Seasonality in river phytoplankton: multivariate analyses of data from the Ohio River and six Kentucky tributaries

Peterson, Christopher G.; Stevenson, R. Jan

doi:10.1007/bf00006036

Cited by 27 publications

(13 citation statements)

References 27 publications

(24 reference statements)

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“…In the St .Lawrence (Cardinal, 1961) as in other studies (Peterson & Stevenson, 1989), seasonal variations were more important than differences among river sites in the determination of phytoplankton composition and abundance (Figure 3) . Seasonal changes in plankton composition were related more strongly 2 1 to water temperature than to nutrients concentrations measured during sampling (Figure 3) .…”

Section: Influence Of Seasons and Of Water Massmentioning

confidence: 67%

Downstream variations of phytoplankton in the St.Lawrence River (Québec, Canada)

1996

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Longitudinal variations of phytoplankton biomass and composition were assessed in a 250 km-long section of the St.Lawrence River, which alternately runs through narrow (< 2 km) river cross sections and wide (up to 10 km) fluvial lakes . In the main river stem, concentrations of suspended matter and total phosphorus increased with distance downstream, whereas light penetration decreased . Seasonal changes in plankton composition and biomass were more important than those resulting from differences in water mass (tributary) of origin . Sampling at three cross river sections and in two fluvial lakes showed a progressive downstream decrease in phytoplankton biomass and changes in size structure and taxonomic composition. River plankton was primarily composed of small (< 10 µm equivalent spherical diameter), truly planktonic cells belonging to Cryptophyceae and diatoms, with Chlorophyceae in summer. Plankton sampled in summer among rooted macrophytes in fluvial lakes exhibited a higher biomass of resuspended periphytic algae than in the main river stem, which contributed slightly to downstream phytoplankton biomass.Successive river cross sections always shared about 50% of their taxa, indicating a rapid downstream transport of algae within the main water mass . However, the proportion of species common to all cross sections was highest during the spring freshet, and lowest during summer low discharge, likely resulting from the development of a distinct flora in fluvial lakes during summer . Conversely, about 30% of the identified taxa were exclusive to a cross section and were replaced by others occurring downstream . Overall, phytoplankton composition along the St .Lawrence River is primarily controlled by advective forces, which result in a homogeneous flora in the main river stem, with a local contribution of resuspended periphyton from fluvial lakes .

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Section: Influence Of Seasons and Of Water Massmentioning

confidence: 67%

Downstream variations of phytoplankton in the St.Lawrence River (Québec, Canada)

1996

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“…We also found informative environmental patterns in the densities and relative abundances of orderlevel taxa, despite probable interspecific variation in responses of taxa to environmental variation (e .g. Peterson & Stevenson, 1989) . The identification of stations with unusual phytoplankton assemblages by DCCA also located water quality problems .…”

Section: Spatial Variationmentioning

confidence: 99%

A comparison of natural and human determinants of phytoplankton communities in the Kentucky River basin, USA

Stevenson

White

1995

Hydrobiologia

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Physical, chemical, and biological characteristics of the Kentucky River and its tributaries were assessed for one year to compare effects of seasonal, spatial, and human environmental factors on phytoplankton . Phytoplankton cell densities were highest in the fall and summer and lowest in the winter . Cell densities averaged 1162 (± 289 SE) cells ml -' . Cell densities were positively correlated to water temperature and negatively correlated to dissolved oxygen concentration and to factors associated with high-flow conditions (such as, suspended sediment concentrations) . Chrysophytes, diatoms, and blue-green algae dominated winter, spring, and summer assemblages, respectively . Ordination analyses (DCCA) indicated that variation in taxonomic composition of assemblages was associated with stream size as well as season .Spatial variation in phytoplankton assemblages and effects of humans was investigated by sampling 55 sites in low flow conditions during August . Phytoplankton density increased with stream size . Assemblages shifted in composition from those dominated by benthic diatoms upstream to downstream communities dominated by blue-green algae and small flagellates . Human impacts were assumed to cause higher algal densities in stream basins with high proportions of agricultural or urban land use than in basins with forested/mined land use . While density and composition of phytoplankton were positively correlated to agricultural land use, they were poorly correlated to nutrient concentrations . Phytoplankton diversity changed with water quality : decreasing with nutrient enrichment and increasing with conditions that probably changed species composition or inhibited algal growth . Human impacts on phytoplankton in running water ecosystems were as great or greater than effects by natural seasonal and spatial factors . Our results indicated that phytoplankton could be useful indicators of water quality and ecosystem integrity in large river systems .

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“…On the other hand, Duarte et al (1992) found in their study that green algae was the dominate species in shallow oligotrophic Florida lakes, but that the algal assemblage of these lakes was highly diverse. In addition, a study conducted by Peterson and Stevenson (1989) on the Ohio River and six Kentucky tributaries indicated that the abundant diatom M. varians and the green algae S. armatus, that was dominant in our winter microcosm, correlated positively with lower surface water temperatures.…”

Section: Divisionmentioning

confidence: 72%

Phytoplankton yield changes after enrichment in microcosm experiments: Applications for predicting progressive eutrophication in a mesotrophic lake, South Africa

Oberholster¹,

Ashton²,

Botha

et al. 2012

Afr. J. Biotechnol.

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Established microcosms containing surface water from the mesotrophic Lake Mokolo were subjected to enrichment of different concentrations with phosphorus. The microcosms were sampled through a 20 day succession period to determine the net effects of increased concentrations of phosphorus in the water column on the phytoplankton community structure during the winter and summer seasons. A significant increase in chlorophyll a (chl-a) was observed when treatments of 30, 40 and 60 µg L -1 P were compared to the controls. On day zero in both the winter and summer microcosm experiments, all four phosphorus treatments had similar species diversity of phytoplankton of the specific seasoned tested (winter: Margalef index = 223; summer: Margalef index = 347). However, 13 days after the addition of 40 and 60 µg L -1 P, the phytoplankton community exhibited a strikingly different species richness (winter: Margalef index = 123; summer: Margalef index = 114). In the winter microcosm experiments, the green alga Scenedesmus armatus dominated the phytoplankton composition at enrichment levels of 40 and 60 µg L -1 P up to day 20. The biovolume of the dinophyceae Ceratium hirundinella declined rapidly after the addition of 40 µg L -1 P in the different summer microcosms. In the summer microcosms, Spondylosium secedens and Microcystis aeruginosa dominated the 40 and 60 µg L -1 P microcosm enrichment experiments.

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Seasonality in river phytoplankton: multivariate analyses of data from the Ohio River and six Kentucky tributaries

Abstract: Two years of physical/chemical and algal abundance data obtained from national Stream-Quality

Cited by 27 publications

References 27 publications

Downstream variations of phytoplankton in the St.Lawrence River (Québec, Canada)

Downstream variations of phytoplankton in the St.Lawrence River (Québec, Canada)

A comparison of natural and human determinants of phytoplankton communities in the Kentucky River basin, USA

Phytoplankton yield changes after enrichment in microcosm experiments: Applications for predicting progressive eutrophication in a mesotrophic lake, South Africa

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