Bio: P. Haridas is an academic researcher. The author has contributed to research in topics: Zooplankton. The author has an hindex of 1, co-authored 1 publications receiving 20 citations.
01 Jan 1980
TL;DR: In this article, seasonal changes in the composition and distribution of zooplankton from the coastal waters of Trivandrum were studied, and it was shown that the effluent discharged from a nearby titanium dioxide factory did not affect the abundance of ZOPs.
Abstract: Seasonal changes in the composition and distribution of zooplankton from the coastal waters of Trivandrum were studied. The study indicated that the effluent discharged from a nearby titanium dioxide factory did not affect the zooplankton abundance. Copepods followed by cladocerans contributed to the bulk of zooplankton. Species composition of zooplankton and their ecology are discussed. Diversity of zooplankton was high in the postmonsoon months and also in April
TL;DR: In this article, the role of ocean currents in molding mesozooplankton community characteristics in these, geographically closer and ecologically important transitional zones was investigated by collecting data from 30 locations in the Gulf of Mannar and the Palk Bay in March 2010 (Spring Intermonsoon), September 2010 (Southwest Monsoon) and January 2011 (Northeast Monsoon).
Abstract: The Gulf of Mannar and the Palk Bay, located between India and Sri Lanka, are the two least studied marine environments in the northern Indian Ocean. We hypothesis, perceptible physical barriers that exist between the deep Gulf of Mannar and shallow Palk Bay, and seasonally reversing surface circulation patterns in the region have a concerted effect on the ecology of these oceanographically important areas. In the present study, data collected from 30 locations in the Gulf of Mannar and the Palk Bay in March 2010 (Spring Intermonsoon), September 2010 (Southwest Monsoon) and January 2011 (Northeast Monsoon) were used to investigate the role of ocean currents in molding mesozooplankton community characteristics in these, geographically closer and ecologically important transitional zones. Spatial difference in salinity was evident in the area with consistently higher values in the Gulf of Mannar as compared to the Palk Bay. The surface salinity was maximal during the Southwest Monsoon followed by the Spring Intermonsoon, and the Northeast Monsoon. These variations in salinity were closely linked with the seasonally reversing ocean currents as revealed in MIKE 21 flow model results. The mesozooplankton community dominated by copepods showed significant difference in species richness between the Gulf of Mannar (81 species) and the Palk Bay (63 species). Non-metric Multidimensional Scaling (NMDS) and Agglomerative Hierarchical Cluster Analysis (AHCA) on Bray–Curtis copepod similarity clearly estranged the Gulf of Mannar and the Palk Bay waters during the Spring Intermonsoon, and the Northeast Monsoon, attributable to the truancy of durable mixing typical of these seasons. In contrast, aided by strong currents, the increased mixing resulted in a homogenous copepod population in the Gulf of Mannar and the Palk Bay during the Southwest Monsoon. Furthermore, the indicator and dominant species analysis for copepods divulged the spatial heterogeneity in species composition during the Spring Intermonsoon and the Northeast Monsoon periods. Multivariate Redundancy Analyses showed salinity as the most important variable accountable for the observed variance in copepod distribution. In general, the copepod community in the Gulf of Mannar was composed both of coastal and offshore species whereas, coastal species largely inhabited the Palk Bay. This kind of a study depicting zooplankton community organization as governed by seasonally reversing monsoon circulation patterns forms the first record from the Indian coastal waters. The findings attain absolute significance considering its ecological implications on oceanographically transitional systems like the Gulf of Mannar, and the Palk Bay.
TL;DR: In this paper, a coastal upwelling situation from the central west coast of India was studied and the abundance of zooplankton was found to be dominated by a few species of herbivores and carnivores.
Abstract: Zooplankton composition and abundance were studied in a coastal upwelling situation from the central west coast of India. Upwelling and associated high biomass was found confined to a narrow coastal span. Zooplankton composition was dominated by a few species of herbivores and carnivores and was generally distinct from non-upwelling and offshore waters. Zooplankton had higher aggregations in the shallow upper mixed layer compared to the stratum below. High variability in zooplankton abundance occurred over short periods. Diel patterns in distribution or migration of zooplankton in inshore waters were not detectable.
30 Mar 2008
TL;DR: In this paper, the microzooplankton (MZP) community was comprised of heterotrophic dinoflagellates, ciliates and copepod nauplii.
Abstract: During the late summer monsoon (LSM), coastal upwelling and river runoff have increased the nutrient concentration in the inshore region of the southeastern Arabian Sea. This has resulted in elevated chlorophyll-a (av. 40±18 mg m−2), phytoplankton abundance (av. 474±116×106 ind. m−2) and primary production (av. 917±616 mg C m−2 d−1). Diatoms were the major component of the phytoplankton community (av. 60±8% of the total abundance) during this period, followed by dinoflagellates (18±12%). However, the inshore locations of 10°N and 13°N transects behaved differently, with an exceptional abundance of phytoflagellates (>1010 ind. m−2). The microzooplankton (MZP) community was comprised of heterotrophic dinoflagellates (av. 60%), ciliates (av. 30%) and copepod nauplii (av. 5%); these showed marked variation in abundance between stations. The highest abundance (av. 283×104 ind. m−2) was at the inshore location of 10°N transect, where phytoflagellates were abundant. Contrasting to the LSM, intense surface layer stratification and depletion of nitrate (with a nitracline at 60 m depth), observed in the southeastern Arabian Sea during the spring intermonsoon (SIM) period, caused low phytoplankton abundance (av. 141±86×106 ind. m−2), chlorophyll-a (av. 19±11 mg m−2) and primary production (av. 146±68 mg C m−2 d−1). High temperature (>29 °C) and nitrate-depleted surface waters favoured the proliferation of Trichodesmium erythraeum at most of the locations. Total abundance of MZP during the SIM was markedly low (av. 20×104±13×104 ind. m−2), as was the species richness and diversity (0.36±0.02 and 0.57±0.15, respectively) compared to the LSM (1.17±0.31 and 2.72±0.34, respectively). During the SIM, the MZP community that occurs in the southeastern Arabian Sea is important, since smaller individuals are widespread and form the majority of phytoplankton community. The present study points also to the fact that the MZP could play an important role, even in nutrient-enriched environment, if smaller phytoplankton are abundant.
01 Jan 1992
TL;DR: In this article, the authors reconsidered the paradox of mesozooplankton (MSP) based on intensive in-situ observations at 39 - 40 locations in the central and eastern Arabian Sea (EAS).
Abstract: In the central and eastern Arabian Sea (EAS), biomass and production of phytoplankton are known to vary spatially and seasonally whereas, biomass of mesozooplankton (MSP) is reported to be constant. This apparent contradiction has been called 'Arabian Sea Paradox'. However, it is important to note that the paradox of MSP is based on a very limited seasonal data (from 5-7 locations). Therefore, we reconsidered the paradox of MSP based on intensive in-situ observations at 39 - 40 locations in the EAS. In agreement with the known seasonal difference in phytoplankton standing stock in the EAS, we analysed the MSP data in two ways using two-way nested ANOVA. In 'basin scale' analysis, MSP data were analysed from the EAS were pooled and seasonal and inshore - offshore variations were analysed for the entire region. In 'regional scale' analysis, MSP data were analysed separately for (a) northern region (north of 15°N) and (b) southern regions (15°N and south of it). Satellite data of chlorophyll a, SST and wind speed were also analysed to show the major differences in oceanographic features in the northern and southern EAS. The analyses showed prominently high chlorophyll a (av. 1mg m -3 ) in the northern region during most of the year through winter convection, open ocean upwelling and lateral advection from the Arabian coast. On the other hand, chlorophyll a was low (av. 0.2mg m -3 ) in the southern region during most of the year mainly due to thermohaline stratification. The MSP biomass was distributed almost in a similar way as that of phytoplankton stock with statistically significant spatial and seasonal variations in the northern and southern regions. In this paper, we review the 'paradox of MSP' and present clear and new evidences to show that this concept is not logically applicable for EAS.