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The Gulf of Maine has undergone dramatic physiographic and oceanographic changes over the last several millenia resulting in some unusual biogeographic consequences. One is that there are pockets of Virginian species, including Crassostra virginica (Eastern Oyster), that survive in isolated warm water pockets, usually at the heads of estuaries. These small and vulnerable populations need documentation, protection, and restoration in order to preserve their genetic characteristics and ecological services. In this contribution, we describe the circumstances whereby tidal restoration made available 2.5 linear km of new habitat area to the relict oyster population of the Marsh River, ME, the northernmost documented native oyster population in the United States. Oysters recruited to the new habitat quickly, demonstrating the restoration potential of isolated, relict populations. The resultant larger population size and areal extent should provide increased stability and survivability of the oyster and its associated community. These observations have implications for both the restoration potential of relict oyster populations and the consequences of climate change. [ABSTRACT FROM AUTHOR]

Abstract: Previous investigations suggest that contaminant transport from the large Kennebec/Androscoggin watershed is an important large-scale process in mid-coast Maine. To investigate this phenomenon, we determined the concentrations of Cd, Cr, Cu, Ni, Pb, Sn and Zn in the surface sediments of 47 stations in the tidal Kennebec/Androscoggin system. Most stations exhibited elevated metal concentrations. Highest levels were found in the main stem of the system. Distribution patterns lead to the conclusion that metals enter the system from the watershed and are transported to the nearshore Gulf of Maine. The coarse-grained, ebb tide dominated flow prevents the accumulation of contaminants in the estuary. This supports the hypothesis of that the Kennebec and Androscoggin watersheds are sources for contaminants observed in the nearshore Gulf of Maine. [ABSTRACT FROM AUTHOR]

Increasingly, remote sensing has become a useful tool for mapping and measuring terrestrial and aquatic environments. Advances in the spatial and spectral resolution of satellite-borne sensors have allowed affordable investigations of littoral macrotidal coastal systems that previously required more costly aircraft-based imagery. In this communication, we compare the results from analysis of a 4 m spatial resolution, multispectral IKONOS satellite image of the intertidal habitats of Islesboro, Maine, USA with that of an aerial compact airborne spectral imager survey of the same regions captured 4 years earlier. There was 72% agreement between the surveys in spite of the temporal gaps between the images. Accuracy varied by habitat class and the perceived error can be assigned to temporal and definitional issues rather than basic acquisition and analytic protocols. Most of the error can be explained by: (1) inadequacy of training sites, (2) temporal variations and (3) class definitions. We conclude that IKONOS imagery provides sufficient spatial and spectral resolution to map and monitor diverse intertidal habitats as found in the macrotidal Gulf of Maine. [ABSTRACT FROM AUTHOR]

In the mid-1990s, an interdisciplinary, multi-institutional team of scientists was assembled to address basic issues concerning biological productivity and the unique co-occurrence of many unusual ecological features in Cobscook Bay, ME. Cobscook Bay is a geologically complex, macrotidal system located on the international border at the mouth of the Bay of Fundy. The strategy adopted by the scientific team was to synthesize the known information on Cobscook Bay, focus new field research on information needs related to basic forcing functions and biological primary productivity, and organize the information in an energy systems model to evaluate the flows of energy and materials through the ecosystem and relate them to the inflows of physical energy using the accounting quantity, emergy. As a consequence of this process, diverse new and existing data have been combined and analyzed, leading to new ways of thinking about the functioning of Cobscook Bay and macrotidal estuaries. The principal finding is that an extraordinary convergence of natural energies creates ideal conditions for supporting the development of ecological organization found in few, if any, other estuarine systems. In this contribution, we review the finding of the component research exercises, discuss their integration into an energy systems model and emergy analysis, and suggest a number of fruitful avenues for future research. [ABSTRACT FROM AUTHOR]

Cobscook Bay, a boreal, macrotidal estuary in the northeastern Gulf of Maine is noted for its species richness and has been the site of extensive natural history investigations. In spite of this level of investigative activity, no quantitative survey of the subtidal, macroinvertebrate communities exist. Here we present the results of a 1975 benthic grab survey of outer Cobscook Bay prior to recent salmon aquaculture and port development. The limited 11-station survey resulted in the identification of 172 taxa. Densities ranged from 870 to 12.970 m-2. Multivariate and qualitative analyses clearly dissected the station set into sandy cove stations and coarse sediment channel stations. Cove stations were characterized by burrowing and tube-dwelling infauna, while channel station fauna was epifaunal. Community distribution is controlled by strong tidal currents and resulting sharp geological discontinuities. Because 70% of the Bay bottom is floored by gravel, the epifaunal community characterizing the channel stations may be the most representative of the Bay. The grab sampler certainly underestimated large filter feeders that may be important in the nutrient budget of the Bay. Future surveys need to be more extensive and use a combination of sampling methods to quantitatively measure all components of the community. [ABSTRACT FROM AUTHOR]

Reliable estimates of the habitat areas of major marine producer groups were needed in support of an ecosystem modeling effort in the macrotidal Cobscook Bay. ME. Results needed in be comprehensive, synoptic, objective, affordable, and on a suitable spatial scale. We chose to address these goals by applying accepted procedures utilizing existing Landsat Thematic Mapper imagery and a computer-generated unsupervised classification. Unsupervised classification of high and low tide Landsat TM images yielded coherent habitat maps that were supported by reference data and independent habitat analyses. The high tide image revealed surface water patterns that supported the existence of a large. Central Bay dipole eddy predicted by a numerical three-dimensional circulation model. Classification of the low tide image resulted in 14 intertidal and water habitat classes being defined. Overall accuracy of the classification was 86%. Good agreement in habitat areas existed between the affordable and easily repeatable satellite survey and four other Cobscook Bay surveys which differed methodologically and temporally. The four studies agreed within 7% of total habitat area and 12% on intertidal habitat area. The area of both brown and green algae in the Bay apparently increased modestly over a 25-year period which saw the introduction of large-scale salmon aquaculture and the advent of intensive dragging for scallops and sea urchins. The increase in both groups is inconsistent with changes induced by nutrient additions observed elsewhere. Landsat imagery appears to be a valuable tool for the management and monitoring of macrotidal environments. [ABSTRACT FROM AUTHOR]

Cobscook Bay, a boreal, macrotidal estuary in the northeastern Gulf of Maine, is noted for its species richness. The Bay area is biogeographically complex due to present temperature regimes as well as historical, climatological, and physiographic changes since the last glaciation. Early investigators recognized the resulting zoological richness, and a significant portion of the collection and taxonomic description of North American marine fauna was centered in the northern Gulf of Maine. A compilation of the results of 19th- and 20th-century research leads to the conclusion that the Cobscook region contains the highest level of marine invertebrate biodiversity in eastern North America north of the tropics. In addition. Cobscook Bay is characterized by noteworthy biological attributes such as the intertidal occurrence of many normally subtidal species and the manifestation of giantism in several populations. These phenomena are summarized briefly as a prelude to a major ecosystem modeling effort. [ABSTRACT FROM AUTHOR]

Cobscook Bay, at the mouth of the Bay of Fundy, exhibits extraordinary natural productivity and ecological richness that has been recognized for millennia. The co-existence of so many remarkable ecological attributes is of both practical and scientific interest and has intrigued researchers for over a century. Nevertheless, the question of why this high productivity and species richness should co-occur in this mid-latitude Bay has not been addressed on an ecosystem level. A grant from the Andrew W. Mellon Foundation through The Nature Conservancy allowed an interdisciplinary, multi-institutional team of marine scientists to investigate the physical, chemical, geological, and biological dynamics of the Bay in an integrated ecosystem context. This special issue of the Northeastern Naturalist presents the results of original field research on the physical forcing functions at work in the Bay and the contributions of the principal primary producers. This knowledge is combined with historical information into an energy systems model and emergy analysis that describes the flows of materials and energy through the system and allows comparisons with other estuarine systems. [ABSTRACT FROM AUTHOR]