Seasonal patterns for Secchi depth, chlorophyll a, total phosphorus, and nutrient limitation differ between nearshore and offshore in Lake Michigan

2020 ◽  
Vol 46 (3) ◽  
pp. 519-527 ◽  
Author(s):  
Steven A. Pothoven ◽  
Henry A. Vanderploeg
1995 ◽  
Vol 52 (8) ◽  
pp. 1812-1815 ◽  
Author(s):  
Robert L. France ◽  
Robert H. Peters ◽  
Robert H. Rishikof

Because total phosphorus and chlorophyll a concentrations vary seasonally within north-temperate lakes, estimates of lake trophic status are usually based on several to many sampling visits. However, because such effort is not always logistically possible, the empirical relationships developed between these trophic status indicators may depend upon seasonal patterns of sampling. Clearly, it is desirable to know if some periods of the year are more likely to produce representative estimates of total phosphorus and chlorophyll a, or, alternatively, if sampling in other periods should be restricted or even avoided. Data from north-temperate lakes are used to examine the degree to which single monthly samples for total phosphorus and chlorophyll a represent seasonal means. Analyses indicate that the least precise and least accurate estimates of the means occur when single-visit synoptic surveys are conducted during April. Not until August to September do single sampling visits provide data that approximate those represented by the means garnered through more frequent sampling.


2017 ◽  
Vol 19 (2) ◽  
pp. 113
Author(s):  
Kusuma Wardani Laksitaningrum ◽  
Wirastuti Widyatmanti

<p align="center"><strong>ABSTRAK</strong></p><p class="abstrak">Waduk 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 <em>Trophic State Index</em> (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 (R<sup>2</sup>) tertinggi. Hasil penelitian merepresentasikan bahwa nilai R<sup>2</sup> kejernihan air sebesar 0,813, total fosfor sebesar 0,268, dan klorofil-a sebesar 0,584. Apabila nilai R<sup>2 </sup>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.</p><p><strong>Kata kunci: </strong>Waduk Gajah Mungkur, citra Landsat 8 OLI, regresi, TSI, status trofik</p><p class="judulABS"><strong>ABSTRACT</strong></p><p class="Abstrakeng">Gajah 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 (R<sup>2</sup>). The results represented that R<sup>2</sup> of water clarity is 0.813, total phosphorus is 0.268, and chlorophyll-a is 0.584. If R<sup>2</sup> 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.</p><p><strong><em>Keywords: </em></strong><em>Gajah Mungkur Reservoir, </em><em>L</em><em>andsat 8 OLI satellite imagery, regression, TSI, trophic state</em></p>


Our Nature ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 48-54
Author(s):  
Ram Bhajan Mandal ◽  
Sunila Rai ◽  
Madhav Kumar Shrestha ◽  
Dilip Kumar Jha ◽  
Narayan Prasad Pandit

An experiment was carried to assess the effect of red algal bloom on growth and production of carp, water quality and profit from carp for 120 days at Aquaculture Farm of Agriculture and Forestry University, Chitwan. The experiment included two treatments: carp polyculture in non-red pond and carp polyculture in red pond with algal bloom each with three replicates. Carp fingerlings were stocked at 1 fish/m2 and fed with pellet containing 24% CP at 3% body weight. Net yield of rohu was found significantly higher (p<0.05) in non-red ponds (0.38±0.01 t ha-1) than red ponds (0.24±0.05 t ha-1). Survival of rohu (84.9±1.4%), bighead (95.2±2.0%) and mrigal (88.1±14.4%) were also significantly higher (p<0.05) in non-red ponds than red ponds. Red algal bloom affected DO, nitrate and chlorophyll-a, nitrite, total nitrogen, total phosphorus, total dissolved solids and conductivity. However, overall carp production and profit from carp remained unaffected.


1988 ◽  
Vol 45 (2) ◽  
pp. 271-279 ◽  
Author(s):  
Hunter J. Carrick ◽  
Rex L. Lowe

The possibility that benthic algae in the nearshore area of Lake Michigan might be growth limited by Si was tested using nutrient-releasing substrata. Nutrient treatments were Si, N + P, Si + N + P, and controls (CONT) and were sampled after 7, 14, and 31 d of exposure. Addition of Si alone had little stimulatory effect on algal biomass, while enrichment with Si + N + P led to the greatest increase in chlorophyll a, particulate Si, total biovolume, and diatom biovolume after 14 d of incubation (P < 0.0001). By day 31, communities on CONT and Si substrata exhibited little change in biomass and remained dominated by diatoms (98% of total biovolume), while algal biomass on both N + P and Si + N + P substrata increased more than eightfold (P < 0.0001) and consisted mainly of Stigeoclonium tenue (Chlorophyta) and Schizothrix calcicolas (Cyanophyta). These results indicate that benthic diatoms in Lake Michigan are not currently limited by Si, but may become Si limited following enrichment with N + P.


2019 ◽  
Vol 19 (5) ◽  
pp. 1500-1506 ◽  
Author(s):  
I. Melendez-Pastor ◽  
E. M. Isenstein ◽  
J. Navarro-Pedreño ◽  
M-H. Park

Abstract Cyanobacteria bloom events have been associated with eutrophication processes, along with hydrologic and climate factors. Missisquoi Bay is a portion of Lake Champlain (USA–Canada) that is highly eutrophic and prone to cyanobacteria blooms and cyanotoxins. This study assessed the spatial–temporal influence of nutrients, turbidity and temperature in cyanobacteria distributions during a bloom event in the summer of 2006. Correlations, generalized linear models (GLMs), geostatistics and local indications of spatial association (LISA) autocorrelation analysis tested the influence of nutrient and non-nutrient explanatory variables in cyanobacteria biovolume. Total phosphorus exhibited a high direct correlation with cyanobacteria biovolume. The best performing GLMs included total phosphorus, total nitrogen, Secchi depth (as turbidity) and temperature as explanatory variables of cyanobacteria biovolume. Variogram analysis of those variables resulted in a better understanding of the underlying spatial variation process of the cyanobacteria bloom event. The LISA test revealed a moderate but stable autocorrelation between cyanobacteria biovolume and total phosphorus from 180 to 1,000 m of weight distance, suggesting the possibility of up-scaling the current results to coarse-resolution satellite imagery for more frequent monitoring of bloom events. The LISA test also revealed the spatial–temporal dynamic (movement of cyanobacteria scums) of high cyanobacteria blooms with high total phosphorus concentration.


2019 ◽  
Vol 31 ◽  
Author(s):  
Jéssica Nayara de Carvalho Leite ◽  
Vanessa Becker

Abstract Aim The aim of this study was to analyze the water quality of a tropical, semi-arid reservoir after a reflooding. In terms of impact on water quality after a drought event, it is expected that there will be improvements with the reflooding. Less algal biomass, increased water transparency, decreased turbidity and low nutrient concentration. Methods This study was performed in a tropical, semi-arid man-made lake (Dourado Reservoir), during an extended drought period. This study consisted of a comparison of three distinct periods determined by water accumulation. The limnological variables, including water transparency, turbidity, electrical conductivity, pH, total phosphorus, soluble reactive phosphorus, and chlorophyll-a were analyzed. A principal component analysis (PCA) was also performed to verify the patterns of the variables in relation to the sample units in the studied periods. Results After water renewal, there was an expressive reduction in chlorophyll-a. Electrical conductivity, pH, and turbidity variables also reduced after the reflooding, indicating an improvement in water quality. There was no reduction in total phosphorus and soluble reactive phosphorus after the reflooding compared to the previous periods. Conclusions The significant reduction in algal biomass after reflooding in Dourado indicates water quality improvement in terms of eutrophication due to the change of the trophic state from eutrophic to mesotrophic.


2019 ◽  
Vol 29 (3) ◽  
Author(s):  
Patrick L. Brezonik ◽  
R. William Bouchard ◽  
Jacques C. Finlay ◽  
Claire G. Griffin ◽  
Leif G. Olmanson ◽  
...  

2012 ◽  
Vol 72 (3) ◽  
pp. 479-487 ◽  
Author(s):  
LPM. Brandão ◽  
T. Fajardo ◽  
E. Eskinazi-Sant'Anna ◽  
S. Brito ◽  
P. Maia-Barbosa

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.


2018 ◽  
Vol 60 (2) ◽  
pp. 135-142 ◽  
Author(s):  
Antonella LUGLIÈ ◽  
Yelda AKTAN ◽  
Paola CASIDDU ◽  
Nicola SECHI

The purpose of this paper was to assess the effect of the diversion of wastewater on the trophic status of Lake Bidighinzu, a hypertrophic man-made lake in Northern Sardinia, used as a drinking water reservoir. There have been problems with potabilization since the early years of the diversion operation, particularly in the summer-autumn period. Data available (August 1978, February 1979 and March 1985) before the reservoir (1987) were compared with those collected during a study carried out in the annual cycle immediately after (1988-1989) and after some years (1994 and 1996-1997). The study examined the dynamics of temperature, main nutrients (total phosphorus, nitrate and ammonia), chlorophyll-a and phytoplanktonic biomass. No particular variation in the water nutrient availability emerged from the comparison between these two situations - especially for total phosphorus, whose annual mean concentrations were similar in the two annual cycles (386 mg P m-3 in 1988-1989 and 305 mg P m-3 in 1996-1997). Chlorophyll-a and biomass were high during each period of study (annual mean values were 17 mg m-3and 3.7 mg l-1 in 1988-1989 and 11 mg m-3and 4.6 mg l-1 in 1996-1997). However, peaks were never higher than values recorded in August 1978 (112 mg m-3and 133 mg l-1) due to an extraordinary bloom of Ceratium hirundinella (O.F. Müller). Species composition of phytoplankton was typical of highly trophic conditions and was frequently characterised by the presence of Cyanophyceae and Bacillariophyceae. Results demonstrated that, ten years after construction of the by-pass, the lake had shown no improvement in its trophic status. This might depend on many factors, among which the most likely might be the non-use or partial use of the diversion system, which allows the sewage to continue to flow into the lake and keep its trophic status almost unchanged.


2020 ◽  
Vol 13 ◽  
pp. 117862211989842
Author(s):  
Hwan Kim ◽  
Inseol Yeo ◽  
Chan-Gyu Park

Water sources are currently facing great challenges from rapid population growth and industrial developments. Investigations into how to remove algal organic matter (AOM) are thus of great importance from an environmental point of view because most lakes and reservoirs in South Korea suffer from algae problems, especially in the summer. Many efforts have been made to remove AOM from the aquatic environment in South Korea. In this study, we focus on development of a new AOM removal system, utilizing waste oyster shells and ferrihydrite as the media of the filtration system. Using this system, the removal rate of AOM was investigated regarding the concentrations of chlorophyll a, total phosphorus, and alginate. It was found that about 92% of the total phosphorus was removed through this system when raw oyster shell powders were heated at 900°C to convert them into calcium oxide powders. The use of a continuous system also led to a reduction of 94.2% in total phosphorus, 78.8% in chlorophyll a, and 43.6% in alginate.


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