University of Maine

About: University of Maine is a education organization based out in Orono, Maine, United States. It is known for research contribution in the topics: Population & Ice sheet. The organization has 8637 authors who have published 16932 publications receiving 590124 citations. The organization is also known as: University of Maine at Orono.

Surface Deformations as Indicators of Deep Ebullition Fluxes in a Large Northern Peatland

Abstract: [1] Peatlands deform elastically during precipitation cycles by small (±3 cm) oscillations in surface elevation. In contrast, we used a Global Positioning System network to measure larger oscillations that exceeded 20 cm over periods of 4–12 hours during two seasonal droughts at a bog and fen site in northern Minnesota. The second summer drought also triggered 19 depressuring cycles in an overpressured stratum under the bog site. The synchronicity between the largest surface deformations and the depressuring cycles indicates that both phenomena are produced by the episodic release of large volumes of gas from deep semi-elastic compartments confined by dense wood layers. We calculate that the three largest surface deformations were associated with the release of 136 g CH4 m−2, which exceeds by an order of magnitude the annual average chamber fluxes measured at this site. Ebullition of gas from the deep peat may therefore be a large and previously unrecognized source of radiocarbon depleted methane emissions from northern peatlands.

Registered Replication Report: Schooler and Engstler-Schooler (1990)

Abstract: Trying to remember something now typically improves your ability to remember it later. However, after watching a video of a simulated bank robbery, participants who verbally described the robber were 25% worse at identifying the robber in a lineup than were participants who instead listed U.S. states and capitals—this has been termed the “verbal overshadowing” effect (Schooler & Engstler-Schooler, 1990). More recent studies suggested that this effect might be substantially smaller than first reported. Given uncertainty about the effect size, the influence of this finding in the memory literature, and its practical importance for police procedures, we conducted two collections of preregistered direct replications (RRR1 and RRR2) that differed only in the order of the description task and a filler task. In RRR1, when the description task immediately followed the robbery, participants who provided a description were 4% less likely to select the robber than were those in the control condition. In RRR2, when the description was delayed by 20 min, they were 16% less likely to select the robber. These findings reveal a robust verbal overshadowing effect that is strongly influenced by the relative timing of the tasks. The discussion considers further implications of these replications for our understanding of verbal overshadowing.

Metabolism of Trimethylamine, Choline, and Glycine Betaine by Sulfate-Reducing and Methanogenic Bacteria in Marine Sediments

Abstract: The response of methanogenesis and sulfate reduction to trimethylamine, choline, and glycine betaine was examined in surface sediments from the intertidal region of Lowes Cove, Maine Addition of these substrates markedly stimulated methanogenesis in the presence of active sulfate reduction, whereas addition of other substrates, including glucose, acetate, and glycine, had no effect on methane production Sulfate reduction was stimulated simultaneously with methanogenesis by the various quaternary amines and all other substrates examined Incubation of exogenous trimethylamine, choline, or glycine betaine with either bromoethane sulfonic acid or sodium molybdate was used to establish pathways of degradation of the substrates Methanogenesis dominated the metabolism of trimethylamine, although limited nonmethanogenic activity, perhaps by sulfate-reducing bacteria, was observed Acetate was oxidized primarily by sulfate reducers Both choline and glycine betaine were fermented stoichiometrically to acetate and trimethylamine; apparently, neither substrate could be utilized directly by methanogens or sulfate reducers, and the activities of fermenters, methanogens, and sulfate reducers were all required to effect complete mineralization These observations support the hypothesis that the presence of quaternary amines can mediate the coexistence of sulfate reduction and methanogenesis in marine surface sediments; they also implicate methanogens in the nitrogen cycle of marine sediments containing quaternary amines

Landscape Ecology Approaches to Wetland Species Conservation: a Case Study of Two Turtle Species in Southern Maine

Abstract: We investigated the habitat use and movements of two turtle species to assess the importance of conserving multiple wetlands and the upland matrix in which they occur. Spotted turtles ( Clemmys guttata) and Blanding's turtles ( Emydoidea blandingii) are considered threatened and endangered, respectively, in Maine where they are near the northeastern periphery of their geographic range. We used resightings of marked individuals (69 spotted, 16 Blanding's) and radiotelemetry (13 spotted, 9 Blanding's, radiotagged for one or two seasons) to investigate the movements and habitat use of both species. Individuals of both species used multiple wetlands throughout the year, including permanent and seasonal pools, forested swamps, and wet meadows. Pools occupied by spotted and Blanding's turtles were small (<0.4 ha), and they were less isolated from other wetlands than pools that did not contain turtles. Both species used uplands extensively for nesting, dormancy, and traveling between wetlands. Turtles traveled 70–570 m (spotted) and 100–1620 m ( Blanding's) to nest, and nests were located 1–120 m (spotted) and 70–410 m ( Blanding's) from the nearest wetland. Spotted and Blanding's turtles entered relatively dormant stages for 15–89 and 3–21 consecutive days, respectively, and upland dormancy sites were 12–80 m (spotted) and 30–110 m ( Blanding's) from the nearest wetland. Total distance traveled overland throughout a season was 0–1680 m and 0–6760 m for radiotagged spotted and Blanding's turtles, respectively. Most spotted turtles followed a seasonal pattern of habitat use: pools for spring activity, upland forest for relative dormancy during part of the summer, and wet meadows or forested swamps for overwintering. A seasonal pattern in the habitat use of Blanding's turtles was not as evident. Our study suggests that protecting small wetlands, maintaining generous terrestrial buffers around individual wetlands, and conserving wetlands in groups are important components of a landscape approach to species conservation. Resumen: Investigamos el uso de habitat y los movimientos de dos especies de tortugas para evaluar la importancia de conservar multiples humedales y la matriz terrestre en la que ocurren. Tortugas manchadas (Clemmys guttata) y tortugas de Blanding ( Emydoidea blandingii) estan consideradas como amenazadas y en peligro, respectivamente, en Maine donde se encuentran cerca de la periferia noreste de su rango geografico. Utilizamos reavistamientos de individuos marcados (69 manchadas, 16 de Blanding ) y radiotelemetria (13 manchadas, 9 de Blanding, radiomarcadas por 1-2 temporadas) para investigar los movimientos y uso de habitat de ambas especies. Los individuos de ambas especies utilizaron multiples humedales a lo largo del ano incluyendo charcas permanentes y temporales, cienagas boscosas y praderas inundadas. Las charcas ocupadas por tortugas manchadas y de Blanding fueron pequenas (<4 ha), y estaban menos aisladas de los demas humedales que no contenian tortugas. Ambas especies usaron terrenos elevados extensivamente para anidar, para los periodos de aletargamiento, para moverse entre humedales. Las tortugas viajaron entre 50 y 570 m (manchadas) y entre 100 y 1620 m (de Blanding ) para anidar, y los nidos se localizaron entre 1 y 120 m (manchadas) y entre 70 y 410 m (de Blanding ) del humedal mas cercano. Las tortugas manchadas y de Blanding entraron en etapas relativo de letargo por 15-89 y 3-21 dias consecutivos, respectivamente, y los sitios de letargo estaban entre 12 y 80 m (manchadas) y 30 y 110 m (de Blanding ) del humedal mas cercano. La distancia total recorrida en tierra en una temporada vario entre 0 y 1680 m y entre 0 y 6760 m para las tortugas manchadas y de Blanding radiomarcadas respectivamente. La mayoria de las tortugas manchadas tuvieron un patron estacional de uso del habitat: charcas para la actividad de primavera, bosque elevado cuando la etapa en letargo la etapa de lefargo relativo durante parte del verano y praderas inundadas o cienagas boscosas durante el invierno. En los movimientos de la tortuga de Blanding no fue evidente un patron estacional de uso de habitat. Nuestro estudio sugiere que la proteccion de humedales pequenos, la presencia de amortiguadores terrestres alrededor de los humedales y la conservacion de humedales en grupos son componentes importantes de una aproximacion de paisaje a la conservacion de especies.