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.

East Antarctic Ice Sheet sensitivity to Pliocene climatic change from a Dry Valleys perspective

Abstract: A case is made for the stability of the East Antarctic Ice Sheet during Pliocene time from landscape development and surficial sediments in the Dry Valleys sector of the Transantarctic Mountains. T...

Global quieting of high-frequency seismic noise due to COVID-19 pandemic lockdown measures.

Abstract: Human activity causes vibrations that propagate into the ground as high-frequency seismic waves. Measures to mitigate the coronavirus disease 2019 (COVID-19) pandemic caused widespread changes in human activity, leading to a months-long reduction in seismic noise of up to 50%. The 2020 seismic noise quiet period is the longest and most prominent global anthropogenic seismic noise reduction on record. Although the reduction is strongest at surface seismometers in populated areas, this seismic quiescence extends for many kilometers radially and hundreds of meters in depth. This quiet period provides an opportunity to detect subtle signals from subsurface seismic sources that would have been concealed in noisier times and to benchmark sources of anthropogenic noise. A strong correlation between seismic noise and independent measurements of human mobility suggests that seismology provides an absolute, real-time estimate of human activities.

The kinematic and hydrographic structure of the Gulf of Maine Coastal Current

Abstract: The Gulf of Maine Coastal Current (GMCC), which extends from southern Nova Scotia to Cape Cod Massachusetts, was investigated from 1998 to 2001 by means of extensive hydrographic surveys, current meter moorings, tracked drifters, and satellite-derived thermal imagery. The study focused on two principal branches of the GMCC, the Eastern Maine Coastal Current (EMCC) that extends along the eastern coast of Maine to Penobscot Bay, and the Western Maine Coastal Current (WMCC) that extends westward from Penobscot Bay to Massachusetts Bay. Results confirm that GMCC is primarily a pressure gradient-driven system with both principal branches increasing their transport in the spring and summer due to fresh-water inflows, and flowing southwestward against the mean wind forcing during this period. In the spring and summer the subtidal surface currents in the EMCC range from 0.15 to 0.30 ms 1 while subtidal WMCC currents range from 0.05 to 0.15 ms 1 . The reduction of southwestward transport near Penobscot Bay is accomplished via an offshore veering of a variable portion of the EMCC, some of which recirculates cyclonically within the eastern Gulf of Maine. The degree of summer offshore veering, versus leakage into the WMCC, varied strongly over the three study years, from nearly complete disruption in 1998 to nearly continuous through-flow in 2000. Observations show strong seasonal and interannual variability in both the strength of the GMCC and the degree of connectivity of its principal branches. r 2005 Elsevier Ltd. All rights reserved.

Effect of varying feedstock-pretreatment chemistry combinations on the formation and accumulation of potentially inhibitory degradation products in biomass hydrolysates.

Abstract: A variety of potentially inhibitory degradation products are produced during pretreatment of lignocellulosic biomass. Qualitative and quantitative interrogation of pretreatment hydrolysates is paramount to identifying potential correlations between pretreatment chemistries and microbial inhibition in downstream bioconversion processes. In the present study, corn stover, poplar, and pine feedstocks were pretreated under eight different chemical conditions, which are representative of leading pretreatment processes. Pretreatment processes included: 0.7% H(2)SO(4), 0.07% H(2)SO(4), liquid hot water, neutral buffer solution, aqueous ammonia, lime, lime with oxygen pressurization, and wet oxidation. Forty lignocellulosic degradation products resulting from pretreatment were analyzed using high performance liquid chromatography in combination with UV spectroscopy or tandem mass spectrometry detection (HPLC-PDA-MS/MS) and ion chromatography (IC). Of these compounds, several have been reported to be inhibitory, including furfural, hydroxymethyl furfural, ferulic acid, 3,4-dihydroxybenzaldehyde, syringic acid among others. Formation and accumulation of monitored compounds in hydrolysates is demonstrated to be a function of both the feedstock and pretreatment conditions utilized.

Climate change and moving species: furthering the debate on assisted colonization.

Abstract: With global climate change looming large in the public psyche, the recent paper by McLachlan et al. (2007) and its popular accompaniment (Fox 2007) are timely indeed. Of course some conservation biologists will not wish to think about the prospect of actively moving species that are threatened with extinction by climate change. For them this would be almost analogous to handing out placebos in the midst of an epidemic and worse yet, these placebos may have serious unintended consequences if translocated species become invasive. They will probably argue that we should focus almost exclusively on two central roles for conservation biology: (1) facilitating natural range shifts by redoubling efforts to maintain or restore large-scale connectivity (Hunter et al. 1988; Hannah et al. 2002) and (2) working with our fellow environmental professionals to avoid carbon-management solutions that will have unacceptable consequences for biodiversity (e.g., by directing biofuel production away from sites that would involve the conversion of native vegetation into fuel farms; Cook & Beyea 2000). These two roles will be very demanding, but I believe we should allocate a small portion of our attention to the issue of assisted colonization that McLachlan et al. (2007) have brought to the fore. McLachlan et al. propose framing the debate around two considerations—perception of risk and confidence in ecological understanding—that can be construed to generate an axis or continuum from scientists who would strongly support assisted colonization to those who would oppose it. I think it is useful to advance this exercise by considering three issues that can also be construed as continua: species that are more or less acceptable to translocate, sites that are more or less acceptable for receiving translocations, and projects that are more or less acceptable because of their socioeconomic ramifications and feasibility. I have used the term assisted colonization in contrast to assisted migration used by McLachlan et al.