scholarly journals A Maastrichtian microbial reef and associated limestones in the Roca Formation of Patagonia (Neuquén Province, Argentina)

Fossil Record ◽  
2006 ◽  
Vol 9 (2) ◽  
pp. 183-197 ◽  
Author(s):  
W. Kiessling ◽  
R. Scasso ◽  
M. Aberhan ◽  
L. Ruiz ◽  
S. Weidemeyer
Keyword(s):  
Green Algae ◽  
Brackish Water ◽  
Strontium Isotope ◽  
Fecal Pellets ◽  
Reef Structure ◽  
Isotope Data ◽  
Water Conditions ◽  
Cement Crusts ◽  
Mixed Carbonate

Abstract. We describe a small microbial reef and associated limestones occurring in a Maastrichtian transgressive succession of mixed carbonate-siliciclastic lithologies at Sierra Huantraico near Chos Malal (Neuquén, Argentina). Strontium isotope data suggest that the reef is of earliest Maastrichtian age. The small reef (0.8 m thick, 2 m wide) is mostly composed of peloidal bindstone, dense stromatolite-cement crusts and thrombolite. Except for some ostracods, no metazoan fossils were found in the reef structure, although the majority of peloids are fecal pellets, probably of larger crustaceans. Small foraminifers with calcite tests and probable green algae have also been noted. Sedimentological data and fossils within and immediately above the reef suggest that the reef was formed in a transgressive systems tract under freshwater to brackish-water conditions. Limestones above the reef are serpulid-bryozoan packstones and intraclast-ooid grainstones. These limestones yield a mixture of typical non-tropical (common serpulids and bryozoans) and typical tropical aspects (common dasycladaceans and ooids). This mosaic is explained by salinity fluctuations, which in our case dominate over temperature in determining the grain associations. Wir beschreiben ein kleines mikrobielles Riff, das in der Sierra Hunatraico (Neuquén, Argentinien) in einer transgressiven, gemischt siliziklastisch-kalkigen Abfolge gefunden wurde. Nach Strontiumisotopen-Datierung ist das Riff in das unterste Maastrichtium zu stellen. Das kleine Riff (0,8 m Mächtigkeit, 2 m Breite) besteht überwiegend aus peloidalem Bindstone, dichten Stromatolith-Zement-Krusten und Thrombolith. Mit Ausnahme von Ostrakoden konnten keine Metazoen in der Riffstruktur nachgewiesen werden, obwohl die Mehrzahl der Peloide als Kotpillen zu interpretieren sind, die vermutlich auf größere Krebse zurückgehen. Kleine Foraminiferen und mögliche Grünalgen sind die einzigen zusätzlich nachweisbaren Eukaryoten. Die Fossilien im Riff und in den überlagernden Kalken sprechen für ein Riffwachstum unter transgressiven aber hyposalinen Bedingungen. Die Kalke über dem Riff tragen ein gemischtes paläoklimatisches Signal, das sowohl typisch nicht-tropische als auch typisch tropische Komponenten beinhaltet. Dieses Mosaik ist möglicherweise durch die starken Salinitätsschwankungen erklärbar und erfordert ein Überdenken der bisherigen Modelle zur klimatischen Steuerung der Karbonatsedimentation. doi:10.1002/mmng.200600007

Transfer of monovalent anions and nitrates especially through nanofiltration membranes in brackish water conditions

2004 ◽  
Vol 40 (3) ◽  
pp. 237-242 ◽  
Author(s):  
L. Paugam ◽  
C.K. Diawara ◽  
J.P. Schlumpf ◽  
P. Jaouen ◽  
F. Quéméneur
Keyword(s):  
Brackish Water ◽  
Nanofiltration Membranes ◽  
Water Conditions

scholarly journals Corrigendum

1983 ◽  
Vol 57 (3) ◽  
pp. 196-196
Keyword(s):  
Brackish Water ◽  
Type Species ◽  
Freshwater Fishes ◽  
Marine Fishes ◽  
Pacific Region ◽  
Larval Form ◽  
Marine Molluscs ◽  
Water Conditions

The Introduction should read as follows:INTRODUCTIONThe Transversotrematidae is believed to be the smallest family of marine trematodes and is restricted to the Indo-Pacific region (Cable, 1974). The members of this family occupy an ectoparasitic niche, inhabiting the recesses beneath the scales of freshwater, brackish-water and marine fishes. Of the seven species in the genus Transversotrema Witenberg, 1944, the cercariae of T. patialense (Soparkar, 1924) Yamaguti, 1958, T. laruei Velasquez, 1958, T. soparkari Pande & Shukla, 1972 and T. chackai Mohandas, 1973 are already known. The larval form of the type species T. haasi Witenberg, 1944, and of T. licinum Manter, 1970 and T. chauhani Agarwal & Singh, 1981 and the adult of Cercaria koliensis Olivier, 1947 are yet to be discovered. The known cercariae develop in gastropod molluscs of the genera Melania or Thiara. An interesting feature in this group is the report of natural infections of Transversotrema haasi and T. licinum in marine fishes. As the adults are found in marine, brackish and freshwater fishes but none of the cercariae have been recorded from marine molluscs, it was thought worthwhile to study the effects of salinity, pH and O2 on survival of the cercaria of T. chackai, found in Melania tuberculata and M. scabra living in fresh and brackish water conditions.

scholarly journals Algoflora of lakes in the Kurgal’sky Nature reserve (Leningrad region)

2021 ◽  
pp. 335-347
Author(s):  
E. V. Stanislavskaya ◽  
A. L. Afanas’eva ◽  
O. A. Pavlova
Keyword(s):  
Chlorophyll A ◽  
Green Algae ◽  
Brackish Water ◽  
Phytoplankton Biomass ◽  
Nature Reserve ◽  
Ecological Status ◽  
Similarity Index ◽  
Leningrad Region ◽  
Algal Flora ◽  
Trophic Conditions

Various algocenosises in the brackish Lake Lipovskoe and ultra-oligotrophic Lake Beloe located in the Kurgal’sky Nature reserve were studied in May and July of 2019. In the algal flora of the lakes studied, we found 291 taxa belonging to 9 orders. The both lakes were characterized by high species richness, namely: 179 and 181 algae taxa were identified in the Lake Lipovskoe and Lake Beloe, respectively. In the Lake Lipovskoe, its phytoplankton was dominated by Cyanophyta, Cryptophyta and Dinophyta, among which brackish-water and marine species were presented. In the periphyton of this Lake, brackish-water diatoms and green algae were the most abundant. In the Lake Beloe, its phytoplankton was dominated by Dinophyta, Bacillariophyta and Chlorophyta; the blue-greens, diatoms and green algae dominated in the periphyton of Lake Beloe. Despite that the lakes are located close to each other, their algal flora is quite different: the Sorensen similarity index between the two lakes was 38% only. The phytoplankton biomass in both lakes was low, increasing from spring to summer. In the Lake Lipovskoe, the phytoplankton biomass varied from 0.45 to 1.9 mg/L, chlorophyll a fluctuated from 3.9 to 7.1 µg/L. In the Lake Beloe, the phytoplankton biomass varied from 0.3 to 1.4 mg/L, chlorophyll a fluctuated from 0.45 to 1.3 µg/L. The periphyton biomass was 20 g/m2  (chlorophyll a being 22 mg/m2 ) and 17 g/m2 (chlorophyll a being 17 mg/m2 ) in the Lake Lipovskoe and Lake Beloe, respectively. Nowadays, the ecological status of both lakes can be considered satisfactory, because based on trophic conditions and species compositions they belong to waterbodies of clean and satisfactory clean conditions (II–III classes of water quality). To preserve the unique flora of the lakes in the Kurgal’sky Nature reserve, nature-protected measures should be strengthened.

The fauna and flora of the March Gravels at Northam Pit, Eye, Cambridgeshire, England

1990 ◽  
Vol 127 (5) ◽  
pp. 453-465 ◽  
Author(s):  
D. H. Keen ◽  
J. E. Robinson ◽  
R. G. West ◽  
F. Lowry ◽  
D. R. Bridgland ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Brackish Water ◽  
Water Conditions ◽  
Temperate Environment

AbstractInvestigations of the March Gravels of Northam Pit, Eye, Cambridgeshire, have provided previously undescribed molluscan, ostracod and foraminiferal faunas together with pollen spectra, which enable a detailed palaeoenvironmental synthesis to be developed. The sediments were laid down in brackish-water conditions and a temperate environment, during a Late Pleistocene temperate stage.

Invertebrate trace fossils and agglutinated foraminifera as indicators of marine influence within the classic Carboniferous section at Joggins, Nova Scotia, Canada

1995 ◽  
Vol 32 (12) ◽  
pp. 2027-2039 ◽  
Author(s):  
Allen W. Archer ◽  
John H. Calder ◽  
Martin R. Gibling ◽  
Robert D. Naylor ◽  
Donald R. Reid ◽  
...  
Keyword(s):  
Nova Scotia ◽  
North America ◽  
Brackish Water ◽  
Eastern North America ◽  
Fluvial Systems ◽  
Biogenic Structures ◽  
Water Conditions ◽  
Marine Influence ◽  
New Evidence ◽  
Agglutinated Foraminifera

The sea cliffs at Joggins, Nova Scotia, are the most extensive and continuous Carboniferous section in eastern North America. Although the section has been considered to have formed within a nonmarine depositional basin, paleobiological information indicates that parts of the section were deposited in brackish water. The occurrence of a trace-fossil assemblage, which includes Cochlichnus, Kouphichnium, and Treptichnus, is part of an assemblage of biogenic structures that apparently reflects paleodeposition within fluvial systems that may have experienced distal marine influences. Presence of agglutinated foraminifera characteristic of brackish-water environments supports this interpretation. This information provides new evidence of brackish-water conditions at Joggins such as those now being widely recognized in other Carboniferous coal-bearing sections.

A potential global stratotype for the Sinemurian–Pliensbachian boundary (Lower Jurassic), Robin Hood's Bay, UK: ammonite faunas and isotope stratigraphy

2000 ◽  
Vol 137 (6) ◽  
pp. 601-607 ◽  
Author(s):  
STEPHEN P. HESSELBO ◽  
CHRISTIAN MEISTER ◽  
DARREN R. GRÖCKE
Keyword(s):  
Sedimentation Rate ◽  
Temperature Drop ◽  
Lower Jurassic ◽  
Strontium Isotope ◽  
Isotope Data ◽  
Strontium Isotope Stratigraphy ◽  
On Line ◽  
Significant Temperature ◽  
Isotope Stratigraphy

A coastal exposure at Wine Haven, Robin Hood's Bay (North Yorkshire, UK) fulfils the criteria for definition as the Global Stratotype Section and Point (GSSP) for the base of the Pliensbachian Stage (Lower Jurassic). This marine sequence was deposited during a long-term transgression and is relatively expanded stratigraphically. A rich fauna of ammonites above and below the boundary interval allows recognition of the Leptechioceras gr. meigeini, Paltechioceras aureolum and Paltechioceras tardecrescens horizons of latest Sinemurian age, and the Bifericeras donovani, and Apoderoceras gr. aculeatum horizons of earliest Pliensbachian age. A suitable level for the boundary is characterized by the faunal association of Bifericeras donovani Dommergues & Meister and Apoderoceras sp. Strontium-isotope stratigraphy, based on analysis of belemnites, yields a calcite 87Sr/86Sr ratio for the suggested boundary level of 0.707425±0.000021 (combined uncertainties based on line fit to stratigraphic dataset (±0.000004) and measurement of the standard (±0.000017)). Alternative uncertainties of ∼±0.000008 are associated with the most extreme interpretation of sedimentation-rate history allowed by the strontium-isotope data (that is, abrupt changes in sedimentation rate at precisely the boundary level); however, sedimentological considerations, and measured strontium-isotope values at the boundary, support condensation rather than hiatus. Belemnite oxygen-isotope data suggest a significant temperature drop (∼5 °C) across the boundary at this locality.

Production de tilapia marin en circuit ferme en eau verte: le Système Aquacole à Recyclage Integral (SARI).

2020 ◽  
Author(s):  
Nicolas de Wilde ◽  
Sylvain Gilles
Keyword(s):  
Fresh Water ◽  
Green Algae ◽  
Breeding System ◽  
Brackish Water ◽  
Energy Savings ◽  
Brachionus Plicatilis ◽  
Clear Water ◽  
Algal Population ◽  
Aquaculture System ◽  
Sarotherodon Melanotheron

Abstract The Integral Recycling Aquaculture System (SARI) is an artificial ecosystem that combines closed-circuit farming of marine tilapia Sarotherodon melanotheron heudelotii with plankton lagooning in brackish water. Compared to conventional closed circuits in clear water, it provides significant advantages in terms of fresh water and energy savings, as well as in terms of health by limiting the introduction of pathogens. A prototype of the SARI located at the IRD Center in Mbour, Senegal, has made it possible to study the functioning of this breeding system. The tilapia S. m. heudelotii, when raised in intensive or semi-intensive mode, promotes the production of the green algae Chlorella sp. which purifies the environment of nitrogenous waste produced by fish. The algal population is regulated by the production of the rotifer Brachionus plicatilis, which itself serves as a complementary feed for the fry in rearing.

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