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  1. Free, publicly-accessible full text available June 1, 2023
  2. Yabe, John (Ed.)
    Totaling at 7.4 billion people, the world’s population is rapidly growing, bringing along with it an increase in waste generation. The impact of this exponential increase in waste generation has resulted in the increased formation and utilization of landfills. In the present day, landfills are utilized to dispose of chemical, hazardous, municipal, and electronic wastes. However, despite their convenience, most landfills are improperly managed and face constant changes from the surrounding environment that interfere with their internal landfill processes. The objectives of this mixed review are to highlight the negative impacts landfills have on the environment and public health as well as outline the need for proper management practices to mitigate these effects. Inadequate management of landfills leads to issues concerning leachate collection and landfill gas (LFG) generation, which give rise to groundwater contamination and air pollution. This paper recognizes the disadvantages of utilizing landfills as the main disposal method by focusing on these two primary effects that improper management of landfills has on the environment and human health. Many experts have also reported that communities within close proximity to improperly managed landfills have an increased risk of health issues. Apart from implementing proper landfill management practices, it is importantmore »to develop solutions to reduce waste generation altogether. This review discusses some of the innovative methods implemented by other countries to reduce landfill waste and the production of greenhouse gases as well as possible steps individuals can take to minimize their ecological footprints.« less
  3. Anil, Arga Chandrashekar (Ed.)
    There is little information on the impacts of climate change on resource partitioning for mixotrophic phytoplankton. Here, we investigated the hypothesis that light interacts with temperature and CO 2 to affect changes in growth and cellular carbon and nitrogen content of the mixotrophic dinoflagellate, Karlodinium veneficum , with increasing cellular carbon and nitrogen content under low light conditions and increased growth under high light conditions. Using a multifactorial design, the interactive effects of light, temperature and CO 2 were investigated on K . veneficum at ambient temperature and CO 2 levels (25°C, 375 ppm), high temperature (30°C, 375 ppm CO 2 ), high CO 2 (30°C, 750 ppm CO 2 ), or a combination of both high temperature and CO 2 (30°C, 750 ppm CO 2 ) at low light intensities (LL: 70 μmol photons m -2 s -2 ) and light-saturated conditions (HL: 140 μmol photons m -2 s -2 ). Results revealed significant interactions between light and temperature for all parameters. Growth rates were not significantly different among LL treatments, but increased significantly with temperature or a combination of elevated temperature and CO 2 under HL compared to ambient conditions. Particulate carbon and nitrogen content increased in responsemore »to temperature or a combination of elevated temperature and CO 2 under LL conditions, but significantly decreased in HL cultures exposed to elevated temperature and/or CO 2 compared to ambient conditions at HL. Significant increases in C:N ratios were observed only in the combined treatment under LL, suggesting a synergistic effect of temperature and CO 2 on carbon assimilation, while increases in C:N under HL were driven only by an increase in CO 2 . Results indicate light-driven variations in growth and nutrient acquisition strategies for K . veneficum that may benefit this species under anticipated climate change conditions (elevated light, temperature and p CO 2 ) while also affecting trophic transfer efficiency during blooms of this species.« less
  4. Oyster aquaculture is one of several methods for the restoration of Delaware Inland Bays; however, little is known about its potential impacts on the benthic community of the bays. In this study, water quality parameters were measured and polychaetes were collected from 24 sampling locations at Rehoboth, Indian River, and Little Assawoman Bays from July to October 2016 and 2017. We aimed to assess the impact of Eastern oyster farming under different stocking densities (50 and 250 oysters/gear) and distances away from the sites where the off-bottom gears are implemented (under gears, one meter, and five meters away). No significant impact was detected on polychaetes’ abundance and richness in regard to the presence of oyster gears. The number of polychaetes and species richness was significantly higher in Little Assawoman Bay in comparison to the Indian River and Rehoboth Bays. Results showed that the Ulva lactuca bloom that happened in 2016 could negatively impact the low abundance and richness observed in the polychaetes community. Similarly, the values of polychaetes abundance and species richness did not change significantly in samples that were taken far from the oyster gears. Dominant polychaetes families were Capitellidae and Glyceridae contributing to more than 70% of polychaetes’more »number of individuals. Our results help to understand the role of oyster aquaculture in restoring the viability in the natural habitat of the Delaware Inland Bays.« less
  5. This research focuses on the efficiency of recommended heavy use area protection (HUAP) pads installed in poultry houses utilizing the Choptank River, a tributary of the Chesapeake Bay. The Chesapeake Bay watershed is severely affected by crop agriculture and poultry feeding operations. Water quality degradation along with scarcity of water is a significant concern in this area, suggesting a need for changes in both environmental and groundwater management practices. Our objective in this study was to compare the efficiency of HUAP in reducing litter spillage and nutrient runoff between two poultry houses, one of which was constructed in 2005 and the other in 2009. The poultry house constructed in 2005 did not have HUAP pads initially; they were built in 2006. The poultry house built in 2009 had the pads from the starting point. We collected soil and water samples each month and analyzed them for pH, electrical conductivity (EC), nitrate, nitrite, total nitrogen, phosphate, and other soil properties throughout the year. The pH of soil and water samples was in the range of 6.8–8.0 and 6.5–7.2, respectively. We collected six water samples in total in the ditch, from points at retention ponds near the farm ditch to sites inmore »wooded areas on the farm. Water sample B (where ditch water meets retention pond water from the poultry farm) had the highest EC value and nitrate, nitrite, and total nitrogen concentrations compared with other water samples. The subsequent water samples downstream had reduced loads of nutrients. The study results suggest that there was a minimum carryover of nutrients from soil into the runoff water, storm ditches, and adjacent stream. There was also a minimal effect of house cleaning and storm events in raising the concentration of nutrients in soil and water samples at our study sites. The older poultry site had higher total nitrogen and phosphorous surrounding the pads, whereas no elevated levels of nutrients were identified at the newer site. The ability of HUAP pads to hold onto contaminates decreases with age and use. This study also shows that the impacts from poultry activities on surface and groundwater can be minimized by using management practices such as HUAP pads. These practices can reduce pollution in the farm, increase productivity, and save farmers and ranchers time and money in the long run.« less