Pikeperch (Stizostedion lucioperca) in its Natural Habitats in Poland

1977 ◽  
Vol 34 (10) ◽  
pp. 1581-1585 ◽  
Author(s):  
Maria Nagięć
Keyword(s):  
Key Words ◽  
Primary Productivity ◽  
Thermal Stratification ◽  
Natural Habitats ◽  
Stizostedion Lucioperca

The distribution and biology of pikeperch, Stizostedion lucioperca, in Poland are reviewed along with the characteristics of lakes where pikeperch are abundant. The characteristics of these lakes include low mean depth, lack of thermal stratification in summer, and intensive mixing of water. These characteristics are discussed in relation to primary productivity, zooplankton composition, abundance of benthos, and fish harvests in lakes and firths. Key words: Percidae, pikeperch lakes, harvest, habitat, Stizostedion lucioperca

Production of amylases by yeasts

1990 ◽  
Vol 36 (11) ◽  
pp. 751-753 ◽  
Author(s):  
Valter R. Linardi ◽  
Katia M. G. Machado
Keyword(s):  
Enzymatic Activity ◽  
Key Words ◽  
Wheat Bran ◽  
Aureobasidium Pullulans ◽  
Natural Habitats ◽  
Semisolid Medium ◽  
Debranching Enzyme ◽  
Candida Kefyr ◽  
Candida Famata ◽  
High Enzymatic Activity

Yeasts (228) isolated for natural habitats were screened for their ability to produce amylases in semisolid medium of wheat bran. Strains of Aureobasidium pullulans, Candida famata, and Candida kefyr showed high enzymatic activity for α-amylase, glucoamylase, and debranching enzyme. Key words: Aureobasidium, Candida, amylolytic yeasts, α-amylase, glucoamylase.

Seasonal Periodicity of Diatoms, and Silicon Limitation in Offshore Lake Michigan, 1975

1977 ◽  
Vol 34 (4) ◽  
pp. 552-558 ◽  
Author(s):  
J. I. Parker ◽  
H. L. Conway ◽  
E. M. Yaguchi
Keyword(s):  
Key Words ◽  
Primary Productivity ◽  
Rapid Growth ◽  
Lake Michigan ◽  
Spring Bloom ◽  
Accumulation Rate ◽  
Biomass Accumulation ◽  
Seasonal Periodicity ◽  
Silicon Uptake ◽  
Bloom Diatom

Diatom biomass maxima occurred in spring and fall and produced a bimodal bloom sequence at an offshore Lake Michigan station. The maximum in May was preceded by rapid growth as indicated by increased values of primary productivity and pigment concentration. As the spring bloom progressed, decreasing nutrient levels apparently slowed diatom growth. The diatom-biomass accumulation rate declined, assimilation quotients were minimal, and soluble reactive silicon was reduced from 13 to 6.8 μmol/ℓ. In summer, after the bloom, diatom biomass and silicon reached seasonal minima of < 250 mg C/m2 and ~ 1.0 μmol/ℓ, respectively. Diatom biomass increased again in October when silicon supplies were replenished and the concentration exceeded 6.6 μmol/ℓ. A critical silicon concentration of ~ 6.5 μmol/ℓ, may control the development and timing of offshore diatom populations in Lake Michigan. Key words: Lake Michigan, diatoms, growth, biomass, periodicity, silicon, uptake, limitation

scholarly journals Contribution of dinitrogen fixation to bacterial and primary productivity in the Gulf of Aqaba (Red Sea)

2013 ◽  
Vol 10 (6) ◽  
pp. 10327-10361 ◽  
Author(s):  
E. Rahav ◽  
B. Herut ◽  
M. R. Mulholland ◽  
B. Voß ◽  
D. Stazic ◽  
...  
Keyword(s):  
Amino Acids ◽  
Primary Productivity ◽  
N2 Fixation ◽  
Thermal Stratification ◽  
Early Spring ◽  
Gulf Of Aqaba ◽  
Bacterial Productivity ◽  
Heterotrophic Prokaryotes ◽  
Experimental Enrichment ◽  
Diazotrophic Community

Abstract. We evaluated the seasonal contribution of heterotrophic and autotrophic diazotrophy to the total dinitrogen (N2) fixation in a representative pelagic station in the northern Gulf of Aqaba in early spring when the water column was mixed and during summer under full thermal stratification. N2 fixation rates were low during the mixed period (∼ 0.1 nmol N L−1 d−1) and were significantly coupled with both primary and bacterial productivity. During the stratified period N2 fixation rates were four-fold higher (∼ 0.4 nmol N L−1 d−1) and were significantly correlated solely with bacterial productivity. Furthermore, while experimental enrichment of seawater by phosphorus (P) enhanced bacterial productivity and N2 fixation rates during both seasons primary productivity was stimulated by P only in the early spring. Metatranscriptomic analyses from the stratified period identified the major diazotrophic contributors as related to heterotrophic prokaryotes from the Euryarchaeota and Desulfobacterales (Deltaproteobacteria) or Chlorobiales (Chlorobia). Moreover, during this season, experimental amendments to seawater applying a combination of the photosynthetic inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) and a mixture of amino acids increased both bacterial productivity and N2 fixation rates. Our findings from the northern Gulf of Aqaba indicate a~shift in the diazotrophic community from phototrophic and heterotrophic populations, including small blooms of the cyanobacterium Trichodesmium, in winter/early spring, to predominantly heterotrophic diazotrophs in summer that may be both P and carbon limited as the additions of P and amino acids illustrated.

Nouvelles observations cytologiques chez Festuca rubra sensu lato (Poaceae) dans l'Est du Canada

1995 ◽  
Vol 73 (8) ◽  
pp. 1289-1294 ◽  
Author(s):  
Martin Dubé ◽  
Pierre Morisset
Keyword(s):  
Chromosome Number ◽  
Key Words ◽  
Natural Habitat ◽  
Festuca Rubra ◽  
Eastern Canada ◽  
Natural Habitats

Sixty-one chromosome number determinations in Festuca rubra L. from eastern Canada show that hexaploids plants (n = 21) are found in both natural habitats and ruderal places, octoploids rhizomatous plants (n = 28) are mostly found in ruderal places, but also in disturbed natural habitats. Morever, one aneuploid (2n = ca. 48) is found from a natural habitat and intercytotype hybrids are found in ruderal places or disturbed natural habitats. Key words: Festuca rubra, cytotypes, hybrids.

Relations Between Exploitation, Yield, and Community Structure in Polish Pikeperch (Stizostedion lucioperca) Lakes, 1966–71

1977 ◽  
Vol 34 (10) ◽  
pp. 1576-1580 ◽  
Author(s):  
Alina Bonar
Keyword(s):  
Community Structure ◽  
Key Words ◽  
Fish Species ◽  
Community Dynamics ◽  
Fish Populations ◽  
Predatory Fish ◽  
Total Catch ◽  
High Yields ◽  
Exploitation Intensity ◽  
Stizostedion Lucioperca

A review of official fishery records maintained on 43 Polish pikeperch (Stizostedion lucioperca) lakes during 1966–71 showed that yield was dependent on exploitation intensity and community structure. Community structure was studied on the basis of three groups of fish: predatory, undesirable, and valuable nonpredatory. The percent of predatory fish was used as an index of community structure. An increase of 1 unit of exploitation intensity increased yield by 0.42–0.50 kg/ha and a 1% increase in predatory fish decreased yield by 0.45–0.49 kg/ha. Undesirable fish predominated in lakes with high yields and predatory fish predominated in lakes with low yields. The largest catches of predatory fish species occurred when their percentage in the total catch reached 25. A more effective regulation of predatory and nonpredatory fish populations may be achieved through controlled exploitation. Key words: Percidae, European pikeperch, Poland, community dynamics, methodology, predators, exploitation, yield

Toxicity of a Mixture of Metals on Freshwater Algae

1978 ◽  
Vol 35 (4) ◽  
pp. 479-481 ◽  
Author(s):  
P. T. S. Wong ◽  
Y. K. Chau ◽  
P. L. Luxon
Keyword(s):  
Water Quality ◽  
Great Lakes ◽  
Key Words ◽  
Green Algae ◽  
Primary Productivity ◽  
Lake Water ◽  
Metal Toxicity ◽  
Culture Medium ◽  
Freshwater Algae ◽  
Water Quality Objectives

Recommended levels of a number of metals for Great Lakes Water Quality Objectives were found to be very toxic to freshwater algae when these metals were present simultaneously in lake water and culture medium. The diatom tested was more sensitive to metal toxicity than the blue-green and green algae. Key words: metals, Water Quality Objectives, toxicity, algae, diatom, primary productivity

scholarly journals Karyotype of some species of Chara and Nitella (Charophyta) from Bangladesh

1970 ◽  
Vol 38 (2) ◽  
pp. 205-207 ◽  
Author(s):  
Wahida Khatun ◽  
Md Mosleh Ud-Deen ◽  
Golam Kabir
Keyword(s):  
Key Words ◽  
Green Algae ◽  
Chara Corallina ◽  
Chromosome Length ◽  
Natural Habitats ◽  
Karyotypic Analysis ◽  
Chara Vulgaris ◽  
Total Frequency ◽  
Standard Karyotype ◽  
Karyotype Formula

Karyotypic analysis of Chara corallina Linn., C. vulgaris Linn., C. gymnopitys Linn. and Nitella translucens Ag. collected from natural habitats revealed that C. corallina has n=42, C. vulgaris and Chara gymnopitys have n=14 while Nitella translucens has n=18 chromosomes. All the species had differences in individual chromosome length, total chromatin length, total frequency between the complements of their chromosomes. The proposed standard karyotype formula were 6Lm + 2Mm +26Msm + 6S1m + 2S2m for Chara corallina, 4Mm + 8S1m + 2S2m for Chara vulgaris, 6Mm + 4S1m + 2S2sm +2S2m for Chara gymnopitys and 6Lm + 2Lsm + 6Mm+ 2Msm + 2S1m for Nitella translucens. Key words: Chara; Nitella; Karyotype; Green algae; Bangladesh DOI: 10.3329/bjb.v38i2.5150 Bangladesh J. Bot. 38(2): 205-207, 2009 (December)

Limnological characteristics, community metabolism and management strategies of a coastal sinkhole in Cuba (Cenote Jennifer)

2020 ◽  
Vol 56 ◽  
pp. 24
Author(s):  
Roberto González-De Zayas ◽  
Liosban Lantigua Ponce de León ◽  
Liezel Guerra Rodríguez ◽  
Felipe Matos Pupo ◽  
Leslie Hernández-Fernández
Keyword(s):  
Hydrogen Sulfide ◽  
Primary Productivity ◽  
Major Ions ◽  
Saline Water ◽  
Management Strategies ◽  
Tourist Destination ◽  
Community Metabolism ◽  
Morphological Studies ◽  
Made In ◽  
Limnological Parameters

The Cenote Jennifer is an important and unique aquatic sinkhole in Cayo Coco (Jardines del Rey Tourist Destination) that has brackish to saline water. Two samplings were made in 1998 and 2009, and 4 metabolism community experiments in 2009. Some limnological parameters were measured in both samplings (temperature, salinity, pH, dissolved oxygen major ions, hydrogen sulfide, nutrients and others). Community metabolism was measured through incubated oxygen concentration in clear and dark oxygen bottles. Results showed that the sinkhole limnology depends on rainfall and light incidence year, with some stratification episodes, due to halocline or oxycline presence, rather than thermocline. The sinkhole water was oligotrophic (total nitrogen of 41.5 ± 22.2 μmol l−1 and total phosphorus of 0.3 ± 0.2 μmol l−1) and with low productivity (gross primary productivity of 63.0 mg C m−2 d−1). Anoxia and hypoxia were present at the bottom with higher levels of hydrogen sulfide, lower pH and restricted influence of the adjacent sea (2 km away). To protect the Cenote Jennifer, tourist exploitation should be avoided and more resources to ecological and morphological studies should be allocated, and eventually use this aquatic system only for specialized diving. For conservation purposes, illegal garbage disposal in the surrounding forest should end.

Multislice imaging of gastrointestinal stromal tumors

2018 ◽  
pp. 3-14
Keyword(s):  
Computed Tomography ◽  
Key Words ◽  
Gold Standard ◽  
Gastrointestinal Stromal Tumors ◽  
Mesenchymal Tumors ◽  
Stromal Tumors ◽  
Preferential Localization ◽  
Multislice Imaging ◽  
Computed Tomography Diagnosis

Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors of the digestive tract (1%). These tumors express the CD 117 in 95% of cases. The stomach is the preferential localization (70%). Diagnosis is difficult and sometimes late. Progress of imaging has greatly improved the management and the prognosis. Computed tomography (CT) is the gold standard for diagnosis, staging, and treatment follow-up. The increasing recognition of GIST’s histopathology and the prolonged survival revealed some suggestive imaging aspects. Key words: gastro-intestinal stromal tumors; computed tomography; diagnosis

METHODS OF CONSULTING ON STUDYING THE DEGREE OF MOISTURE SUPPLY OF SLOPE LANDS FOR AGRICULTURAL PRODUCTION IN AZERBAIJAN

2018 ◽  
Author(s):  
Prof.RAE Aliev Z.H.
Keyword(s):  
Key Words ◽  
Agricultural Production ◽  
Soil Ecology ◽  
Arable Soil ◽  
Clean Technology ◽  
Agricultural Product ◽  
Current Information ◽  
Moisture Supply ◽  
Managerial System

The current information on moisture and the temperature of the ground in managerial system by production to agricultural product necessary, in the first place, for taking the operative decisions at development ecological clean technology irrigation under growing agricultural cultures to achieve the maximum harvest. Key words: aerospace methods, COW, moisture, moisture test, arable, soil, ecology, vafer humidity, drill, graduation, tool, etc.

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