What, if anything, is a brackish-water fauna?

1989 ◽  
Vol 80 (3-4) ◽  
pp. 235-240 ◽  
Author(s):  
R. S. K. Barnes
Keyword(s):  
Species Diversity ◽  
Brackish Water ◽  
Competing Species ◽  
Soft Sediments

ABSTRACTThe nature of the fauna of brackish-water environments is reviewed. It is concluded that: (a) a specific brackish-water macrofauna does not exist; (b) in salinities of >c. 5-8‰ the fauna is one that also occurs in soft sediments under fully marine conditions when circumstances (possibly the absence of competing species) permit; (c) in salinities of <c. 5‰ the fauna is essentially a freshwater one; and (d) inability to cope physiologically with brackish water is not a factor of major importance in limiting species diversity in these habitats, except in the vicinity of 5‰ salinity. Caution is therefore advised in assigning brackish status to past environments on the basis of their preserved fauna.

scholarly journals Species Composition Features of Zoopankton in Mineralized Water Bodies from Specially Protected Natural Territories in Ulug-Khem Basin (Republic of Tuva)

2021 ◽  
pp. 398-414
Author(s):  
A. К. Kirova
Keyword(s):  
Species Diversity ◽  
Species Composition ◽  
Brackish Water ◽  
Anthropogenic Impact ◽  
Water Bodies ◽  
Natural Objects ◽  
Mineralized Water ◽  
The Status ◽  
Favorable Conditions ◽  
Specially Protected Natural Territories

The species composition of zooplankton in mineralized water bodies located in the Ulug-Khem basin (Republic of Tuva) was studied. These lakes have the status of natural monuments of regional significance. In total we recorded 53 species of microscopic Custaceans and Rotifers from 32 genera, 13 families, and 8 orders. Cladocera comprises 53% of the species. The dependence of the species diversity on the level of mineralization was revealed; 89% of the species were found in brackish water bodies. The zooplankton composition of the hyperhaline lakes Dus-Khol (Svatikovo) and Cheder has remained constant for many dozen years. The zooplankton includes some species known only from Republic of Tuva in Russia, namely, Microcyclops afganicus and Macrotrix tabrizensis. M. asiaticus and Alona irinae, rare for the fauna of Russia, live in the lake Haak-Hol. A decrease in the total numbers of zooplankton is observed in the lakes, namely: in the lake Dus-Khol, it has decreased by 4 times, in the lake Khadyn it has decreased by 10–19 times as compared to the middle of the last century. Despite the lack of intermediate information, we regard this as a consequence of anthropogenic impact. The emergence of an indicator of pollution (Brachionus nilsoni) in the lake Khadin confirms this version. At the same time, the stable finding of species rare for the fauna of Russia indicates the presence of favorable conditions for their development and life, which increases the value of the reservoirs themselves, which are already unique natural objects.

scholarly journals Brackish water Oscillatoriaceae from North 24-Parganas, West Bengal, India

1970 ◽  
Vol 15 (1) ◽  
pp. 31-38
Author(s):  
Nurmohammad Naskar ◽  
K.R. Naskar ◽  
C.R. Sen
Keyword(s):  
Species Diversity ◽  
Water Temperature ◽  
Brackish Water ◽  
West Bengal ◽  
Present Communication ◽  
Close Relationship ◽  
Plant Taxon ◽  
Salinity Levels ◽  
Brackish Water Species ◽  
Water Species

The present communication enumerates 40 taxa of Oscillatoriaceae from the brackish water wetlands of North 24-Parganas district of West Bengal. Out of the reported taxa, 12 are from each of Lyngbya and Oscillatoria, 6 from each of Phormidium and Spirulina, 2 belong to Schizothrix, and Hydrocoleum and Katagnymene are represented by one species each. A close relationship was observed between seasonal water temperature and salinity levels of the wetlands in enhancing algal population.Keywords: Brackish water, species diversity, ecosystem, Oscillatoriaceae, North 24-Parganas, West BengalDOI: 10.3329/bjpt.v15i1.909Bangladesh J. Plant Taxon. 15(1): 31-38, 2008 (June) 

scholarly journals Effects of rapid evolution on species coexistence

2019 ◽  
Vol 116 (6) ◽  
pp. 2112-2117 ◽  
Author(s):  
Simon P. Hart ◽  
Martin M. Turcotte ◽  
Jonathan M. Levine
Keyword(s):  
Population Dynamics ◽  
Species Diversity ◽  
Interspecific Competition ◽  
Species Coexistence ◽  
Rapid Evolution ◽  
Empirical Work ◽  
Niche Differentiation ◽  
Ecological Communities ◽  
Competing Species ◽  
Ecological Processes

Increasing evidence for rapid evolution suggests that the maintenance of species diversity in ecological communities may be influenced by more than purely ecological processes. Classic theory shows that interspecific competition may select for traits that increase niche differentiation, weakening competition and thus promoting species coexistence. While empirical work has demonstrated trait evolution in response to competition, if and how evolution affects the dynamics of the competing species—the key step for completing the required eco-evolutionary feedback—has been difficult to resolve. Here, we show that evolution in response to interspecific competition feeds back to change the course of competitive population dynamics of aquatic plant species over 10–15 generations in the field. By manipulating selection imposed by heterospecific competitors in experimental ponds, we demonstrate that (i) interspecific competition drives rapid genotypic change, and (ii) this evolutionary change in one competitor, while not changing the coexistence outcome, causes the population trajectories of the two competing species to converge. In contrast to the common expectation that interspecific competition should drive the evolution of niche differentiation, our results suggest that genotypic evolution resulted in phenotypic changes that altered population dynamics by affecting the competitive hierarchy. This result is consistent with theory suggesting that competition for essential resources can limit opportunities for the evolution of niche differentiation. Our finding that rapid evolution regulates the dynamics of competing species suggests that ecosystems may rely on continuous feedbacks between ecology and evolution to maintain species diversity.

Species diversity of the marine diatom genus Skeletonema in Japanese brackish water areas

2013 ◽  
Vol 79 (6) ◽  
pp. 923-934 ◽  
Author(s):  
Machiko Yamada ◽  
Mayuko Otsubo ◽  
Yuki Tsutsumi ◽  
Chiaki Mizota ◽  
Naoki Iida ◽  
...  
Keyword(s):  
Species Diversity ◽  
Brackish Water ◽  
Marine Diatom ◽  
Diatom Genus

scholarly journals Diversity of Trichoptera emergence and their longitudinal distribution along streams in central Palawan, the Philippines

Zoosymposia ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 53-62
Author(s):  
WOLFRAM MEY ◽  
HENDRIK FREITAG
Keyword(s):  
Species Diversity ◽  
Real Number ◽  
Brackish Water ◽  
The Philippines ◽  
Species Level ◽  
Longitudinal Distribution ◽  
The Real ◽  
Number Of Species ◽  
Emergence Traps ◽  
Single Locality

Trichoptera emergences were cumulatively collected from two rivers in central Palawan over 11 months by use of specially modified emergence traps. The quantitative samples were identified at species level. Fifty morphospecies, of which fifteen have been recently newly described, are recognized. The highest species diversity was found in pristine headwater streams. Leptoceridae were most speciose with eleven Oecetis spp., four Leptocerus spp., two Adicella spp., and one species each of Tagalopsyche, Triaenodes, and Triplectides. Highest abundances were observed for Ecnomus cabayugani (Ecnomidae), Dipseudopsis digitata, and Hyalopsyche winkleri (Dipseudopsidae) which contributed alone 34% of the annual emergence. A mid-stream site where mayflies were mainly absent had the highest Trichoptera emergence, brackish water sites the lowest. Many species in Palawan (44% of the taxa) were recorded at a single locality, suggesting that they are stenoecious and that the real number of species on the island might be distinctly higher. This is the first study ever covering quantitative and species-level Trichoptera emergence data for a longitudinal river course.

scholarly journals Distribution patterns of macrofaunal species diversity in subtidal soft sediments: biodiversity–productivity relationships from the MacroBen database

2009 ◽  
Vol 382 ◽  
pp. 253-264 ◽  
Author(s):  
V Escaravage ◽  
PMJ Herman ◽  
B Merckx ◽  
M Wlodarska-Kowalczuk ◽  
JM Amouroux ◽  
...  
Keyword(s):  
Species Diversity ◽  
Distribution Patterns ◽  
Soft Sediments ◽  
Macrofaunal Species

Diatoms in the Early Valdai (Weichselian) sediments in Lake Ladoga basin

2019 ◽  
pp. 225-228
Author(s):  
Anna V. Ludikova
Keyword(s):  
Species Diversity ◽  
High Energy ◽  
Lake Ladoga ◽  
Diatom Assemblages ◽  
Marine Diatoms ◽  
Selective Preservation

The pioneer diatom study of the Early Weichselian (Valdai) sediments in Lake Ladoga basin was performed. The specifics of the diatom assemblages (co-occurrence of ecologically incompatible taxa, poor species diversity, low diatom concentration and selective preservation) suggest that during the Early Weichselian time intense erosion of previously deposited marine Eemian (Mikulino) sediments prevailed, which resulted in re-deposition of marine diatoms. The sedimentation took place in high-energy environments unfavorable for diatom accumulation and preservation.

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