Contribution of size fractions of planktonic algae to primary organic productivity in the coastal waters of Cochin- south west coast of lndia

This thesis entitled ���Contribution of size fractions of planktonic algae to primary organic productivity in the coastal waters of cochin,south west coast of india���. Marine ecosystems planktonic algae are the most important primary producers on wliich considerable attention is being given on account of their supreme status in the marine food chain.The study of primary production in the Indian Ocean started With DANA (I928-30),, John Murray t I933-34). Discovery ( I934) and Albatross (I947-48) expeditions which tried to evaluate productivity from nutrients and standing crop of phytoplankton .The bioproductivity of the marine environment is dependent on various primary producers. ranging in size from picoplankton to larger macro phytoplankton. The quantity and quality of various size fractions of planktonic algae at any locality depend mainly on the hydrographic conditions of the area .In the coastal waters of Cochin- south west coast of lndia. Planktonic algal community is composed mainly of the diatoms, the dinoflagellates, the blue-green algae and the silicoflagellates, the former two contributing the major flora and found distributed in the all size fractions. The maximum number of species of diatoms at station 1 and station 2 was found in the pre-monsoon season.. The size groups of planktonic algae greater than 53 um are dominated by filamentous- chain forming and colonial diatoms. The coastal waters of Cochin. planktonic algae less than 53 um in size contribute significantly to primary productivity and the biodiversity of the microflora, indicating the presence of rich fishery resources in the south west coast of india.The study of different size fractions of planktonic algae and their relative contribution to the primary organic production is a useful tool for the estimation of the quantity and quality of fisheries.A deeper investigation on the occurrence of these microalgae and proper identification of their species would be of immense help for the assessment of the specificity and magnitude of fishery resources.

Eutrophication and the management of planktonic algae: What Vollenweider couldn't tell us

The ���Vollenweider model��� is a sophisticated mathematical statement about the long-range behaviour of (mainly temperate) lakes and their ability to support phytoplankton chlorophyll. Misapplication of the model, against which Vollenweider himself warned, has led to many misconceptions about the dynamics of plankton in lakes and reservoirs and about how best to manage systems subject to eutrophication. This contribution intends to frame the most important issues in context of the phosphorus- loading and phosphorus-limitation concepts. Emphasis is placed on the need to distinguish rate-limitation from capacity-limitation, to understand which is more manageable and why, to discern the mechanisms of internal recycling and their importance, and to appreciate the respective roles of physical and biotic components in local control of algal dynamics. Some general approaches to the management of water quality in lakes and reservoirs to eutrophication are outlined.

Immunodetection of planktonic algae

Interest in the identification and characterisation of cyanobacteria and dinoflagellates in aquatic environments is increasing rapidly due to the perceived roles of these organisms in primary production and nuisance aspects in terms of water treatment and public health. Techniques for the identification and quantification of these organisms currently are limited, and the application of molecular approaches provides fundamental taxonomic information and techniques of practical value. Antigenic properties of algal cells may be useful taxonomic markers. Immunodetection techniques utilise the specificity of the antibody/antigen association as a probe for recognising and distinguishing between microorganisms according to their cell- surface chemistry. Immunofluorescent detection of unicellular cyanobacteria and dinoflagellates has been studied with success in marine and freshwater ecosystems and a range of techniques and results are presented and discussed. The most recent advances in the study of planktonic algae have come with the application of continuous flow cytometric methods (CFC). Flow cytometry makes use of the autofluorescence properties of the algal cells, which alone can be used to demonstrate their presence and permit their quantification in natural water samples. When used in conjunction with immunolabelling techniques, the potential of CFC analysis is broadened to study the serological/strain composition of plankters in natural populations. Changes in algal strains represented within and between waters over periods of time are reported and discussed, along with the ecological issues thus raised.

Distribution of planktonic foraminifera in the Southern Ocean (maps)

There are about 30 species of planktonic Foraminifera, as contrasted with the more than 4200 benthic species in the oceans of the world. Most of the planktonic species belong to the families Globigerinidae and Globorotaliidae. Of the 30 species, 9 occur in Antarctic and Subantarctic waters; however, none of these cold-water species are restricted to the Southern Ocean, except possibly the newly recognized Globorotalia cavernula (Be, 1967b). These species are distributed in broad zones of similar temperature in both the Northern and Southern Hemispheres. Hence, it is not possible to refer to these species as endemic to the Antarctic or Subantarctic, although some of them do appear in very high concentrations of 10 specimens/m**3 or more in the Antarctic regions. The plankton samples upon which the accompanying maps are based were collected between 1960 and 1965 on the research vessels Eltanin of the National Science Foundation (U.S. Antarctic Research Program), and Vema and Conrad of the Lamont Geological Observatory. All surface (0 m to 10 m) and vertical (0 m to 300 m) tows were obtained with plankton nets of uniform mesh size and material (NITEX202 = 202 ��m mesh-aperture width) and were provided with flowmeters for quantitative readings of amounts of water filtered.

(Figure 4) Stratigraphic distribution of planktonic foraminifera in DSDP Hole 93-604

During Deep Sea Drilling Project Leg 93, upper Miocene through Quaternary sediments were continuously cored in Hole 604, located on the upper continental rise of the New Jersey transect (western North Atlantic). A detailed biostratigraphic study of these strata has been made using the vertical distribution of planktonic foraminifers. The Quaternary climatic zonation of Ericson and Wollin (1968) has been tentatively delineated and all the Pliocene zones and subzones (sensu Berggren, 1977) have been recognized. The rate of sedimentation was slow during most of the Pliocene but underwent a significant acceleration in the early Pleistocene. Quantitative variations in the distribution of planktonic foraminifers appear to be influenced by various factors, such as hydrodynamic winnowing resulting from the action of bottom currents and surficial thermal conditions caused by climatic changes. Both dissolution intervals and brief increases in the coarser detrital input seem, most of the time, to be correlated with indications of climatic cooling and may correspond to glacial events or cycles. This chapter delineates a precursor stage in the inception of Northern Hemisphere glaciation at 3 Ma and wide-scale Quaternary glacial-interglacial cycles. Data from a detailed study of Hole 604 are briefly compared with the main sedimentary and microfaunal features of contemporaneous series previously drilled along the east American margin in the northwestern Atlantic. One of the striking observations appears to be the intense redistribution of sediments that affected this region in Neogene-Quaternary times.

Distribution of planktonic foraminifers, d18O and d13C in Globigerinoides sacculifer as well as Cibicidoides kullenbergi at DSDP Holes 90-590A and 90-590B

High biogenic sedimentation rates in the late Neogene at DSDP Site 590 (1293 m) provide an exceptional opportunity to evaluate late Neogene (late Miocene to latest Pliocene) paleoceanography in waters transitional between temperate and warm-subtropical water masses. Oxygen and carbon isotope analyses and quantitative planktonic foraminiferal data have been used to interpret the late Neogene paleoceanographic evolution of this site. Faunal and isotopic data from Site 590 show a progression of paleoceanographic events between 6.7 and 4.3 Ma, during the latest Miocene and early Pliocene. First, a permanent depletion in both planktonic and benthic foraminiferal d13C, between 6.7 and 6.2 Ma, can be correlated to the globally recognized late Miocene carbon isotope shift. Second, a 0.5 per mil enrichment in benthic foraminiferal d18O between 5.6 and 4.7 Ma in the latest Miocene to early Pliocene corresponds to the latest Miocene oxygen isotopic enrichment at Site 284, located in temperate waters south of Site 590. This enrichment in d18O coincides with a time of cool surface waters, as is suggested by high frequencies of Neogloboquadrina pachyderma and low frequencies of the warmer-water planktonic foraminifers, as well as by an enrichment in planktonic foraminiferal d18O relative to the earlier Miocene. By 4.6 Ma, benthic foraminiferal d18O values become depleted and remain fairly stable until about 3.8 Ma. The early Pliocene (~4.3 to 3.2 Ma) is marked by a significant increase in biogenic sedimentation rates (37.7 to 83.3 m/m.y.). During this time, heaviest values in planktonic foraminiferal d18O are associated with a decrease in the gradient between surface and intermediate-water d13C and d18O, a 1.0 per mil depletion in the d13C of two species of planktonic foraminifers, and a mixture of warm and cool planktonic foraminiferal elements. These data suggest that localized upwelling at the Subtropical Divergence produced an increase in surface-water productivity during the early Pliocene. A two-step enrichment in benthic foraminiferal d18O occurs in the late Pliocene sequence at Site 590. A 0.3 per mil average enrichment at about 3.6 Ma is followed by a 0.5 per mil enrichment at 2.7 Ma. These two events can be correlated with the two-step isotopic enrichment associated with late Pliocene climatic instability and the initiation of Northern Hemisphere glaciation.

Distribution of planktonic foraminifera in DSDP Hole 31-296 (Table III)

Late Neogene planktonic foraminiferal biostratigraphy of DSDP Site 296, Leg 31, reveals this site as an ideal reference section for correlation of Blow's low-latitude zonation with the mid-latitude zonation for temperate faunal assemblages developed in this paper and earlier for DSDP Site 310, Leg 31 (Keller). Abundance of temperate species of Globorotalia (G. inflata, G. puncticulata, G. crassaformis, G. conomiozea) permit correlation with the zonal subdivision developed at Site 310 based on these species. Evolutionary changes within the Globorotalia inflata group also appear to be consistent biostratigraphie markers in mid latitudes; a primitive variety of this species first appears at about 3.3-3.1 Ma, G. inflata praeinflata appears at about 2.6 Ma, and the modern form appears at about 2.2-2.1 Ma. Quantitative analyses of planktonic foraminifera at DSDP Site 296 reveal an inversely reciprocal frequency oscillation between species of Globorotalia and the Globigerina-Globigerinita group. Cool climatic periods are characterized by high frequencies in the Globigerina-Globigerinita group and low frequencies in the Globorotalia group, whereas warm intervals are marked by high frequencies in the Globorotalia group and low frequencies in the Globigerina-Globigerinita group. Five cool paleoclimatic events can be recognized between early Pliocene and late Pleistocene: 4.4 Ma, 3.2-3.1 Ma, 2.4-2.2 Ma, 1.2 Ma, and 0.7 Ma. These paleoclimatic/paleoceanographic events have also been recognized in planktonic foraminifera of the Central and Northeast Pacific DSDP Sites 310 and 173 and also correlate to cold events recognized in oxygen isotope measurements of DSDP Site 310 and in equatorial Pacific cores.

Variability in the distribution of planktonic fish eggs and larvae in the nearshore waters off Bombay

Distribution of planktonic fish eggs and larvae in the nearshore waters off Bombay was studied during November 1979 to December 1980. Monthly samples were collected along three transects (Versova, Mahim and Thana) covering eleven stations which represented different environmental conditions. Fish eggs and larvae were common in the area of study with maximum abundance in December 1979 and April/August 1980. Mean density of fish eggs was maximum along the Mahim transect while population of larvae was more in the Versova transect. Total number of families of fish larvae represented in the collections increased from nearshore to offshore area.

Distribution of planktonic decapods with special reference to Acetes from nearshore waters of Bombay

Distribution and seasonal variation of decapod larvae were studied from 8 stations off Versova and Mahim during Nov. 1979 to Dec. 1980. Decapod larvae were encountered throughout the year contributing 7.27% of total zooplankton. Numerically, they were more to Versova (av. 1766/100 m super(3)) than Mahim (av. 970/100 m super(3)). Acetes) spp. were common along both the transects. They were represented by Acetes indicus, A. siibogae and A. erythraeus. The effect of physico-chemical parameters in the occurrence of decapod larvae is discussed.

Spatial distribution of benthic algae in the Gangqu River, Shangrila, China

This study consisted of sampling benthic algae at 32 sites in the Gangqu River, an important upstream tributary of the Yangtze River. Our aims were to characterize the benthic algae communities and relationships with environmental variables. Among the 162 taxa observed, Achnanthes linearis and Achnanthes lanceolata var. elliptica were the dominant species (17.10% and 14.30% of the total relative abundance, respectively). Major gradients and principal patterns of variation within the environmental variables were detected by principal component analysis (PCA). Then non-metric multidimensional scaling (NMS) divided all the sites into three groups, which were validated by multi-response permutation procedures (MRPP). Canonical correspondence analysis (CCA) indicated that three environmental variables (TN, TDS, and TP) significantly affected the distribution of benthic algae. Weighted averaging regression and cross-calibration produced strong models for predicting TN and TDS concentration, which enabled selection of algae taxa as potentially sensitive indicators of certain TN and TDS levels: for TN, Achnanthes lanceolata, Achnanthes lanceolata var. elliptica, and Cymbella ventricosa var. semicircularis; for TDS, Cocconeis placentula, Cymbella alpina var. minuta, and Fragilaria virescens. The present study represents an early step in establishing baseline conditions. Further monitoring is suggested to gain a better understanding of this region.

Vertical distribution and migration of planktonic rotifers in Xiangxi Bay of the three Gorges Reservoir, China

We investigated diel vertical migrations (DVM) and distributions of rotifers in summer, 2004 and spring, 2005, in Xiangxi Bay of the Three Gorges Reservoir, China. Water temperature, pH, conductivity, and phytoplankton were closely related to rotifer vertical distribution, while dissolved oxygen had no relationship with the vertical distribution of rotifers. The species composition and population density of rotifers changed significantly between seasons. However, rotifer vertical distributions in both seasons were similar. They aggregated at specific depths in the water column. All the rotifer species inhabited the surface layers (0.5-5 m). Generally, the rotifers did not display DVM except for Polyarthra vulgaris (in summer), which performed reverse migration. The reason that rotifers did not perform DVM may be explained by the low abundance of competitors and predators and the high density of food resources at the surface strata.

Distribution of epilithic algae in the Xiangxi River system and their relationships with environmental factors

The spatial pattern of epilithic algae in the Xiangxi River system was studied in relation to several environmental factors by two-way indictor species analysis (TWINSPAN), detrended correspondence analysis (DCA), and canonical correspondence analysis (CCA). Eighty-nine taxa including diatoms, green algae, and blue-green algae were observed. Diatoms were dominant, and Cocconeis placentula, Cymbella minuta, Diatoma vulgare, and Gomphonema angustatum appeared in most of sampling sites. By TWINSPAN and DCA, thirty-one sites were divided into three groups based on composition and relative richness of benthic algae. CCA indicated that SiO2, pH, total phosphorus, Ca2+, velocity, elevation, and Cl- were significant environmental factors affecting the distribution of algae communities. In this minimal subset, SiO2 and pH were the most influential variables.

Studies on the ecophysiology of periphytic algae in cochin estuary

The estuaries are highly productive ecosystems and characteristically are more productive than the adjacent river or sea. Estuarine producers which include planktonic algae, periphyton, herpobenthos as well as macrophytes are capable of nearly year round photosynthesis. Productivity of an environment is mainly the contribution of various groups of autotrophic flora. Any quantitative estimation excluding any one of these would be an underestimation. Periphyton plays a very important role in the productivity of estuarine and coastal waters. It has been reported that periphytic algae attain high biomass (Moss, 1968; Hansson, 1988a) and may contribute up to 80% of the primary production (Persson gt gtt, 1977); Considerable amount of work has been done on the productivity in Cochin backwaters by different investigators (Qasim, 1973, 1979; Nair gt gtt, 1975; Gopi��� nathan gt gtt, 1984). All of them have estimated the primary production based only on phytoplankton of the estuary. Considering the contribution of other autotrophic components of the estuary such as periphyton (haptobenthos), sediment flora (herpebenthos) and macropytes, the productivity estimated by earlier authors were essentially underestimations. The present work is an attempt inter glig to assess the contribution of periphytic flora towards the total organic production in the estuary