Are Aquaculture Practices Sustaining Our Goal to Restore Oysters (Crassostrea virginica)?

Coastal areas are home to a wealth of economic and natural resources and are the most developed areas in the nation with fast increase in human population. Over 50% of the nation’s population resides in 17% of the contiguous U.S. coastal areas. It is critical that consideration be given to the impact humans have on these coastal ecosystems and to the methods which are currently being utilized to enhance and restore these coastal habitats. In this chapter, we compare the status of the Eastern oyster, Crassostrea virginica, in two east coast estuaries: the Delaware Inland Bays, Delaware and Apalachicola Bay, Florida. Many ecological services, which are provided by oysters, such as their filtration, benthic and pelagic coupling, and habitat forming characteristics, have been extensively studied and discussed. Many regional economies in the United States of which the harvest of Eastern oysters was a major component, struggled with the collapsed fishery due to habitat limitation, water quality, sedimentation, parasitic diseases and other land use impacts. In response to these issues, oyster aquaculture has grown and is now a major part of the working waterfront where traditional wild oyster populations used to thrive. Research focusing on the ecological effects of oysters farm-raised with commercial aquaculture equipment is becoming more prolific as the industry moves away from a wild harvest fishery to a cultivated product. The oyster fishery may be recouped if the demand for oysters is supplied with oysters from aquaculture operations. Our primary goal in this chapter is to increase awareness about the potential benefits and some of the challenges facing the increased presence of aquaculture in these estuary systems

Relationship between Land Use and Water Quality and its Assessment Using Hyperspectral Remote Sensing in Mid- Atlantic Estuaries

Mid-Atlantic coastal waters are under increasing pressures from anthropogenic disturbances at various temporal and spatial scales exacerbated by the climate change. According to the National Oceanic Atmospheric Association (NOAA), 10 of the 22 estuaries in the Mid-Atlantic, including the Chesapeake Bay, exhibit high levels of eutrophic conditions while seven, including Delaware Bay, exhibit low conditions. Chesapeake Bay is the largest estuarine system in the United States and undergoes frequent eutrophication and low dissolved oxygen events. Although substantially lower in nutrients compared to other Mid-Atlantic Estuaries, the biological, chemical, and ecological status of the Delaware Bay has changed in the past few decades due to high coastal tourism, increased local resident populations, and agricultural activities which have increased nutrient inputs into this shallow coastal bay. As stated by the Academy of Natural Sciences, although the nutrient load has reduced since the Clean Water Act, years of nutrient accumulation, contaminations, and sedimentation have impacted estuarine systems substantially, long-term monitoring is lacking, and ecological responses are not well quantified. Eutrophication within the Bays has degraded water quality conditions advanced by sedimentation. Understanding the quality of the water in any aquatic ecosystem is a critical first step in order to identify characteristics of that ecosystem and draw conclusions about how well adapted the system is in terms of anthropogenic activity and climate change. Determining water quality in intertidal creeks along the Chesapeake and Delaware coastlines is important because land cover is constantly changing. Many of these tidal creeks are lined with forested riparian buffers that may be intercepting nutrients from running off into the waterways. Identifying water conditions, coupled with the marsh land cover, provides a strong foundation to see if the buffer systems are providing the ecosystem services they are designed to provide. Our primary goal in this chapter is to provide research findings on the application of the hyperspectral remote sensing to monitor specific land-use activities and water quality. Along with hyperspectral remote sensing, our monitoring was coupled with the integration of remotely sensed data, global positioning system (GPS), and geographic information system (GIS) technologies that provide a valuable tool for monitoring and assessing waterways in the Mid-Atlantic Estuaries

Bi-Directional Waterway Reveals Nutrient Runoff From Cropland

Blackbird Creek is the waterway that empties into the Delaware Bay. The lower 21 km of the creek has been shown to have appreciable salinity measurements, suggesting that this portion is influenced by tidal fluctuations. Fourteen sampling stations were established within this lateral range in order to examine the nutrient dynamics of the creek at various points in time. Our objective was to monitor potential changes in water quality conditions, especially on nutrients, in the creek during the day using the low and high tides as the predominating driver for the change. Temperature, pH, dissolved oxygen, conductivity, and salinity were monitored bi-weekly at each station. Concentrations of dissolved nitrate (NO3), nitrite (NO2), ammonia (NH3), orthophosphate (PO4), alkalinity (Alk), and turbidity (Tbd) were measured at each station over the course of the field season. Average concentrations were generally low for the nitrogen species: NH4 = 0.11 mgL−1, NO3 = 0.30 mgL−1, NO2 = 0.02 mgL−1. Average alkalinity (92 mgL−1 CaCO3) and turbidity (71 FTU) concentrations were appropriate given the nature of the marsh environment. The average PO4 concentration, however, was elevated (= 0.44 mgL−1). The EPA recommends values under 0.1 mgL−1 for this type of waterway. When considered separately, nutrient concentrations on outgoing tides were elevated relative to nutrient concentrations on incoming tides. Overall, the highest concentrations for all parameters occurred at low tide before the shift to the next incoming tide. This suggests that there are greater nutrient concentrations upstream than downstream. Given that land use in the Blackbird Creek watershed is primarily agricultural, it is likely that upstream pore water input from cropland is influencing the nutrient dynamics of the waterway. This information is key to understanding the efficiency of the riparian buffer system that has been established in the watershed and to allow for opportunities for improvement to mitigate nutrient runoff from agricultural fields

The Effect of a Small Ruminant Farm Operation and Sustainable Farm Practices: Soil Quality and Run-Off at the University Hickory Hill Farm, Delaware

This project was designed to evaluate the effect of ruminant grazing practices at Hickory Hill Farm on the surrounding environment by measuring soil nutrients and runoff chemistry. Three pastures on the farm (Goat, Cattle and Control) were selected for soil sampling and nutrient analyses were recorded. Physical water quality parameters were conducted on the runoff collected from the farm after Hurricane Sandy. The sites with animal activity had higher levels of sulfate, phosphate, nitrate, Mehlich 3 phosphorus and conductivity when compared to control site. However, the control site had slightly higher pH and chloride levels. Nitrogen and phosphorous levels were very low at the control site when compared with the cattle and goat sites. Overall, soil quality was not found to be severely degraded from ruminant grazing activities. It will be vital to continue monitoring the farm to ensure its management practices are allowing optimal farm profitability and environmental health

Diversity of Diatom Communities in Delaware Tidal Wetland and Their Relationship to Water Quality

Diatoms are strongly influenced by water quality and serve as indicators of water quality degradation in freshwater systems. Here, sediment and water samples were collected from four sites in Blackbird Creek, DE, a salt marsh characterized as mostly freshwater to low saline brackish (<8ppt). Recent changes in land use resulted in increased agricultural activity, suggesting the need to develop water quality indicators in this region. To test the hypothesis that diatom community composition changes seasonally with variations in water quality parameters, sediment and water samples were collected in 2009 and 2010 for analysis. Water temperature, salinity, pH, and dissolved oxygen were measured as well as water and sediment dissolved nutrient concentrations (nitrate, ammonia, and total and reactive phosphorous). DNA was extracted from sediments and changes in diatom community composition were evaluated by amplification of 18S rRNA gene using diatom-specific primers, followed by Terminal Restriction Fragment Length Polymorphism (TRFLP) analysis. Shannon (H') index for TRFLP profiles ranged from 2.5 to 3.0 and Simpson (Ds) index was 0.9 which infers moderate levels of diatom species richness and high diversity in these study sites. Although there were no water quality parameters that were significantly correlated with diatom community composition as determined by TRFLP patterns, temperature was the most highly correlated (r = 0.203). Dissolved oxygen, salinity, and pH of water also had moderate but insignificant impacts on the diatom community. Further analysis of cloned 18S rRNA sequences revealed the presence of diatom taxa that tolerate wide salinity ranges, and included Navicula, Cyclotella, Thalassiosira and Skeletonema. Entomoneis sp. were also present in the spring and fall seasons. Overall, results in this study demonstrate significant differences in water qualities among the study years but little change in diatom community composition between study sites and seasons, but may serve as a baseline for future studies

Sustainable Farm Practice: Study of Total and Soluble Phosphorus in a Poultry Farm Equipped with Heavy Use Area Protection Pads, Dover, Delaware

Poultry litter contains high concentrations of water-soluble phosphorus and is readily transported in the farm run-off. This research aims to study the efficiency of heavy use area protection (HUAP) pads in decreasing litter spillage and phosphorous run-off at a Delaware poultry facility. Soil and water samples were analyzed for pH, total phosphorous, orthophosphate, and Mehlich III phosphorous throughout 2012. It has been hypothesized that the efficiency of HUAP pads would be reduced over time. Mehlich III phosphorus ranged from 22.82-200 mg/kg at site I, and 48.17 – 1179.6 mg/kg at site II, which were greater than the optimal soil concentrations. However, in the run-off, orthophosphate and total phosphorous levels were less than 0.05mg/L, and below U.S. EPA limits. This confirms that the HUAP pads, along with vegetative buffer strips, restricted the seepage of phosphorous into the run off. The results suggest minimal loss of nutrients from poultry house to water bodies. Keywords: Poultry Farm, Heavy Use Area Protection, HUAP, Phosphorus, Soil Testin

Microplastics and their interactions with microbiota

As a new pollutant, Microplastics (MPs) are globally known for their negative impacts on different ecosystems and living organisms. MPs are easily taken up by the ecosystem in a variety of organisms due to their small size, and cause immunological, neurological, and respiratory diseases in the impacted organism. Moreover, in the impacted environments, MPs can release toxic additives and act as a vector and scaffold for colonization and transportation of specific microbes and lead to imbalances in microbiota and the biogeochemical and nutrients dynamic. To address the concerns on controlling the MPs pollution on the microbiota and ecosystem, the microbial biodegradation of MPs can be potentially considered as an effective environment friendly approach. The objectives of the presented paper are to provide information on the toxicological effects of MPs on microbiota, to discuss the negative impacts of microbial colonization of MPs, and to introduce the microbes with biodegradation ability of MPs

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. Delaware's 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 toward 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 further away from 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 10 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

Efficacy of Heavy Use Area Protection (HUAP) Pads in Poultry Farm

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 in 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