The impact of agricultural activities on water quality: a case for collaborative catchment-scale management using integrated wireless sensor networks

The challenge of improving water quality is a growing global concern, typified by the European Commission Water Framework Directive and the United States Clean Water Act. The main drivers of poor water quality are economics, poor water management, agricultural practices and urban development. This paper reviews the extensive role of non-point sources, in particular the outdated agricultural practices, with respect to nutrient and contaminant contributions. Water quality monitoring (WQM) is currently undertaken through a number of data acquisition methods from grab sampling to satellite based remote sensing of water bodies. Based on the surveyed sampling methods and their numerous limitations, it is proposed that wireless sensor networks (WSNs), despite their own limitations, are still very attractive and effective for real-time spatio-temporal data collection for WQM applications. WSNs have been employed for WQM of surface and ground water and catchments, and have been fundamental in advancing the knowledge of contaminants trends through their high resolution observations. However, these applications have yet to explore the implementation and impact of this technology for management and control decisions, to minimize and prevent individual stakeholder’s contributions, in an autonomous and dynamic manner. Here, the potential of WSN-controlled agricultural activities and different environmental compartments for integrated water quality management is presented and limitations of WSN in agriculture and WQM are identified. Finally, a case for collaborative networks at catchment scale is proposed for enabling cooperation among individually networked activities/stakeholders (farming activities, water bodies) for integrated water quality monitoring, control and management

The influences of basic physical properties of clayey silt and silty sand on its laboratory electrical resistivity value in loose and dense conditions

Non-destructive test which refers to electrical resistivity method is recently popular in engineering, environmental, archaeological and mining studies. Based on the previous studies, the results on electrical resistivity interpretation were often debated due to lack of clarification and evidences in quantitative perspective. Traditionally, most of the previous result interpretations were depending on qualitative point of view which is risky to produce unreliable outcomes. In order to minimise those problems, this study has performed a laboratory experiment on soil box electrical resistivity test which was supported by an additional basic physical properties of soil test like particle size distribution test (d), moisture content test (w), density test (ρbulk) and Atterberg limit test (LL, PL and PI). The test was performed to establish a series of electrical resistivity value (ERV) with different quantity of water content for clayey silt and silty sand in loose and dense condition. Apparently, the soil resistivity value was different under loose (L) and dense (C) conditions with moisture content and density variations (silty SAND = ERVLoose: 600 - 7300 Ωm & ERVDense: 490 - 7900 Ωm while Clayey SILT = ERVLoose: 13 - 7700 Ωm & ERVDense: 14 - 8400 Ωm) due to several factors. Moreover, correlation of moisture content (w) and density (ρbulk) due to the ERV was established as follows; Silty SAND: w(L) = 638.8ρ-0.418, w(D) = 1397.1ρ-0.574, ρBulk(L) = 2.6188e-6E-05ρ, ρBulk(D) = 4.099ρ-0.07 while Clayey SILT: w(L) = 109.98ρ-0.268, w(D) = 121.88ρ-0.363, ρBulk(L) = -0.111ln(ρ) + 1.7605, ρBulk(D) = 2.5991ρ-0.037 with determination coefficients, R2 that varied from 0.5643 – 0.8927. This study was successfully demonstrated that the consistency of ERV was greatly influenced by the variation of soil basic physical properties (d, w, ρBulk, LL, PL and PI). Finally, the reliability of the ERV result interpretation can be enhanced due to its ability to produce a meaningful outcome based on supported data from basic geotechnical properties

Amphibian Mortality on Roads: A Case Study in Santa Cruz Long-toed Salamander Habitat

Amphibian populations have been declining at higher rates than bird and mammal populations. Agriculture, urbanization, including roads, and resource extraction continue to put pressure on all species. Roads in particular, are major sources of mortality. The Santa Cruz long-toed salamander (Ambystoma macrodactylum croceum), one of the most critically endangered species in the US, is one amphibian that is declining as a result of anthropogenic impacts, especially habitat loss and fragmentation due to urban development. Migration across roads puts these salamanders at risk from road-related death. This thesis quantified the rate of road mortality to these salamanders and other common amphibians during two A. m. croceum breeding-migration seasons in 2011-13 in a portion of the subspecies\u27 range. Vehicular traffic was a major source of mortality to the salamander. Through traffic doubled the overall vehicle load on roads where the A. m. croceum migrated to and from breeding ponds. The Pacific chorus frog was also killed on the roads. This common species can be used as an indicator of road mortality risk for rarer amphibians. This study indicated that measures to reduce road mortality to the Santa Cruz long-toed salamander could include restricting vehicular traffic on roads adjacent to salamander ponds by limiting traffic to residential use only during breeding migrations, installing structures to protect A. m. croceum while crossing roads, and potentially assisting animals crossing roads at nighttime during the breeding migrations

Research report 1987-1989: Environmental Quality Laboratory and Environmental Engineering Science, W. M. Keck Laboratories

This research biennial report for 1987-89 covers the activities of both the Environmental Engineering Science program and the Environmental Quality Laboratory for the period October 1987-November 1989. Environmental Engineering Science is the degree-granting academic program housed in the Keck Laboratories, with associated research projects. The Environmental Quality Laboratory is a research center focusing on large scale problems of environmental quality and natural resources. All the faculty and students involved in EQL projects are part of one of the regular academic programs, with the largest number being in Environmental Engineering Science. Hence the convenience of this combined report. In the lists of students, degrees, and research projects we have included some students in other degree programs who are working on environmental topics under one of the professors associated with EES and/or EQL. Caltech's small size and flexible structure allows professors to participate in more than one academic program including the supervision of doctoral students. The report starts with brief descriptions of EQL and EES, then lists the people - professors, research staff, visitors and consultants, support staff, and graduate students. Next is a listing of our research sponsors and donors, to whom we are all indebted for making these programs possible. The main part of the report presents the research summaries for all our activities including publications during the period October 1987 - November 1989. Also included at the end of the report is a listing of books published during 1987-89 (which do not appear in the research summaries) and information about a major smog conference held in 1988. It is hoped this report will be a useful reference not only for prospective students and visitors but also for the entire EES and EQL group

Science-based restoration monitoring of coastal habitats, Volume Two: Tools for monitoring coastal habitats

Healthy coastal habitats are not only important ecologically; they also support healthy coastal communities and improve the quality of people’s lives. Despite their many benefits and values, coastal habitats have been systematically modified, degraded, and destroyed throughout the United States and its protectorates beginning with European colonization in the 1600’s (Dahl 1990). As a result, many coastal habitats around the United States are in desperate need of restoration. The monitoring of restoration projects, the focus of this document, is necessary to ensure that restoration efforts are successful, to further the science, and to increase the efficiency of future restoration efforts

The biology and culture of tropical oysters

Reviews the biology and ecology of oysters, and experimental and culture techniques used in the tropics; describes problems in tropical oyster farming and identifies research needs to further develop this form of aquaculture. Three oyster genera are discussed: Ostrea, Crassostrea and Saccostrea. The advantages and disadvantages of various species of each genus with regard to aquaculture are also described.Oyster culture, Tropics, Biology

Comparison Between Acute Toxicity And Chemical Analysis Of Natural Gas Drilling Effluent Samples Using Penaeus Monodon

The regulation of point source discharges usually based on specific chemicals which describe thresholds below which no adverse impact on the receiving water. The limitation of this technique includes the fact that it does not take into account interactions among toxicants (e.g. additivity, synergism, antagonism). Therefore, toxicity testing is recommended as integrated approach for identifying toxic pollutants to complement chemical-specific analysis by assessing the sum toxicity of all components in the mixture. The objective of this research was the assessment of Penaeus monodon (PM) as an indicator species for toxicity testing through comparisons between results from 48-h LC50 and chemical analysis of the natural gas drilling effluent. Chemical analysis of effluent samples was performed in order to determine concentrations of BTEX (benzene, toluene, ethyl benzene, xylene) and heavy metals (Cr, Ni, Cu, As, Pb, Cd). Average 48-h LC50\u27s for PM was 2,94 % for effluent and 0.68 g/l for KCl. Comparison between acute toxicity and chemical analysis showed a significant correlation between toluene concentrations and 48-h LC50 in PM (p<0.05). No significant correlation was found between the detectable heavy metal concentrations and acute toxicity data in PM. Results suggest that the lack of correlation between toxicity and almost all chemical parameters indicates that toxicity testing is much more useful for monitoring toxicity of effluents than chemical analysis. Additional studies are needed to identify alternative toxicity endpoints as sensitive indicators of impacts on the environment

Thermal limits and preferences of large branchiopods (Branchiopoda: Anostraca and Spinicaudata) from temporary wetland arid zone systems

Highlights: • Thermal biology of rock-pool and pan specialist branchiopods were contrasted. • Wetland type was not a good predictor of branchiopod thermal preference/limits. • Spinicaudatans preferring higher temperatures than anostracans. • Spinicaudatans were more tolerant of high temperatures than anostracans. • Anostracans may be more susceptible to projected climatic warming. Abstract: Large branchiopods are specialist crustaceans adapted for life in temporary, thermally dynamic wetland ecosystems. Certain large branchiopod species are, however, restricted to specific temporary wetland types, exemplified by their physico-chemical and hydroperiod characteristics. Here, we contrasted the thermal preference and critical thermal maxima (CTmax) and minima (CTmin) of southern African anostracans and spinicaudatans found exclusively in either temporary rock-pool or pan wetland types. We hypothesized that environment of origin would be a good predictor of thermal preference and critical thermal limits. To test this, Branchiopodopsis tridens (Anostraca) and Leptestheria brevirostris (Spinicaudata) were collected from rock-pool habitats, while Streptocephalus cafer (Anostraca) and a Gondwanalimnadia sp. (Spinicaudata) were collected from pan habitats. In contrast to our hypothesis, taxonomic relatedness was a better predictor of CTmax and temperature preference than environment of origin. Spinicaudatans were significantly more tolerant of high temperatures than anostracans, with L. brevirostris and Gondwanalimnadia sp. median CTmax values of 45.1 °C and 44.1 °C, respectively, followed by S. cafer (42.8 °C) and B. tridens (41.4 °C). Neither environment or taxonomic relatedness were good predictors of CTmin trends, with B. tridens (0.9 °C) and Gondwanalimnadia sp. (2.1 °C) having the lowest median CTmin values, followed by L. brevirostris (3.4 °C) and S. cafer (3.6 °C). On the contrary, temperature preferences differed according to taxa, with spinicaudatans significantly preferring higher temperatures than anostracans. Leptestheria brevirostris and Gondwanalimnadia sp. both spent most time at temperatures 30–32 °C, S. cafer at 18–20 °C and B. tridens at 21–23 °C. Constrained thermal traits reported here suggest that the studied anostracans might be more susceptible to projected climatic warming than the spinicaudatans, irrespective of habitat type, however, these taxa may also compensate through phenotypic plasticity

Bivalve mollusc culture research in Thailand

An account of research, which explored new biological and socioeconomic perspectives on bivalve mollusc culture to increase production and to improve the livelihood of farmers. It presents a review of the pathways in which aquatic macrophytes may be involved in the food production process, directly as human food, as livestock fodder, as fertilizer (mulch and manure, ash, green manure, compost, biogas slurry), and as food for aquatic herbivores, such as fish, turtles, rodents and manatees. Suggests research areas.Mollusc culture, Research programmes, ICLARM publications, Thailand, Bivalvia

School of Marine Science Graduate Catalog 2000-2001

Catalog for the Graduate program of the School of Marine Science at the College of William & Mary for the listed academic year