Biomonitoring of freshwater environment

2008 ◽  
pp. 47-79
Author(s):  
M E Conti
Keyword(s):  
Freshwater Environment

Laboratory studies of the effects of Mollusca on alkalinity of their freshwater environment

1984 ◽  
Vol 62 (5) ◽  
pp. 793-797 ◽  
Author(s):  
J. Brian Rooke ◽  
Gerald L. Mackie
Keyword(s):  
Acid Rain ◽  
Potential Role ◽  
Laboratory Studies ◽  
Freshwater Environment ◽  
Acid And Base

A series of aquaria containing various combinations of water, sediments, and molluscs was used to investigate the effects of molluscs on alkalinity of the water. Live molluscs acidified the water, and dead decomposing molluscs were associated with an increase in alkalinity in the aquaria. Aquaria containing dead molluscs had more stable alkalinity concentrations than other aquaria when all received additions of natural acid rain (pH 4.1). Nonmolluscan invertebrates liberated acid-neutralizing materials from the sediments but the source was quickly depleted. A hypothesis of temporal disjunction between periods of molluscan acid and base production is given which indicates a potential role for molluscs in the sources and cycling of carbonates in acidifying environments.

scholarly journals A meta-analysis reveals the environmental and host factors shaping the structure and function of the shrimp microbiota

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5382 ◽  
Author(s):  
Fernanda Cornejo-Granados ◽  
Luigui Gallardo-Becerra ◽  
Miriam Leonardo-Reza ◽  
Juan Pablo Ochoa-Romo ◽  
Adrian Ochoa-Leyva
Keyword(s):  
Developmental Stage ◽  
High Throughput Sequencing ◽  
Meta Analysis ◽  
Biological Factor ◽  
Rrna Gene ◽  
Wild Type ◽  
Biological Factors ◽  
Sequencing Data ◽  
Freshwater Environment ◽  
The Impact

The shrimp or prawn is the most valuable traded marine product in the world market today and its microbiota plays an essential role in its development, physiology, and health. The technological advances and dropping costs of high-throughput sequencing have increased the number of studies characterizing the shrimp microbiota. However, the application of different experimental and bioinformatics protocols makes it difficult to compare different studies to reach general conclusions about shrimp microbiota. To meet this necessity, we report the first meta-analysis of the microbiota from freshwater and marine shrimps using all publically available sequences of the 16S ribosomal gene (16S rRNA gene). We obtained data for 199 samples, in which 63.3% were from marine (Alvinocaris longirostris, Litopenaeus vannamei and Penaeus monodon), and 36.7% were from freshwater (Macrobrachium asperulum, Macrobrachium nipponense, Macrobranchium rosenbergii, Neocaridina denticulata) shrimps. Technical variations among studies, such as selected primers, hypervariable region, and sequencing platform showed a significant impact on the microbiota structure. Additionally, the ANOSIM and PERMANOVA analyses revealed that the most important biological factor in structuring the shrimp microbiota was the marine and freshwater environment (ANOSIM R = 0.54, P = 0.001; PERMANOVA pseudo-F = 21.8, P = 0.001), where freshwater showed higher bacterial diversity than marine shrimps. Then, for marine shrimps, the most relevant biological factors impacting the microbiota composition were lifestyle (ANOSIM R = 0.341, P = 0.001; PERMANOVA pseudo-F = 8.50, P = 0.0001), organ (ANOSIM R = 0.279, P = 0.001; PERMANOVA pseudo-F = 6.68, P = 0.001) and developmental stage (ANOSIM R = 0.240, P = 0.001; PERMANOVA pseudo-F = 5.05, P = 0.001). According to the lifestyle, organ, developmental stage, diet, and health status, the highest diversity were for wild-type, intestine, adult, wild-type diet, and healthy samples, respectively. Additionally, we used PICRUSt to predict the potential functions of the microbiota, and we found that the organ had more differentially enriched functions (93), followed by developmental stage (12) and lifestyle (9). Our analysis demonstrated that despite the impact of technical and bioinformatics factors, the biological factors were also statistically significant in shaping the microbiota. These results show that cross-study comparisons are a valuable resource for the improvement of the shrimp microbiota and microbiome fields. Thus, it is important that future studies make public their sequencing data, allowing other researchers to reach more powerful conclusions about the microbiota in this non-model organism. To our knowledge, this is the first meta-analysis that aims to define the shrimp microbiota.

scholarly journals Thermokarst lake development in syngenetic ice-wedge polygon terrain in the Eastern Canadian Arctic (Bylot Island, Nunavut)

2019 ◽  
Author(s):  
Frédéric Bouchard ◽  
Daniel Fortier ◽  
Michel Paquette ◽  
Vincent Boucher ◽  
Reinhard Pienitz ◽  
...  
Keyword(s):  
Sediment Cores ◽  
Canadian Arctic ◽  
Climatic Conditions ◽  
Gradual Transition ◽  
Freshwater Environment ◽  
Cooling Period ◽  
Lake Development ◽  
Thermokarst Lake ◽  
Ice Wedge ◽  
Eastern Canadian Arctic

Abstract. Thermokarst lakes are widespread and diverse across permafrost regions and they are considered significant contributors to global greenhouse gas emissions. Paleoenvironmental reconstructions documenting the inception and development of these ecologically important water bodies are generally limited to Pleistocene-age permafrost deposits (Yedoma) of Siberia, Alaska, and the western Canadian Arctic. Here we present the gradual transition from syngenetic ice-wedge polygon terrains to a thermokarst lake in the Eastern Canadian Arctic. We combine geomorphological surveys with paleolimnological reconstructions from sediment cores in an effort to characterize local landscape evolution from terrestrial to freshwater environment. Located on an ice-rich and organic-rich polygonal terrace, the studied lake is now evolving through active thermokarst, as revealed by subsiding and eroding shores, and was likely created by water pooling within a pre-existing topographic depression. Organic sedimentation in the valley started during the mid-Holocene, as documented by the oldest organic debris found at the base of one sediment core and dated at 4.8 kyr BP. Local sedimentation dynamics were initially controlled by fluctuations in wind activity, local moisture and vegetation growth/accumulation, as shown by alternating loess (silt) and peat layers. Fossil diatom assemblages were likewise influenced by local hydro-climatic conditions and reflect a broad range of substrates available in the past (both terrestrial and aquatic). Such conditions likely prevailed until ~ 2000 BP, when peat accumulation stopped as water ponded the surface of degrading ice-wedge polygons, and the basin progressively developed into a thermokarst lake. Interestingly, this happened in the middle of the Neoglacial cooling period, likely under wetter-than-average conditions. Thereafter, the lake continued to develop as evidenced by the dominance of aquatic (both benthic and planktonic) diatom taxa in organic-rich lacustrine muds. Based on these interpretations, we present a four-stage conceptual model of thermokarst lake development during the late Holocene, including some potential future trajectories. Such a model could be applied to other formerly glaciated syngenetic permafrost landscapes.

Chitin dynamics in the freshwater environment

1991 ◽  
Vol 19 (5) ◽  
pp. 371-377 ◽  
Author(s):  
Shingo Miyamoto ◽  
Hidekazu Yamamoto ◽  
Humitake Seki
Keyword(s):  
Freshwater Environment

Juveniles and larvae of eleven fish species collected from three countries of the Arabian Gulf and the Arabian Sea

2021 ◽  
Vol 325 (4) ◽  
pp. 457-468
Author(s):  
L.A. Jawad ◽  
F. Mutlak ◽  
A.R.M. Mohamed ◽  
J.M. Al-Mamry ◽  
E.K. Hameed ◽  
...  
Keyword(s):  
Early Life ◽  
Arabian Sea ◽  
Arabian Gulf ◽  
Early Life History ◽  
Freshwater Environment ◽  
Life History Stages ◽  
Tenualosa Ilisha ◽  
Sparidentex Hasta ◽  
Available Information ◽  
First Time

The finding of larval and juvenile specimens from the Omani coast of the Arabian Sea and the Arabian Gulf waters of Saudi Arabia and Iraq is reported for the first time. Based on available information, one larva was a leptocephalus, Conger sp. (family Congridae) and one larva of an acronurus stage belonging to the genus Acanthurus (family Acanthuridae). Also juveniles of the following families are included in the present study: Clupeidae – Tenualosa ilisha (Hamilton, 1822) and Nematalosa sp.; Dactylopteridae – Dactyloptena orientalis (Cuvier, 1829); Gobiidae – Acentrogobius sp.; Bothidae – Arnoglossus aspilos (Bleeker, 1851); Scatophagidae – Scatophagus argus (Linnaeus, 1766); Sparidae – Acanthopagrus arabicus Iwatsuki, 2013 and Sparidentex hasta (Valenciennes, 1830); Tetraodontidae – Lagocephalus sp. The discovery of the barred rather than spotted juveniles of S. argus collected from pure freshwater environment of the Shatt al-Arab River, Basrah, Iraq was remarkable; it raises questions whether there is more than one species within the nominal S. argus. For both larvae and juveniles of bothid flounders, the olfactory organ is a useful character for the examination of the developmental stage of the metamorphosing specimens. The occurrence of the different early life history stages of fishes from the three Arabian countries shows the needs them to be studied further so that inferences about the areas and periods of spawning and development of these fishes can be made more accurately.

Emerging Threats of Microplastic Contaminant in Freshwater Environment

2021 ◽  
pp. 247-258
Author(s):  
Pratik Ghosh ◽  
Ritwik Patra ◽  
Prasanta Patra ◽  
Nabarun Chandra Das ◽  
Suprabhat Mukherjee ◽  
...  
Keyword(s):  
Freshwater Environment
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