Picophytoplankton community dynamics in a tropical river estuary and adjacent semi-enclosed water body

2021 ◽  
Vol 83 (4) ◽  
Author(s):  
Smita Mitbavkar ◽  
Aseem R. Rath ◽  
Arga Chandrashekar Anil
Keyword(s):  
Water Body ◽  
Community Dynamics ◽  
River Estuary ◽  
Tropical River

Assessment of heavy metal pollution in surficial sediments from a tropical river-estuary-shelf system: A case study of Kelantan River, Malaysia

2017 ◽  
Vol 125 (1-2) ◽  
pp. 492-500 ◽  
Author(s):  
Ai-jun Wang ◽  
Chui Wei Bong ◽  
Yong-hang Xu ◽  
Meor Hakif Amir Hassan ◽  
Xiang Ye ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Pollution ◽  
Heavy Metal Pollution ◽  
River Estuary ◽  
Surficial Sediments ◽  
Tropical River ◽  
System A

scholarly journals Biotic vs. abiotic forcing on plankton assemblages varies with season and size class in a large temperate estuary

2020 ◽  
Vol 42 (2) ◽  
pp. 221-237 ◽  
Author(s):  
Gretchen Rollwagen-Bollens ◽  
Stephen Bollens ◽  
Eric Dexter ◽  
Jeffery Cordell
Keyword(s):  
Community Dynamics ◽  
Abiotic Factors ◽  
River Estuary ◽  
Multiple Time Scales ◽  
Nutrient Concentrations ◽  
Winter Period ◽  
Zooplankton Abundance ◽  
Multiple Time ◽  
P Availability ◽  
Lower Estuary

Abstract Large river estuaries experience multiple anthropogenic stressors. Understanding plankton community dynamics in these estuaries provides insights into the patterns of natural variability and effects of human activity. We undertook a 2-year study in the Columbia River Estuary to assess the potential impacts of abiotic and biotic factors on planktonic community structure over multiple time scales. We measured microplankton and zooplankton abundance, biomass and composition monthly, concurrent with measurements of chlorophyll a, nutrient concentrations, temperature and salinity, from a dock in the lower estuary. We then statistically assessed the associations among the abundances of planktonic groups and environmental and biological factors. During the late spring high flow period of both years, the lower estuary was dominated by freshwater and low salinity-adapted planktonic taxa, and zooplankton grazers were more strongly associated with the autotroph-dominated microplankton assemblage than abiotic factors. During the early winter period of higher salinity and lower flow, nutrient (P) availability exerted a strong influence on microplankton taxa, while only temperature and upwelling strength were associated with the zooplankton assemblage. Our results indicate that the relative influence of biotic (grazers) and abiotic (salinity, flow, nutrients and upwelling) factors varies seasonally and inter-annually, and among different size classes in the estuarine food web.

Interactions of Ipomoea aquatica and Utricularia reflexa with phytoplankton densities in a small water body in northern Nigeria

2012 ◽  
Vol 41 (2) ◽  
Author(s):  
Mathias Chia ◽  
Michael Adelanwa ◽  
Zakari Ladan ◽  
Dora Iortsuun ◽  
Sewuese Adanyi ◽  
...  
Keyword(s):  
Water Body ◽  
Community Dynamics ◽  
Phytoplankton Community ◽  
The Other ◽  
Phytochemical Screening ◽  
Negative Effects ◽  
Ipomoea Aquatica ◽  
Small Water ◽  
Small Water Body ◽  
Ft Ir

AbstractThe interactions of Ipomoea aquatica and Utricularia reflexa with phytoplankton densities were studied in a small water body in Zaria, Nigeria from June to November 2007. The negative effects of both macrophytes on 10 out of 15 phytoplankton taxa, including Staurastrum sp., Netrium sp., Ulothrix sp., Marssionella sp. and Closterium sp. were differentiated from other environmental effects. U. reflexa, on the other hand, showed positive associations with species like Actinocyclus sp., Palmellopsis sp., Spirotaenia sp., Microcystis sp. and Marssionella sp. Qualitative phytochemical screening and FT-IR analyses confirmed the presence of glycosides, anthraquinone, saponins, steroids, triterpenes, flavonoids, and alkaloids in Ipomoea aquatica and Utricularia reflexa. The observed variations in phytoplankton community dynamics were closely related to the presence of these macrophytes as well as the environmental conditions in the pond.

scholarly journals Bioaccumulation of heavy metals in some commercially important fishes from a tropical river estuary suggests higher potential health risk in children than adults

PLoS ONE ◽  
2019 ◽  
Vol 14 (10) ◽  
pp. e0219336 ◽  
Author(s):  
A. S. Shafiuddin Ahmed ◽  
Sharmin Sultana ◽  
Ahasan Habib ◽  
Hadayet Ullah ◽  
Najiah Musa ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Health Risk ◽  
River Estuary ◽  
Tropical River ◽  
Potential Health ◽  
Potential Health Risk ◽  
Commercially Important

Rare unclassified 16S rRNA operational taxonomic units from the uncharted Engaño Bay (Argentinean Patagonia)

2018 ◽  
Vol 64 (1) ◽  
pp. 91-96
Author(s):  
Andrea Y. Calvo ◽  
Julieta M. Manrique ◽  
Leandro R. Jones
Keyword(s):  
16S Rrna ◽  
Community Dynamics ◽  
Sequence Data ◽  
River Estuary ◽  
Fragmented Habitats ◽  
Operational Taxonomic Units ◽  
Microbial Community Dynamics ◽  
Argentinean Patagonia ◽  
Culture Independent ◽  
Taxonomic Assignments

Rare microbes make up most of the diversity of marine microbiomes, and recent works have highlighted their importance for microbial community dynamics and in fragmented habitats. Rare taxa have been infrequently studied in comparison with abundant groups, and rare unclassified sequences are common in culture-independent studies. Here, we describe a detailed analysis of nonclassifiable sequences from the Chubut river estuary at the Argentinean Patagonia. Standard taxonomic assignments of environmental 16S rRNA sequences resulted in about 13% unclassified operational taxonomic units (OTUs). The potential affiliations of these OTUs could be narrowed by mapping the classification software assignments on a phylogeny obtained directly from our environmental sequence data. Customized BLAST analyses were remarkably consistent with these phylogenetic assignments, especially when the unclassified OTUs were blasted against sequences from cultured and type microorganisms. In addition, our BLAST analyses revealed significant similarities between several unclassified OTUs and a plethora of unclassified sequences from around the world. Further phylogenetic comparisons with 6194 carefully selected reference sequences showed that these unclassified sequences may correspond to 5 unnamed groups, possibly encompassing ranks from subclass to family inside the Alphaproteobacteria, and to an unknown Gracilibacteria lineage. Overall, these results demonstrate the value of straight phylogenetic analysis, customized BLAST searches, and comparisons with sequences from type material, for the systematic study of rare unclassified sequences.

The Ord River Estuary: A Regulated Wet-Dry Tropical River System

2013 ◽  
pp. 131-152 ◽  
Author(s):  
Barbara J. Robson ◽  
Peter C. Gehrke ◽  
Michele A. Burford ◽  
Ian T. Webster ◽  
Andy T. Revill ◽  
...  
Keyword(s):  
River Estuary ◽  
River System ◽  
Tropical River

Distribution Characteristics and Potential Ecological Risk Assessments and Heavy Metals in Surface Sediments and Water Body of the Yalu River Estuary China

2014 ◽  
Vol 522-524 ◽  
pp. 88-91
Author(s):  
Yao Qing Wu ◽  
Li Li
Keyword(s):  
Heavy Metals ◽  
Ecological Risk ◽  
Water Body ◽  
Surface Sediments ◽  
Risk Index ◽  
River Estuary ◽  
Potential Ecological Risk ◽  
Yalu River ◽  
Total Hg ◽  
Ecological Risk Assessments

Surface sediments and water body of the Yalu River estuary were monitored to evaluate the spatial distribution and the enrichment condition of heavy metals: As, Cu, Cd, Cr, Hg, Pb and Zn. Surface sediment samples and water samples were collected from 5 stations, at seven month intervals from May 2012 to November 2012. The correlation of the heavy metals in the surface sediments and the water body was analyzed by using Pearson method. And the method of potential ecological risk index presented by Hakanson was used to evaluate the potential ecological risk of heavy metal pollution in the Yalu River estuary. The results showed that, the order of heavy metals spatial fluctuation degree was Zn > Cr > Pb > Cu > total As > Cd > total Hg, the fluctuation degree of total contents of heavy metals was A1 > A3 > A2 ≈ A4 > A5. The evaluation of potential ecological risk showed that, total Hg reflected considerate ecological risk, total As and Cd reflected moderate ecological risk, and the rest of the heavy metals posed a low ecological risk.

scholarly journals River regulation alters drivers of primary productivity along a tropical river-estuary system

2011 ◽  
Vol 62 (2) ◽  
pp. 141 ◽  
Author(s):  
M. A. Burford ◽  
A. T. Revill ◽  
D. W. Palmer ◽  
L. Clementson ◽  
B. J. Robson ◽  
...  
Keyword(s):  
Primary Production ◽  
Primary Productivity ◽  
Light Attenuation ◽  
River Estuary ◽  
River Regulation ◽  
Tropical River ◽  
Seasonal Flow ◽  
Freshwater Zone ◽  
High Concentrations ◽  
Downstream Flow

Worldwide, rivers continue to be dammed to supply water for humans. The resulting regulation of downstream flow impacts on biogeochemical and physical processes, potentially affecting river and estuarine productivity. Our study tested the hypothesis that primary production in the downstream freshwater reaches of a dammed river was less limited by light and nutrients relative to downstream estuarine primary production. In a tropical dryland Australian river estuary, we found that water-column primary productivity was highest at freshwater sites that had lowest light attenuation. Nitrogen may also have limited primary productivity. Below the freshwater zone was a region of macrotidal mixing with high concentrations of suspended soil particles, nutrients and chlorophyll a, and lower but variable primary productivity rates. Light controlled productivity, but the algal cells may also have been osmotically stressed due to increasing salinity. Further downstream in the estuary, primary productivity was lower than the freshwater reaches and light and nutrient availability appear to be a factor. Therefore the reduced magnitude of peak-flow events due to flow regulation, and the resulting decrease in nutrient export, is likely to be negatively impacting estuarine primary production. This has implications for future development of dams where rivers have highly seasonal flow.

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