Fluctuations of the population of Daphnia laevis Birge 1878: a six-year study in a tropical lake

The fluctuation of the population of Daphnia laevis in Lake Jacaré (Middle River Doce, Minas Gerais) was monitored monthly (at one point in the limnetic region) for six years (2002-2007) as part of the Program of Long-Term Ecological Research (LTER/UFMG). The following parameters were also monitored: water temperature, pH, electrical conductivity, dissolved oxygen, chlorophyll a, total phosphorus, phosphate, total nitrogen, nitrate, nitrite, ammonia, and densities of Chaoborus and ephippia of Daphnia laevis in the sediment. A seasonal pattern was observed in the fluctuation of D. laevis, with higher densities recorded during periods of circulation (May-August). A significant correlation was found between the density of D. laevis and temperature (r = -0.47, p = 0.0001), chlorophyll-a (r = -0.32, p = 0.016) and indicators of the lake's trophic status (total phosphorus, r = 0.32, p = 0.007 and trophic state, r = 0.36, p = 0.003), as well as Chaoborus density (r = 0.43 and p = 0.002). These results indicate that changes in the physical and chemical characteristics of the water related with stratification and circulation of the lake may have a direct (temperature, total phosphorous) or an indirect (food availability, presence of predators, ephippia eclosion) influence on the fluctuation of the D. laevis population.

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Trophic Status and Phytoplankton Limitation Conditions in a Few Bulgarian and Hungarian Danube River Wetlands

Transylvanian Review of Systematical and Ecological Research ◽

10.1515/trser-2015-0084 ◽

2016 ◽

Vol 18 (2) ◽

pp. 19-28

Author(s):

Roumen Kalchev ◽

Árpád Berczik ◽

Michaela Beshkova ◽

Mária Dinka ◽

Hristina Kalcheva ◽

...

Keyword(s):

Chlorophyll A ◽

Total Nitrogen ◽

Total Phosphorus ◽

Trophic State ◽

Trophic Status ◽

Danube River ◽

Trophic State Index ◽

Secchi Disk ◽

State Index

Abstract The phytoplankton limitation conditions in a few Bulgarian and Hungarian wetlands and in two more sampling sites, one for each Danube stretch, were investigated by means of trophic state index of Carlson (1977) for phytoplankton chlorophyll-a (CHL), Secchi disk depths (SD), total phosphorus (TP), and total nitrogen (TN) concentrations. Phytoplankton of both river sites was not limited by non-algal turbidity, nor was they phosphorus and nitrogen limited. In summer months the studied wetlands were predominantly nitrogen limited, while in spring and autumn limitation by non-algal turbidity prevailed.

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Trophic Status of the Dniester Delta Lakes in 2006-2017

Visnyk of V. N. Karazin Kharkiv National University series "Ecology" ◽

10.26565/1992-4259-2018-18-04 ◽

2018 ◽

Keyword(s):

Chlorophyll A ◽

Trophic State ◽

Trophic Status ◽

Physicochemical Characteristics ◽

Nitrogen And Phosphorus ◽

Trophic Index ◽

Summer Time ◽

First Time

Purpose. Assessment of trophic status of the Dniester deltaic part lakes (Bile, Svine, Tudorovo and Putrino) in 2006-2017. Methods. Determination of hydrological, hydrochemical and hydrobiological characteristics of the lakes aquatic environment has been performed using standard methodologies. Three indicators of eutrophication have been used: chlorophyll a concentration, number of bacterioplankton, trophic indices TSI and TRIX. Results. Peculiarities of physicochemical characteristics of water in the Dniester deltaic lakes have been analysed. Increased nutrients concentration has been revealed in all the lakes during past 12 years. The lowest oxygen content and oxygen saturation was established in water of the Putrino Lake, where at the same time the highest concentrations of total nitrogen and phosphorus were observed. Analysis of long-term changes of chlorophyll a and bacterioplankton has been done. Based on the lakes integrated study in summer time of 2006-2017, assessment of water trophic state has been for the first time performed for each deltaic lake. Statistical interrelations between trophic state indicators and physicochemical characteristics of the lakes have been revealed. Conclusions. It was established that the assessment of four deltaic lakes trophic status based on chlorophyll a, bacterioplankton and TSI trophic index practically coincided and evidenced increased of the lakes’ trophic status and decrease of water quality in 2012-2017 compared with previous years. All the eutrophication indicators in water of the lakes Svine, Tudorovo and Putrino during six last years corresponded to hypertrophic status, while in the Bile Lake most of eutrophication indicators were lower and corresponded to eutrophic status. Trophic index TRIX, which was developed for seawater assessment, practically always showed somewhat higher trophic status of the lakes than other indicators.

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Seasonal Variations of Zooplankton, Chlorophyll-A and Nutrients in Phewa Lake, Pokhara Valley, Nepal

Ecoprint An International Journal of Ecology ◽

10.3126/eco.v16i0.3473 ◽

1970 ◽

Vol 16 ◽

pp. 51-57

Author(s):

Md. Akbal Husen ◽

Ram Prasad Dhakal

Keyword(s):

Chlorophyll A ◽

Phytoplankton Biomass ◽

Dominant Species ◽

Trophic Status ◽

Seasonal Pattern ◽

Zooplankton Species ◽

Total Phosphorous ◽

Different Seasons ◽

Pokhara Valley ◽

Lake Phewa

In order to understand trophic status of lake Phewa, largest lake (535 ha) in Pokhara valley, seasonal pattern of zooplanktons, chlorophyll a and nutrients level in water column was examined from January to December 2005. Total zooplanktons density was highest in January and November, showed bimodal pattern in Lake Phewa. The sequence of dominant species of zooplankton was Nauplius > Kerratella > Cyclops > Daphnia > Eodiaptomus in this lake. Correlation between zooplankton species and nutrients level was established. The Chlorophyll- a as an indicator of phytoplankton biomass peaks in November and chlorophyll-a concentration was found lower in winter months. The NH4-N ranged between zero to 0.021 mg/l with mean of 0.003 mg/l. The annual concentration of nitrate+nitrite (NO3+NO2) was found upto 0.148 mg/l (mean= 0.013 mg/l), soluble reactive phosphate (PO4-P) ranged from zero to 0.003 mg/l (mean= 0.001 mg/l), and total phosphorous ranged upto 0.052 mg/l (mean= 0.009 mg/l) in lake Phewa in 2005. Based on nutrients and chlorophyll-a dynamics, the lake varied from mesotrophic to eutrophic in different seasons. The Phewa Lake fluctuated from oligo-mesotrophic in monsoon seasons to meso-eutrophic in dry periods. Key words: Zooplanktons, nutrients, chlorophyll. DOI: 10.3126/eco.v16i0.3473ECOPRINT 16: 51-57, 2009

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Zooplankton Diversity in the Water Resource Area of the Mid-Line Project of South to North Water Division

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.356-360.199 ◽

2011 ◽

Vol 356-360 ◽

pp. 199-203

Author(s):

Yu Ying Li ◽

Zheng Tian Zhang ◽

Wei Yin ◽

Lan Qun Hu ◽

Zi An Liang ◽

...

Keyword(s):

Water Resource ◽

Water Samples ◽

Trophic Status ◽

Ecological Research ◽

Standard Methods ◽

Danjiangkou Reservoir ◽

Long Term Ecological Research ◽

North Water

Danjiangkou reservoir is the water resource area of the mid-line project of south to north water division. Zooplanktons are monitored at thirteen ecological stations in Danjiangkou reservoir and its typical branch rivers in August 2010 in order to establish the scientific foundation of the databank of the long-term ecological research and the layout of ecological project of the water resource. The water samples are collected using standard methods. Saprobic system is used to evaluate the trophic status of the water resource area of the min-line project. The samples contained 154 species (varieties), 110 genera of zooplankton, of which rotifea is the most, accounting for 35%, followed by copepods, protozoa and cladoceran. There are 6 species (varieties) saprobic indicators, of which β-mesosaporbic indicators account for 66.7%. No hyper-mesotrophic indicators of zooplankton occurred in the water samples. Therefore, Danjiangkou reservoir is under β-mesosaporbic status and suitable for the requirement of the water quality of the mid-line project.

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APLIKASI CITRA LANDSAT 8 OLI UNTUK IDENTIFIKASI STATUS TROFIK WADUK GAJAH MUNGKUR WONOGIRI, JAWA TENGAH

MAJALAH ILMIAH GLOBE ◽

10.24895/mig.2017.19-2.633 ◽

2017 ◽

Vol 19 (2) ◽

pp. 113

Author(s):

Kusuma Wardani Laksitaningrum ◽

Wirastuti Widyatmanti

Keyword(s):

Chlorophyll A ◽

Total Phosphorus ◽

Trophic State ◽

Water Clarity ◽

Coefficient Of Determination ◽

Physical Factors ◽

Landsat 8 ◽

Trophic State Index ◽

Landsat 8 Oli ◽

State Index

ABSTRAKWaduk Gajah Mungkur (WGM) adalah bendungan buatan yang memiliki luas genangan maksimum 8800 ha, terletak di Desa Pokoh Kidul, Kecamatan Wonogiri, Kabupaten Wonogiri. Kondisi perairan WGM dipengaruhi oleh faktor klimatologis, fisik, dan aktivitas manusia yang dapat menyumbang nutrisi sehingga mempengaruhi status trofiknya. Tujuan dari penelitian ini adalah mengkaji kemampuan citra Landsat 8 OLI untuk memperoleh parameter-parameter yang digunakan untuk menilai status trofik, menentukan dan memetakan status trofik yang diperoleh dari citra Landsat 8 OLI, dan mengevaluasi hasil pemetaan dan manfaat citra penginderaan jauh untuk identifikasi status trofik WGM. Identifikasi status trofik dilakukan berdasarkan metode Trophic State Index (TSI) Carlson (1997) menggunakan tiga parameter yaitu kejernihan air, total fosfor, dan klorofil-a. Model yang diperoleh berdasar pada rumus empiris dari hasil uji regresi antara pengukuran di lapangan dan nilai piksel di citra Landsat 8 OLI. Model dipilih berdasarkan nilai koefisien determinasi (R2) tertinggi. Hasil penelitian merepresentasikan bahwa nilai R2 kejernihan air sebesar 0,813, total fosfor sebesar 0,268, dan klorofil-a sebesar 0,584. Apabila nilai R2 mendekati 1, maka semakin baik model regresi dapat menjelaskan suatu parameter status trofik. Berdasarkan hasil kalkulasi diperoleh distribusi yang terdiri dari kelas eutrofik ringan, eutrofik sedang, dan eutrofik berat yaitu pada rentang nilai indeks 50,051 – 80,180. Distribusi terbesar adalah eutrofik sedang. Hal tersebut menunjukkan tingkat kesuburan perairan yang tinggi dan dapat membahayakan makhluk hidup lain.Kata kunci: Waduk Gajah Mungkur, citra Landsat 8 OLI, regresi, TSI, status trofikABSTRACTGajah Mungkur Reservoir is an artificial dam that has a maximum inundated areas of 8800 ha, located in Pokoh Kidul Village, Wonogiri Regency. The reservoir’s water conditions are affected by climatological and physical factors, as well as human activities that can contribute to nutrients that affect its trophic state. This study aimed to assess the Landsat 8 OLI capabilities to obtain parameters that are used to determine its trophic state, identifying and mapping the trophic state based on parameters derived from Landsat 8 OLI, and evaluating the results of the mapping and the benefits of remote sensing imagery for identification of its trophic state. Identification of trophic state is based on Trophic State Index (TSI) Carlson (1997), which uses three parameters there are water clarity, total phosphorus, and chlorophyll-a. The model is based on an empirical formula of regression between measurements in the field and the pixel values in Landsat 8 OLI. Model is selected on the highest value towards coefficient of determination (R2). The results represented that R2 of water clarity is 0.813, total phosphorus is 0.268, and chlorophyll-a is 0.584. If R2 close to 1, regression model will describe the parameters of the trophic state better. Based on the calculation the distribution consists of mild eutrophic, moderate eutrophic, and heavy eutrophic that has index values from 50.051 to 80.18. The most distribution is moderate eutrophication, and it showed the high level of trophic state and may harm other living beings.Keywords: Gajah Mungkur Reservoir, Landsat 8 OLI satellite imagery, regression, TSI, trophic state

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