSW3km, samples were collected in two-litre capacity plastic bottles from the surface water and 1 ml of Lugol’s solution and 3-4 drops of formalin were added to it33. The sample was allowed for sedimentation of phytoplankton for 48 hrs and then the plankton settled at the bottom was concentrated to known volume (10ml), for further analysis. The taxa were identified up to possible taxonomic level34-37 using a compound microscope. For density, 1ml of the sample with proper mixing was counted using Sedgwick-Rafter cell and reported as a number of cells per unit volume30. Biodiversity indices such as Shannon Weiner diversity (H’), Margalef Richness (d) and Pielou’s Evenness (J’) were computed by using software Primer (Ver.6), developed by Plymouth laboratory U. K38. Cluster analysis was performed to discern similarities in plankton occurrence between sampling stations. Graphical representations like k-dominance curve, Bray Curtis similarity were figured based on the square root of transformed data. Results Water temperature varied between 25.20C and 30.10C. The highest temperature (30.10C) was recorded in post-monsoon season at S SW5 station (fig. 2). Salinity ranged between 31.6%o and 35.6%o, and higher values were recorded in pre-monsoon season at S SW5 station (fig. 3). D.O varied from 5.7mgl-1 to 8.1mgl-1. The maximum value (8.1mgl-1) was recorded at S SW1 station during pre-monsoon and minimum (5.7mgl-1) at C SW3 station during the post-monsoon season (fig. 4). Higher dissolved oxygen with average 8.2mgl-1 was observed during the winter season (Feb 2013), might be due to bloom of Trichodesmium erythraeum. Total alkalinity varied -1 between 63.1- 89.1 mgl (fig. 5). The range of Fig. 1 — Study area nutrients such as nitrite, phosphate,and silicates was: KHOT et al.: PHYTOPLANKTON AROUND JAITAPUR COAST 2431 1.9-14.7 µmol/l, 0.4-0.9 µmol/l and 12.2- 46.3 µmol/l, respectively. Ammonia ranged between 0.4-1.6 µmol/l. Maximum nitrite concentrations were found during the post-monsoon season(C SW3km, C SW 5km)as compared to winter season (Dec-Feb). Ammonia and silicate concentrations were found to be maximum during the post-monsoon season (N SW5km, CSW1km,and S SW5km). As compared to the north side, the locations to the south from the reference point of Jaitapur resulted in high silicate concentrations. Fig. 2 0 0 Water temperature ranged from 23.2 C to 30.5 C at inshore locations. The highest temperature (30.50C) was recorded in pre-monsoon at N SW10 station (fig. 6). Salinity varied between 15.0%o and 35.6%o. Minimum salinity was recorded in monsoon season at S SW5 and N SW10 stations due to the high influx of freshwater from estuaries (fig. 7). D.O varied from 5.0mgl-1to 8.7mgl-1. Maximum D.O was recorded in monsoon season at S SW15, N SW10and N SW30 station due to the influx of fresh water (fig. 8). Minimum DO was recorded in post monsoon season Fig. 3 where the average abundance of Skeletonema costatumwas high. Total alkalinity varied between 50.0 and 91.8 mgl-1 (fig. 9). The range of nitrite, phosphate, silicate,and ammonia was found to be Fig. 4 Fig. 6 Fig. 5 Fig. 2 — Temperature, 3: Salinity, 4: Dissolved Oxygen, 5: Alkalinity variations at offshore Fig. 7 2432 INDIAN J. MAR. SCI., VOL. 47, NO. 12, DECEMBER 2018 composition analysis revealed maximum contribution by Bacillariophyceae (81.1%) followed by Dinophyceae (13%), Desmophyceae (2.68%), Chrysophyceae (2.25%), and Cyanophyceae (0.9%). The percentage of diatoms showed a declining trend from post-monsoon (Sep-Nov) to winter period(Dec-Feb), whereas, the reverse was seen in the case of dinoflagellates (fig. 14-15). A massive bloom of blue-green algae Trichodesmium erythraeum (227100cells/l)was recorded at all stations during 2012-2013 in winter, except at station C SW1, Fig. 8 replacing Chaetoceros (31200 cells/litre), Pleurosigma (16000cells/l), Bellerochea (14400cells/l) and Nitzschia (11200cells/l). Dominant and common genera, recorded during both the years, were species of Skeletonema, Nitzschia, Asterionella, Chaetoceros, Bellerochea, Navicula, Coscinodiscus, Rhizosolenia, Odontella, Thalassionema, Thalassiosira, Ceratium, Dinophysis, and Protoperidinium. Analysis of data with regards to season revealed maximum density in monsoon (284.3 cells/l) followed by pre-monsoon (172.2 cells/l) and post-monsoon (134.2 cells/l) (fig. 12) at Inshore locations. Average Fig. 9 phytoplankton density was higher in 2013-2014 Fig. 6 — Temperature, 7: Salinity, 8: Dissolved Oxygen, 9: Alkalinity (167.7cells/l) as compared to 2012-2013 (90.9cells/l). variations at inshore Maximum density was recorded at N SW30, S SW15 1.4-14.7 µmol/l, 0.4-0.8 µmol/l, 3.9- 32.1 µmol/l and and N SW10 km stations (fig. 13) possibly as the 0.5-3.4 µmol/l, respectively.