Evidence of chromosomal damage in common eiders (Somateria mollissima) from the Baltic Sea     

Matson CW  Franson JC  Hollmén T  Kilpi M  Hario M  Flint PL  Bickham JW 《Marine pollution bulletin》2004,49(11-12):1066-1071

Common eiders nesting in the Baltic Sea are exposed to generally high levels of contaminants including potentially genotoxic polycyclic aromatic hydrocarbons and organochlorines. Blood samples were collected from eiders at eight sites in the Baltic Sea and two sites in the Beaufort Sea. DNA content variation was estimated using the flow cytometric method, and subsequently utilized as a biomarker of genetic damage. We observed no significant differences in genetic damage among populations within either the Baltic or Beaufort Seas. However, eider populations from the Baltic Sea had significantly elevated estimates of genetic damage compared to populations from the Beaufort Sea.  相似文献   

Upward-thickening patterns and lateral continuity of Permian sand-rich turbidite channel fills, Laingsburg Karoo, South Africa   总被引：1，自引：0，他引：1  

Martin Grecula  Stephen S. Flint  Henry De V. Wickens†  Stephen D. Johnson‡ 《Sedimentology》2003,50(5):831-853

Abstract Analysis of extensive exposures of the Permian Laingsburg Formation, Karoo basin, South Africa, have enabled a detailed reconstruction of the base of slope stratigraphy and palaeoenvironments in a deep-water system characterized by a very narrow grain-size range (fine sandstone). The deposits include an ≈ 4 km wide and 80 m thick channel complex, fringed by sandy sheet deposits that extend laterally for at least 6 km across depositional strike. Within the channel complex, individual channel fills are marked by shallow basal erosion surfaces draped by thin, parallel-stratified beds of very fine sandstone and siltstone, interpreted as flow tails to largely bypassing flows. These thin beds are overlain by 0·4 to 5 m thick beds of structureless, fine-grained sandstone that represent the majority of the channel fills. The basal packages may be partially to completely removed by localized scour in the axial zone of the channel complex but can be mapped laterally into overbank areas where they thicken and are dominated by rippled fine sandstones with intercalated siltstones. Axial confinement resulted from subtle topography on the basin floor, whereby the lower, dense parts of the initially erosive and bypassing flows were partially confined in the lows and the more dilute, slower moving upper parts of the flows deposited sheet-like successions across slightly elevated overbank areas. The narrow grain-size distribution prohibited the formation ofcoarse-grained residual bypass deposits during the initial phases of channel formation. With decreasing magnitude, later flows became more depositional, filling remaining axial depressions with thick-bedded structureless sandstone. The smaller volumes of late-stage sediment were more axially focused, producing local scour-and-fill features and starvation of the overbank areas. Resulting grain-size vertical profiles are complex. The basal flow tail packages and overlying massive deposits form a thickening and slightly coarsening-upward trend in the channel fills. The overbank deposits show a thinning- and fining-upward profile as a result of less bypass plus late-stage starvation of sand. Application of traditional deep-water facies models could therefore potentially lead to erroneous interpretations of the channel complex as a prograding lobe and the overbank sheets as channel-fills.  相似文献   

Long-term estuarine variability and associated biological response     

R. Warren Flint 《Estuaries and Coasts》1985,8(2):158-169

Corpus Christi Bay, one of seven major Texas estuaries, is characterized by low freshwater inflow, small tidal flushing, low annual rainfall, and high evaporation rates. Minimal exchange of water makes this estuary sensitive to episodic environmental variation caused by sudden surges of freshwater from flooding rains or hurricanes. It is suggested that this episodic variability stimulates estuarine production. For the last 11 years, detailed data have been collected on benthic community structure, primary and secondary productivity, and sediment nutrient regeneration which are combined with other information, such as fishery yields, into a reconstructed long-term data set. During this same period significant environmental changes in the estuary have been documented. In 1979 the lowest salinity recorded over the 11-year record was related to a short-term, high intensity rainfall. The benthos responded with abundance and biomass levels far greater than any other year during the study interval. Correlated with increased benthic production were large increases in shrimp yields. During more subtle changes with respect to freshwater input in 1981, significant alterations in primary productivity were quantified. Primary, secondary, and tertiary carbon production estimates derived from the reconstructed long-term data base indicated the benthos as a major link between primary producers and other consumers. Carbon flow from primary producers, however, appeared inadequate to support benthic production. Nutrient recycling was judged to provide more than 90% of nitrogen needed to support phytoplankton production and was considered a major factor influencing ecosystem function. The matching of biological responses to significant environmental changes in this estuary provided insight into ecosystem function and stressed the importance of short-term variability. Although recycling was identified as a major source of nutrients supporting primary production, it was concluded that episodic environmental change from freshwater input provided a much needed stimulus to productivity. These episodic changes replaced materials lost through recycling and sustained productivity over the long term.  相似文献   

Export fluxes of biogenic matter in the presence and absence of seasonal sea ice cover in the Chukchi Sea     

Catherine Lalande  Jacqueline M. Grebmeier  Paul Wassmann  Lee W. Cooper  Mikhail V. Flint  Valentina M. Sergeeva 《Continental Shelf Research》2007

Drifting sediment traps were deployed at 9 stations in May-June (ice-covered conditions) and July-August (ice-free conditions) 2004 in the Chukchi Sea to investigate the variability in export fluxes of biogenic matter in the presence and absence of sea ice cover. Measurements of chlorophyll-a (Chl-a), particulate organic carbon (POC), particulate nitrogen (PN), phytoplankton, zooplankton fecal pellets, and the stable carbon isotope composition (δ¹³C) of the sinking material were performed along Barrow Canyon (BC) and a parallel shelf-to-basin transect from East Hanna Shoal (EHS) to the Canada Basin. POC export fluxes were similarly high in the presence (378±106 mg C m⁻² d⁻¹) and in the absence of ice cover (442±203 mg C m⁻² d⁻¹) at the BC stations, while fluxes were significantly higher in the absence (129±98 mg C m⁻² d⁻¹) than in the presence of ice cover (44±29 mg C m⁻² d⁻¹) at the EHS stations. The C/N ratios and δ¹³C values of sinking organic particles indicated that POC export fluxes on the Chukchi continental shelf were mostly composed of freshly produced labile material, except at the EHS stations under ice cover where the exported matter was mostly composed of refractory material probably advected into the EHS region. Chl-a fluxes were higher under ice cover than in ice-free water, however, relatively low daily loss rates of Chl-a and similar phytoplankton carbon fluxes in ice-covered and ice-free water suggest the retention of phytoplankton in the upper water column. An increase in fecal pellet carbon fluxes in ice-free water reflected higher grazing pressure in the absence of ice cover. Elevated daily loss rates of POC at the BC stations confirmed other indications that Barrow Canyon is an important area of carbon export to the basin and/or benthos. These results support the conclusion that there are large spatial and temporal variations in export fluxes of biogenic matter on the Chukchi continental shelf, although export fluxes may be similar in the presence and in the absence of ice cover in highly productive regions.  相似文献   

Development of Technology for Integrated Instrumental Underwater Observations Related to Russian Arctic Ecosystems     

Rimsky-Korsakov  N. A.  Flint  M. V.  Pojarkov  S. G.  Anisimov  I. M.  Belevitnev  Y. I.  Pronin  A. A.  Tronza  S. N. 《Oceanology》2019,59(4):612-615

Oceanology - Abstract—The article touches upon methodological problems of studying the underwater fauna, plant, and micro- and mesorelief of the near-bottom zone of the Russian Arctic seas in...  相似文献   

Seasonal Dynamics of Biogeochemical Processes in the Water Column of the Northeastern Black Sea     

I.?I.?Rusanov  A.?Yu.?LeinEmail author  P.?N.?Makkaveev  A.?A.?Klyuvitkin  M.?D.?Kravchishina  M.?V.?Ivanov  M.?V.?Flint 《Oceanology》2018,58(1):57-70

Integrated studies on the hydrochemistry and water column rates of microbial processes in the eastern sector of the Black Sea along a standard 100-miles transect off Gelendzhik from the coast to the central part of the sea at water depths of 100–2170 m show that a series of warm winters and the absence of intense convective winter mixing resulted in a relatively low content of suspended particulate matter (SPM), particulate organic carbon (POC), and nutrients in the water column in March 2009. The relatively high SPM concentrations and the presence of isotopically light POC at the offshore station are indicative of the supply of terrigenous material from land and low contributions of phytoplanktonic organic matter to the composition of SPM. This may explain the low rates of biogeochemical processes in the water column near the coast. The surface layer at deep-water stations is dominated by isotopically heavy phytoplanktonic organic matter. This suggests that the supply of terrigenous material from land was insufficient in offshore deep-water areas. Therefore, warm winters and insufficient nutrient supply do not prevent photosynthesis in the photic layer of the deep-water zone, which generates organic substrates for heterotrophic aquatic communities. The results of isotopic analysis of POC, measurements of the rates biogeochemical processes, and the hydrochemical characteristics of the water column can be used to determine the nature and seasonal variability of the POC composition.  相似文献   

Picophytoplankton Distribution at the Ob River Section and in the Western Part of the Kara Sea     

Belevich  T. A.  Ilyash  L. V.  Demidov  A. B.  Flint  M. V. 《Oceanology》2019,59(6):871-880

Oceanology - The spatial distribution of picophytoplankton abundance, biomass, chlorophyll a and the contribution of picoalgae to the total chlorophyll a was studied in the outer Ob River estuary...  相似文献   

Multidisciplinary Program of Field Studies of the Ecosystem in the Atlantic Sector of the Southern Ocean (December 2019–March 2020)     

Morozov  E. G.  Flint  M. V.  Spiridonov  V. A.  Tarakanov  R. Yu. 《Oceanology》2019,59(6):989-991

Oceanology - The research program of the dynamics and ecosystem of the Drake Passage and Scotia Sea is scientifically substantiated. Measurements will be carried out by the interdepartmental...  相似文献   

Effects of climate change and urban development on the distribution and conservation of vegetation in a Mediterranean type ecosystem     

Bray J. Beltrán  Janet Franklin  Alexandra D. Syphard  Helen M. Regan  Lorraine E. Flint  Alan L. Flint 《International journal of geographical information science》2014,28(8):1561-1589

Climate and land-use changes are projected to threaten biodiversity over this century. However, few studies have considered the spatial and temporal overlap of these threats to evaluate how ongoing land-use change could affect species ranges projected to shift outside conservation areas. We evaluated climate change and urban development effects on vegetation distribution in the Southwest ecoregion, California Floristic Province, USA. We also evaluated how well a conservation network protects suitable habitat for rare plant species under these change projections and identified primary sources of uncertainty. We used consensus-based maps from three species distribution models (SDMs) to project current and future suitable habitat for 19 species representing different functional types (defined by fire-response – obligate seeders, resprouting shrubs – and life forms – herbs, subshrubs), and range sizes (large/common, small/rare). We used one spatially explicit urban growth projection; two climate models, emission scenarios, and probability thresholds applied to SDMs; and high-resolution (90 m) environmental data. We projected that suitable habitat could disappear for 4 species and decrease for 15 by 2080. Averaged centroids of suitable habitat (all species) were projected to shift tens (up to hundreds) of kilometers. Herbs showed a small-projected response to climate change, while obligate seeders could suffer the greatest losses. Several rare species could lose suitable habitat inside conservation areas while increasing area outside. We concluded that (i) climate change is more important than urban development for vegetation habitat loss in this ecoregion through 2080 due to diminishing amounts of undeveloped private land in this region; (ii) the existing conservation plan, while extensive, may be inadequate to protect plant diversity under projected patterns of climate change and urban development, (iii) regional assessments of the dynamics of the drivers of biodiversity change based on high-resolution environmental data and consensus predictive mapping, such as this study, are necessary to identify the species expected to be the most vulnerable and to meaningfully inform regional-scale conservation.  相似文献   

An acoustic emission landslide early warning system for communities in low-income and middle-income countries     

N. Dixon  A. Smith  J. A. Flint  R. Khanna  B. Clark  M. Andjelkovic 《Landslides》2018,15(8):1631-1644

Early warning systems for slope instability are needed to alert users of accelerating slope deformation behaviour, enable evacuation of vulnerable people, and conduct timely repair and maintenance of critical infrastructure. Communities exposed to landslide risk in low- and middle-income countries seldom currently instrument and monitor slopes to provide a warning of instability because existing techniques are complex and prohibitively expensive. Research and field trials have demonstrated conclusively that acoustic emission (AE) monitoring can be an effective approach to detect accelerating slope movements and to subsequently communicate warnings to users. The objective of this study was to develop and assess a simple, robust, low-cost AE monitoring system to warn of incipient landslides, which can be widely deployed and operated by communities globally to help protect vulnerable people. This paper describes a novel AE measurement sensor that has been designed and developed with the cost constrained to a few hundred dollars (US). Results are presented from physical model experiments that demonstrate performance of the AE system in measuring accelerating deformation behaviour, with quantifiable relationships between AE and displacement rates. Exceedance of a pre-determined trigger level of AE can be used to communicate an alarm to users in order to alert them of a slope failure. Use of this EWS approach by communities worldwide would reduce the number of fatalities caused by landslides.  相似文献