Cladoceran body length and Secchi disk transparency in northeastern U.S. lakes

Mean cladoceran body length of 59 northeastern U.S. lakes was estimated from functional groups that broadly define taxonomic, body size, and grazing potential. Multiple regression of body length, color, and chlorophyll a or total phosphorus against Secchi disk transparency explained 72% and 83% of the variation across lakes, respectively. Analysis that included body length, color, and particulate carbon, a proxy for light backscattering and absorption by suspended organic particles, explained 85% of the variance in transparency. Body length was as important a predictor of water clarity as chemical factors. Furthermore, body length was significantly correlated to temporal variation in transparency within lakes. Because cladocerans primarily filter organic particles in size ranges having high light attenuation efficiencies, body length was consistently more strongly correlated to transparency than to chlorophyll a. Monitoring cladoceran body length should help to distinguish changes in lake transparency due to nutrient loading from changes that reflect fish population size structure and predation intensity on zooplankton. This simple size index can greatly increase the interpretative value of Secchi transparency observations to lake managers.

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Effect of Organic Color and Turbidity of Secchi Disk Transparency

Journal of the Fisheries Research Board of Canada ◽

10.1139/f78-222 ◽

1978 ◽

Vol 35 (11) ◽

pp. 1410-1416 ◽

Cited By ~ 41

Author(s):

Patrick L. Brezonik

Keyword(s):

Regression Analysis ◽

Linear Relationship ◽

Key Words ◽

Multiple Regression Analysis ◽

Chlorophyll A ◽

Light Attenuation ◽

Secchi Disk ◽

Concentrated Solutions ◽

Secchi Disk Transparency ◽

Statistical Relationships

Secchi disk transparency in lakes is a function not only of the turbidity caused primarily by plankton, but also of the organic color level in the water. Multiple regression analysis of data from 55 Florida lakes yielded a close-fitting equation of the type (SD)−1 = a(Color) + b(Turbidity) + c. The statistical relationships between inverse transparency and chlorophyll a and between log transparency and log chlorophyll a exhibited greater scatter. Experiments in which concentrated solutions of humic substances were added to a large plastic "limno-bag" verified the linear relationship between (SD)−1 and color content but yielded a different slope than that obtained by regression analysis. The maximum possible transparency (assuming zero turbidity) was similar for both the experimental and regression relationships at color levels above 50 platinum (Pt) units, but increasingly divergent results were predicted by the two approaches at lower color levels. At a color of 100 Pt units, the maximum Secchi disk transparency is about 2.4–2.8 m. Because of the crudeness of transparency measurements, use of the above regression equation to compute transparencies from measured turbidities appears to be more reliable than use of the experimentally derived equation. Key words: Secchi disk, transparency, color, turbidity, trophic indicator, chlorophyll a, light attenuation

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Climate and Hydrological Factors Affecting Variation in Chlorophyll Concentration and Water Clarity in the Bahia Almirante, Panama

Smithsonian Contributions to the Marine Sciences ◽

10.5479/10088/19175 ◽

2012 ◽

pp. 323-334

Author(s):

Rachel Collin ◽

Luis D'Croz ◽

Plinio Gondola ◽

Juan B. Del Rosario

Keyword(s):

Wind Speed ◽

Chlorophyll A ◽

Phytoplankton Biomass ◽

Nutrient Loading ◽

Rapid Development ◽

Chlorophyll Concentration ◽

Water Clarity ◽

Annual Rainfall ◽

Bocas Del Toro ◽

Factors Affecting

Water clarity and productivity are fundamentally important for the distribution of tropical marine organisms. In the Caribbean, changes in nutrient loading that result from rapid development are thought to have caused increased planktonic productivity, reduced water clarity, and reduced reef and seagrass health. Here we analyze chlorophyll a concentration and water clarity from eight years of environmental monitoring in Bocas del Toro, Panama. Chlorophyll a concentrations did not vary significantly among the six sampled sites and showed no significant temporal changes, despite the recent rapid development in the region, accompanied by scant wastewater treatment. In contrast, water clarity increased significantly during the study period. Because chlorophyll a does not vary closely with water clarity, Secchi depths are likely to reflect changes in suspended particulate matter rather than in phytoplankton biomass. Secchi depths decreased with rainfall and wind speed but increased with solar radiation, supporting the idea that clarity was not tightly linked to phytoplankton biomass. The decrease in annual rainfall, but not wind speed, over the past eight years suggests that the long-term trend in Secchi readings is the result of changes in rainfall patterns.

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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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Seagrass depth range and water quality in southern Moreton Bay, Queensland, Australia

Marine and Freshwater Research ◽

10.1071/mf9960763 ◽

1996 ◽

Vol 47 (6) ◽

pp. 763 ◽

Cited By ~ 95

Author(s):

EG Abal ◽

WC Dennison

Keyword(s):

Water Quality ◽

Chlorophyll A ◽

Suspended Solids ◽

Light Attenuation ◽

River Mouth ◽

Total Suspended Solids ◽

Quality Parameters ◽

Depth Range ◽

Moreton Bay ◽

A Site

Correlations between water quality parameters and seagrass depth penetration were developed for use as a biological indicator of integrated light availability and long-term trends in water quality. A year-long water quality monitoring programme in Moreton Bay was coupled with a series of seagrass depth transects. A strong gradient between the western (landward) and eastern (seaward) portions of Moreton Bay was observed in both water quality and seagrass depth range. Higher concentrations of chlorophyll a, total suspended solids, dissolved and total nutrients, and light attenuation coefficients in the water column and correspondingly shallower depth limits of the seagrass Zostera capricorni were observed in the western portions of the bay. Relatively high correlation coefficient values (r2 > 0.8) were observed between light attenuation coefficient, total suspended solids, chlorophyll a, total Kjeldahl nitrogen and Zostera capricorni depth range. Low correlation coefficient values (r2 < 0.8) between seagrass depth range and dissolved inorganic nutrients were observed. Seagrasses had disappeared over a five-year period near the mouth of the Logan River, a turbid river with increased land use in its watershed. At a site 9 km from the river mouth, a significant decrease in seagrass depth range corresponded to higher light attenuation, chlorophyll a, total suspended solids and total nitrogen content relative to a site 21 km from the river mouth. Seagrass depth penetration thus appears to be a sensitive bio-indicator of some water quality parameters, with application for water quality management.

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Water quality assessment using Sentinel-2 imagery with estimates of chlorophyll a, Secchi disk depth, and Cyanobacteria cell number: the Cantareira System reservoirs (São Paulo, Brazil)

Environmental Science and Pollution Research ◽

10.1007/s11356-021-12975-x ◽

2021 ◽

Author(s):

Marcelo Pompêo ◽

Viviane Moschini-Carlos ◽

Marisa Dantas Bitencourt ◽

Xavier Sòria-Perpinyà ◽

Eduardo Vicente ◽

...

Keyword(s):

Water Quality ◽

Quality Assessment ◽

Chlorophyll A ◽

Water Quality Assessment ◽

Cell Number ◽

Sao Paulo ◽

São Paulo ◽

Secchi Disk ◽

Secchi Disk Depth ◽

Sentinel 2

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Particulate light attenuation in a large subtropical lake

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f95-172 ◽

1995 ◽

Vol 52 (8) ◽

pp. 1803-1811 ◽

Cited By ~ 20

Author(s):

Karl E. Havens

Keyword(s):

Surface Water ◽

Trophic State ◽

Nutrient Loading ◽

Light Attenuation ◽

Algal Growth ◽

Progressive Increase ◽

Trophic State Index ◽

Littoral Region ◽

Relative Contribution ◽

Total Light

Deviations among Carlson's trophic state index values were used to quantify a 12-year history of seston composition and underwater light attenuation in Lake Okeechobee, Florida, U.S.A. Deviations between chlorophyll a, total phosphorus, and transparency-based trophic state indices indicated that (i) light attenuation is generally dominated by phosphorus-rich abiotic particles; (ii) abiotic light attenuation is maximal in a central lake region overlying soft mud sediments, and minimal in a near-littoral region overlying hard sand; and (iii) there has been a progressive increase in the relative contribution of algal pigments to total light attenuation between 1980 and 1992. Coincident with that 12-year trend, there have been declines in external nitrogen loads, lake water nitrogen:phosphorus ratios, and wind velocities. Surface water temperatures in the lake have significantly increased. Explanations for the trend in light attenuation include (i) more favorable meteorological conditions for algal growth, which increased the contribution of algae to overall light attenuation and (ii) reduced nitrogen:phosphorus ratios favoring proliferation of buoyant cyanobacteria, which are more effectively sampled by surface water monitoring. In either case, the trend did not coincide historically with enhanced nutrient loading, the common cause of algal proliferation in lakes.

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