Mapping and Restoration Inventory of Fringing Marsh Habitat in the Casco Bay Estuary, Project Report

During the spring and summer of 2007 a survey of the fringing marshes existing along the mainland coast of Casco Bay was commissioned by the Casco Bay Estuary Partnership and the U.S. Environmental Protection Agency. The work was performed by personnel supervised by the Wells National Estuarine Research Reserve (WNERR) in Wells, Maine. A delineation of fringing marshes based on aerial photography was performed during the spring and early summer months. This delineation, based upon aerial imagery taken in 2003, identified approximately 1,160 marsh units along the mainland coast of Casco Bay (islands were omitted from this study). Later in the summer, after maturation of marsh vegetation, survey teams were dispatched in two separate efforts in support of the image-based identification. Boat transects were taken along representative shorelines and fringing marshes detected were marked at each end with a GPS point allowing an approximation of marsh location, and extent, to be recorded. Survey teams on foot visited a number of randomly-selected sample points and performed on-site measurement of marsh area (total, high marsh, low marsh, and major invasive patches), an estimate (based on elevation differences) of potential total marsh area after a forty centimeter (40 cm) rise in average sea level, and performed a \u27rapid assessment\u27 of marsh characteristics and degradation condition. Based on the estimated average fringing marsh area, there is approximately 41 hectares of marsh covering nearly 150 km of the mainland coastline of Casco Bay. While some marsh is very healthy, development and other factors have taken their toll. The average impact assessment score was 73% (100% would be a \u27perfect\u27 score, with no problems); the median was just slightly higher at 75%. The average degradation score was 0.17 (with unity, \u271\u27, being the worst possible 1 score and \u270\u27 the best); similarly, the median was slightly better at 0.15. The image-based identification performed well in identifying marshes. Based on 2007 \u27surface truth\u27 provided by the boat transects, the image delineation (from 2003 imagery) identified between 50% and 70% (depending on the radius of tolerance used to define detection of a single marsh) of the marshes. When changes to the marshes over time are considered, this reflects favorably on its use. The marshes identified can serve as a basis for further efforts to find, assess, improve, and protect marshes in Casco Bay

Maine\u27s Salt Marshes: Their Functions, Values, and Restoration

This illustrated resource booklet for Maine residents educates the reader about the properties and functions of salt marshes. It also facilitates leadership and participation in restoration efforts by providing information for further resources

Ecological Functions And Values Of Fringing Salt Marshes Susceptible To Oil Spills In Casco Bay, Maine

Casco Bay is the largest oil port in Maine and northern New England, handling over 20 million tons of crude oil and oil products annually. The susceptibility of the Bay’s estuarine habitats, especially its fringing salt marshes, to potential spill events was the impetus for this study. Although much has been learned to date about the effects of oil spills on estuarine habitats around the world, there is a real need for site-specific knowledge of the structures and functions of local habitats so that resource managers can be prepared in the event of a spill. Our study focused specifically on the value of Casco Bay’s fringing salt marshes to shellfish and finfish production, to vegetation production and diversity, and as buffers against sea level rise and coastal erosion. The work we have accomplished has been the first study of the fringing salt marshes of Casco Bay that has explored the biotic communities (fish, invertebrates and plants) of these marshes in conjunction with the physical properties of these sites. Knowledge of these local fringing salt marsh habitats will be invaluable in improving the effectiveness of oil spill cleanup operations, accurate assessment of natural resource damages caused by spills, and the restoration of impacted sites. In addition, the data acquired in this study provide an initial set of benchmarks upon which to build a program to assess long-term change in Casco Bay tidal marsh habitats

A Comprehensive Wetland Program For Fringing Salt Marshes In The York River, Maine

The overall goal of this project was to assist the Town of York, Maine, in its efforts to monitor and protect the fringing salt marshes along the York River. In particular, the project focused on potential impacts to the marshes due to shoreline development pressures. Specific objectives included (1) gathering baseline data about the marshes (2) developing a set of indicators to be used in future monitoring, and (3) generating management recommendations

Rethinking the Freshwater Eel: Salt Marsh Trophic Support of the American Eel, Anguilla rostrata

Despite the fact that Anguilla rostrata (American eel) are frequently captured in salt marshes, their role in salt marsh food webs and the influence of human impacts, such as tidal restrictions, on this role remains unclear. To better understand salt marsh trophic support of A. rostrata, eels were collected from tidally restricted and unrestricted salt marsh creeks within three New England estuaries. Gut contents were examined, and eel muscle tissue was analyzed for carbon and nitrogen stable isotope values and entered into MixSir mixing models to understand if salt marsh food sources are important contributors to eel diet. Data suggest that eel prey rely heavily on salt marsh organic matter and eels utilize salt marsh secondary production as an energetic resource over time, and thus can be considered salt marsh residents. Gut contents indicate that A. rostrata function as top predators, feeding primarily on secondary consumers including other fish species, crustaceans, and polychaetes. Higher A. rostrata trophic position measured upstream of reference creeks suggests that severe tidal restrictions may result in altered food webs, but it is not clear how this impacts the overall fitness of A. rostrata populations in New England salt marshes.University of New Hampshire. Sea Grant ProgramUniversity of New Hampshire. Marine Program (William R. Spaulding Endowment

Expression and localization of NRF2/Keap1 signalling pathway genes in mouse preimplantation embryos exposed to free fatty acids.

Obese women experience greater incidence of infertility, with reproductive tracts exposing preimplantation embryos to elevated free fatty acids (FFA) such as palmitic acid (PA) and oleic acid (OA). PA treatment impairs mouse preimplantation development in vitro, while OA co-treatment rescues blastocyst development of PA treated embryos. In the present study, we investigated the effects of PA and OA treatment on NRF2/Keap1 localization, and relative antioxidant enzyme (Glutathione peroxidase; Gpx1, Catalase; Cat, Superoxide dismutase; Sod1 and γ-Glutamylcysteine ligase catalytic unit; Gclc) mRNA levels, during in vitro mouse preimplantation embryo development. Female mice were superovulated, mated, and embryos cultured in the presence of bovine Serum albumin (BSA) control or PA, or OA, alone (each at 100 μM) or PA + OA combined (each at 100 μM) treatment. NRF2 displayed nuclear localization at all developmental stages, whereas Keap1 primarily displayed cytoplasmic localization throughout control mouse preimplantation development in vitro. Relative transcript levels of Nrf2, Keap1, and downstream antioxidants significantly increased throughout control mouse preimplantation development in vitro. PA treatment significantly decreased blastocyst development and the levels of nuclear NRF2, while OA and PA + OA treatments did not. PA and OA treatments did not impact relative mRNA levels of Nrf2, Keap1, Gpx1, Cat, Sod1 or Gclc. Our outcomes demonstrate that cultured mouse embryos display nuclear NRF2, but that PA treatment reduces nuclear NRF2 and thus likely impacts NRF2/KEAP1 stress response mechanisms. Further studies should investigate whether free fatty acid effects on NRF2/KEAP1 contribute to the reduced fertility displayed by obese patients

Constitutive Expression of PU.1 in Fetal Hematopoietic Progenitors Blocks T Cell Development at the Pro-T Cell Stage

AbstractThe essential hematopoietic transcription factor PU.1 is expressed in multipotent thymic precursors but downregulated during T lineage commitment. The significance of PU.1 downregulation was tested using retroviral vectors to force hematopoietic precursors to maintain PU.1 expression during differentiation in fetal thymic organ culture. PU.1 reduced thymocyte expansion and blocked development at the pro-T cell stage. PU.1-expressing cells could be rescued by switching to conditions permissive for macrophage development; thus, the inhibition depends on both lineage and developmental stage. An intact DNA binding domain was required for these effects. PU.1 expression can downregulate pre-Tα, Rag-1, and Rag-2 in a dose-dependent manner, and higher PU.1 levels induce Mac-1 and Id-2. Thus, downregulation of PU.1 is specifically required for progression in the T cell lineage

Experimental and Natural Warming Elevates Mercury Concentrations in Estuarine Fish

Marine food webs are the most important link between the global contaminant, methylmercury (MeHg), and human exposure through consumption of seafood. Warming temperatures may increase human exposure to MeHg, a potent neurotoxin, by increasing MeHg production as well as bioaccumulation and trophic transfer through marine food webs. Studies of the effects of temperature on MeHg bioaccumulation are rare and no study has specifically related temperature to MeHg fate by linking laboratory experiments with natural field manipulations in coastal ecosystems. We performed laboratory and field experiments on MeHg accumulation under varying temperature regimes using the killifish, Fundulus heteroclitus. Temperature treatments were established in salt pools on a coastal salt marsh using a natural temperature gradient where killifish fed on natural food sources. Temperatures were manipulated across a wider range in laboratory experiments with killifish exposed to MeHg enriched food. In both laboratory microcosms and field mesocosms, MeHg concentrations in killifish significantly increased at elevated temperatures. Moreover, in field experiments, other ancillary variables (salinity, MeHg in sediment, etc.) did not relate to MeHg bioaccumulation. Modeling of laboratory experimental results suggested increases in metabolic rate as a driving factor. The elevated temperatures we tested are consistent with predicted trends in climate warming, and indicate that in the absence of confounding factors, warmer sea surface temperatures could result in greater in bioaccumulation of MeHg in fish, and consequently, increased human exposure