Reconnaissance survey of benthic communities of a potential borrow site off Tangier Island, Virginia : report to Virginia Airports Authority

The Virginia Institute of Marine Science was called on to render advice and services to the Virginia Airports Authority concerning the environmental impact and design of an extension of the runway of the airport on Tangier Island, Virginia. The southern end of the present runway is now being threatened by the erosion due to the rapid retreat of the western shore of Tangier Island (Fig. 1). Extending the runway would require the stabilization of the shoreline in the vicinity of the runway and filling a tract of subaqueous bottom

Multi-metric Conservation Assessment for the Imperiled Clinch Dace

Planning frameworks allow managers to spatially prioritize actions to promote species conservation. Traditional aquatic conservation planning frameworks are often organized at the ecological community or ecosystem level, which often neglect imperiled taxa occupying species-poor assemblages. In this study, we develop a multi-metric conservation assessment for the 15 geographically distinct candidate conservation areas (CCAs) occupied by the imperiled Clinch Dace (Chrosomus sp. cf. saylori). Clinch Dace habitat is threatened by anthropogenic landscape alterations, especially for coal mining and timber harvest. Our framework used four metrics to assess the conservation value of each subpopulation of Clinch Dace namely: “habitat condition”, “viability”, conservation “opportunity” and conservation “feasibility”. Occupancy models were used to determine the most influential habitat variables to Clinch Dace presence and habitat data collected for each occupied stream were used to score habitat condition in each CCA. Clinch Dace survey data were used to assess demographic population viability to highlight areas where Clinch Dace are most likely to persist. Next, we used the metrics of opportunity and feasibility to identify opportunities for reclamation as well as landownership patterns that may be bridges or barriers to conservation action. Habitat condition and viability varied among our 15 CCAs and highlighted opportunities for specific management actions including habitat conservation in some watersheds and needs for restoration in others. The feasibility metric showed that variation exists in the average lot-parcel size along occupied stream reaches, which may affect the success of some conservation actions. We recommend that managers utilize the data summarized in this study, along with stakeholder input, in a structured-decision making approach to develop specific outreach and management plans targeted to stakeholders in individual watersheds and provide an example of such a framework

First-year Experience Course: Problem Solving, Inquiry, and Integration

In an effort to address academic deficiencies outlined in recent studies, Virginia Tech’s College of Natural Resources and Environment redesigned its first-year experience class to fit their activities into three components of activities: problem solving, inquiry, and integrative learning. The problem solving component required students to define a problem, identify problem-solving strategies, and propose solutions and hypotheses. The inquiry component of the first-year experience included selecting a research topic, learning how to access information about the topic, learning how to evaluate existing information about the topic, and deciding which information to use to achieve desired results about the topic. The final component of the program, integration of learning, connected different programs of study with in-class learning and outside experience. This component also stressed exploring the relationship between student’s self and their learning experiences. To evaluate these three categories, the Motivated Strategies for Learning Questionnaire and the Information Literacy Test surveys were administered to the students at the beginning of the semester and the end of the semester in order to evaluate student growth in each category, as well as students’ own self-awareness. Quantitative analysis of these two surveys illustrates the effectiveness of the assignments associated with each component. Knowledge gained from the redevelopment of the class, quantitative analysis of the surveys, and plans for additional amendments to the class will be shared during conference proceedings

Sustainability Beliefs of First-year Students in Natural Resources

A crux of the environmental problem is change resistance and few college students possess the critical analysis and persuasive communication skills needed to engage in this dialogue. Furthermore, there is little appreciation among college students for the diversity of beliefs regarding sustainability issues. We surveyed students enrolled in a First-Year Experience class in Virginia Tech’s College of Natural Resources and Environment. We used the Dunlap and Van Liere New Environmental Paradigm (NEP) measurement scale to assess the individual student orientations toward nature and the environment. The students enrolled in this class had enrolled voluntarily based on their interest in the study of the environment or natural resources. Therefore, it was no surprise that the score reflected a belief orientation towards sustainability. Survey results allowed these first-year students to discover the range of opinion among members of a relatively homogeneous sample. The survey provided insights regarding the human-centered or eco-centered orientation of their student peers. We used these findings to encourage revision of a draft problem-solving essay. We plan further use of the NEP measurement scale in our curriculum and encourage its adoptions by instructors involved in pedagogy of sustainable thinking

Land Use and Salinity Drive Changes in SAV Abundance and Community Composition

Conserving and restoring submerged aquatic vegetation (SAV) are key management goals for estuaries worldwide because SAV integrates many aspects of water quality and provides a wide range of ecosystem services. Management strategies are typically focused on aggregated abundance of several SAV species, because species cannot be easily distinguished in remotely sensed data. Human land use and shoreline alteration have been shown to negatively impact SAV abundance, but the effects have varied with study, spatial scale, and location. The differences in reported effects may be partly due to the focus on abundance, which overlooks within-community and among-community dynamics that generate total SAV abundance. We analyzed long-term SAV aerial survey data (1984-2009) and ground observations of community composition (1984-2012) in subestuaries of Chesapeake Bay to integrate variations in abundance with differences in community composition. We identified five communities (mixed freshwater, milfoil-Zannichellia, mixed mesohaline, Zannichellia, and Ruppia-Zostera). Temporal variations in SAV abundance were more strongly related to community identity than to terrestrial stressors, and responses to stressors differed among communities and among species. In one fifth of the subestuaries, the community identity changed during the study, and the probability of such a change was positively related to the prevalence of riprapped shoreline in the subestuary. Mixed freshwater communities had the highest rates of recovery, and this may have been driven by Hydrilla verticillata, which was the single best predictor of SAV recovery rate. Additional species-specific and community-specific research will likely yield better understanding of the factors affecting community identity and SAV abundance, more accurate predictive models, and more effective management strategies

The Functional ecology of submerged aquatic vegetation in the lower Chesapeake Bay

The research program, The Functional Ecology of Submerged Aquatic Vegetation in the Lower Chesapeake Bay (EPA/CBP Grant No. R805974), is an integrative effort composed of seven principal investigators. The research team has worked since July 1978 at one study site, the Vaucluse Shores area, to develop and institute a coherent research program on SAV ecological relationships. The principal studies have focused on plant productivity, metabolism and nutrient cycling, the role of resident consumers in SAV community dynamics, the role of migratory species and efforts to develop a realistic, ecosystem simulation model of SAV communities. The preliminary results of the first years study in these research areas are contained in the following report. Many interpretations remain preliminary at this time. We welcome comments and criticisms and in particular ideas concerning data interpretation. Questions concerning specific aspects of the various sections should be addressed to the following: 1. Productivity, Metabolism and Nutrient Cycling; R. L. Wetzel 2. Resident Consumers; R. J. Orth 3. Migratory Consumers; J. V. Merriner 4. Ecosystem Modelling; R. L. Wetze

Submersed Aquatic Vegetation in Chesapeake Bay: Sentinel Species in a Changing World

Chesapeake Bay has undergone profound changes since European settlement. Increases in human and livestock populations, associated changes in land use, increases in nutrient loadings, shoreline armoring, and depletion of fish stocks have altered the important habitats within the Bay. Submersed aquatic vegetation (SAV) is a critical foundational habitat and provides numerous benefits and services to society. In Chesapeake Bay, SAV species are also indicators of environmental change because of their sensitivity to water quality and shoreline development. As such, SAV has been deeply integrated into regional regulations and annual assessments of management outcomes, restoration efforts, the scientific literature, and popular media coverage. Even so, SAV in Chesapeake Bay faces many historical and emerging challenges. The future of Chesapeake Bay is indicated by and contingent on the success of SAV. Its persistence will require continued action, coupled with new practices, to promote a healthy and sustainable ecosystem

Long-term Annual Aerial Surveys of Submersed Aquatic Vegetation (SAV) Support Science, Management, and Restoration

Aerial surveys of coastal habitats can uniquely inform the science and management of shallow, coastal zones, and when repeated annually,theyrevealchangesthatareotherwisedifficulttoassess fromground-basedsurveys.Thispaperreviewstheutilityofalongterm(1984–present)annualaerialmonitoringprogramforsubmersedaquaticvegetation(SAV)inChesapeakeBay,itstidaltributaries, and nearby Atlantic coastal bays, USA. We present a series of applications that highlight the program’s importance in assessing anthropogenic impacts, gauging water quality status and trends, establishing and evaluating restoration goals, and understanding the impactofcommercialfishingpracticesonbenthichabitats.Theseexamplesdemonstratehowperiodicallyquantifyingcoverageofthis important foundational habitat answers basic research questions locally, as well as globally, and provides essential information to resource managers. New technologies are enabling more frequent and accurate aerial surveys at greater spatial resolution and lower cost. These advances will support efforts to extend the applications described here to similar issues in other areas

Alveolar hypoxia, alveolar macrophages, and systemic inflammation

Diseases featuring abnormally low alveolar PO2 are frequently accompanied by systemic effects. The common presence of an underlying inflammatory component suggests that inflammation may contribute to the pathogenesis of the systemic effects of alveolar hypoxia. While the role of alveolar macrophages in the immune and defense functions of the lung has been long known, recent evidence indicates that activation of alveolar macrophages causes inflammatory disturbances in the systemic microcirculation. The purpose of this review is to describe observations in experimental animals showing that alveolar macrophages initiate a systemic inflammatory response to alveolar hypoxia. Evidence obtained in intact animals and in primary cell cultures indicate that alveolar macrophages activated by hypoxia release a mediator(s) into the circulation. This mediator activates perivascular mast cells and initiates a widespread systemic inflammation. The inflammatory cascade includes activation of the local renin-angiotensin system and results in increased leukocyte-endothelial interactions in post-capillary venules, increased microvascular levels of reactive O2 species; and extravasation of albumin. Given the known extrapulmonary responses elicited by activation of alveolar macrophages, this novel phenomenon could contribute to some of the systemic effects of conditions featuring low alveolar PO2

Paxillin Mediates Sensing of Physical Cues and Regulates Directional Cell Motility by Controlling Lamellipodia Positioning

Physical interactions between cells and the extracellular matrix (ECM) guide directional migration by spatially controlling where cells form focal adhesions (FAs), which in turn regulate the extension of motile processes. Here we show that physical control of directional migration requires the FA scaffold protein paxillin. Using single-cell sized ECM islands to constrain cell shape, we found that fibroblasts cultured on square islands preferentially activated Rac and extended lamellipodia from corner, rather than side regions after 30 min stimulation with PDGF, but that cells lacking paxillin failed to restrict Rac activity to corners and formed small lamellipodia along their entire peripheries. This spatial preference was preceded by non-spatially constrained formation of both dorsal and lateral membrane ruffles from 5–10 min. Expression of paxillin N-terminal (paxN) or C-terminal (paxC) truncation mutants produced opposite, but complementary, effects on lamellipodia formation. Surprisingly, pax−/− and paxN cells also formed more circular dorsal ruffles (CDRs) than pax+ cells, while paxC cells formed fewer CDRs and extended larger lamellipodia even in the absence of PDGF. In a two-dimensional (2D) wound assay, pax−/− cells migrated at similar speeds to controls but lost directional persistence. Directional motility was rescued by expressing full-length paxillin or the N-terminus alone, but paxN cells migrated more slowly. In contrast, pax−/− and paxN cells exhibited increased migration in a three-dimensional (3D) invasion assay, with paxN cells invading Matrigel even in the absence of PDGF. These studies indicate that paxillin integrates physical and chemical motility signals by spatially constraining where cells will form motile processes, and thereby regulates directional migration both in 2D and 3D. These findings also suggest that CDRs may correspond to invasive protrusions that drive cell migration through 3D extracellular matrices