Dissolved and particulate organic carbon, suspended particulate matter concentrations, and their optical proxies colored dissolved organic matter absorption and backscattering coefficients were studied in Galveston Bay, Texas, following the extreme flooding of Houston and surrounding areas due to Hurricane Harvey (25-29 August 2017) using field and ocean color observations. A three-step empirical-semianalytic algorithm for determination of colored dissolved organic matter absorption and backscattering coefficients revealed the dynamics of dissolved organic carbon and particle distribution from Visible and Infrared Imaging Radiometric Suite ocean color. Environmental drivers, especially floodwater discharge and winds, strongly influenced the spatiotemporal distribution of dissolved/particulate material in the bay and shelf waters following the hurricane passage.
View Article and Find Full Text PDFThe characteristics of fluorescent components of dissolved organic matter (DOM) were examined using excitation emission matrix (EEM) fluorescence spectroscopy combined with parallel-factor analysis (PARAFAC) for seawater samples obtained from the northern Gulf of Mexico (NGoM) before, during, and after the 2010 Deepwater Horizon (DwH) oil spill. An EEMs PARAFAC modeling of samples collected within 16 km of the wellhead during the oil spill in May 2010, which included one typical subsurface sample with a PAH concentration of 1.09 μg/L, identified two humic-like and two previously reported oil-like components.
View Article and Find Full Text PDFNanotechnol Sci Appl
September 2014
Foodborne disease is an important source of expense, morbidity, and mortality for society. Detection and control constitute significant components of the overall management of foodborne bacterial pathogens, and this review focuses on the use of nanosized biological entities and molecules to achieve these goals. There is an emphasis on the use of organisms called bacteriophages (phages: viruses that infect bacteria), which are increasingly being used in pathogen detection and biocontrol applications.
View Article and Find Full Text PDFA simple semi-analytical model to estimate total suspended sediment matter (3S) was established for estimating TSM concentrations in Changjiang River Estuary. The results indicate that 3S model with near-infrared wavelengths provide good estimates of TSM concentrations in the study region. Furthermore, the applicability of 3S model was evaluated using an independent data set taken from Oujiang river estuary during September 2012.
View Article and Find Full Text PDFHere we present laboratory measurements of phytoplankton absorption for cultures and natural water samples using two different spectrophotometers, an Ultrapath system and a double beam spectrophotometer equipped with an integrating sphere (Lambda 850). The Ultrapath system provides simplified optics with high throughput efficiency, portability, and is relatively less expensive in comparison to conventional spectrophotometers. A more robust algorithm for correction of pathlength amplification (β) for particles retained on filter paper was determined for Lambda 850 in comparison to the Ultrapath.
View Article and Find Full Text PDFJ Environ Sci (China)
February 2011
Absorption and fluorescence properties of chromophoric dissolved organic matter (CDOM) along a 124 km transect in the Barataria Basin, a large estuary located in Louisiana, USA, were investigated during high and low flow periods of the Mississippi River in the spring and winter of 2008-2009. Mean CDOM absorption at 355 nm from the marine to the freshwater end member stations ranged from (3.25 +/- 0.
View Article and Find Full Text PDFChromophoric dissolved organic matter (CDOM) variability in Barataria Basin, Louisiana, USA,was examined by excitation emission matrix (EEM) fluorescence combined with parallel factor analysis (PARAFAC). CDOM optical properties of absorption and fluorescence at 355nm along an axial transect (36 stations) during March, April, and May 2008 showed an increasing trend from the marine end member to the upper basin with mean CDOM absorption of 11.06 + or - 5.
View Article and Find Full Text PDFEnergetic meteorological events such as frontal passages and hurricanes often impact coastal regions in the northern Gulf of Mexico that influence geochemical processes in the region. Satellite remote sensing data such as winds from QuikSCAT, suspended particulate matter (SPM) concentrations derived from SeaWiFS and the outputs (sea level and surface ocean currents) of a nested navy coastal ocean model (NCOM) were combined to assess the effects of frontal passages between 23-28 March 2005 on the physical properties and the SPM characteristics in the northern Gulf of Mexico. Typical changes in wind speed and direction associated with frontal passages were observed in the latest 12.
View Article and Find Full Text PDFThe northern Gulf of Mexico is a region that has been frequently impacted in recent years by natural disasters such as hurricanes. The use of remote sensing data such as winds from NASA's QuikSCAT satellite sensor would be useful for emergency preparedness during such events. In this study, the performance of QuikSCAT products, including JPL's latest Level 2B (L2B) 12.
View Article and Find Full Text PDFThe characteristics of a dual-fiber-optic sensor for measurements of chlorophyll fluorescence in aquatic environments were evaluated with a theoretical model. Consideration was given to sampling variability and package effects associated with particles (e.g.
View Article and Find Full Text PDFDuring the passage of a cold front in March 2002, bio-optical properties examined in coastal waters impacted by the Mississippi River indicated that westward advective flows and increasing river discharge containing high concentrations of nonalgal particles contributed significantly to surface optical variability. A comparison of seasonal data from three cruises indicated spectral models of absorption and scattering to be generally consistent with other coastal environments, while their parameterization in terms of chlorophyll (Chl) alpha concentration showed seasonal variability. The exponential slope of the colored dissolved organic matter (CDOM) averaged 0.
View Article and Find Full Text PDFListeria monocytogenes can survive and grow in refrigerated foods with pH values of approximately 4.0 to 5.0 and salt concentrations of 3 to 4%.
View Article and Find Full Text PDFGrowth and survival of six human isolates of the pathogenic Arcobacter spp. in the presence of selected environmental factors were studied. Four strains of Arcobacter butzleri and two strains of Arcobacter cryaerophilus were exposed to pH levels of 3.
View Article and Find Full Text PDFA rapid, high-temperature double-sided grilling-broiling (DGB) system was compared to a single-sided broiling (SSB) system for cooking of foodservice ground beef patties to reduce microbial numbers and maintain textural quality. Patties (110 g) containing either Escherichia coli O157:H7 or Listeria monocytogenes (10(6-7) CFU/g) were cooked to target internal temperatures of 60 or 68 degrees C on each cooking system and immediately removed from the grills without the additional holding time at 60 or 68 degrees C that is recommended for foodservice cooking of ground beef patties. Actual final internal temperature attained, position on the grill, degree of doneness, cooking time, after-cook weight, texture characteristics, and bacterial counts of the patties were monitored.
View Article and Find Full Text PDFIndian J Chest Dis Allied Sci
April 1978