The respiratory environment of the Namib Desert Golden Mole     

Roger S. Seymour  Mary K. Seely 《Journal of Arid Environments》1996,32(4):453-461

We measured the partial pressure of oxygen (PO₂) in the interstitial gas surrounding the sand-swimming Namib moleEremitalpa granti namibensis. At a sand temperature of 26 °C, which produced a nearly maximal rate of oxygen consumption, thePO₂near the noses of the animals averaged only 0·9 kPa (6·7 Torr) below the level in the free atmosphere. High oxygen availability was a result of the notably low metabolic rate in the 20 g mammals and the dry, porous and metabolically inactive nature of dune sand. A mathematical model indicated that normal mammals weighing 200 g or more could comfortably exist completely encased in dune sand. We concluded that the moles' small size and low metabolic rate are not adaptations to hypoxia or hypercapnia underground but are probably related to low food availability and the energetic cost of foraging in their desert environment.  相似文献   

Data buoy measurements of phytoplankton dynamics in southampton water, UK, a temperate latitude estuary with high nutrient inputs     

Paul N. Wright  David J. Hydes  Mary Lou Lauria  Jonathan Sharples  Duncan A. Purdie 《Ocean Dynamics》1997,49(2-3):203-211

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To Be or Not to Be…     

Mary P. Anderson 《Ground water》2004,42(1):1-1

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Advection Within Shallow Pore Waters of a Coastal Lagoon, Florida   总被引：2，自引：0，他引：2  

Jaye E. Cable  Jonathan B. Martin  Peter W. Swarzenski  Mary K. Lindenberg  Joel Steward 《Ground water》2004,42(7):1011-1020

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Viruses as potential regulators of regional brown tide blooms caused by the alga,Aureococcus anophagefferens     

Mary Downes Gastrich  Justine A. Leigh-Bell  Christopher J. Gobler  O. Roger Anderson  Steven W. Wilhelm  Martha Bryan 《Estuaries and Coasts》2004,27(1):112-119

Blooms of the brown tide organismAureccoccus anophagefferens have recurred in the coastal bays in New Jersey since 1995 and in the coastal bays of Long Island since 1985. Intracellular viral-like particles (VLPs) were documented during 1999–2000 brown tide blooms in Little Egg Harbor, New Jersey, but it was not determined whether cells were infected during the termination of the bloom. The objective of this study was to determine if VLPs infected and lysed natural populations ofA. anophagefferens in coastal bays of New Jersey and New York in 2002 with the same frequency as in 1999–2000 and especially at the termination of the bloom. Our results confirmed that the highest percentage (37.5%) of VLP-infected cells occurred at the termination of the brown tide bloom in New Jersey in 2002. Intracellular VLPs were present throughout the bloom event. The percentage of visibly infected cells was higher at the beginning of the bloom than during the peak of the bloom. The intracellular VLPs in natural populations ofA. anophagefferens were consistent in size and shape (approximately 140 nm in diameter) and comparable to those in previous studies. Concentrated viral isolates, prepared from waters during brown tide blooms in New York and New Jersey in 2002, infected healthy laboratoryA. anophagefferens cultures in vitro. The viral isolates associated with the highest laboratory viral activity (lysis positive) were concentrated from water samples having the highest viral and bacteria concentrations. The intracellular viruses in these virally infected laboratory cultures ofA. anophagefferens were similar in size and shape to those found in natural populations. The successful isolation of a virus specific toA. anophagefferens from a brown tide bloom in the field, the similarity of ultrastructure of VLPs infecting both natural populations and laboratory infected cultures, and the pattern of VLP infection during bloom activity in combination with the observed high percentage of VLP-infected cells during bloom termination, supports, the hypothesis that viruses may be a major source of mortality for brown tide blooms in regional coastal bays of New Jersey and New York.  相似文献   

A Comparison of Public Lands and Farmlands for Grassland Bird Conservation     

Mary Ann Cunningham 《The Professional geographer》2005,57(1):51-65

Midwestern states have invested extensively in grasslands for wildlife conservation, yet these public lands make up a minority of grassland habitat. How effective are public grasslands, relative to private lands, for conserving native songbird populations? I compare private and public lands in southern Minnesota using bird survey data from Conservation Reserve Program (CRP) fields and public lands and assessing fragmentation in a GIS. Bird abundance and diversity were greater on CRP lands. Vegetation composition, field isolation, and field size appear to explain differences in bird counts. Land cover data show that grassland habitat on public lands is scarce and widely scattered. The CRP provides more, and here better, habitat for grassland birds. Funding partly explains this disparity. Trends in farm set‐aside program rules and distribution, which can be vary greatly over time, will strongly influence the success or failure of biodiversity conservation in this region.  相似文献   

Repositioning ourselves     

Robin Kearns  Scott Nichol  Mary Flaws Editors 《New Zealand geographer》2005,61(1):1-2

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A tree‐ring width based drought reconstruction for southeastern China: links to Pacific Ocean climate variability          下载免费PDF全文

Feng Chen  Shulong Yu  Yujiang Yuan  Huiqin Wang  Mary Gagen 《Boreas: An International Journal of Quaternary Research》2016,45(2):335-346

We present a drought reconstruction for southeastern China based on a tree‐ring width chronology of Cryptomeria fortunei developed from two sampling sites in central Fujian. A reconstruction of July–February drought variability, spanning AD 1855–2011, was developed by calibrating total tree‐ring width data with the self‐calibrating Palmer drought severity index (scPDSI). The reconstruction was verified against an independent data set, and accounts for 36% of the actual scPDSI variance during the period 1955–2011. Relatively dry intervals were reconstructed between AD 1859–1880, 1899–1911, 1927–1933, 1946–1959, 1964–1970 and 1987–1997. Relatively wet conditions prevailed during 1855–1858, 1881–1898, 1912–1926, 1934–1945, 1960–1963, 1971–1986 and 1998–2011. Comparisons between our scPDSI reconstruction and a moisture‐sensitive tree‐ring width record from Vietnam revealed consistencies between the two data sets, suggesting similar drought regimes. Spectral peaks of 2.2–6.4 years may be indicative of El Niño‐Southern Oscillation (ENSO) activity, as also suggested by the significant correlations with sea surface temperatures (SSTs) in the eastern equatorial and southeastern Pacific Ocean and an extreme event analysis. The analysis of links between our scPDSI reconstruction and the large‐scale regional climatic variation shows that there is a relationship between regional drought variation and East Asian summer monsoon (EASM) intensity.  相似文献   

Rethinking the PhD in geography: overview and introduction     

Mark Boyle  Kenneth E. Foote  Mary Gilmartin 《GeoJournal》2015,80(2):159-168

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A critical evaluation of multi‐proxy dendroclimatology in northern Finland     

Danny McCarroll  Mervi Tuovinen  Rochelle Campbell  Mary Gagen  Håkan Grudd  Risto Jalkanen  Neil J. Loader  Iain Robertson 《第四纪科学杂志》2011,26(1):7-14

Twentieth‐century summer (July–August) temperatures in northern Finland are reconstructed using ring widths, maximum density and stable carbon isotope ratios (δ¹³C) of Scots pine tree rings, and using combinations of these proxies. Verification is based on the coefficient of determination (r²), reduction of error (RE) and coefficient of efficiency (CE) statistics. Of the individual proxies, δ¹³C performs best, followed by maximum density. Combining δ¹³C and maximum density strengthens the climate signal but adding ring widths leads to little improvement. Blue intensity, an inexpensive alternative to X‐ray densitometry, is shown to perform similarly. Multi‐proxy reconstruction of summer temperatures from a single site produces strong correlations with gridded climate data over most of northern Fennoscandia. Since relatively few trees are required (<15) the approach could be applied to long sub‐fossil chronologies where replication may be episodically low. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献