scholarly journals Influences of environmental parameters and phytoplankton productivity on benthic invertebrates in a tropical oligotrophic lake, northern Malaysia

2021 ◽  
Author(s):  
Mustafizur M. Rahman ◽  
Ahmad Fathi ◽  
Stephen R. Balcombe ◽  
Bryan Nelson ◽  
Akbar John
Keyword(s):  
Benthic Invertebrates ◽  
Environmental Parameters ◽  
Oligotrophic Lake ◽  
Phytoplankton Productivity

Optimizing models for remotely estimating primary production in Antarctic coastal waters

2000 ◽  
Vol 12 (1) ◽  
pp. 20-32 ◽  
Author(s):  
H.M. Dierssen ◽  
M. Vernet ◽  
R.C. Smith
Keyword(s):  
Primary Production ◽  
Primary Productivity ◽  
Coastal Waters ◽  
Time Series Data ◽  
Cold Water ◽  
Water System ◽  
Environmental Parameters ◽  
Day Length ◽  
Series Data ◽  
Phytoplankton Productivity

Primary productivity and associated biogeochemical fluxes within the Southern Ocean are globally significant, sensitive to change and poorly known compared to temperate marine ecosystems. We present seasonal time series data of chlorophyll a, primary productivity and in-water irradiance measured in the coastal waters of the Western Antarctica Peninsula and build upon existing models to provide a more optimum parameterization for the estimation of primary productivity in Antarctic coastal waters. These and other data provide strong evidence that bio-optical characteristics and phytoplankton productivity in Antarctic waters are different from temperate waters. For these waters we show that over 60% of the variability in primary production can be explained by the surface chlorophyll a concentration alone, a characteristic, which lends itself to remote sensing models. If chlorophyll a concentrations are accurately determined, then the largest source of error (13–18%) results from estimates of the photoadaptive variable (PBopt). Further, the overall magnitude of PBopt is low (median 1.09 mg C mg chl−1 h−1) for these data compared to other regions and generally fits that expected for a cold water system. However, the variability of PBopt over the course of a season (0.4 to 3 mg C mg chl−1 h−1) is not consistently correlated with other possible environmental parameters, such as chlorophyll, sea surface temperature, incident irradiance, day length, salinity, or taxonomic composition. Nonetheless, by tuning a standard depth-integrated primary productivity model to fit representative PBopt values and the relatively uniform chlorophyll-normalized production profile found in these waters, we can improve the model to account for approximately 72–73% variability in primary production both for our data as well as for independent historic Antarctic data.

scholarly journals Phytoplankton Community at Intensive Cultivation System of Whiteleg Shrimp, Litopenaeus vannamei in Probolinggo, East Java

el–Hayah ◽  
2017 ◽  
Vol 6 (3) ◽  
pp. 79
Author(s):  
Nasrullah Bai Arifin ◽  
Muhammad Fakhri ◽  
Ating Yuniarti ◽  
Anik Martinah Hariati
Keyword(s):  
Chlorophyll A ◽  
Litopenaeus Vannamei ◽  
Environmental Parameters ◽  
Nutrient Content ◽  
Ammonia Nitrogen ◽  
Culture Period ◽  
Phytoplankton Productivity ◽  
Cultivation System ◽  
Whiteleg Shrimp ◽  
Shrimp Cultivation

Phytoplankton is a source of natural feed for shrimp cultivation in the pond. Phytoplankton productivity increases by the increasing nutrient content in the pond. Feed and metabolic waste is the sources of nutrient for phytoplankton growth. This study aimed to evaluate productivity and identify phytoplankton at intensive whiteleg shrimp, <em>Litopenaeus vannamei </em>cultivation system. This study was conducted at three intensive whiteleg shrimp located in Probolinggo, East Java. Samples were collected on the early and the late of culture period (day 17 and 87 after stocking). Four environmental parameters including total of ammonia nitrogen (TAN), nitrate, orthophosphate, total of suspended solid (TSS), and chlorophyll-a were measured. Identification and density of phytoplankton were also performed of each pond. The result showed that productivity of three ponds was 22,893.83 kg/ha to 23,600.61 kg/ha with an average size 12.74 g to 14.35 g. During culture period, the concentration of TAN, TSS and chlorophyll-a tended to increase. Meanwhile, the average of both nitrate and orthophosphate tended to decline. Several phytoplankton identified in this study were in the genus of <em>Oocystis, </em><em>Chlorella, Nannochloropsis, Chaetoceros</em>, <em>Stephanodiscus, </em><em>Nitzschia, Coscinodiscus, Cyclotella </em>and <em>Ulothrix. </em>Phytoplankton of the group Chlorophyta is predominance for pond 1 and 2, while pond 3 was dominated by phytoplankton in the group of Diatom/Baccillariophyta. This study indicated that the present of phytoplankton in the pond provide natural feed and good environmental condition for shrimp cultivation.

Electron Microscopy in the Study of Natural Phytoplankton Assemblages

1985 ◽  
Vol 43 ◽  
pp. 620-623
Author(s):  
Linda Sicko-Goad
Keyword(s):  
Electron Microscopy ◽  
Aquatic Environment ◽  
Size Range ◽  
Physical Parameters ◽  
Specific Information ◽  
Phytoplankton Assemblages ◽  
Phytoplankton Productivity ◽  
Ecosystem Effects ◽  
Time Of Year ◽  
Species Specific

Although the use of electron microscopy and its varied methodologies is not usually associated with ecological studies, the types of species specific information that can be generated by these techniques are often quite useful in predicting long-term ecosystem effects. The utility of these techniques is especially apparent when one considers both the size range of particles found in the aquatic environment and the complexity of the phytoplankton assemblages.The size range and character of organisms found in the aquatic environment are dependent upon a variety of physical parameters that include sampling depth, location, and time of year. In the winter months, all the Laurentian Great Lakes are uniformly mixed and homothermous in the range of 1.1 to 1.7°C. During this time phytoplankton productivity is quite low.

HUBUNGAN KEPADATAN BIVALVIA DENGAN PARAMETER LINGKUNGAN DI PESISIR TANJUNG PURA KABUPATEN BANGKA TENGAH

2020 ◽  
Vol 13 (2) ◽  
pp. 112-121
Author(s):  
Sudiyar . ◽  
Okto Supratman ◽  
Indra Ambalika Syari
Keyword(s):  
Negative Impact ◽  
Principal Component ◽  
Environmental Parameters ◽  
Data Retrieval ◽  
Distribution Patterns ◽  
Random System ◽  
System Method ◽  
Relationship Of ◽  
The Relationship ◽  
Anadara Granosa

The destructive fishing feared will give a negative impact on the survival of this organism. This study aims to analyze the density of bivalves, distribution patterns, and to analyze the relationship of bivalves with environmental parameters in Tanjung Pura village. This research was conducted in March 2019. The systematic random system method was used for collecting data of bivalves. The collecting Data retrieval divided into five research stasions. The results obtained 6 types of bivalves from 3 families and the total is 115 individuals. The highest bivalve density is 4.56 ind / m², and the lowest bivalves are located at station 2,1.56 ind / m²,  The pattern of bivalve distribution in the Coastal of Tanjung Pura Village is grouping. The results of principal component analysis (PCA) showed that Anadara granosa species was positively correlated with TSS r = 0.890, Dosinia contusa, Anomalocardia squamosa, Mererix meretrix, Placamen isabellina, and Tellinella spengleri were positively correlated with currents r = 0.933.

Recirculation versus flow-through rainbow trout laboratory Flavobacterium columnare challenge

2020 ◽  
Vol 139 ◽  
pp. 213-221
Author(s):  
C Birkett ◽  
R Lipscomb ◽  
T Moreland ◽  
T Leeds ◽  
JP Evenhuis
Keyword(s):  
Rainbow Trout ◽  
Environmental Parameters ◽  
Cumulative Effects ◽  
Flavobacterium Columnare ◽  
Replacement Rate ◽  
Bacterial Concentration ◽  
Water Replacement ◽  
Dose Concentration ◽  
Flow Through ◽  
And Control

Flavobacterium columnare immersion challenges are affected by water-related environmental parameters and thus are difficult to reproduce. Whereas these challenges are typically conducted using flow-through systems, use of a recirculating challenge system to control environmental parameters may improve reproducibility. We compared mortality, bacterial concentration, and environmental parameters between flow-through and recirculating immersion challenge systems under laboratory conditions using 20 rainbow trout families. Despite identical dose concentration (1:75 dilution), duration of challenge, lot of fish, and temperature, average mortality in the recirculating system (42%) was lower (p < 0.01) compared to the flow-through system (77%), and there was low correlation (r = 0.24) of family mortality. Mean days to death (3.25 vs. 2.99 d) and aquaria-to-aquaria variation (9.6 vs. 10.4%) in the recirculating and flow-through systems, respectively, did not differ (p ≥ 0.30). Despite 10-fold lower water replacement rate in the recirculating (0.4 exchanges h-1) compared to flow-through system (4 exchanges h-1), differences in bacterial concentration between the 2 systems were modest (≤0.6 orders of magnitude) and inconsistent throughout the 21 d challenge. Compared to the flow-through system, dissolved oxygen during the 1 h exposure and pH were greater (p ≤ 0.02), and calcium and hardness were lower (p ≤ 0.03), in the recirculating system. Although this study was not designed to test effects of specific environmental parameters on mortality, it demonstrates that the cumulative effects of these parameters result in poor reproducibility. A recirculating immersion challenge model may be warranted to empirically identify and control environmental parameters affecting mortality and thus may serve as a more repeatable laboratory challenge model.

STRUCTURE AND DYNAMICS OF ENVIRONMENTAL PARAMETERS OF HUMAN INTESTINAL MICROBIOME IN DIFFERENT CLIMATIC AND ECOLOGICAL ZONES OF ST. PETERSBURG

2020 ◽  
pp. 31-36
Author(s):  
Bugero N.V. ◽  
Ilyina N.A. ◽  
Aleksandrova S.M.
Keyword(s):  
Environmental Parameters ◽  
Intestinal Microbiome ◽  
Ecological Niches ◽  
Horizontal Structure ◽  
Ecological Zones ◽  
Qualitative And Quantitative ◽  
Symbiotic Relationships ◽  
Structure And Dynamics ◽  
Quantitative Changes ◽  
Micro Organisms

In order to understand the structure and dynamics of symbiotic relationships of human intestinal biotope micro-organisms, taxonomic constancy indices, the degree of contagion of the biocenosis under study and floristic significance were investigated, which made it possible to detect qualitative and quantitative changes in the microecology of the biotope being studied in persons living in different ecologically heterogeneous territories of Saint Petersburg. The contagiosity index estimated the distribution of species in space. Persons living in the ecologically disadvantaged Kirov district of the city have been found to show a reliable increase in this indicator for the obligate microflora: bifido and lacto bacteria, intestinal columns and bacteroids, compared to the resort district, which is considered a relatively favourable area for residence. On the contrary, there has been a reliable decrease in this indicator in the group of opportunistic micro-organisms (fungi of the genus Candida, staphylococcus, clostridium, etc.), resulting in the liberation of ecological niches successfully occupied by transient flora. This ratio reveals an imbalance of participation in the horizontal structure of the intestine ecosystem of the main symbiotes and representatives of the transient flora. To analyse the structure of symbiotic relationships, the constancy indices that form the microflora of the individuals of the groups studied were investigated. The analysis of the data obtained suggested that the dominant species in both groups were optional-anaerobic bifido and lactobacteria and oblique-anaerobic bacteroids. It should be noted, however, that in the residents of the dysfunctional Kirovsky district, against the background of the reduced constancy of the normal flora, opportunistic micro-organisms have entered. The floral significance index was also declining in the obligate flora of this group and increased for opportunistic species. Thus, the study of the environmental characteristics of the intestinal biotope using different ecological parameters for persons living in different technogenic load regions of St. Petersburg has shown that in the Kirov district with an unfavourable environmental situation there are compensated qualitative and quantitative changes in the intestinal microbiocenosis, resulting in a change in the hierarchy in the overall structure of micro-organisms.

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