The growth of transplanted aquatic bryophytes in six boreal lakes varying in trophic state

Abstract Coloured lakes are often productive. While their increased productivity can be the consequence of internal recycling of phosphorus (P), the impact of humic substances on these interactions is largely unexplored. Here we elucidated the spatial variations in sediment P release by diffusion in four Finnish lakes with high trophic state. For further insights regarding possible implications of humic substances on sediment P release, we extended our analysis to lakes worldwide using data from the scientific literature. Variations in sediment P release rates (RR) in four Finnish lakes were largely explained by trophic state and mixing state of the water column. P release by diffusion was positively correlated with the iron-bound P fraction, but negatively with the organic-P fraction in surface sediment. Furthermore, the diffusive flux of P correlated positively with the RR predicted from a published model based on total P concentration (positive effect) and organic matter content (negative effect) in surface sediments. Analysis of the worldwide data confirmed the importance of humic substances in internal P recycling. While dissolved organic carbon (DOC) in water correlated positively with RR in oligotrophic lakes, the correlation was negative in lakes of higher trophic state. The implications for internal P loading and primary production, however, are not so straightforward. In a multiple-stressor world (climate change, eutrophication), response of internal P load in boreal lakes to changes in DOC is particularly unpredictable. This is because the variables relevant to internal P loading, i.e. RR and anoxic factor, may be affected in a reverse direction.

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Assessment of the Current Trophic State of Lake Onega by Primary Production of Phytoplankton

Hydrobiological Journal ◽

10.1615/hydrobj.v43.i5.60 ◽

2007 ◽

Vol 43 (5) ◽

pp. 87-90 ◽

Cited By ~ 2

Author(s):

Ye. V. Tekanova ◽

T. M. Timakova

Keyword(s):

Primary Production ◽

Trophic State ◽

Lake Onega

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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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