Trace analysis of hydrocarbons in coral cores from Saudi Arabia   总被引：1，自引：0，他引：1  

Anita Poulsen  Kathryn Burns  Janice Lough  Diane Brinkman  Steven Delean 《Organic Geochemistry》2006,37(12):1913

As part of a long-term environmental assessment of the impact of the 1991 Gulf War on coral reefs, the Australian Institute of Marine Science (AIMS) conducted growth and chemistry studies on coral cores from the Arabian Gulf. Twenty-eight cores were collected from four coral reefs located offshore from Saudi Arabia.Annual coral growth bands surrounding the 1991 oil spill were analysed in selected cores. Additionally, in cores that extended to the early 1980s, annual layers from 1980 to 1986 were analysed for possible residues from the 1983–4 oil spill caused by the Nowruz oil field blowout during the Iraq–Iran war. Both major spill events were targeted to provide additional confidence in relating oil concentrations to specific pollution events. We detected petroleum biomarkers in several coral annual bands related to the major pollution events. However, the oil remaining in these cores has been altered over time and the biomarker ratios found in these oil residues differed from Gulf crude oils.The concentrations of hydrocarbons were compared with the growth parameters of the coral cores. Only one sample may have recorded an “impact” of oil exposure. There was no other correspondence between slight changes in growth parameters between years and the trace chemistry. Therefore, chemical analysis enabled detection of the exposure incident, but provided no insight into the amount of oil to which the coral had been exposed. The chemical data can only infer biological impact if growth was significantly decreased.The average coral growth characteristics of Porites from the four sites in the Arabian Gulf were normal, as predicted from the average water temperatures of the region. There was an indication of an overall decline in growth over time, which should be monitored in the future.  相似文献   

The Signature of Sea Spray in the Hexos Turbulent Heat Flux Data   总被引：7，自引：0，他引：7  

Edgar L Andreas  Janice Decosmo 《Boundary-Layer Meteorology》2002,103(2):303-333

The role of sea spray intransferring heat and moisture across the air-sea interface has remained elusive. Some studies have reported that sea spray does not affect the turbulent air-sea heat fluxes for 10-m wind speeds up to at least 25 m s^-1, while others have reported important spray contributions for wind speeds as low as 12 m s^-1. One goal of the HEXOS (Humidity Exchange over the Sea) program was to quantify spray's contribution to the turbulent air-sea heat fluxes, but original analyses of the HEXOS flux data found the spray signal to be too small to be reliably identified amid the scatter in the data. We look at the HEXOS data again in the context of the TOGA-COARE bulk flux algorithm and a sophisticated microphysical spray model. This combination of quality data andstate-of-the-art modelling reveals a distinct spray signature in virtually all HEXOS turbulent heat flux data collected in winds of 15 m s^-1 and higher. Spray effects are most evident in the latent heat flux data, where spray contributes roughly 10% of the total turbulent flux in winds of 10 m s^-1 and between 10 and 40% in winds of 15–18 m s^-1. The spray contribution to the total sensible heat flux is also at least 10% in winds above 15 m s^-1. These results lead to a new, unified parameterization for the turbulent air-sea heat fluxes that should be especially useful in high winds because it acknowledges both the interfacial and spray routes by which the sea exchanges heat and moisture with the atmosphere.  相似文献   

Washington Women: Practicing Geography in the U.S. Government, 1915–1970s     

Janice Monk 《The Professional geographer》2017,69(4):683-693

Histories of geography, especially those dealing with the twentieth century, tend to focus on geographic thought or academia rather than on practice in other arenas such as government agencies. In the United States during that period, however, the latter included a higher proportional representation of women professionals than did research-oriented universities. This article examines the careers of selected women geographers who had long-term and senior positions in Washington, DC, in agencies such as the Library of Congress, Bureau of the Census, the Department of State, and the Office of Naval Research. Drawing on sources including directories, the archives and oral history collections of the Society of Woman Geographers, and interviews conducted in the late 1980s and early 1990s, I explore four main themes: how these women came to government work, aspects of the intersections of personal and professional lives, ways in which economic and political contexts shaped their opportunities and experiences, and the nature of their contributions.  相似文献   

The Use of Fossil Caddisfly Assemblages in the Reconstruction of Flow Environments from Floodplain Paleochannels of the River Trent, England     

M. T. Greenwood  P. J. Wood  W. A. Monk 《Journal of Paleolimnology》2006,35(4):747-761

This paper examines the use of fossil larval trichopteran communities to investigate and describe the flow environment of a paleochannel network in the middle reaches of the River Trent floodplain (UK). Previous research utilising fossil insect communities (principally O. Coleoptera, O. Chironomidae) has focussed upon climate reconstruction. However, larval trichopteran communities (O. Trichoptera) also offer an aquatic signal, giving information regarding channel habitat structure and flow environments. The taxonomic diversity of each fossil community and the categorisation of each taxon into a known flow group, using the “LIFE” methodology, facilitates the reconstruction of the river flow conditions at each site based upon known faunal associations with mean flow velocity. A total of 49 trichopteran taxa were recorded from 17 paleochannels (n = 170 samples). Detrended Correspondence Analysis (DCA) identified a environmental gradient on the first DCA axis that reflected variability in flow, from rapid/fast flow to slow flowing and standing water habitats. In addition, two distinct faunal groups were identified on the second DCA axis characteristic of (i) small nutrient rich lentic habitats; and (ii) larger water bodies displaying features of both lentic, lotic and ephemeral habitats where marginal vegetation is abundant on a mineral substratum. The results demonstrate that larval Trichoptera can be used in paleolimnological research to reconstruct a flow signal and provide additional information regarding the aquatic habitat structure. Their wider use in describing the aquatic environment, in association with other proxies (e.g., Chironomidae and Coleoptera), may provide a more holistic understanding of floodplain paleoenvironment succession.  相似文献   

The identification of hydrological indices for the characterization of macroinvertebrate community response to flow regime variability     

T.P. Worrall  M.J. Dunbar  C.A. Extence  C.L.R. Laizé  W.A. Monk 《水文科学杂志》2014,59(3-4):645-658

Abstract

The importance of flow regime variability for maintaining ecological functioning and integrity of river ecosystems has been firmly established in both natural and anthropogenically modified systems. River flow regimes across lowland catchments in eastern England are examined using 47 variables, including those derived using the Indicators of Hydrologic Alteration (IHA) software. A principal component analysis method was used to identify redundant hydrological variables and those that best characterized the hydrological series (1986–2005). A small number of variables (<6) characterized up to 95% of the statistical variability in the flow series. The hydrological processes and conditions that the variables represent were found to be significant in structuring the in-stream macroinvertebrate community Lotic-invertebrate Index for Flow Evaluation (LIFE) scores at both the family and species levels. However, hydrological variables only account for a relatively small proportion of the total ecological variability (typically <10%). The research indicates that a range of other factors, including channel morphology and anthropogenic modification of in-stream habitats, structure riverine macroinvertebrate communities in addition to hydrology. These factors need to be considered in future environmental flow studies to enable the characterization of baseline/reference conditions for management and restoration purposes.