scholarly journals Measuring the Impact of the COVID-19 Shutdown on Great Lakes Water Quality Using Remote Sensing

2021 ◽  
Vol 8 ◽  
Author(s):  
Karl R. Bosse ◽  
Michael J. Sayers ◽  
Robert A. Shuchman ◽  
John Lekki ◽  
Roger Tokars
Keyword(s):  
Remote Sensing ◽  
Water Quality ◽  
Great Lakes ◽  
Infrared Imaging ◽  
Harmful Algal Bloom ◽  
Water Clarity ◽  
Anthropogenic Pressure ◽  
Short Term ◽  
Western Basin ◽  
The Impact

The states of Michigan and Ohio issued shutdown orders in mid-March 2020 in an attempt to slow the spread of the coronavirus (COVID-19), resulting in widespread disruption to economic and human activity. This study, which was commissioned by NASA headquarters, utilized satellite remote sensing data from the Visible Infrared Imaging Radiometer Suite sensor onboard the Suomi National Polar-orbiting Partnership satellite to investigate whether these changes in activity led to any short-term changes in water quality in the Great Lakes region by comparing 2020 data to a historic baseline. The water quality parameters examined included chlorophyll-a (CHL) and total suspended solids (TSS) concentrations, water clarity, and harmful algal bloom (HAB) extent. These parameters were investigated in two Great Lakes basins which experience significant anthropogenic pressure: the western basin of Lake Erie (WBLE) and Saginaw Bay in Lake Huron (SBLH). TSS concentrations in April 2020 were below the historic baseline in both basins, and largely remained low until September. SBLH also experienced elevated CHL concentrations in April which persisted through the summer. Additionally, the WBLE HAB extent was down in 2020 after an early end to the growing season. However, this investigation found that the COVID-19 shutdowns were likely not a direct driver of these short-term anomalies. Instead, recent trends in the indicators and co-occurring anomalies in hydrological and meteorological conditions (e.g., lake temperature, river discharge, and wind speed) appeared to be more responsible for the detected water quality changes. Future work will investigate whether the shutdowns have a long-term or delayed impact on Great Lakes water quality.

scholarly journals Temporal Variation of Chlorophyll-a Concentrations in Highly Dynamic Waters from Unattended Sensors and Remote Sensing Observations

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2699 ◽  
Author(s):  
Jian Li ◽  
Liqiao Tian ◽  
Qingjun Song ◽  
Zhaohua Sun ◽  
Hongjing Yu ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Water Quality ◽  
Chlorophyll Fluorescence ◽  
Chlorophyll A ◽  
Temporal Variations ◽  
Lake Area ◽  
Short Term ◽  
Chl A ◽  
Spatio Temporal

Monitoring of water quality changes in highly dynamic inland lakes is frequently impeded by insufficient spatial and temporal coverage, for both field surveys and remote sensing methods. To track short-term variations of chlorophyll fluorescence and chlorophyll-a concentrations in Poyang Lake, the largest freshwater lake in China, high-frequency, in-situ, measurements were collected from two fixed stations. The K-mean clustering method was also applied to identify clusters with similar spatio-temporal variations, using remote sensing Chl-a data products from the MERIS satellite, taken from 2003 to 2012. Four lake area classes were obtained with distinct spatio-temporal patterns, two of which were selected for in situ measurement. Distinct daily periodic variations were observed, with peaks at approximately 3:00 PM and troughs at night or early morning. Short-term variations of chlorophyll fluorescence and Chl-a levels were revealed, with a maximum intra-diurnal ratio of 5.1 and inter-diurnal ratio of 7.4, respectively. Using geostatistical analysis, the temporal range of chlorophyll fluorescence and corresponding Chl-a variations was determined to be 9.6 h, which indicates that there is a temporal discrepancy between Chl-a variations and the sampling frequency of current satellite missions. An analysis of the optimal sampling strategies demonstrated that the influence of the sampling time on the mean Chl-a concentrations observed was higher than 25%, and the uncertainty of any single Terra/MODIS or Aqua/MODIS observation was approximately 15%. Therefore, sampling twice a day is essential to resolve Chl-a variations with a bias level of 10% or less. The results highlight short-term variations of critical water quality parameters in freshwater, and they help identify specific design requirements for geostationary earth observation missions, so that they can better address the challenges of monitoring complex coastal and inland environments around the world.

Effects of sewage discharges on microbial components in tropical coastal waters (Senegal, West Africa)

2008 ◽  
Vol 59 (7) ◽  
pp. 614 ◽  
Author(s):  
Marc Bouvy ◽  
Enora Briand ◽  
Maimouna M. Boup ◽  
Patrice Got ◽  
Christophe Leboulanger ◽  
...  
Keyword(s):  
Water Quality ◽  
Heterotrophic Nanoflagellates ◽  
Anthropogenic Pressure ◽  
The European Union ◽  
Aquatic Communities ◽  
African Countries ◽  
Before And After ◽  
Near Shore ◽  
Bathing Water Quality ◽  
The Impact

Coastal ecosystems are frequently submitted to anthropogenic pressure but little is known about how the dynamics of aquatic communities can be altered. The impact of urban and industrial discharges on microbial plankton was studied in Hann Bay near Dakar (Senegal) on the Atlantic Ocean. Spatial patterns were studied using three transects, with a total of 20 stations, during two periods in May and November (before and after the seasonal upwelling), revealing a clear contrast between near shore stations and the intermediate and seaward stations. In November, phytoplankton were associated with dissolved nutrient availability (e.g. with nitrate, r = 0.76) whereas in May, phytoplankton were more correlated with microbial variables (e.g. with heterotrophic nanoflagellates, r = 0.63). Most samples (40) failed to meet the quality levels for the faecal indicator bacteria (FIB) defined by the European Union bathing water quality directive. The topography plays a major role in water circulation explaining the presence of FIB at the seaward stations. The high prevalence of FIB during the two periods suggests chronic pollution and a potential risk to recreational swimmers and fish consumers in Hann Bay. Thus, as demonstrated in various temperate systems, the decline of water quality constitutes a serious problem in many West African countries.

Corrigendum to: Effects of sewage discharges on microbial components in tropical coastal waters (Senegal, West Africa)

2008 ◽  
Vol 59 (9) ◽  
pp. 838 ◽  
Author(s):  
Marc Bouvy ◽  
Enora Briand ◽  
Maimouna M. Boup ◽  
Patrice Got ◽  
Christophe Leboulanger ◽  
...  
Keyword(s):  
Water Quality ◽  
Heterotrophic Nanoflagellates ◽  
Anthropogenic Pressure ◽  
The European Union ◽  
Aquatic Communities ◽  
African Countries ◽  
Before And After ◽  
Near Shore ◽  
Bathing Water Quality ◽  
The Impact

Coastal ecosystems are frequently submitted to anthropogenic pressure but little is known about how the dynamics of aquatic communities can be altered. The impact of urban and industrial discharges on microbial plankton was studied in Hann Bay near Dakar (Senegal) on the Atlantic Ocean. Spatial patterns were studied using three transects, with a total of 20 stations, during two periods in May and November (before and after the seasonal upwelling), revealing a clear contrast between near shore stations and the intermediate and seaward stations. In November, phytoplankton were associated with dissolved nutrient availability (e.g. with nitrate, r = 0.76) whereas in May, phytoplankton were more correlated with microbial variables (e.g. with heterotrophic nanoflagellates, r = 0.63). Most samples (40) failed to meet the quality levels for the faecal indicator bacteria (FIB) defined by the European Union bathing water quality directive. The topography plays a major role in water circulation explaining the presence of FIB at the seaward stations. The high prevalence of FIB during the two periods suggests chronic pollution and a potential risk to recreational swimmers and fish consumers in Hann Bay. Thus, as demonstrated in various temperate systems, the decline of water quality constitutes a serious problem in many West African countries.

Moderate-Resolution Remote Sensing and Geospatial Analyses of Microclimates, Mounds, and Maize in the Northern Great Lakes

2014 ◽  
Vol 2 (3) ◽  
pp. 195-207 ◽  
Author(s):  
Meghan C.L. Howey ◽  
Michael Palace ◽  
Crystal H. McMichael ◽  
Bobby Braswell
Keyword(s):  
Remote Sensing ◽  
Great Lakes ◽  
Remote Sensing Data ◽  
Sensing Data ◽  
Inland Lakes ◽  
Maize Cultivation ◽  
Geospatial Analyses ◽  
Moderate Resolution ◽  
Burial Mounds ◽  
The Impact

AbstractRemote sensing applications are increasingly common in archaeology but they often focus on high resolution imagery and direct archaeological site detection. Moderate spatial resolution remote sensing instruments, which have (near) daily repeat intervals, but contain less detailed spectral and spatial information, have been employed much less frequently in archaeology. However, moderate remote sensing data offer distinct advantages for archaeological research as they can be used to relate archaeological, ecological, and climactic data at vast spatial scales. To show this potential, we use moderate remote sensing data to examine the impact of landscape heterogeneity on the spread of indigenous maize horticulture in the northern Great Lakes during Late Precontact (ca. AD 1200-1600). Analyzing National Aeronautics and Space Administration (NASA) Moderate Resolution Imaging Spectroradiometer (MODIS) imagery, we identify differences in freeze/thaw cycles across inland lakes in Michigan, showing that some large inland lakes produce a microclimatic amelioration, possibly extending the growing season for prehistoric maize cultivation. Conducting geospatial analyses, we find that burial mounds and maize cultivation practices were associated preferentially with larger inland lakes with microclimates. We could not have found these dynamic interrelationships between microclimates, burial mounds, and maize cultivation if not for both the frequent temporal imaging and large spatial coverage provided by moderate resolution remote sensing imagery.

scholarly journals Using GIS and Remote Sensing Techniques to Study Water Quality Changes and Spectral Analysis of Tigris River within Mosul City, North of Iraq

2019 ◽  
pp. 2300-2307
Author(s):  
Muthanna F. Allawai ◽  
Bushra A. Ahmed
Keyword(s):  
Remote Sensing ◽  
Water Quality ◽  
Chlorophyll A ◽  
Near Infrared ◽  
Water Clarity ◽  
Seasonal Difference ◽  
Near Infrared Reflectance ◽  
Gis And Remote Sensing ◽  
Tigris River ◽  
Remote Sensing Techniques

     The aim of the study is the measuring of changes in the spectral reflectivity water quality, analyzing the seasonal difference of Tigris River within Mosul City in the north of Iraq using Geographic Information Systems (GIS) and remote sensing techniques during the period (2014-2018). For this paper, Satellite images of the 8 Landsat in 2018 for four seasons have been selected in order to study the seasonal changes on the river they took place during 2018.  A total of ten sample datasets were taken at the upstream, midstream and downstream along the Tigris River. This research focuses on analyzing the locational variance of reflectance, analyzing seasonal difference, and finding modeling algal amount change. There are distinctive reflectance differences among the downstream, mid-stream and upstream areas. Red, green, blue and near-infrared reflectance values decreased significantly toward the upstream. Results also showed that reflectance values are significantly associated with the seasonal factor. In the case of long-term trends, reflectance values have slightly increased in the downstream, while decreased slightly in the mid-stream and upstream. The modeling of chlorophyll-a and Secchi disk depth implies that water clarity has decreased over time while chlorophyll-a amounts have decreased. The decreasing water clarity seems to be attributed to other reasons than chlorophyll-a.

scholarly journals Water Quality Properties Derived from VIIRS Measurements in the Great Lakes

2020 ◽  
Vol 12 (10) ◽  
pp. 1605
Author(s):  
Seunghyun Son ◽  
Menghua Wang
Keyword(s):  
Water Quality ◽  
Great Lakes ◽  
Lake Erie ◽  
Infrared Imaging ◽  
Seasonal Pattern ◽  
Secchi Depth ◽  
Phytoplankton Production ◽  
Quality Properties ◽  
Chl A ◽  
Freshwater Inputs

Refined empirical algorithms for chlorophyll-a (Chl-a) concentration, using the maximum ratio of normalized water-leaving radiance nLw(λ) at the blue and green bands, and Secchi depth (SD) from nLw(λ) at 551 nm, nLw(551), are proposed for the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the Suomi National Polar-orbiting Partnership (SNPP) satellite in the Great Lakes. We demonstrated that water quality properties and phytoplankton production can be successfully monitored and assessed using the new regional Chl-a and SD algorithms, with reasonably accurate estimates of Chl-a and SD from the VIIRS-SNPP ocean color data in the Great Lakes. VIIRS-derived Chl-a and SD products using the proposed algorithms provide the temporal and spatial variabilities in the Great Lakes. Overall, Chl-a concentrations are generally low in lakes Michigan and Huron, while Chl-a data are highest in Lake Erie. The seasonal pattern shows that overall low Chl-a concentrations appear in winter and high values in June to September in the lakes. The distribution of SD in the Great Lakes is spatially and temporally different from that of Chl-a. The SD data are generally lower in summer and higher in winter in most of the Great Lakes. However, the highest SD in Lake Erie appears in summer, and lower values in winter. Significantly high values in Chl-a, and lower values in SD, in the nearshore regions, such as Thunder Bay, Saginaw Bay, and Whitefish Bay, can be related to the very shallow bathymetry and freshwater inputs from the land. The time series of VIIRS-derived Chl-a and SD data provide strong interannual variability in most of the Great Lakes.

scholarly journals An analysis of the long-term variation in stream water quality for three upland catchments at Loch Dee (Galloway, S.W. Scotland) under contrasting land management

2004 ◽  
Vol 8 (3) ◽  
pp. 422-435 ◽  
Author(s):  
S. J. Langan ◽  
D. Hirst
Keyword(s):  
Water Quality ◽  
Land Management ◽  
Stream Water ◽  
Base Flow ◽  
Sea Salt ◽  
Stream Water Quality ◽  
Short Term ◽  
Term Variation ◽  
The Impact

Abstract. A long term record of water chemistry, consisting of twenty years of weekly spot samples, from three sub-catchments draining into a loch and the loch outflow in Galloway, S.W. Scotland have been analysed. The analysis undertaken consisted of a three component statistical trend model. The technique allows the identification of long-term, seasonal and short-term trends, as well as differentiation between base flow and high flow responses. The land usage in the three sub-catchments is moorland, forest and forest plus lime. The results show that, since the mid-1980s, there has been a gradual decline in stream-water sulphate of the same order as reductions in the deposition of non-marine sulphate. Superimposed on this trend are somewhat random but considerable perturbations to this decline, caused by sea-salt deposition. There is no evidence of changes in surface water nitrate concentrations. The influence of different land management is evident in the sulphate, nitrate and pH data, whilst variations in calcium concentrations are also a product of differences in hydrological routing and the impact of sea-salt episodes. Keywords: trend analysis, acid deposition, land management, water quality, sea-salts, Galloway, S.W. Scotland

Rehabilitation of Lake Ontario: the Role of Nutrient Reduction and Food Web Dynamics

1991 ◽  
Vol 48 (8) ◽  
pp. 1574-1580 ◽  
Author(s):  
John H. Hartig ◽  
James F. Kitchell ◽  
Donald Scavia ◽  
Stephen B. Brandt
Keyword(s):  
Water Quality ◽  
Great Lakes ◽  
Food Web ◽  
Toxic Substance ◽  
Lake Ontario ◽  
The United States ◽  
Food Web Dynamics ◽  
Food Web Interactions ◽  
The Impact

The Laurentian Great Lakes have a complex history of changes due to eutrophication, invasion of exotic species, and fisheries and phosphorus management practices. Remedial actions have reduced nutrient loadings and enhanced the role of food web interactions in improving water quality. Workshops sponsored through the United States – Canada international Joint Commission have addressed the relative importance of nutrient abatement and/or food web manipulation in affecting water quality trends. Both controls have combined to enhance water clarity in Lake Michigan. Lake Ontario has already exhibited the effects of nutrient controls and may be on the verge of manifesting food web controls. Research and monitoring recommendations to elucidate the effects of nutrient and food web controls include the following: (1) water quality and fisheries agencies must coordinate monitoring activities, standardize techniques, and establish and maintain long-term data sets to evaluate the effects of water quality and fisheries programs separately and together; (2) controlled, mesoscale, whole-system experiments should be performed to quantify rates (e.g. growth, predation, etc.) of food web interactions; and (3) the scientific community should promote research which quantifies the impact of changes in food web dynamics on changes in toxic substance levels in Great Lakes fishes.

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