A proposed multiple-use zoning scheme for the Irish Sea.: An interpretation of current legislation through the use of GIS-based zoning approaches and effectiveness for the protection of nature conservation interests     

Suzanne J. Boyes  Michael Elliott  Shona M. Thomson  Stephen Atkins  Paul Gilliland 《Marine Policy》2007

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A community-wide intercomparison exercise for the determination of dissolved iron in seawater     

Andrew R. Bowie  Eric P. Achterberg  Peter L. Croot  Hein J.W. de Baar  Patrick Laan  James W. Moffett  Simon Ussher  Paul J. Worsfold 《Marine Chemistry》2006

The first large-scale international intercomparison of analytical methods for the determination of dissolved iron in seawater was carried out between October 2000 and December 2002. The exercise was conducted as a rigorously “blind” comparison of 7 analytical techniques by 24 international laboratories. The comparison was based on a large volume (700 L), filtered surface seawater sample collected from the South Atlantic Ocean (the “IRONAGES” sample), which was acidified, mixed and bottled at sea. Two 1-L sample bottles were sent to each participant. Integrity and blindness were achieved by having the experiment designed and carried out by a small team, and overseen by an independent data manager. Storage, homogeneity and time-series stability experiments conducted over 2.5 years showed that inter-bottle variability of the IRONAGES sample was good (< 7%), although there was a decrease in iron concentration in the bottles over time (0.8–0.5 nM) before a stable value was observed. This raises questions over the suitability of sample acidification and storage.  相似文献   

Ten-year record of Thalassiosira nordenskioeldii population dynamics: comparison of aquaculture and non-aquaculture sites in the Quoddy Region     

Smith  Aaron C.; Martin  Jennifer L.; Ehrman  James M.; Kaczmarska  Irena 《ICES Journal of Marine Science》2001,58(2):391-397

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Understanding mackerel migration off Scotland: Tracking with echosounders and commercial data, and including environmental correlates and behaviour     

Walsh  Martin; Reid  David G.; Turrell  William R. 《ICES Journal of Marine Science》1995,52(6):925-939

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Copepod grazing during spring blooms: Does Calanus pacificus avoid harmful diatoms?     

Andrew W. Leising  James J. Pierson  Claudia Halsband-Lenk  Rita Horner  James Postel 《Progress in Oceanography》2005,67(3-4):384

During late winter and spring of 2002 and 2003, 24, 2–3 day cruises were conducted to Dabob Bay, Washington State, USA, to examine the grazing, egg production, and hatching success rates of adult female Calanus pacificus and Pseudocalanus newmani. The results of the copepod grazing experiments for C. pacificus are discussed here. Each week, copepod grazing incubation experiments from two different depth layers were conducted. Grazing was measured by both changes in chlorophyll concentration and cell counts. In 2002, there was one moderate bloom consisting mainly of Thalassiosira spp. in early February, and a larger bloom in April comprised of two Chaetoceros species and Phaeocystis sp. Similarly, in 2003, there were two blooms, an early one dominated by Thalassiosira spp., and a later one consisting of Chaetoceros spp. and Thalassiosira spp. Clearance rates on individual prey species, as calculated by cell counts, showed that C. pacificus are highly selective in their feeding, and may have much higher clearance rates on individual taxa than rates calculated from bulk chlorophyll disappearance. During weeks of high phytoplankton concentration, the copepods generally ate phytoplankton. However, they often rejected the most abundant phytoplankton species, particularly certain Thalassiosira spp., even though the rejected prey were often of the same genus and similar size to the preferred prey. It is speculated that this avoidance may be related to the possible deleterious effects that certain of these diatom species have on the reproductive success of these copepods. During weeks of medium to low phytoplankton concentration, the copepods selectively ate certain species of phytoplankton, and often had high electivity for microzooplankton. The selection mechanism must consist of active particle rejection most likely based on detection of surface chemical properties, since the diatoms that were selected were of the same genus, nearly the same size, and at lower numerical abundance than those cells that were avoided. The grazing choices made by these copepods may have important consequences for the overall ecosystem function within coastal and estuarine systems through changes in the transfer efficiency of energy to higher trophic levels.  相似文献   

Relative molar mass distributions of chromophoric colloidal organic matter in coastal seawater determined by Flow Field-Flow Fractionation with UV absorbance and fluorescence detection     

Martin Hassellv 《Marine Chemistry》2005,94(1-4):111

A new method for the characterization of chromophoric colloidal organic matter in seawater has been applied to samples from the Baltic Sea, Kattegatt and Skagerrak seas. Size fractionation of the sample by Flow Field-Flow Fractionation and measurement of the fluorescent and UV absorbing properties of the individual size fractions result in a relative molar mass distribution (RMM) of the optical properties. The RMM distributions have been used to estimate number and weight average relative molar masses, and polydispersity indices. At least two sources of coloured organic matter were identified from the ratio of fluorescence to UV: the Baltic surface water and the Skagerrak deep water. The dominating processes were mixing and dilution, but processes such as photo bleaching of fluorescence are also believed to be important. The RMM distribution derived from UV detection (1150–1300 Dalton) increased with increasing salinity while that derived for fluorescence (1500–1250 Dalton) decreased with increasing salinity. The specific UV absorbance taken as a proxy of the aromaticity of the chromophoric organic material showed decreasing trend with both increasing salinity and increasing UV derived weight average relative molar mass. Increasing polydispersity of the colloidal material was also observed as a function of salinity.  相似文献   

Bathymetry of the Tonga Trench and Forearc: a map series   总被引：1，自引：0，他引：1  

Wright  Dawn J.  Bloomer  Sherman H.  MacLeod  Christopher J.  Taylor  Brian  Goodlife  Andrew M. 《Marine Geophysical Researches》2000,21(5):489-512

Four new bathymetric maps of the Tonga Trench and forearc between 14 °S and 27 °S display the important morphologic and structural features of this dynamic convergent margin. The maps document a number of important geologic features of the margin. Major normal faults and fault lineaments on the Tonga platform can be traced along and across the upper trench slope. Numerous submarine canyons incised in the landward slope of the trench mark the pathways of sediment transport from the platform to mid- and lower-slope basins. Discontinuities in the trench axis and changes in the morphology of the landward slope can be clearly documented and may be associated with the passage and subduction of the Louisville Ridge and other structures on the subducting Pacific Plate. Changes in the morphology of the forearc as convergence changes from normal in the south to highly-oblique in the north are clearly documented. The bathymetric compilations, gridded at 500- and 200-m resolutions and extending along 500 km of the landward trench slope and axis, provide complete coverage of the outer forearc from the latitude of the Louisville Ridge-Tonga Trench collision to the northern terminus of the Tonga Ridge. These maps should serve as a valuable reference for other sea-going programs in the region, particularly the Ocean Drilling Program (ODP) and the National Science Foundation MARGINS initiative.  相似文献   

Validating management simulation models and implications for communicating results to stakeholders     

Pastoors  Martin A.; Poos  Jan Jaap; Kraak  Sarah B. M.; Machiels  Marcel A. M. 《ICES Journal of Marine Science》2007,64(4):818-824

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Short-term and interannual variability of redox-sensitive chemical parameters in hypoxic/anoxic bottom waters of the Chesapeake Bay     

Brent L. Lewis  Brian T. Glazer  Paul J. Montbriand  George W. Luther III  Donald B. Nuzzio  Timothy Deering  Shufen Ma  Stephen Theberge 《Marine Chemistry》2007,105(3-4):296-308

A combination of CTD casts, discrete bottle sampling and in situ voltammetric microelectrode profiling was used to examine changing redox conditions in the water column at a single station south of the Bay Bridge in the upper Chesapeake Bay in late July/early August, 2002–2005. Short-term (2–4 h) fluctuations in the oxic/suboxic/anoxic interface were documented using in situ voltammetric solid-state electrodes. Profiles of dissolved oxygen and sulfide revealed tidally-driven vertical fluctuations of several meters in the depth and thickness of the suboxic zone. Bottom water concentrations of sulfide, Mn²⁺ and Fe²⁺ also varied over the tidal cycle by approximately an order of magnitude. These data indicate that redox species concentrations at this site varied more due to physical processes than biogeochemical processes. Based on analysis of ADCP data, tidal currents at this station were strongly polarized, with the principal axis of tidal currents aligned with the mainstem channel. Together with the chemical data, the ADCP analysis suggests tidal flushing of anoxic bottom waters with suboxic water from north of the site. The present study is thus unique because while most previous studies have focused on processes across relatively stable redox interfaces, our data clearly demonstrate the influence of rapidly changing physical mixing processes on water column redox chemistry.Also noted during the study were interannual differences in maximum bottom water concentrations of sulfide, Mn²⁺ and Fe²⁺. In 2003, for example, heavy spring rains resulted in severe hypoxia/anoxia in June and early July. While reported storm-induced mixing in late July/early August 2003 partially alleviated the low-oxygen conditions, bottom water concentrations of sulfide, Mn²⁺ and Fe²⁺ were still much higher than in the previous year. The latter implies that the response time of the microbial community inhabiting the suboxic/anoxic bottom waters to changing redox conditions is slow compared to the time scale of episodic mixing events. Bottom water concentrations of the redox-sensitive chemical species should thus be useful as a tracer to infer prior hypoxic/anoxic conditions not apparent from ambient oxygen levels at the time of sampling.  相似文献   

The contribution of atmospheric acid deposition to ocean acidification in the subtropical North Atlantic Ocean     

Nicholas R. Bates  Andrew J. Peters   《Marine Chemistry》2007,107(4):547-558

The absorption of anthropogenic CO₂ and atmospheric deposition of acidity can both contribute to the acidification of the global ocean. Rainfall pH measurements and chemical compositions monitored on the island of Bermuda since 1980, and a long-term seawater CO₂ time-series (1983–2005) in the subtropical North Atlantic Ocean near Bermuda were used to evaluate the influence of acidic deposition on the acidification of oligotrophic waters of the North Atlantic Ocean and coastal waters of the coral reef ecosystem of Bermuda. Since the early 1980's, the average annual wet deposition of acidity at Bermuda was 15 ± 14 mmol m^− 2 year^− 1, while surface seawater pH decreased by 0.0017 ± 0.0001 pH units each year. The gradual acidification of subtropical gyre waters was primarily due to uptake of anthropogenic CO₂. We estimate that direct atmospheric acid deposition contributed 2% to the acidification of surface waters in the subtropical North Atlantic Ocean, although this value likely represents an upper limit. Acidifying deposition had negligible influence on seawater CO₂ chemistry of the Bermuda coral reef, with no evident impact on hard coral calcification.  相似文献