⁴⁰Ar-³⁹Ar incremental heating experiments were performed on volcanic rocks recovered by drilling during Ocean Drilling Program Leg 152, southeast Greenland Margin (63°N), and Deep Sea Drilling Project Leg 81, southwest Rockall Plateau (56°N). Both of these legs drilled into thick sections of submerged lava flows, known as seaward-dipping reflector sequences,...
Lavas from seamounts of the central Galápagos Platform and the Carnegie Ridge increase in age with distance from the western edge of the platform, consistent with a hotspot model for the generation of these features. The areal distribution of seamount ages suggests that the pattern of dispersed volcanism seen on...
The pre-Tertiary oceanic crust exposed on the west coast of Costa Pica has been broadly referred to as the Nicoya Complex. This study was designed to determine the age of the Nicoya Complex in the Nicoya Peninsula, Playa Jaco, and the Quepos Peninsula using Ar-40-Ar-39 radiometric dating and to assess...
At the submerged margins of the North Atlantic, andesitic to dacitic and basaltic volcanic rocks occur together. The silicic rocks were derived by processes requiring the presence of continental crust (crustal anatexis and/or contamination of mafic magmas) while the majority of the basaltic lavas had little or no contact with...
The U.S. Air Force models many naturally occurring
phenomena. To validate such models, an automated data
collection system is used. Since validation is dependent
upon correct data, an inexpensive method to detect
erroneous data was investigated. The method uses a Wiener
filter to predict values one sample in advance. If...
Fast ice flow and unstable ice sheet behavior were characteristic features of the Lake Michigan Lobe of the southern Laurentide Ice Sheet. Such behavior may result from some combination of subglacial-sediment deformation and decoupled sliding at the ice-bed interface. Both mechanisms depend on high water pressure relative to ice pressure....
Application of N fertilizer is a common forest management practice in the Pacific
Northwest, yet the long-term influence of fertilization on forest soil properties is not well known. Although elevated N often increases mineralization of C and N from labile organic matter, negative effects have been documented in recalcitrant organic...
Red alder (Alnus rubra Bong.) is recognized as an important source of nitrogen to
ecosystems that it inhabits. I examined N dynamics within alder trees, alder leaf litter, and the soil beneath alder leaf litter. ¹⁵Nitrogen, a stable isotope of N, was used as a tracer to follow the movement...
As the Galápagos hot spot is approached from the west along the Galápagos Spreading Center there are systematic increases in crustal thickness and in the K/Ti, Nb/Zr, ³He/⁴He, H₂O, and Na₂O content of lavas recovered from the spreading axis. These increases correlate with progressive transitions from rift valley to axial...
Nitrogen incorporation from red alder (Alnus rubra Bong.) into an Oregon upland mesic forest soil was studied by tracing the fate of 15N added as 15N-labeled alder leaf litter. The recovery of 15N in vegetation, litter, light- and heavy-fractions of the soil, the chloroform-labile (microbial biomass) pool, and the whole...
The degree to which carbon concentration (CC) of woody detritus varies by tree taxa, stage of decay, tissue
type (i.e., bark versus wood), and vertical orientation was examined in samples of 60 tree species
from the Northern Hemisphere. The mean CC of 257 study samples was 49.3% with a range...
The International Food Policy Research Institute (IFPRI) and the International Center for Living Aquatic Resources Management (ICLARM), in collaboration with the Food and Agricultural Organization of the United Nations (FAO), are presently attempting to model supply and demand for highly aggregated fish categories within the context of IFPRI's IMPACT global...
A new dataset synthesizes in situ and remote sensing observations from research ships deployed to the southeastern tropical Pacific stratocumulus region for 7 years in boreal fall. Surface meteorology, turbulent and radiative fluxes, aerosols, cloud properties, and rawinsonde profiles were measured on nine ship transects along 20°S from 75° to...
DYNAMO and TOGA-COARE observations and reanalysis-based surface flux products are
used to test theories of atmosphere-ocean interaction that explain the Madden-Julian
Oscillation (MJO). Negative intraseasonal outgoing longwave radiation, indicating deep
convective clouds, is in phase with increased surface wind stress, decreased solar heating,
and increased surface turbulent heat flux—mostly evaporation—from...
DYNAMO and TOGA-COARE observations and reanalysis-based surface flux products are
used to test theories of atmosphere-ocean interaction that explain the Madden-Julian
Oscillation (MJO). Negative intraseasonal outgoing longwave radiation, indicating deep
convective clouds, is in phase with increased surface wind stress, decreased solar heating,
and increased surface turbulent heat flux—mostly evaporation—from...
Full Text:
. de Szoeke1, James B. Edson2, June R. Marion1, ChristopherW. Fairall3, and 3
Ludovic Bariteau3 4
The International Food Policy Research Institute (IFPRI), the World Fish Center (ICLARM), and the Food and Agriculture Organization (FAO), are collaborating to incorporate fish into IMPACT, a global model of food supply and demand that estimates market-clearing prices for 28 commodities in 36 regions. Results of the projections to 2020...
The structure of global supply and demand for fish has changed dramatically over the past few decades. Traditional marine fisheries increased and reached its peak in the 1990s, while aquaculture has expanded rapidly since the 1970s, making it one of the fastest growing sectors in all of agriculture. Fish has...