Potential Effects of Global Warming on Waterfowl Populations Breeding in the Northern Great Plains

The Prairie Pothole Region (PPR) of the Northern Great Plains is the most important breeding area for waterfowl in North America. Historically, the size of breeding duck populations in the PPR has been highly correlated with spring wetland conditions. We show that one indicator of climate conditions, the Palmer Drought Severity Index (PDSI), is strongly correlated with annual counts (from 1955 to 1996) of both May ponds (R2 = 0.72, p < 0.0001) and breeding duck populations (R2 = 0.69, p < 0.0001) in the Northcentral U.S., suggesting the utility of PDSI as an index for climatic factors important to wetlands and ducks. We then use this relationship to project future pond and duck numbers based on PDSI values generated from sensitivity analyses and two general circulation model (GCM) scenarios. We investigate the sensitivity of PDSI to fixed changes in temperature of 0°C, +1.5°C, +2.5°C, and +4.0°C in combination with fixed changes in precipitation of -10%, +0%, +7%, and +15%, changes spanning the range of typically-projected values for this region from human-induced climatic change. Most (11 of 12) increased temperature scenarios tested result in increased drought (due to greater evapotranspiration under warmer temperatures) and declining numbers of both wetlands and ducks. Assuming a doubling of CO2 by 2060, both the equilibrium and transient GCM scenarios we use suggest a major increase in drought conditions. Under these scenarios, Northcentral U.S. breeding duck populations would fluctuate around means of 2.1 or 2.7 million ducks based on the two GCMs, respectively, instead of the present long-term mean of 5.0 million. May pond numbers would fluctuate around means of 0.6 or 0.8 million ponds instead of the present mean of 1.3 million. The results suggest that the ecologically and economically important PPR could be significantly damaged by climate changes typically projected. We make several recommendations for policy and research to help mitigate potential effects.     

Community structure and nutrition of deep methane-seep macrobenthos from the North Pacific (Aleutian) Margin and the Gulf of Mexico (Florida Escarpment)

Methane seeps occur at depths extending to over 7000 m along the world's continental margins, but there is little information about the infaunal communities inhabiting sediments of seeps deeper than 3000 m. Biological sampling was carried out off Unimak Island (3200–3300 m) and Kodiak Island (4500 m) on the Aleutian margin, Pacific Ocean and along the Florida Escarpment (3300 m) in the Gulf of Mexico to investigate the community structure and nutrition of macrofauna at these sites. We addressed whether there are characteristic infaunal communities common to the deep‐water seeps or to the specific habitats (clam beds, pogonophoran fields, and microbial mats) studied here, and ask how these differ from background communities or from shallow‐seep settings sampled previously. We also investigated, using stable isotopic signatures, the utilization of chemosynthetically fixed and methane‐derived organic matter by macrofauna from different regions and habitats. Within seep sites, macrofaunal densities were the greatest in the Florida microbial mats (20,961 ± 11,618 ind·m⁻²), the lowest in the Florida pogonophoran fields (926 ± 132 ind·m⁻²), and intermediate in the Unimak and Kodiak seep habitats. Seep macrofaunal densities differed from those in nearby non‐seep sediments only in Florida mat habitats, where a single, abundant species of hesionid polychaete comprised 70% of the macrofauna. Annelids were the dominant taxon (>60%) at all sites and habitats except in Florida background sediments (33%) and Unimak pogonophoran fields (27%). Macrofaunal diversity (H′) was lower at the Florida than the Alaska seeps, with a trend toward reduced richness in clam bed relative to pogonophoran field or non‐seep sediments. Community composition differences between seep and non‐seep sediments were evident in each region except for the Unimak margin, but pogonophoran and clam bed macrofaunal communities did not differ from one another in Alaska. Seep δ¹³C and δ¹⁵N signatures were lighter for seep than non‐seep macrofauna in all regions, indicating use of chemosynthetically derived carbon. The lightest δ¹³C values (average of species’ means) were observed at the Florida escarpment (−42.8‰). We estimated that on average animal tissues had up to 55% methane‐derived carbon in Florida mats, 31–44% in Florida clam beds and Kodiak clam beds and pogonophoran fields, and 9–23% in Unimak seep habitats. However, some taxa such as hesionid and capitellid polychaetes exhibited tremendous intraspecific δ¹³C variation (>30‰) between patch types. Overall we found few characteristic communities or features common to the three deep‐water seeps (>3000 m), but common properties across habitats (mat, clam bed, pogonophorans), independent of location or water depth. In general, macrofaunal densities were lower (except at Florida microbial mats), community structure was similar, and reliance on chemosynthesis was greater than observed in shallower seeps off California and Oregon.     

cDNA cloning,sequencing, and differential expression of a heart-type fatty acid-binding protein in the mummichog (Fundulus heteroclitus)

A heart fatty acid-binding protein (H-FABP) cDNA was isolated from the liver of the mummichog (Fundulus heteroclitus) and the complete cDNA sequence and predicted amino acid sequence was determined. This cDNA binds to a mRNA product of 0.95 kb with the highest level of RNA expression in the male liver, gills, and gonads. Exposure of mummichogs to the polycyclic aromatic hydrocarbon (PAH) pyrene significantly down-regulated H-FABP expression at the highest concentration. This study provides evidence that environmentally relevant toxicants can modulate H-FABP expression.     

Fine scale study of a small overlapping spreading center system at 12°54′ N on the East Pacific Rise

Overlapping spreading centers (OSCs) are a type of ridge axis discontinuity found along intermediate and fast spreading centers. The ridges at these locations overlap and curve towards each other. and are separated by an elongate overlap basin. A high resolution Deep-Tow survey was conducted over the 12°54 N OSC (offset 1.6 km) on the East Pacific Rise in order to study the structure of a small OSC on a fine scale. A detailed tectonic study and Deep-Tow 3-D magnetic inversion were performed on the data. Towards the tips of both limbs, the apparent age of lava flows increases, the density of exposed faults and fissures increases, and the axial graben loses definition and disappears. No active hydrothermal vents were detected in the area. These observations suggest that the magmatic budget steadily decreases along axis approaching and OSC, even where the offset is small. In contrast with OSCs which have a large offset (>5 km), the 3-D magnetic inversion solution for this OSC produced no evidence for highly magnetized areas near the tip of either spreading center.     

Marine administration and spatial data infrastructure

This paper reviews the emergence of the spatial dimension of marine and coastal zone administration, and examines several initiatives around the world that contribute to this idea. Spatial data have been recognised as an important resource to improve decision-making and resource management in both the land and marine environments in terms of sustainable development. Many countries are developing Spatial Data Infrastructures (SDIs) to improve access and sharing of spatial data, however, most of these initiatives stop at the coastline. Recently, global and regional activities such as the 3rd United Nations Convention on the Law of the Sea (UNCLOS) and the Sustainable Development Strategy for the Seas of East Asia (SDS-SEA) have brought to international attention the importance of effective administration of the marine and coastal environments.     

New constraints on the width of the zone of active faulting on the East Pacific Rise 8° 30′ N – 10° 00′ N from Sea Beam Bathymetry and SeaMARC II Side-scan Sonar

Sea Beam bathymetry and SeaMARC II side-scan sonar data are used to constrain the width of the zone of active faulting (plate boundary zone) to be 90 km (0.8 Ma) wide along the East Pacific Rise 8° 30N – 10° 00N. Fault scarps, identified on the basis of contoured, shaded relief and slope intensity maps of bathymetry, are measured. These scarp measurements, used in conjunction with data from a separate near-axis study, show that both inward- and outward-facing fault scarps increase in height away from the ridge axis, reaching average heights of 100 m at 0.8±0.2 Ma, 45±10 km from the ridge axis. Beyond this distance, there is no significant increase in scarp height. Earlier studies had suggested that the width of the zone of active faulting for outward-dipping faults might be significantly narrower than for inward-dipping faults. A lower crustal decoupling zone between brittle crust and strong upper mantle is predicted to exist out to 20–200 km from the ridge based on previously published lithospheric models. Such a decoupling zone may explain why outward-dipping faults continue to be active as far off-axis as inward-dipping faults. If the width of the zone of active faulting is controlled by the width of a lower crustal decoupling zone, our observations predict an 90 km wide decoupling zone in the lower oceanic crust at this location.     

Alternative and Virtual Rurality: Agriculture and The Countryside as Embodied in American Imagination

Affection for agrarian livelihoods and rural and small‐town environments has long been held by residents in many of the world's “more developed” countries. Although the rural proportion of the U.S. population has shrunk to a minority over the last century, fondness for rurality continues to manifest itself in a number of ways. Attachment to the rural ideal or rural idyll can be considered as attachment to the idea of a type of place, rather than specific place attachment. Based on literature, field observation, computer searches, and data from the U.S. Census of Agriculture, connections to idea(l)s of rurality apparent in popular culture are identified and illustrated. These include rural and agricultural tourism, small‐scale farming and large‐lot rural subdivisions, urban agriculture, farmers’ markets and community‐supported agriculture, creation of housing developments around farm activities, and rural‐named housing and business developments. Idealized relationships with rurality call upon health and well‐being, connecting to nature, aesthetics, privacy, and respect and nostalgia for rural livelihoods.     

Magnetic components contributing to the NRM of Middle Siwalik red beds

The components of the NRM in Middle Siwalik red beds are carried by two phases of hematite, a red pigment phase and a specular hematite phase. We present evidence in the form of a conglomerate test that the specularite phase carries a remanence acquired during or shortly after deposition. The red pigment, however, post-dates deposition, in many cases by at least one reversal boundary. This secondary component has a higher coercivity but a lower blocking temperature in these rocks and can therefore be selectively removed by thermal demagnetization to reveal a primary magnetization useful for magnetostratigraphic studies.     

Vulnerability of Hampton Roads,Virginia to Storm-Surge Flooding and Sea-Level Rise

Sea-level rise will increase the area covered by hurricane storm surges in coastal zones. This research assesses how patterns of vulnerability to storm-surge flooding could change in Hampton Roads, Virginia as a result of sea-level rise. Physical exposure to storm-surge flooding is mapped for all categories of hurricane, both for present sea level and for future sea-level rise. The locations of vulnerable sub-populations are determined through an analysis and mapping of socioeconomic characteristics commonly associated with vulnerability to environmental hazards and are compared to the flood-risk exposure zones. Scenarios are also developed that address uncertainties regarding future population growth and distribution. The results show that hurricane storm surge presents a significant hazard to Hampton Roads today, especially to the most vulnerable inhabitants of the region. In addition, future sea-level rise, population growth, and poorly planned development will increase the risk of storm-surge flooding, especially for vulnerable people, thus suggesting that planning should steer development away from low-lying coastal and near-coastal zones.