The Consequences of Shoreline Development for Near-Shore Communities in Chesapeake Bay, USA: A Before-After Control-Impact Study

Hardened shorelines and their construction introduce stressors to a system by altering near-shore habitats. They can reduce biodiversity and abundance of benthic infauna and marsh-edge nekton and epifauna. In this study, I investigated the impacts of shoreline development on near-shore communities using a temporal and spatial approach, by use of a before-after control-impact (BACI) study design at four sub-estuaries within Chesapeake Bay that represent three different types of shoreline change. The BACI study was used to examine infaunal density, biomass, and diversity for two size classes of infauna (3-mm: larger species and adults, 500-!m: smaller species and juveniles), as well as abundance of blue crabs and abundance and diversity of near-shore fishes before and after shorelines were modified. Data were analyzed with Akaike’s Information Criterion to compare candidate sets of linear models that contained year, shoreline treatment, sediment grain size, and salinity as predictors. In response to shoreline modification, infaunal density and biomass increased at sites that were newly developed (Timberneck, Dandy, and Holly Cove), but decreased at the site that changed from bulkhead to living shoreline (Windy Hill). In addition, infaunal diversity decreased at Timberneck and Windy Hill. Blue crab abundance increased at Timberneck, remained constant at Dandy, and decreased at Holly Cove. Blue crab abundance decreased at Windy Hill, though this may not be a shoreline modification response, as crabs concomitantly decreased at control shorelines. Fish abundance and diversity showed no distinct shoreline response at any site, which may reflect their transient nature. At Timberneck, infaunal responses to shoreline modification were mainly driven by changes in habitat. At Dandy, and Holly Cove, infaunal responses to shoreline modification were mainly driven by opportunistic species. At Windy Hill, infaunal responses were driven by a more uniform reduction in all species after the conversion. Sediment grain size was an important predictor of infaunal response variables at Timberneck and Holly Cove, and also changed concomitantly with shoreline modification at Timberneck. Salinity was an infrequent predictor of infaunal responses, though it did vary between years. The importance of opportunistic species and changes in sediment grain size one year after shoreline modification emphasizes the need to monitor shoreline modifications as ecological disturbances and changes in habitat, and the need to consider the role of shoreline modification in ecological succession rather than compare shorelines as static habitats. Lengths of shorelines that were modified were generally short, except at Windy Hill. Negative impacts of shoreline modification at Windy Hill likely reflect a larger disturbance than other sites, and a longer time needed to see positive improvements expected with a living shoreline. Fish species are more motile in nature, may be faster positive responders to positive changes in shoreline condition than infaunal benthos, and provided a first look at the positive effects of living shorelines at Windy Hill

Human Influence at the Coast: Upland and Shoreline Stressors Affect Coastal Macrofauna and Are Mediated by Salinity

Anthropogenic stressors can affect subtidal communities within the land-water interface. Increasing anthropogenic activities, including upland and shoreline development, threaten ecologically important species in these habitats. In this study, we examined the consequences of anthropogenic stressors on benthic macrofaunal communities in 14 subestuaries of Chesapeake Bay. We investigated how subestuary upland use (forested, agricultural, developed land) and shoreline development (riprap and bulkhead compared to marsh and beach) affected density, biomass, and diversity of benthic infauna. Upland and shoreline development were parameters included in the most plausible models among a candidate set compared using corrected Akaike\u27s Information Criterion. For benthic macrofauna, density tended to be lower in subestuaries with developed or mixed compared to forested or agricultural upland use. Benthic biomass was significantly lower in subestuaries with developed compared to forested upland use, and biomass declined exponentially with proportion of near-shore developed land. Benthic density did not differ significantly among natural marsh, beach, and riprap habitats, but tended to be lower adjacent to bulkhead shorelines. Including all subestuaries, there were no differences in diversity by shoreline type. In low salinities, benthic Shannon (H\u27) diversity tended to be higher adjacent to natural marshes compared to the other habitats, and lower adjacent to bulkheads, but the pattern was reversed in high salinities. Sediment characteristics varied by shoreline type and contributed to differences in benthic community structure. Given the changes in the infaunal community with anthropogenic stressors, subestuary upland and shoreline development should be minimized to increase benthic production and subsequent trophic transfer within the food web

A chemical survey of exoplanets with ARIEL

Thousands of exoplanets have now been discovered with a huge range of masses, sizes and orbits: from rocky Earth-like planets to large gas giants grazing the surface of their host star. However, the essential nature of these exoplanets remains largely mysterious: there is no known, discernible pattern linking the presence, size, or orbital parameters of a planet to the nature of its parent star. We have little idea whether the chemistry of a planet is linked to its formation environment, or whether the type of host star drives the physics and chemistry of the planet’s birth, and evolution. ARIEL was conceived to observe a large number (~1000) of transiting planets for statistical understanding, including gas giants, Neptunes, super-Earths and Earth-size planets around a range of host star types using transit spectroscopy in the 1.25–7.8 μm spectral range and multiple narrow-band photometry in the optical. ARIEL will focus on warm and hot planets to take advantage of their well-mixed atmospheres which should show minimal condensation and sequestration of high-Z materials compared to their colder Solar System siblings. Said warm and hot atmospheres are expected to be more representative of the planetary bulk composition. Observations of these warm/hot exoplanets, and in particular of their elemental composition (especially C, O, N, S, Si), will allow the understanding of the early stages of planetary and atmospheric formation during the nebular phase and the following few million years. ARIEL will thus provide a representative picture of the chemical nature of the exoplanets and relate this directly to the type and chemical environment of the host star. ARIEL is designed as a dedicated survey mission for combined-light spectroscopy, capable of observing a large and well-defined planet sample within its 4-year mission lifetime. Transit, eclipse and phase-curve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allow us to measure atmospheric signals from the planet at levels of 10–100 part per million (ppm) relative to the star and, given the bright nature of targets, also allows more sophisticated techniques, such as eclipse mapping, to give a deeper insight into the nature of the atmosphere. These types of observations require a stable payload and satellite platform with broad, instantaneous wavelength coverage to detect many molecular species, probe the thermal structure, identify clouds and monitor the stellar activity. The wavelength range proposed covers all the expected major atmospheric gases from e.g. H2O, CO2, CH4 NH3, HCN, H2S through to the more exotic metallic compounds, such as TiO, VO, and condensed species. Simulations of ARIEL performance in conducting exoplanet surveys have been performed – using conservative estimates of mission performance and a full model of all significant noise sources in the measurement – using a list of potential ARIEL targets that incorporates the latest available exoplanet statistics. The conclusion at the end of the Phase A study, is that ARIEL – in line with the stated mission objectives – will be able to observe about 1000 exoplanets depending on the details of the adopted survey strategy, thus confirming the feasibility of the main science objectives.Peer reviewedFinal Published versio

Appendix C. Detailed results for mixed model analysis and tests of bias.

Detailed results for mixed model analysis and tests of bias

Appendix D. A table of log response ratios partitioned by consumer attributes.

A table of log response ratios partitioned by consumer attributes

Appendix B. A list of publications for the meta-analysis.

A list of publications for the meta-analysis

Appendix A. Search string and detailed description of data collection, construction of log response ratios, mixed model analysis, and tests of bias.

Search string and detailed description of data collection, construction of log response ratios, mixed model analysis, and tests of bias