Pleistocene glaciation events shape genetic structure across the range of the American lobster, Homarus americanus

A north/south discontinuity along the northeastern coast of North America in the genetic structure of the American lobster (Homarus americanus) was detected using a suite of 13 microsatellite loci assessed using spatial analyses. Population genetic data laid over existing data on physiographic changes and sea-surface temperatures were used to reconstruct the Pleistocene distribution of this species. A postglacial northern-edge colonization model best explains the relative genetic homogeneity of the northern region compared to the southern region centred in the Gulf of Maine. Population genetic analyses identified significant structure (range of standardized theta 0-0.02) but no significant evidence for isolation by distance. The novel application of spatial genetic analyses to a marine species allowed us to interpret these results by providing a greater insight into the evolutionary factors responsible for shaping the genetic structure of this species throughout is natural range.

Phocine distemper virus in seals, East Coast, United States, 2006

In 2006 and 2007, elevated numbers of deaths among seals, constituting an unusual mortality event, occurred off the coasts of Maine and Massachusetts, United States. We isolated a virus from seal tissue and confirmed it as phocine distemper virus (PDV). We compared the viral hemagglutinin, phosphoprotein, and fusion (F) and matrix (M) protein gene sequences with those of viruses from the 1988 and 2002 PDV epizootics. The virus showed highest similarity with a PDV 1988 Netherlands virus, which raises the possibility that the 2006 isolate from the United States might have emerged independently from 2002 PDVs and that multiple lineages of PDV might be circulating among enzootically infected North American seals. Evidence from comparison of sequences derived from different tissues suggested that mutations in the F and M genes occur in brain tissue that are not present in lung, liver, or blood, which suggests virus persistence in the central nervous system.

City visioning and the turn to community:The case of Derry/Londonderry

In the 1980s, urban re-imaging and place marketing were vital elements in the strategies of post-industrial cities aiming to redefine their role, make themselves more competitive and attract global investment and tourists. By the early 1990s, the questionable effects of trickle-down economics on deprived housing estates and the rediscovery of the 'community' as a social partner shifted both the substance and process of vision exercises. This paper examines the experience of building an input into a city vision that aimed to address social and ethno-religious segregation in Derry/Londonderry. Designing a consensus statement for a city that cannot agree its name, was wrecked by bloody violence and has its hinterland fractured by a contested international border, is a difficult and delicate process. The city had a population of 105 800 people in 1998, but is divided by the river Foyle between the mainly Catholic Cityside (to the north and west) and the mainly Protestant Waterside (to the south and east). The analysis connects with the literature on urban policy that emphasises the importance of argumentation and democratic debate in strategic planning and local regeneration (Forester, 1989; Healey, 1996). The paper concludes by arguing that strategies for 'listening' would help to shape a vision that could mobilise community interests around some common urban regional issues and help to promote social and ethno-religious polarisation as mainstream policy concerns.

Exceptionally Long Distance Transport of Volcanic Ash: Implications for Stratigraphy, Hazards and the Sourcing of Distal Tephra Deposits

Cryptotephras (tephra not visible to the naked eye) form the foundation of the tephrostratigraphic frameworks used in Europe to date and correlate widely distributed geologic, paleoenvironmental and archaeological records. Pyne-O'Donnell et al. (2012) established the potential for developing a similar crypto-tephrostratigraphy across eastern North America by identifying multiple tephra, including the White River Ash (east; WRAe), St. Helens We and East Lake, in a peat core located in Newfoundland. Following on from this work, several ongoing projects have examined additional peat cores from Michigan, New York State, Maine, Nova Scotia and Newfoundland to build a tephrostratigraphic framework for this region. Using the precedent set by recent research by Jensen et al.(in press) that correlated the Alaskan WRAe to the European cryptotephra AD860B, unknown tephras identified in this work were not necessarily assumed to be from "expected" source areas (e.g. the Cascades). Here we present several examples of the preservation of tephra layers with an intercontinental distribution (i.e. WRAe and Ksudach 1), from relatively small magnitude events (i.e. St. Helens layer T, Mono Crater), and the first example of a Mexican ash in the NE (Volcan Ceboruco, Jala pumice). There are several implications of the identification of these units. These far-travelled ashes: (1) highlight the need to consider "ultra" distal source volcanoes for unknown cryptotephra deposits,. (2) present an opportunity for physical volcanologists to examine why some eruptions have an exceptional distribution of ash that is not necessarily controlled by the magnitude of the event. (3) complicate the idea of using tephrostratigraphic frameworks to understand the frequency of eruptions towards aiding hazard planning and prediction (e.g. Swindles et al., 2011). (4) show that there is a real potential to link tropical and mid to high-latitude paleoenvironmental records. Jensen et al. (in press) Transatlantic correlation of the Alaskan White River Ash. Geology. Pyne-O'Donnell et al. (2012). High-precision ultra-distal Holocene tephrochronology in North America. Quaternary Science Reviews, 52, 6-11. Swindles et al. (2011). A 7000 yr perspective on volcanic ash clouds affecting northern Europe. Geology, 39, 887-890.

A mid to late Holocene cryptotephra framework from eastern North America

Holocene cryptotephras of Alaskan and Pacific Northwestern origin have recently been detected ca. 7000 km away on the east coast of North America. This study extends the emerging North American tephrochronological framework by geochemically characterising seventeen cryptotephra layers from four newly explored peatlands. All detected tephras were deposited during the late Holocene, with no horizons present in the peat between ca. 3000–5000 years ago. The prevalence of the Alaskan White River Ash eastern lobe (AD 847 ± 1) is confirmed across the eastern seaboard from Newfoundland to Maine and a regional depositional pattern from Mount St Helens Set W (AD 1479–1482) is presented. The first occurrences of four additional cryptotephras in eastern North America are described, three of which may originate from source regions in Mexico, Kamchatka (Russia) and Hokkaido (Japan). The possibility of such tephras reaching eastern North America presents the opportunity to link palaeo-archives from the tropics and eastern Asia with those from the western Atlantic seaboard, aiding inter-regional comparisons of proxy-climatic records.

Genetic structure of the lumpfish Cyclopterus lumpus across the North Atlantic

Lumpfish, or lumpsucker, Cyclopterus lumpus (Linnaeus, 1758) is widely distributed in the North Atlantic Ocean. It has a considerable economic value and substantial fisheries occur in several North Atlantic regions owing to the use of its fully ripe internal egg masses in the ovaries as an alternative to sturgeon caviar. Despite being intensively fished in several locations, biological knowledge is limited and no genetic structure information is available. In this study, the stock structure of C. lumpus was investigated across the North Atlantic using ten microsatellite loci. Out of ten loci, two exhibited higher level of differentiation but their inclusion/ exclusion from the analyses did not drastically change the observed genetic pattern. A total of three distinct genetic groups were detected: Maine-Canada-Greenland, Iceland-Norway and Baltic Sea. These results, discussed in terms of origin of differentiation, gene flow, and selection, showed that gene flow was rather limited among the detected groups, and also between Greenland and Maine-Canada.