University of North Carolina at Wilmington

About: University of North Carolina at Wilmington is a education organization based out in Wilmington, North Carolina, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 3329 authors who have published 6797 publications receiving 186308 citations.

Climate‐induced changes in the suitable habitat of cold‐water corals and commercially important deep‐sea fishes in the North Atlantic

Abstract: The deep sea plays a critical role in global climate regulation through uptake and storage of heat and carbon dioxide. However, this regulating service causes warming, acidification and deoxygenation of deep waters, leading to decreased food availability at the seafloor. These changes and their projections are likely to affect productivity, biodiversity and distributions of deep-sea fauna, thereby compromising key ecosystem services. Understanding how climate change can lead to shifts in deep-sea species distributions is critically important in developing management measures. We used environmental niche modelling along with the best available species occurrence data and environmental parameters to model habitat suitability for key cold-water coral and commercially important deep-sea fish species under present-day (1951-2000) environmental conditions and to project changes under severe, high emissions future (2081-2100) climate projections (RCP8.5 scenario) for the North Atlantic Ocean. Our models projected a decrease of 28%-100% in suitable habitat for cold-water corals and a shift in suitable habitat for deep-sea fishes of 2.0°-9.9° towards higher latitudes. The largest reductions in suitable habitat were projected for the scleractinian coral Lophelia pertusa and the octocoral Paragorgia arborea, with declines of at least 79% and 99% respectively. We projected the expansion of suitable habitat by 2100 only for the fishes Helicolenus dactylopterus and Sebastes mentella (20%-30%), mostly through northern latitudinal range expansion. Our results projected limited climate refugia locations in the North Atlantic by 2100 for scleractinian corals (30%-42% of present-day suitable habitat), even smaller refugia locations for the octocorals Acanella arbuscula and Acanthogorgia armata (6%-14%), and almost no refugia for P. arborea. Our results emphasize the need to understand how anticipated climate change will affect the distribution of deep-sea species including commercially important fishes and foundation species, and highlight the importance of identifying and preserving climate refugia for a range of area-based planning and management tools.

Flow dynamics and sedimentation in spartina alterniflora and phragmites australis marshes of the chesapeake bay

Abstract: The introduction of invasive species such as Phragmites australis in the Chesapeake Bay has been viewed to be deleterious to habitat quality. Little is known, however, on the extent to which the replacement of Spartina alterniflora by Phragmites affects hydrodynamics and sediment trapping on the surface of impacted marshes. This study examined sediment deposition, sediment mobility, and flow conditions in adjacent Phragmites australis and Spartina alternifora marshes in Prospect Bay, Maryland, USA in order to determine if differences in plant morphology affect surficial flow properties and particle dispersion patterns. Measures of fine-scale flow dynamics, total suspended sediment (TSS) concentration, and particulate deposition were obtained at various distances from open water across the marsh surface over four sequential tidal cycles in Fall 1999. The hydrodynamic data indicate that both the gross and fine-scale properties of tidal flows were similar in both types of vegetation and that flow conditions were conductive to particle deposition. TSS concentrations did not differ between canopy types and decreased over time in both systems. There was no difference in TSS reduction over distance between Spartina and Phragmites. The sediment trap data indicate that maximum deposition occurs closer to open water in both Spartina and Phragmites and that the organic content of deposited matter increased with distance into the marsh interior. This study provides the first in situ, high resolution, over-marsh flow data for marshes dominated by Phragmites. The data provided herein suggest that differences in vegetative cover do not significantly affect flow regime, sediment transport, and sediment deposition patterns in the marsh systems examined.

Rainfall stimulation of primary production in western Atlantic Ocean waters:roles of different nitrogen sources and co-limiting nutrients

Abstract: Using shipboard bioassays, we examined the roles rainfall, individual and combined nutrients play in accelerating primary production in coastal, Gulf Stream and pelagic (Sargasso Sea) locations in the North Atlantic Ocean off North Caroli.na, USA, from 1993 to 1995. Photosynthetic CO, fixation and net chlorophyll a (chl a) production were measured In replicated bioassays to assess individual and combined impacts of d~fferent constituents of atmospheric deposition, including natural rainfall, a synthetic rain mix, dissolved inorganic nitrogen (DIN; NH,', NO3-), dssolved organlc nitrogen (DON; urea), phosphorus (POA3-) and iron (as EDTA-chelated and unchelated FeC13). Natural rainfall and DIN additions most often stimulated CO2 fixation and chl a production, but frequencies and magnitudes of biostimulation, relative to controls, varied between these indicators. Spatial differences in the types and magnitudes of stimulation were also observed. When added in equimolar amounts, NH.,' was, at times, more stimulatory than NO<. The NOT stimulation was significantly enhanced by Fe-EDTA. Urea was marginally stimulatory at the coastal location. Pod3was never stimulatory. Fe-EDTA and EDTA by themselves stimulated production only at the offshore locations, suggesting increased Fe limitation with increasing distance from land. Synthetic rain, which contained both sources of DIN, but not Fe, generally proved less stimulatory per unit N than natural rainfall. Results lndlcate a broad sensitivity of these waters to N additions, which in the case of NOT are enhanced by Fe-EDTA. At all locations, the h ~ g h level of stimulation of primary production attributable to natural rain may be due to the supply of both DIN and CO-limiting nutnents (e.g. Fe), contributing to the eutroph~cation potential of waters downwind of urban, industrial and agricultural emissions.

Who is left out: exploring social boundaries in entrepreneurial ecosystems

Abstract: This study attempts to develop our understanding of the ecosystem as a complex social construct by advancing a social network perspective. Based on personal interviews we model the entrepreneurial ecosystems of two municipalities through a diverse network of entrepreneurs, investors, and institutional leaders. The two ecosystems were characterized and compared on measures related to the level of connectivity between actors, the existence of social boundaries, the role and position of actors with certain attributes (e.g. women, minorities) and the presence of ties in multiple social contexts (e.g. friend and investor). Our results suggest that entrepreneurial ecosystems consist of different social clusters, forming boundaries along venture type (e.g. high-growth, lifestyle), type of support institution (e.g. university, government agency), gender, race, and ethnicity. High-growth/technology entrepreneurs, for example, were predominantly white, male and strongly connected to technology commercialization and acceleration programs. In contrast, entrepreneurs operating survival ventures are mainly non-white, female and often socially disconnected from the main institutions. We also found differences with respect to network connectivity between stakeholders in both ecosystems. Based on our findings, we draw managerial implications for different stakeholders of the entrepreneurial ecosystem.

Evidence for a transgressive barrier within a regressive strandplain system: Implications for complex coastal response to environmental change

Abstract: Clastic, depositional strandplain systems have the potential to record changes in the primary drivers of coastal evolution: climate, sea-level, and the frequency of major meteorological and oceanographic events This study seeks to use one such record from a southern Brazilian strandplain to highlight the potentially-complex nature of coastal sedimentological response to small changes in these drivers Following a 2 to 4 m highstand at ca 5·8 ka in southern Brazil, falling sea-level reworked shelf sediment onshore, forcing coastal progradation, smoothing the irregular coastline and forming the 5 km wide Pinheira Strandplain, composed of ca 500 successive beach and dune ridges Sediment cores, grab samples and >11 km of ground-penetrating radar profiles reveal that the strandplain sequence is composed of well-sorted, fine to very-fine quartz sand Since the mid-Holocene highstand, the shoreline prograded at a rate of ca 1 to 2 m yr−1 through the deposition of a 4 to 6 m thick shoreface unit; a 1 to 3 m thick foreshore unit containing ubiquitous ridge and runnel facies; and an uppermost beach and foredune unit However, the discovery of a linear, 100 m wide barrier ridge with associated washover units, a 3 to 4 m deep lagoon and 250 m wide tidal inlet within the strandplain sequence reveals a period of shoreline transgression at 3·3 to 2·8 ka during the otherwise regressive developmental history of the plain The protected nature of Pinheira largely buffered it from changes in precipitation patterns, wave energy and fluvial sediment supply during the time of its formation However, multiple lines of evidence indicate that a change in the rate of relative sea-level fall, probably due to either steric or ice-volume effects, may have affected this coastline Thus, whereas these other potential drivers cannot be fully discounted, this study provides insights into the complexity of decadal-scale to millennial-scale coastal response to likely variability in sea-level change rates