The marine and fresh-water plankton
01 Jul 1956-Journal of Ecology (Michigan State University Press)-Vol. 44, Iss: 2, pp 617
About: This article is published in Journal of Ecology.The article was published on 1956-07-01 and is currently open access. It has received 134 citations till now. The article focuses on the topics: Plankton.
TL;DR: The Tinto River ecosystem can be described as a function of three main groups of variables: pH values, metal concentrations, and biological productivity, which suggested a close relationship between the acidic pH values and abundance of both chemolithotrophic bacteria and filamentous fungi.
Abstract: We studied the correlation between physicochemical and biological characteristics of an acidic river, the Tinto River, in Southwestern Spain The Tinto River is an extreme environment characterized by its low pH (mean of 22) and high concentrations of heavy metals (Fe 23 g/L, Zn 022 g/L, Cu 011 g/L) These extreme conditions are the product of the metabolic activity of chemolithotrophic microorganisms, including iron- and sulfur-oxidizing bacteria, that can be found in high concentrations in its waters The food chain in the river is very constrained and exclusively microbial Primary productivity in the Tinto River is the sum of photosynthetic and chemolithotrophic activity Heterotrophic bacteria and fungi are the major decomposers and protists are the major predators A correlation analysis including the physicochemical and biological variables suggested a close relationship between the acidic pH values and abundance of both chemolithotrophic bacteria and filamentous fungi Chemolithotrophic bacteria correlated with the heavy metals found in the river A principal component analysis of the biotic and abiotic variables suggested that the Tinto River ecosystem can be described as a function of three main groups of variables: pH values, metal concentrations, and biological productivity
TL;DR: Overall invasion risk from biofouling may be comparable or exceed that of ballast water discharge, and these findings adjust upward by an order of magnitude the number of species collected from a single ship.
Abstract: Anthropogenic biological invasions are a leading threat to aquatic biodiversity in marine, estuarine, and freshwater ecosystems worldwide. Ballast water discharged from transoceanic ships is commonly believed to be the dominant pathway for species introduction and is therefore increasingly subject to domestic and international regulation. However, compared to species introductions from ballast, trans-location by biofouling of ships' exposed surfaces has been poorly quantified. We report translocation of species by a transoceanic bulk carrier intercepted in the North American Great Lakes in fall 2001. We collected 944 individuals of at least 74 distinct freshwater and marine taxa. Eight of 29 taxa identified to species have never been observed in the Great Lakes. Employing five different statistical techniques, we estimated that the biofouling community of this ship comprised from 100 to 200 species. These findings adjust upward by an order of magnitude the number of species collected from a single ship. Thus, overall invasion risk from biofouling may be comparable or exceed that of ballast water discharge.
TL;DR: Substrata were arranged in a manner allowing in situ measurement of particle depletion as a function of the abundance of suspension-feeders and time, suggesting the possibility of competition for food in dense assemblages of suspension feeders.
Abstract: Substrata were arranged in a manner allowing in situ measurement of particle depletion as a function of the abundance of suspension-feeders and time. The abundance of two suspension-feeding groups, bryozoans and sponges, and of two planktonic fractions, naked and bacterial cells, were monitored. In one experiment, organism-cover increased through time and in another it remained low through time. As organism-cover increased, food availability per organism decreased, whereas when it remained low, food availability remained high. High levels of depletion measured suggest the possibility of competition for food in dense assemblages of suspension feeders.
TL;DR: In this paper, the authors developed a mathematical model for predicting phytoplankton succession in more dynamic environments, such as estuaries and coastal waters, based on equilibrium resource competition theory.
Abstract: The global increase of noxious bloom occurrences has increased the need for phytoplankton management schemes. Such schemes require the ability to predict phytoplankton succession. Equilibrium Resource Competition theory, which is popular for predicting succession in lake systems, may not be useful in more dynamic environments, such as estuaries and coastal waters. We developed a mathematical model better suited to nonsteady state conditions. Our model incorporated luxury consumption of nonlimiting nutrients and cell starvation processes into a cell-quota-based nutrient-phytoplankton scheme. Nutrient pools described included nitrogen and phosphorus. Phytoplankton groups characterized in the model were a phosphorus-specialist, a nitrogen-specialist, and an intermediate group. We emphasized competition for nutrients under conditions of continuous and pulsing nutrient supply, as well as different nutrient loading ratios. Our results suggest that delivering nutrients in a pulsing fashion produces dramatic differences in phytoplankton community composition over a given period, that is, reduction of accumulated biomass of slower growing algae. Coastal managers may be able to inhibit initiation of slow-growing noxious blooms in estuaries and coastal waters by pulsing nutrients inputs from point sources, such as sewage treatment plants.
TL;DR: Growth and glazing responses of the m~xotrophic dinoflagellate Fraglhdlum subglobosum were studled as a function of prey concentration, prey specles and light Intensity in laboratory cultures, indicating that food uptake by F sub globosum stimulated photosynthesis at low prey concentrations.
Abstract: ABSTFUCT Growth and glazing responses of the m~xotrophic dinoflagellate Fraglhdlum subglobosum were studled as a function of prey concentration, prey specles and light Intensity in laboratory cultures In monospeclflc (exclusively phototrophlc) cultures the growth rate of F subglobosum was 0 16 d ' (doubling tlnle 4 3 d ) at a light lntenslty of 4 5 pm01 photons m '5.' In cultures supplied with the phototrophic dinoflagellate Ceratlum tnpos at a slmllar llght lntenslty the growth rate of F subglobosum reached a maximum level of 0 5 d ' (doubling time 1 4 d ) at a prey concentrat~on of ca 10 C tnpos cells m1 ' The functional response of F subglobosum followed a Holling type I functional response At prey concentrations which resulted in maximum growth rate growth yleld equalled ca 40% However, at prey concentrations whlch led to lower growth rates, growth yield exceeded l o o % , indicating that food uptake by F subglobosum stimulated photosynthesis at low prey concentrations When C trlpos cells were added In excess, growth and Ingestion rate of F subglobosum Increased with light intensity withln the studied range (9 to 45 pm01 photons m-' S ' ) Growth rates of F subglobosum were h ~ g h e r with C tnpos as food than with C furca and C fusus
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01 Jan 1953