One indicator of health in estuarine and coastal ecosystems is the ability of local waters to tra... more One indicator of health in estuarine and coastal ecosystems is the ability of local waters to transmit sunlight to planktonic, macrophytic, and other submerged vegetation for photosynthesis. The concentration of coloured dissolved organic matter (CDOM) is a primary factor affecting the absorption of incident sunlight in coastal and estuarine waters. In estuaries, CDOM concentrations vary due to changes in salinity gradients, inflows of industrial and domestic effluents, and the production of new dissolved organic matter from marine biologic activity. CDOM absorption data have been collected from a variety of waters. However, there are a limited number of measurements along the US east coast and a general lack of data from New England waters. This study characterized the temporal and spatial variability of CDOM absorption over an annual cycle in Narragansett Bay and Block Island Sound (Rhode Island). Results suggested that, in Narragansett Bay, the magnitude of CDOM absorption is related to the seasonal variability of freshwater input from surrounding watersheds and new CDOM production from in situ biologic activity. The data show that the average CDOM absorption coefficient at 412 nm was 0•45 m 1 and the average spectral slope was 0•020 nm 1 .
A particle entrainment simulator was used to experimentally produce representative estuarine resu... more A particle entrainment simulator was used to experimentally produce representative estuarine resuspension conditions to investigate the resulting transport of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) to the overlying water column. Contaminants were evaluated in bulk sediments, size fractionated sediments, resuspended particulate material and in some cases, dissolved phases during the experiments. The two types of sediments used in the experiments, dredged material and bedded estuarine sediment, represented gradients in contaminant loadings and sediment textural characteristics. For the bedded sediment, resuspension tended to winnow the sediments of finer particles. However, in the case of the more highly contaminated dredge material, non-selective resuspension was most common. Resuspension resulted in up to orders of magnitude higher particle-bound organic contaminant concentrations in the overlying water column. Dissolved phase PAH changes during resuspension were variable and at most, increased by a factor of three. The sifting process resulted in the partitioning of fine and coarse particle contaminant loading. For bedded sediments, accurate predictions of PAH and PCB loadings on resuspended particles were made using the mass of resuspended particles of different sizes and the concentrations of contaminants in the particle pools of the bulk sediment. However, due possibly to contributions from other unmeasured particles (e.g. colloids), predictions were not possible for the dredge material. Thus, knowledge of the redistribution and fate of colloids may be important. The partitioning of PAHs between the dissolved and particulate phases during resuspension events was predicted to within a factor of two from the amount of organic carbon in each of the resuspended samples. These experiments show that contaminant transport is a function of the chemistry and textural characteristics of the bulk sediment and the winnowing action during resuspension events. Existing relationships of resuspension and settling velocity are probably useful in predicting chemical redistribution.
International Journal of Remote Sensing, Mar 25, 2014
The public reporting burden for this collection of information is estimated to average 1 hour per... more The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to the Department of Defense, Executive Services and Communications Directorate (0704-0188). Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.
Application of the Quasi-Analytical Algorithm and Contrast Threshold Theory to Retrieve Secchi Depth from Optically Complex Lakes and Reservoirs of the Continental US using Landsat 8
Inland waters across the United States (US) are at potential risk for increased outbreaks of toxi... more Inland waters across the United States (US) are at potential risk for increased outbreaks of toxic cyanobacteria blooms events resulting from elevated water temperatures and extreme hydrologic events attributable to climate change and increased nutrient loadings associated with intensive agricultural practices. Current monitoring efforts are limited in scope due to resource limitations, analytical complexity, and data integration efforts. The goals of this study were to validate an algorithm for satellite imagery that could potentially be used to monitor surface cyanobacteria events in near real-time to provide a compressive monitoring capability for freshwater lakes (N 100 ha). The algorithm incorporated narrow spectral bands specific to the European Space Agency's (ESA's) MEdium Resolution Imaging Spectrometer (MERIS) instrument that were optimally oriented at phytoplankton pigment absorption features including phycocyanin at 620 nm. A validation of derived cyanobacteria cell counts was performed using available in situ data assembled from existing monitoring programs across eight states in the eastern US over a 39-month period (2009-2012). Results indicated that MERIS provided robust estimates for low (10,000-109,000 cells/mL) and very high (N 1,000,000 cells/mL) cell enumeration ranges (approximately 90% and 83%, respectively). However, the results for two intermediate ranges (110,000-299,000 and 300,000-1,000,000 cells/mL) were substandard, at approximately 28% and 40%, respectively. The confusion associated with intermediate cyanobacteria cell count ranges was largely attributed to the lack of available taxonomic data and distinction of natural counting units for the in situ measurements that would have facilitated conversions between cell counts and cell volumes. The results of this study document the potential for using MERISderived cyanobacteria cell count estimates to monitor freshwater lakes (N100 ha) across the eastern US.
ABSTRACT The Hyperspectral Imager for the Coastal Ocean (HICO) was used to derive chlorophyll-a (... more ABSTRACT The Hyperspectral Imager for the Coastal Ocean (HICO) was used to derive chlorophyll-a (chl-a) based on the normalized difference chlorophyll index (NDCI) in two Gulf of Mexico coastal estuaries. Chl-a data were acquired from discrete in situ water sample analysis and above-water hyperspectral surface acquisition system (HyperSAS) remote sensing reflectance in Pensacola Bay (PB) and Choctawhatchee Bay (CB). NDCI algorithm calibrations and validations were completed on HICO data. Linear and best-fit (polynomial) calibrations performed strongly with R 2 of 0.90 and 0.96, respectively. The best validation of NDCI resulted with an R 2 of 0.74 and root-mean-square error (RMSE) of 1.64 µg/L. A strong spatial correspondence was observed between NDCI and chl-a, with higher NDCI associated with higher chl-a and these areas were primarily located in the northern PB and eastern CB at the river mouths. NDCI could be effectively used as a qualitative chl-a monitoring tool with a reduced need for site-specific calibration.
Cyanobacterial harmful algal blooms (cyanoHAB) cause human and ecological health problems in lake... more Cyanobacterial harmful algal blooms (cyanoHAB) cause human and ecological health problems in lakes worldwide. The timely distribution of satellite-derived cyanoHAB data is necessary for adaptive water quality management and for targeted deployment of water quality monitoring resources. Software platforms that permit timely, useful, and cost-effective delivery of information from satellites are required to help managers respond to cyanoHABs. The Cyanobacteria Assessment Network (CyAN) mobile device application (app) uses data from the European Space Agency Copernicus Sentinel-3 satellite Ocean and Land Colour Instrument (OLCI) in near realtime to make initial water quality assessments and quickly alert managers to potential problems and emerging threats related to cyanobacteria. App functionality and satellite data were *
Ocean color algorithms have been successfully developed to estimate chlorophyll a and total suspe... more Ocean color algorithms have been successfully developed to estimate chlorophyll a and total suspended solids concentrations in coastal and estuarine waters but few have been created to estimate light absorption due to colored dissolved inorganic matter (CDOM) and salinity from the spectral signatures of these waters. In this study, we used remotely sensed reflectances in the red and blue-green portions of the visible spectrum retrieved from Medium Resolution Imaging Spectrometer (MERIS) and the International Space Station (ISS) Hyperspectral Imager for the Coastal Ocean (HICO) images to create a model to estimate CDOM absorption. CDOM absorption results were then used to develop an algorithm to predict the surface salinities of coastal bays and estuaries in New England, Middle Atlantic, and Gulf of Mexico regions. Algorithm-derived CDOM absorptions and salinities were successfully validated using laboratory measured absorption values over magnitudes of~0.1 to 7.0 m´1 and field collected CTD data from oligohaline to polyhaline (S less than 5 to 18-30) environments in
International Journal of Remote Sensing, Aug 22, 2013
Sustainable practices require a long-term commitment to creating solutions to environmental, soci... more Sustainable practices require a long-term commitment to creating solutions to environmental, social, and economic issues. The most direct way to ensure that management practices achieve sustainability is to monitor the environment. Remote sensing technology has the potential to accelerate the engagement of communities and managers in the implementation and performance of best management practices. Over the last few decades, satellite technology has allowed measurements on a global scale over long time periods, and is now proving useful in coastal waters, estuaries, lakes, and reservoirs, which are relevant to water quality managers. Comprehensive water quality climate data records have the potential to provide rapid water quality assessments, thus providing new and enhanced decision analysis methodologies and improved temporal/spatial diagnostics. To best realize the full application potential of these emerging technologies an open and effective dialogue is needed between scientists, policy makers, environmental managers, and stakeholders at the federal, state, and local levels. Results from an internal US Environmental Protection Agency qualitative survey were used to determine perceptions regarding the use of satellite remote sensing for monitoring water quality. The goal of the survey was to begin understanding why management decisions do not typically rely on satellite-derived water quality products.
Water clarity has long been used as a visual indicator of the condition of water quality. The cla... more Water clarity has long been used as a visual indicator of the condition of water quality. The clarity of waters is generally valued for esthetic and recreational purposes. Water clarity is often assessed using a Secchi disk attached to a measured line and lowered to a depth where it can be no longer seen. We have applied an approach which uses atmospherically corrected Landsat 8 data to estimate the water clarity in freshwater bodies by using the quasi-analytical algorithm (QAA) and Contrast Theory to predict Secchi depths for more than 270 lakes and reservoirs across the continental US. We found that incorporating Landsat 8 spectral data into methodologies created to retrieve the inherent optical properties (IOP) of coastal waters was effective at predicting in situ measures of the clarity of inland water bodies. The predicted Secchi depths were used to evaluate the recreational suitability for swimming and recreation using an assessment framework developed from public perception o...
Water clarity has long been used as a visual indicator of the condition of water quality. The cla... more Water clarity has long been used as a visual indicator of the condition of water quality. The clarity of waters is generally valued for aesthetic and recreational purposes. Water clarity is often assessed using a Secchi disk, attached to a measured line and lowered to a depth where it can be no longer seen. We have applied an approach which uses atmospherically corrected Landsat 8 data to estimate water clarity in freshwater bodies by using the Quasi-Analytical Algorithm (QAA) and Contrast Theory to predict Secchi depths for more than 270 lakes and ponds across the continental US. We found that incorporating Landsat 8 spectral data into methodologies created to retrieve the inherent optical properties (IOP) of coastal waters was effective at predicting in-situ measures of the clarity of inland lakes. The predicted Secchi depths were used to evaluate the recreational suitability for swimming and recreation using an assessment framework developed from public perception of water clarit...
Data for a large environmental monitoring project that were managed for several years in SASot da... more Data for a large environmental monitoring project that were managed for several years in SASot datasets were recently loaded into an Oracle~ database. In order to meet the needs of users who rely on SAS for reporting and statistical analyses, an interface between Oracle and SAS must be maintained. SAS provides twO products that facilitate this interface: the SQL procedure, and the SASI ACCESS facility. This paper will describe how these tools were used to convert a database from SAS datasets to Oracle tables and to maintain links between Oracle and the SAS system. Special attention will be paid to: (1) Proc SQL, which allows SAS to process Standard· Query Language commands; (2) SAS/ACCESS view descriptors, which can be created to make Oracle tables directly accessible to SAS procedures; (3) the SQL pass-through facility, which makes it possible to submit SQL commands to the Oracle server from a SAS job; and (4) the DBLOAD procedure, which can copy a SAS dataset directly into an Orac...
This Thesis (open access) is brought to you for free and open access by the Jack N. Averitt Colle... more This Thesis (open access) is brought to you for free and open access by the Jack N. Averitt College of Graduate Studies (COGS) at Digital Commons@Georgia Southern. It has been accepted for inclusion in Electronic Theses & Dissertations by an authorized administrator of Digital
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