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Nutrient loading and coastal plankton blooms: Seasonal interannual successions and effects on secondary production

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A 13-year field analysis of the Perdido Bay system (Gulf of Mexico) indicated that orthophosphate and ammonia loading from a pulp mill was associated with a series of plankton blooms. Bloom species (10) followed distinct seasonal and interannual trends that included the replacement of initial diatom blooms by raphidophytes and dinoflagellates. Long-term habitat changes associated with river flow rates (drought/flood cycles) defined varying susceptibility to bloom development. The initiation and proliferation of plankton blooms were also affected by seasonal changes of temperature, phosphorus and nitrogen loading, and associated nutrient concentration gradients. Plankton blooms were associated with deterioration of secondary production through food web interactions. The bivalve Rangia cuneata was an indicator of such effects. Most scientific efforts continue to overlook the world-wide impacts of anthropogenous nutrient loading and associated plankton blooms due to the lack of long-term analyses of species-specific, community-level phytoplankton assemblages and the replacement of ecosystem studies with patch-quilt ecological efforts that depend on disorganized and inadequate data acquisition and uncoordinated multidisciplinary efforts

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In early January 1989, a dense phyto‐plankton bloom occurring in Big Glory Bay, Stewart Island, New Zealand, was associated with chinook salmon kills. The total loss was estimated to be NZ$17 million. Water samples collected between 5 and 6 January showed Heterosigma cf. akashiwo as the dominant species. This bloom is the first record of Heterosigma in New Zealand, and is the first New Zealand record linking this species to salmon kills. During the period of salmon mortality, Heterosigma attained densities of nearly 2 × 10 cells 1, and was found in greatest concentration on the north‐west side of Big Glory Bay where lowest Secchi disk depths were recorded. Histopathological investigations of salmon which were affected by the bloom revealed gill and intestine pathology characterised by degenerative changes of the branchial epithelium and vasculature. The pathology observed was similar to that reported for Gyrodiniwn aweolum in Atlantic salmon. Impairment of respiratory and osmoregulatory function of gills was implicated as the cause of death in fish exposed to Heterosigma bloom.
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The Antarctic marine benthic diatom Entopyla australis var. gigantea (Grev.) Fricke was collected as an epiphyte on red algae at Anvers Island, Antarctica. Cells of E. australis var. gigantea form ribbon-shaped colonies, and the sibling cells are attached by means of mucilage extruded through the apical pore fields of concave valves. No interlocking marginal spines were found in this SEM study. The cingulum is composed of a series of many open bands with elaborations of ligulae (described as rudimentary septa in the literature) at the poles. Each band has a single row of slits at the advalvar margin of the pars interior. The heterovalvate frustule is flexed in girdle view. Valves have simple multiseriate striae arranged alternately on the two sides of the zigzag sternum, but pronounced marginal ridges are seen only in the convex valve. Concave valves have prominent apical pore fields, whereas the convex valves do not. Rimportulae present on both the valves follow the “one per pole” pattern, but differ in structure and orientation of slits on each valve. On the basis of material from Greville's original collection, we designate the lectotype (BM 10265) in this study and confirm our identification of Antarctic specimens. E. australis var. gigantea appears to have continued from the late Oligocene-early Miocene to the present, with its possible centre of distribution on the eastern Pacific coasts.
Eighty-four species of blue-green algae were recorded from the intertidal zone of the Gulf of Elat (Aqaba) and four hypersaline coastal pools. Heterocystous forms (sixteen) were restricted to the intertidal, although significant rates of nitrogen fixation (acetylene reduction) were measured in non-heterocystous communities in coastal pools. Species distribution, the colour and surface morphology of thick mats are determined by salinity, frequency of wetting and desiccation. Distinct horizontal zonation patterns occur in coastal pools. Coccoid and non-filamentous forms such as Entophysalis and Pleurocapsa grow associated with gypsum crusts around the periphery of the pools, while filamentous forms (Lyngbya, Microcoleus) become abundant towards the central regions. Complex stratification is apparent in many communities. In different coastal pools mat communities have a similar structure; Lyngbya aestuarii and pennate diatoms at the surface, then coccoid blue-green algae (Aphanorhece, Synechococcus), a bright green layer of Microcoleus chthofloplastes and finally deeper layers of phototrophic bacteria. In mangrove forests, Scytonema and a number of species of Rivulariaceae form conspicllous growths on aerial pneumatophores while non-heterocystous forms are restricted to the sediment surface. Complex stratification is apparent in many communities. In different coastal pools mat communities have a similar structure; Lyngbya aestuarii and pennate diatoms at the surface, then coccoid blue-green algae (Aphanorhece, Synechococcus), a bright green layer of Microcoleus chthofloplastes and finally deeper layers of phototrophic bacteria. In mangrove forests, Scytonema and a number of species of Rivulariaceae form conspicllous growths on aerial pneumatophores while non-heterocystous forms are restricted to the sediment surface.
A long-term (9.5 yr) study addressed the relationship of the trophic organization of a river-dominated Gulf of Mexico estuary with interannual trends of freshwater input and biological controlling features. Alluvial river flow characteristics were evaluated with respect to Seasonal and interannual changes in physical, chemical, and biological trends in the receiving estuary. Infaunal and epifaunal macroinvertebrates and fishes taken over the period of sampling in the Apalachicola Bay system were transformed into their trophic equivalents. The long-term trophic organization of the bay was then related to observed changes in the physical and chemical conditions in the receiving estuary with particular attention to long-term response to a 2-yr drought. Within limited natural bounds of freshwater flow from the Apalachicola River, there was little change in the trophic organization of the receiving estuary over prolonged periods. The physical instability of the estuary was actually a major component in the continuation of a biologically stable estuarine system. However, when a specific threshold of freshwater reduction was reached during a prolonged natural drought, we suggest that the clarification of the normally turbid and highly colored river-estuarine system led to rapid changes in the pattern of primary production, which, in turn, were associated with major changes in the trophic structure of the system. Increased light penetration due to the cessation of river how was an important factor in the temporal response of bay productivity and herbivore/omnivore abundance. There was a dichotomous response of the estuarine trophic organization, with herbivores and omnivores responsive to river-dominated physicochemical factors whereas the carnivores responded to biological factors. Trophic response time could be measured in months to years from the point of the initiation of low-flow conditions. The reduction of nutrient loading during the drought period was postulated as a major cause of the loss of productivity of the river-dominated estuary during and after the drought period. Recovery of such productivity with resumption of increased river hows was likewise a long-term event. Based on the observed trends in the bay, postulated permanent reductions of freshwater flows due to anthropogenous activities could lead to major reductions of biological productivity in the Apalachicola Bay system. The long-term data indicated that, with reduction of freshwater flow below a level specific for the receiving system, the physically controlled, highly productive river-estuarine system would become a species-rich, biologically controlled bay with substantially reduced productivity.
The interspecific relationships of three euryhaline species of Cyclotella (Bacillariophyta) commonly encountered in large numbers in Choctawhatchee Bay, north-eastern Gulf of Mexico, and their relationships to the other species of the genus, are discussed with particular reference to the origin of euryhalinity in this predominantly freshwater genus. Frustule morphology of Cyclotella choctawhatcheeana sp. nov. is described on the basis of light and scanning electron microscopic observations. The cingulum structure of C. striata (Kutzing) Grunow is also described.
In late summer 1982 an intense dinoflagellate bloom occurred close inshore off West‐land, New Zealand. This bloom was essentially made up of a monospecific surface population of Prorocentrum micans. This species alone accounted for 92–98% of integrated phytoplankton cell carbon (PPC) close inshore. Dinoflagellates also formed the largest proportion of PPC further offshore, except off Karamea Bight where phytoflagellates predominated. Diatoms were most plentiful close inshore off Wanganui Bluff, coincident with the elevation of dissolved inorganic nitrogen in upwelled water. There was a general shift in the predominant phytoplankton size class from 25–30 μm nearshore to 0–5 μm further offshore. The size fractionation of chlorophyll a also showed a marked onshore‐offshore relationship — the proportion of 5–20 μm (nanoplankton) and 20–200 μm (microplankton) fractions decreased dramatically seawards while the proportion of 0.2–5 μm (picoplankton) fraction increased progressively seawards. Close inshore the >20 μm fraction accounted for >66% of total chorophyll a and >56% of total primary productivity, while < 20 μm fraction contributed to >89% of total chlorophyll a and >85% of the total offshore oceanic production.
A combined field descriptive/experimental and laboratory experimental study was carried out to determine the relationships of water quality, qualitative and quantitative light factors and sediment characteristics in the definition of the distribution of submerged aquatic vegetation (SAV) offshore of two streams, one polluted and one natural, that drain into the northeastern Gulf of Mexico. Release of pulp mill effluents into a small drainage system were associated with increased loading of dissolved organic carbon (DOC), water color and nutrients to offshore areas relative to an unpolluted reference system. This loading resulted in changes of water quality factors and light transmission characteristics in the receiving Gulf area. Sediments in affected offshore areas were characterized by increased silt/clay fractions and altered particle size relative to reference sites. Based on the field data, the best (statistically significant) predictors of SAV distribution were photic depths, qualitative aspects of wave length distributions, water quality factors (color, DOC and chlorophyll a) and sediment characteristics. Photic depths were good predictors of SAV distribution, with depth as an important modifying factor. Mesocosm experiments showed that pulp mill effluent in direct contact with Thalassia testudinum and Syringodium filiforme had significant adverse impacts on growth at relatively low concentrations (1–2%) of effluent. Light mesocosm experiments indicated that light levels in inshore Fenholloway areas were associated with reduced growth of Halodule wrightii, S. filiforme and T. testudinum. Field transfer experiments showed that altered sediment and water quality in inshore polluted areas induced significant adverse effects on growth indices of all three species. By comparing the field and experimental results, a hierarchy of habitat requirements for the subject seagrass species was determined. Salinity, temperature and depth restraints are important habitat variables that control seagrass growth; when such variables are not limiting, light, sediment and nutrient characteristics become important in the determination of the distribution of seagrasses in coastal areas.
A study of nutrient limitation of phytoplankton biomass production with emphasis on nitrate-nitrogen (NO3 −) and ortho-phosphate-phosphorus (PO4 3−) was conducted in Perdido Bay, Alabama-Florida. The experimental design employed 18-1 outdoor microcosms operated in a static renewal mode. Phytoplankton growth responses (i.e., growth stimulation) measured as chlorophyll a (chl a) fell into three principal categories: primary P stimulation occurred mostly during the cooler months at the upper bay (tidal brackish) and mid bay (lower mesohaline) stations; a total of 12 out of 36 experiments; primary N stimulation occurred mostly during the warmer months primarily at the mid-bay station and infrequently at the upper and lower bay stations (upper mesohaline); a total of 7 out of 36 experiments; and N+P costimulation occurred primarily during the warmer months in the upper bay and mid bay and during both warmer and cooler months of the lower bay; a total of 17 out of 36 experiments. Primary P stimulation was generally associated with high ratios of dissolved inorganic nitrogen (DIN) to dissolved inorganic phosphate (DIP) (ratio range: 18 to 288). Conversely, primary N stimulation was associated with decreasing DIN:DIP ratios (range 8–46). Redfield ratios of particulate organic N (PON) to particulate organic P (POP) often indicated N limitation (i.e., values often less than 10). PON:chl a ratios often indicated N sufficiency, but three occasions were noted where PON:POP and PON:chl a ratios were not congruent. It is difficult to reconcile the inorganic and organic N and P ratios with the relatively low DIP and DIN concentrations. The phytoplankton assemblage appeared not to be strongly nutrient-limited but, given a nutrient increase, responded differentially to N and P, both seasonally and along the longitudinal salinity gradient. Grazing pressure in concert with nutrient limitation was advanced as an hypothesis to explain N+P co-limitation.
Phytoplankton productivity and mean photic zone chlorophyll a concentrations ranged from 0.01 g C m−2 d−1 (December) to 2.22 g C m−2 d−1 (July) and from 0.8 μg Chl l−1 (December) to 6.4 μg Chl l−1 (July), respectively. Dissolved inorganic nutrient concentrations were high throughout the year, and (with the possible exception of silicate during the summer) temporal variations were not correlated with concurrent variations in phytoplankton productivity. Chlorophyll a specific phytoplankton productivity was regulated by light and temperature. Nanoplankton growth accounted for increases in phytoplankton productivity above 0.25 g C m−2 d−1 within the lower Estuary. Except during the summer when phytoplankton growth rates were high, increases in phytoplankton biomass were related to the advection of phytoplankton into the lower Hudson Estuary from Raritan Bay or the Apex of the New York Bight. Although major nutrient concentrations were consistently high, netplankton growth rates were apparently less than flushing rates and, therefore, too low to generate blooms in the lower Estuary.
This report documents rapid and widespread mortality of the seagrass Thalassia testudinum Banks ex Konig (turtle grass) in Florida Bay at the southern tip of the Florida peninsula (USA). More than 4000 ha of seagrass beds have been completely lost in recurring episodes of mortality since summer 1987. An additional 23 000 ha have been affected to a lesser degree. Loss of T. testudinum, the dominant macrophyte species in this highly productive system, may affect ecosystem function within the bay as well as estuarine-dependent sport and commercial fisheries. A pathogenic protist related to the causal agent of the eelgrass wasting disease may be involved in the mortality and may place T. testudinum populations outside Florida Bay at risk. Environmental factors and chronic hypoxia of below-ground T. testudinum tissue may also contribute to the die-off.
Oxygen Dynamics in the Chesapeake Bay synthesizes the findings of a research program that examined, for example, the specific sources and nature of organic matter, the dynamics or organisms which consume dissolved oxygen and organic matter, the role of chemical oxidation in the water column and at the sediment-water boundary, the relative importance of physical circulation, and the distribution of these forcing factors both spatially and over time. (Copyright (c) 1992 Maryland Sea Grant College.)
Miraltia throndsenii gen.nov., sp.nov., a small centric diatom from Gulf of Naples coastal waters, is described. The ultrastructural features of the species are very similar to those reported for the family Chaetoceraceae. However, a new generic name is proposed due to the presence of a single seta per valve. A description of the resting spores, presumably formed within auxospores, is also given. The phylogenetic position of the new genus within the family Chaetoceraceae is discussed.
Heterosigma akashiwo and its related algae were re-examined by light and electron microscopes using cultured materials including type cultures of bothH. akashiwo andH. inlandica as well as specimens referred to asOlisthodiscus luteus maintained in CCAP and UTEX. All the strains examined were similar to one another in appearance and ultrastructural features. They can be accommodated in a single species,H. akashiwo, which has been invalidly published. In this paper, the genus is validly desribed by providing a Latin diagnosis and designating a type species. Ultrastructural characteristics are also given for the genus.
Florida Bay is a unique subtropical estuary at the southern tip of the Florida peninsula. Recent ecological changes (seagrass die-off, algal blooms, increased turbidity) to the Florida Bay ecosystem have focused the attention of the public, commercial interests, scientists, and resource managers on the factors influencing the structure and function of Florida Bay. Restoring Florida Bay to some historic condition is the goal of resource managers, but what is not clear is what an anthropogenically-unaltered Florida Bay would look like. While there is general consensus that human activities have contributed to the changes occurring in the Florida Bay ecosystem, a high degree of natural system variability has made elucidation of the links between human activity and Florida Bay dynamics difficult. Paleoecological analyses, examination of long-term datasets, and directed measurements of aspects of the ecology of Florida Bay all contribute to our understanding of the behavior of the bay, and allow quantification of the magnitude of the recent ecological changes with respect to historical variability of the system.
Certain metals have been investigated in paper mills effluent channel and in the river Tungabhadra in relation to their distribution, seasonal fluctuations and their effect, if any, on algae. The concentrations of various metals analysed are in the order of Zn>Cu>Pb>Ni>Co>Mn. In general these metals indicated an increase in their concentration along with the increase in the concentrations of chlorides, total hardness, sulphates and total alkalinity. Blue-greens and diatoms seem to be more tolerant to these ions than Chlorophyceae.Stigeoclonium exhibited very good growth at high concentrations of zinc, copper and nickel and at low concentrations of cobalt and lead.Schizomeris attained good growth when the lead concentration was high and cobalt was low.
This paper describes the linkage of a three-dimensional hydrodynamic circulation model with descriptive and experimental biological data concerning oyster (Crassostrea virginica) population dynamics in the Apalachicola Estuary (Florida, U.S.A.). Our intent was to determine the direct and indirect role of Apalachicola River flow in the maintenance of oyster production. Results of a monthly field sampling programme conducted on the oyster reefs in the Apalachicola system during 1985–1986 were used to develop statistical models relating several life-history characteristics of oysters to physical-chemical aspects of water quality. The same life-history characteristics were related statistically to output from a circulation model of Apalachicola Bay. Highest oyster densities and overall bar growth were found in the vicinity of the confluence of high salinity water moving westwards from St George Sound and river-dominated (low salinity) water moving south and eastwards from East Bay. With the exception of models for oyster mortality, the predictive capability of results from the parallel modelling efforts was low. A time-averaged model was developed for oyster mortality during the summer of 1985 by running a regression analysis with averaged predictors derived from the hydrodynamic model and observed (experimental) mortality rates throughout the estuary. A geographic information system was then used to depict the results spatially and to compare the extent of expected mortality in 1985 and 1986. High salinity, relatively low-velocity current patterns, and the proximity of a given oyster bar to entry points of saline Gulf water into the bay were important factors that contribute to increased oyster mortality. Mortality was a major determinant of oyster production in the Apalachicola Estuary with predation as a significant aspect of such mortality. By influencing salinity levels and current patterns throughout the bay, the Apalachicola River was important in controlling such mortality. Oyster production rates in the Apalachicola system depend on a combination of variables that are directly and indirectly associated with freshwater input as modified by wind, tidal factors, and the physiography of the bay. River flow reduction, whether through naturally occurring droughts, through increased upstream anthropogenous (consumptive) water use, or a combination of the two, could have serious adverse consequences for oyster populations. By coupling hydrodynamic modelling with descriptive and experimental biological data, we were able to determine the effects of potential freshwater diversions on oyster production in Apalachicola Bay.
Typescript. Thesis (M.S.)--Florida State University, 1973. Includes bibliographical references.
Towards the end of the 1980s, living plankton flora of the world ocean amounted to 474-504 genera and 3444–4375 species if one neglects the increase rate of taxa during the latest years In the above figures, the lower estimate is that of the ‘reliable’ taxa (of practical value for identification tasks), whereas the higher estimate includes the insufficiently known or doubtful organisms, and synonyms are excluded. The frequency distribution of the numbers of species per genus confirms the general hyperbolic law, which implies that a relatively large number of genera are uni- or paucispecific.
Seasonal changes in the diatom flora in the estuary of the Damour River
  • L E Squires
  • N A Sinnu
Distribution and seasonal abundance of Oscillatoria nigroviridis Thwaites ex. Gomant in the waters of Visakhapatnam Harbour
  • V E Premila
  • M U Rao
Studies on marine planktonic diatoms: V. Morphology and distribution of Leptocylindrus minimus
  • P H Hargraves
Analysis of data concerning the Florida Everglades Ecosystem
  • R J Livingston
  • G C Woodsum
An evaluation of the scientific basis for ?restoring? Florida Bay by increasing freshwater runoff from the Everglades
  • L E Brand
Bloom dynamics of the toxic dinoflagellate Gymnodinium catenatum, with emphasis on Tasmanian and Spanish coastal waters
  • G M Hallegreaff
  • S Fraga
  • D M Anderson
  • A Cembella
  • G M Hallagraeff
Studies on the source of shellfish poison in Lake Hamana. III. Poisonous effects on shellfishes feeding on Prorocentrum sp
  • M Nakazima
Benthic-pelagic interactions: Nutrient and oxygen dynamics
  • W M Kemp
  • W R Boynton
  • D E Smith
  • G Leffler
  • Mackiernan
Management of natural populations
  • C L Mackenzie
  • V S Kennedy
  • R I E Newell
  • A F Eble
Influences of river flow on the dynamics of phytoplankton in a partially stratified estuary
  • T C Malone
  • L H Crocker
  • S E Pike
  • B A Wendler
The Florida Everglades, Florida Bay, and coral reefs of the Florida Keys: An Ecosvstem Sourcebook.
  • J W Porter
  • K G Porter
Causes of oyster mortality in South Puget Sound
  • R D Cardwell
  • S Olsen
  • M I Carr
  • E W Sanborn
Biotic phase-shifts in Florida Bay and bank reef communities of the Florida Keys: linkages with historical freshwater flows and nitrogen loading from the Everglades runoff
  • B E Lapointe
  • W R Matzie
  • P J Barile
  • J W Porter
  • K G Porter