Lathadevi Karuna Chintapenta

Effects of High Hydrostatic Pressure on the Physical, Microbial, and Chemical Attributes of Oysters (Crassostrea virginica).

The change in the quality attributes (physical, microbial, and chemical) of oysters (Crassostrea virginica) after high hydrostatic pressure (HHP) treatment at 300 MPa at room temperature (RT, 25 °C) 300, 450, and 500 MPa at 0 °C for 2 min and control oysters without treatment were evaluated over 3 wk. The texture and tissue yield percentages of oysters HHP treated at 300 MPa, RT increased significantly (P < 0.05) compared to control. Aerobic and psychrotrophic bacteria in control oysters reached the spoilage point of 7 log CFU/g after 15 d. Coliform counts (log MPN/g) were low during storage with total and fecal coliforms less than 3.5 and 1.0. High pressure treated oysters at 500 MPa at 0 °C were significantly higher (P < 0.05) than oysters HHP treated at 300 MPa at 0 °C in lipid oxidation values. The highest pressure (500 MPa) treatment in this study, significantly (P < 0.05) decreased unsaturated fatty acid percentage compared to control. The glycogen content of control oysters at 3 wk was significantly higher (P < 0.05) when compared to HHP treated oysters [300 MPa, (RT); 450 MPa (0 °C); and 500 MPa (0 °C)]. HHP treatments of oysters were not significantly different in pH, percent salt extractable protein (SEP), and total lipid values compared to control. Based on our results, HHP prolongs the physical, microbial, and chemical quality of oysters.

Effects of Microbial and Heavy Metal Contaminants on Environmental/Ecological Health and Revitalization of Coastal Ecosystems in Delaware Bay

The presence of heavy metals, excess nutrients, and microbial contaminants in aquatic systems of coastal Delaware has become a public concern as human population increases and land development continues. Delawares coastal lagoons have been subjected to problems commonly shared by other coastal Mid-Atlantic states: turbidity, sedimentation, eutrophication, periodic hypoxic/anoxic conditions, toxic substances, and high bacterial levels. The cumulative impact of pollutants from run-off and point sources has degraded water quality, reduced the diversity and abundance of various fish species, invertebrates, and submerged aquatic vegetation. The effects are especially pronounced within the manmade dead end canal systems. In this article, we present selected case studies conducted in the Delaware Inland Bays. Due to the ecological services provided by bivalves, our studies in Delaware Inland Bays are geared towards oysters with special focus on the microbial loads followed by the water quality assessments of the bay. The relationships between oysters (Crassostrea virginica), microbial loads and nutrient levels in the water were investigated. The heavy metal levels monitored near the waste water treatment plant in the inland bays are marginally higher than the recommended EPA limits Also, our studies confirmed that aerobic bacteria and Vibrionaceae levels are salinity dependent. Total bacteria in oysters increased when nitrate and total suspended solids increased in the waters. Studies such as these are important because every year millions of Americans consume raw oysters. Data collected over the last ten years from our studies may be used to build a predictive index of conditions that are favorable for the proliferation of human pathogenic bacteria. Results from this study will benefit the local community by helping them understand the importance of oyster aquaculture and safe consumption of oysters while making them appreciate their ecological and commercial values. This will also be of tremendous help to the commercial shellfish aquaculture farms to predict poor conditions to prevent oysters’ consumption when bacterial levels are high in water.

Water Quality Analysis of Agriculturally Impacted Tidal Blackbird Creek, Delaware

Blackbird Creek, Delaware is a small watershed in northern Delaware that has a significant proportion of land designated for agricultural land use. The Blackbird Creek water monitoring program was initiated in 2012 to assess the condition of the watershed’s habitats using multiple measures of water quality. Habitats were identified based on percent adjacent agricultural land use. Study sites varying from five to fourteen were sampled biweekly during April and November, 2012-2015. Data were analyzed using principal component analysis and generalized linear modeling. Results from these first four years of data documented no significant differences in water quality parameters (dissolved oxygen, pH, temperature, salinity, inorganic nitrate, nitrite, ammonia, orthophosphate, alkalinity, and turbidity) between the two habitats, although both orthophosphate and turbidity were elevated beyond EPA-recommended values. There were statistically significant differences for all of the parameters between agriculture seasons. The lack of notable differences between habitats suggests that, while the watershed is generally impacted by agricultural land use practices, there appears to be no impact on the surface water chemistry. Because there were no differences between habitats, it was concluded that seasonal differences were likely due to basic seasonal variation and were not a function of agricultural land use practices.

Land Use Impacts: The Effects of Non-Native Grasses on Marsh and Aquatic Ecosystems

Tidal marsh systems serve as great examples of dynamic ecosystems that can provide numerous lessons in restoration ecology. The ecosystem services which are provided by naturally functioning marsh habitats, in conjunction with the diverse assemblages of nekton which utilize those habitats, have long been underappreciated. Unfortunately, misplaced beliefs and unintentional but harmful actions persist in the face of some of the most large-scale and coordinated scientific efforts towards achieving the preservation, remediation, and reclamation of these spatially dynamic systems. An important aspect of the restoration process is to gauge the success of any management practices that have been employed. Our program focus over the past five years has been to look at the impacts of land use and land cover on aquatic health and marsh habitat. Progress towards any goals should be consistently monitored to ensure that responses to habitat management put the ecosystem on a satisfactory trajectory in terms of achieving desired structure and function.

Pigment production from a mangrove Penicillium

A mangrove Penicillium producing red pigment was cultured in an optimized medium that was designed by the authors previously and used in this study. The purpose of this study was to identify the pigment and also to study the effect of bio elements on pigment production. Pigment from the medium was efficiently extracted using chloroform, ethyl acetate and n-butanol. Most of the red pigment was extracted into ethyl acetate and further purified by preparative thin layer chromatography. From 1 H and 13 C NMR data supported by electronic imaging mass spectrometry, structure of the compound was elucidated as 2-(4-acetyl phenyl) acetic acid. The yield of pigment produced was studied with respect to various salts and bio elements. Salts at high concentrations (sodium chloride, ammonium sulfate, and sodium nitrite) had a drastic effect on pigment yield because most of the pigment remained adhered to the mycelium instead of diffusing into the medium. Also, when bio elements were supplemented to the medium; calcium, iron, and zinc enhanced pigment yield whereas; potassium, magnesium, copper and manganese did not have significant impact on pigment production. Lead had a drastic negative effect on the pigment yield. Therefore, this study proves that salts and bio elements play a major role in the production of various metabolites from mangrove fungi. Keywords: Penicillium , 2-(4-acetyl phenyl) acetic acid, bio elements, salts, soluble pigment. African Journal of Biotechnology , Vol 13(26) 2668-2674

Delaware Inland Bays and Market Oyster (Crassostrea virginica) Quality for Consumption

Consumption of raw oysters is known to cause serious health conditions due to bioaccumulation of contaminants. As filter feeders, oysters ingest bacteria along with phytoplankton from their surrounding habitats. Ensuring seafood safety for human consumption is always a concern. Since oysters are consumed raw, disease causing organisms, environmental contaminants, toxins, chemicals, and even physical hazards such as soils and metals retained in the oysters can enter through feeding. The objective of this study was to determine the quality of oysters collected from Delaware Inland Bays (DIB) and compare them with market oysters. Environmental parameters were monitored from local waters of DIB classified as closed versus open for shellfish harvesting. Total aerobic bacteria and vibrio were higher in market oysters during the warmer months, with open water having the least microbial loads. There were no significant differences in total vibrio counts between the study sites ( ), but significant differences were recorded over time ( ). Water temperature and turbidity were directly proportional to total vibrio in oysters, and salinity was inversely related. Research findings in this study may help bring awareness of changes in bacterial loads due to seasonal changes and additional handling and storage.

Overview on Sustainable Animal Farming in Relationship to Climate Change in Delmarva

The Intergovernmental Panel on Climate Change (IPCC), established by the United Nations and World Meteorological Organization, has determined with a 90% confidence interval that humans have very likely contributed to a net warming of the Earth due to an increase in the emissions of greenhouse gases, aerosols, and land use changes. This warming has caused glacial melting to accelerate and subsequently sea level is now a very tangible issue. In addition, extreme precipitation events are happening more often in certain geographic regions. The last few decades have seen tremendous efforts focused on the collection and distribution of scientific data to better understand trends and future projections/scenarios of climate change and how society must adapt to those changes. As science concerning global climate change advances, societal awareness and understanding of the issue appears to be lagging behind. Does the public have a solid understanding of the mechanisms and consequences of climate change? Depending on the type of government, public views can significantly influence the government to develop better climate policies. Therefore, public voice is vital in influencing political decisions concerning climate change. Clear communication of scientific knowledge can empower people to safely steer future generations out of harm’s way - sharing and understanding fosters more of the same possibility. This case study discusses one of the interactive classroom activities which facilitated the active engagement of students in a discussion of local issues and potential avenues to adapt to climate change. Because climate change affects everything on our planet, animal farms on Delmarva represent one of the many economically and socially critical variables that must be protected through preemptive adaptations. Conversely, farm operations affect the rate of climate change, as well as the surrounding environment. With modern management practices and technology, farming effects on the environment and climate can be drastically reduced. On the other hand, if operations are not managed properly they can also have a negative impact on the environment and climate. Through suggestions and the adoption of modern practices, animal farming can become sustainable and environmentally friendly. The earth’s climate is inherently dynamic, but with the adoption of sustainable farming practices on a global scale the rate of climate change may be decelerated.