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1.
The Continuous Plankton Recorder (CPR) Type I was first used in Antarctic waters during the 1925–1927 Discovery Expedition, and has been used successfully for 70 years to monitor plankton in the North Sea and North Atlantic Ocean. Sixty-five years later the CPR as a Type II version returned to Antarctic waters when the Australian Antarctic Division initiated a survey of the Southern Ocean on RSV Aurora Australis south of Australia and west to Mawson. The objectives are to study regional, seasonal, interannual and long-term variability in zooplankton abundance, species composition and community patterns, as well as the annual abundance and distribution of krill larvae. The survey covers a large area from 60°E to 160°E, and south from about 48°S to the Antarctic coast—an area of more than 14 million km2. Tows are conducted throughout the shipping season, normally September to April, but occasionally as early as July (midwinter). The large areal and temporal scale means that it is difficult to separate temporal and geographical variation in the data. Hence, CPRs are now also towed on the Japanese icebreaker Shirase in collaboration with the Japanese Antarctic programme. Shirase has a fixed route and time schedule, travelling south on 110°E in early December and north on 150°E in mid-March each year, and will serve as an important temporal reference for measuring long-term interannual variability and to help interpret the Australian data. Since 1991, over 90 tows have been made, providing over 36,000 nautical miles of records. The most successful seasons to date have been the 1997/1998, 1999/2000 and 2000/2001 austral summers with 20, 31 and 26 tows, respectively. The 1999/2000 season included a unique, nearly simultaneous three-ship crossing of the Southern Ocean along 25° 30’E, 110°E and 157°E. Typical CPR tows show very high abundance of zooplankton in the uppermost 20 m of the permanently open ocean zone between the sea-ice zone and the Sub-Antarctic Front; this is an area thought to be oligotrophic. Appendicularians and small calanoid and cyclopoid copepods dominate the plankton. By comparison the surface waters of the sea-ice zone have low species diversity and abundances. Zooplankton data, and hence distribution patterns, can be time- and geo-coded to GPS data and environmental data collected by the ships’ underway monitoring system (e.g. fluorescence, water temperature, salinity, and meteorological data). 相似文献
2.
Since the beginning of the Continuous Plankton Recorder (CPR) survey in 1931, information on the abundance of a large number of plankton species or taxa has been obtained on a monthly basis in the northern North Atlantic. The many different ecological issues in which the survey has been involved have led to the application of a range of statistical methods. In this paper, we review some of the methods applied to the CPR data by presenting new and up-to-date analyses. Special attention is devoted to multivariate analysis, which has been used extensively to extract information from the CPR database. Results obtained from recently applied geostatistical methods on CPR data are then considered. An example of a time series decomposition by the use of Eigenvector filtering is presented to illustrate time-series analysis. 相似文献
3.
The Continuous Plankton Recorder: concepts and history, from Plankton Indicator to undulating recorders 总被引：1，自引：0，他引：1
P. C. Reid J. M. Colebrook J. B. L. Matthews J. Aiken Continuous Plankton Recorder Team 《Progress in Oceanography》2003,58(2-4):117
Alister Hardy conceived the Continuous Plankton Recorder (CPR) survey in the 1920s as a means of mapping near-surface plankton in space and time, interpreting the changing fortunes of the fisheries and relating plankton changes to hydrometeorology and climatic change. The seed he planted has grown to become the most extensive long-term survey of marine organisms in the world and the breadth of his vision becomes ever more apparent. The survey has now run for over 70 years and its value increases with every passing decade. Operating from ‘ships of opportunity’ the machines used are robust, reliable and easy to handle. Wherever possible, all the sampling and analytical methods have not been changed to maintain the consistency of the time series. Computerisation and the development of new statistical approaches have increased our ability to handle the large quantities of information generated and enhance the sensitivity of the data analyses. This overview, based on almost 900 papers, recounts the various phases in the history of the survey. It starts with the Indicator Survey (1921–1934), the deployment of the first CPR on the Discovery Expedition (1924–1927) and the early CPR survey in the North Sea (1931–1939). The survey reopened in 1946 after the Second World War and expanded across the North Atlantic to North America from 1959. Taxonomic studies were initiated and an emphasis was placed on patterns of distribution, which were seen to reflect the varying oceanographic conditions. The years 1968–1976 saw further expansion with operations even in the American Great Lakes, publication of a Plankton Atlas and initial evidence for a downward trend in plankton biomass. At about this time electronic instrumentation was attached to CPRs to make additional measurements and work was started on the development of a new generation of undulating Continuous Plankton and Environmental Recorders (CPERs). In 1976 the survey moved to Plymouth. Scientific priorities in the UK changed in the subsequent decade and funding became more difficult to secure even though some of the CPR papers being published at the time are now regarded as classics in plankton ecology. In 1988 the UK Natural Environment Research Council (NERC) decided to close the survey. An international rescue operation led to the creation of the Sir Alister Hardy Foundation for Ocean Science (SAHFOS) in 1990, which has continued with consortium funding from a number of countries, and from 1999 again included NERC. The scientific rationale of the survey has gained credibility as concern over climate change and other anthropogenic effects has grown and as the key role that plankton plays as an indicator of large-scale environmental conditions becomes ever more apparent. Recently, the survey became an integral component of the Global Ocean Observation System (GOOS) and expanded into the North Pacific. It plays a complementary role in many large international and multidisciplinary projects and is providing inspiration, advice and support to daughter surveys elsewhere in the world. At the start of a new millennium, Hardy’s vision from the 1920s is a powerful driving force not just in international biological oceanography, but in global environmental science. 相似文献
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S. D. Batten R. Clark J. Flinkman G. Hays E. John A. W. G. John T. Jonas J. A. Lindley D. P. Stevens A. Walne 《Progress in Oceanography》2003,58(2-4):193
The Continuous Plankton Recorder has been deployed for 70 years. Although modifications to the machine have been relatively minor, there has been a steady increase in the speed at which it is towed, creating a need to quantify what effects this may have had on its sampling characteristics. Additionally, because the CPR database is one of the longest and most geographically extensive biological time series in the world, and scientists are currently focusing on gaining understanding about climate-induced ecological changes, there is increasing pressure to quantify the sampling performance and relate the CPR data to data collected by other plankton samplers. Many of these issues of consistency and comparability have been investigated throughout the decades of the CPR survey. The primary aim of this study is to draw together the results of those investigations, updating or integrating them where applicable. A secondary aim is to use the CPR database to address other previously unexamined issues. We show that the increase in speed of tow has had no effect on the depth of sampling and the mechanical efficiency of the internal mechanism, but that at the highest tow speeds there is some evidence that flow may be reduced. Depth of tow may also be dependent on the ship operating a particular route. We describe the processing procedures used to ensure consistency of analysis and detail the changes in taxonomic resolution that have occurred through the course of the survey. Some consistency issues remain unresolved, such as the effects of adding heavy instrumentation to the attitude of the CPR in the water and possible effects on sampling performance. The reduction of flow caused by clogging of the filtering mesh has now been quantified through the addition of flowmeters and each CPR sample can now be calibrated for measured, or derived, filtered volume. Although estimates of abundances for large areas have been shown to be unaffected by recalibration, absolute quantification of plankton abundance is necessary to enable comparisons with other sampling devices. Several studies have now been undertaken that compare plankton abundances obtained with the CPR with those obtained using vertical nets at specific locations on the European continental shelf. Although catches by the CPR are almost always lower, seasonal cycles are replicated in each comparison, and interannual variability generally agrees between time series. The relative catch rates for an individual species by each device appear to be consistent, probably because of the organisms’ behaviour and attributes of the sampling device. We are now able to develop calibration factors to convert CPR catches to absolute abundances that can be integrated with other data sets where appropriate, which should increase the applicability and utility of CPR data. 相似文献
6.
A set of 103 997 free air gravity anomalies in 6′x 10′ blocks has been compiled covering Europe including the Mediterranean Sea, North Sea, Norwegian Sea, Baltic Sea and parts of the North Atlantic Ocean. Concerning sea areas, this data set is based on a collection of point free air gravity anomalies. Anomalies for land areas have been compiled resp. computed from free air gravity anomaly maps or Bouguer anomaly maps and partly from supplied mean values of convenient small block size. Remaining gaps have been interpolated by means of least squares prediction filtering. The precision of the compiled mean free air gravity anomalies is estimated to ±7 mgal, verified by a comparison of independent gravity anomaly sets. 相似文献
7.
E.J.H. Head D.D. Sameoto 《Deep Sea Research Part II: Topical Studies in Oceanography》2007,54(23-26):2686
Continuous Plankton Recorder (CPR) sampling on the Newfoundland and Scotian shelves covers three multi-year periods characterised by negative (1962–1971), positive (1992–2000) and negative/neutral (2001–2003) values of the NAO index. Water temperatures respond differently to changes in the NAO in different regions: a positive NAO index tends to lead to reduced temperatures on the Newfoundland shelf and to increased temperatures on the central/western Scotian shelf, and a negative NAO index to the reverse. Since the 1960s, the hydrographic changes due to the NAO have been superimposed on a freshening of the water column throughout the region, which is attributed to increased contribution of Arctic water outflow. Changes in plankton abundance measured by the CPR for the three time periods were generally, but not always, similar on the Newfoundland and eastern and western regions of the Scotian shelf, although Arctic species (e.g. Calanus glacialis, Calanus hyperboreus) were notably more abundant and warm water species (e.g. Metridia lucens, euphausiids) less abundant on the Newfoundland shelf than on the Scotian shelf. Three categories of phytoplankton (colour, diatoms, dinoflagellates) increased in abundance in the 1990s, and these increases generally persisted into 2001–2003. This is believed to be a response to the persistent freshening of the water column, probably due to increased stratification. The Arctic species C. glacialis and C. hyperboreus also showed persistent increases in abundance after 1992, perhaps due to increased transport from the Arctic, although the abundance of the Arctic slope water species Metridia longa decreased. Two groups, Calanus 1–4 and euphausiids, both thought to play important roles in the food chain, showed persistent decreases in abundance after 1992, especially on the Newfoundland shelf. In all regions, Calanus finmarchicus 5–6, Oithona spp. and Centropages hamatus abundance changed in association with variations in the NAO, although no common mechanism could be identified. C. finmarchicus 5–6 abundance decreased in the 1990s and increased after 2001, while the other two species showed the opposite pattern. Centropages typicus and M. lucens abundance on the Scotian shelf increased with rising temperature. This is attributed to increased production rates for the former and an increased influx of warm, M. lucens-rich, slope water on to the shelf for the latter. A comparison between ring net and CPR sampling on the Newfoundland shelf suggests that the Calanus 1–4 category is dominated by C. finmarchicus and that late stage C. glacialis and C. hyperboreus are grossly under-sampled compared to late stage C. finmarchicus. 相似文献
8.
Andrew J. Kenny Hein Rune Skjoldal Georg H. Engelhard Peter J. Kershaw James B. Reid 《Progress in Oceanography》2009,81(1-4):132
An ecosystem approach to the management of the marine environment has received considerable attention over recent years. However, there are few examples which demonstrate its practical implementation. Much of this relates to the history of existing marine monitoring and assessment programmes which (for many countries) are sectoral, making it difficult to integrate monitoring data and knowledge across programmes at the operational level.To address this, a scientific expert group, under the auspices of the International Council for the Exploration of the Sea (ICES), prepared a plan for how ICES could contribute to the development of an Integrated Ecosystem Assessment (IEA) for the North Sea by undertaking a pilot study utilising marine monitoring data. This paper presents the main findings arising from the expert group and in particular it sets out one possible integrated approach for assessing the relative significance of environmental forcing and fishing pressure on the ecological status of the North Sea, it then compares the findings with assessments made of other Large Marine Ecosystems (LMEs).We define the North Sea ecosystem on the basis of 114 state and pressure variables resolved as annual averages between 1983 and 2003 and at the spatial scale of ICES rectangles. The paper presents results of integrated time-series and spatial analysis which identifies and explains significant spatial and temporal gradients in the data. For example, a significant shift in the status of the North Sea ecosystem (based upon 114 state-pressure variables) is identified to have occurred around 1993. This corresponds to previously documented shifts in the environmental conditions (particularly sea surface temperature) and changes in the distribution of key species of plankton (Calanus sp.), both reported to have occurred in 1989. The difference in specific timing between reported regime shifts for the North Sea may be explained, in part, by time-lag dependencies in the trophic structure of the ecosystem with shifts in higher trophic levels occurring later than 1989.By examining the connection (or relatedness) between ecosystem components (e.g. environment, plankton, fish, fishery and seabirds) for the identified regime states (1983–1993; 1993–2003) we conclude that both the North Sea pelagic and benthic parts of the ecosystem were predominantly top-down (fishery) controlled between 1983 and 1993, whereas between 1993 and 2003 the pelagic stocks shifted to a state responding mainly to bottom-up (environment) influences. However, for the demersal fish stocks between 1993 and 2003 top-down (fishery) pressure dominated even though over this period significant reductions in fishing pressure occurred. The present analysis, therefore, provides further evidence in support of the need for precautionary management measures taken in relation to setting fishery quotas. 相似文献
9.
Ingrid KrönckeHenning Reiss Jacqueline D. EggletonJohn Aldridge Magda J.N. BergmanSabine Cochrane Johan A. CraeymeerschSteven Degraer Nicolas DesroyJean-Marie Dewarumez Gerard C.A. DuineveldKarel Essink Hans HillewaertMarc S.S. Lavaleye Andreas MollStefan Nehring Richard NewellEivind Oug Thomas PohlmannEike Rachor Mike RobertsonHeye Rumohr Michaela SchratzbergerRebecca Smith Edward Vanden Berghe Jan van DalfsenGert van Hoey Magda VincxWouter Willems Hubert L. Rees 《Estuarine, Coastal and Shelf Science》2011,94(1):1-15
The North Sea Benthos Project 2000 was initiated as a follow-up to the 1986 ICES North Sea Benthos Survey with the major aim to identify changes in the macrofauna species distribution and community structure in the North Sea and their likely causes.The results showed that the large-scale spatial distribution of macrofauna communities in the North Sea hardly changed between 1986 and 2000, with the main divisions at the 50 m and 100 m depth contours. Water temperature and salinity as well as wave exposure, tidal stress and primary production were influential environmental factors on a large (North Sea-wide) spatial scale.The increase in abundance and regional changes in distribution of various species with a southern distribution in the North Sea in 2000 were largely associated with an increase in sea surface temperature, primary production and, thus, food supply. This can be most likely related to the North Sea hydro-climate change in the late 1980s influenced by the variability in the North Atlantic Oscillation (NAO). Only one cold-temperate species decreased in abundance in 2000 at most of the stations. Indications for newly established populations of offshore non-native species were not found.Differences in macrofauna community structure on localised spatial scales were predominantly found north of the 50 m depth contour off the British coast along the Flamborough Head Front towards the Dogger Bank, off the coast of Jutland and at the Frisian Front. These changes were most likely attributed to stronger frontal systems in 2000 caused by the increased inflow of Atlantic water masses in relation to the hydro-climate change in the late 1980s. 相似文献
10.
W. van Raaphorst C. J. M. Philippart J. P. C. Smit F. J. Dijkstra J. F. P. Malschaert 《Journal of Sea Research》1998,39(3-4)
Distribution patterns of suspended particulate matter (SPM) in the surface water of the North Sea were calculated on the basis of: (1) the 1973–1993 data base of the EC MAST North West European Shelf Programme (NOWESP); and (2) composite reflectance images constructed from data that were collected by the NOAA/AVHRR satellite in 1990–1991. Three models were used for interpolating the in situ data: (1) a distance-weighted interpolation algorithm in which only the in situ data are taken into account; (2) an algorithm in which the ratios between the measured SPM concentrations and reflectances are interpolated, and the distribution of SPM is calculated from the field of interpolated ratios and the synoptic reflectance image; and (3) a distance-weighted algorithm similar to model-1, but with an additional weight factor that is based on local differences in reflectance. The models were tested for periods of 1 and 3 weeks in September 1990 and January 1991, and for the merged set consisting of all in situ data measured in September and January, respectively, between 1973 and 1993. Model-2 and -3 gave largely similar results and had a performance superior to model-1, particularly because they showed more detailed structures in the spatial distributions. Validations and cross-validations showed that the absolute concentrations of SPM predicted by the models were too low at high in situ concentrations and too high at low in situ concentrations. This shortcoming was due to the relatively high degree of smoothing that we applied in the models to account for the large variance of the in situ data. Semivariograms and correlograms indicated that the in situ data had substantial variability and were poorly correlated even at short distances. Only for the 20-year-merged data set did some correlation (
%) exist for stations
km from each other. Monthly distributions of SPM were calculated with model-3 and the 20-year data set. The distributions confirm the main patterns previously found by others, such as the turbidity plume crossing the North Sea from southeast England towards the depository in the Skagerrak and the Norwegian Channel. The distributions indicate that materials from this plume may be deposited in the central North Sea in spring and summer and eroded again in autumn and winter. Areas with maximum SPM concentrations were identified off the Belgian coast and north of the Wadden Sea, particularly in winter, from which particles are entrained into the main current in a narrow strip along the continental coast to the German Bight. The results suggest that the two main fluxes of SPM in the North Sea, off England and along the continental coast, remain largely separated until they both end in the Skagerrak. 相似文献
11.
Regime shift and principal component analysis of a spatially disaggregated database capturing time-series of climatic, nutrient and plankton variables in the North Sea revealed considerable covariance between groups of ecosystem indicators. Plankton and climate time-series span the period 1958–2003, those of nutrients start in 1980. In both regions, the period from 1989 to 2001 identified in principal component 1 had warmer surface waters, higher Atlantic inflow and stronger winds, than the periods before or after. However, it was preceded by a regime shift in both open (PC2) and coastal (PC3) waters during 1977 towards more hours of sunlight and higher water temperature, which lasted until 1997. The relative influence of nutrient availability and climatic forcing differed between open and coastal North Sea regions. Inter-annual variability in phytoplankton dynamics of the open North Sea was primarily regulated by climatic forcing, specifically by sea surface temperature, Atlantic inflow and co-varying wind stress and NAO. Coastal phytoplankton variability, however, was regulated by insolation and sea surface temperature, as well as Si availability, but not by N or P. Regime shifts in principal components of hydrographic and climatic variables (explaining 55 and 61% of the variance in coastal and open water variables) were detected using Rodionov's sequential t-test. These shifts in hydroclimatic variables which occurred around 1977, 1989, 1997 and 2001, were synchronized in open and coastal waters, and were tracked by open water chlorophyll and copepods, but not by coastal plankton. North–central–south or open-coastal spatial breakdowns of the North Sea explained similar amounts of variability in most ecosystem indicators with the exception of diatom abundance and chlorophyll concentration, which were clearly better explained using the open-coastal configuration. 相似文献
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A large amount of nutrient and chlorophyll data from the North Sea were compiled and organised in a research data base to produce annual cycles on a relatively fine spatial resolution of 1° in each horizontal direction. The data originate from many different sources and were partly provided by the ECOMOD data base of the Institut fur Meereskunde in Hamburg and partly by ICES in Copenhagen to cover the time range from 1950 to 1994. While the annual cycles of nutrients and chlorophyll derived for the continental coastal zone are representative for the decade 1984–1993 only, those for the remaining parts of the North Sea may be considered climatological annual cycles based on data from more than four decades. The composite data set of climatological annual cycles of medians and their climatological ranges is well suited to serve for validational and forcing purposes for ecosystem models of the North Sea, which have a resolution larger than or equal to 1° in both longitude and latitude. The annual cycles of the macronutrients and chlorophyll presented here for 1° × 1° squares in the North Sea show especially that sufficient observational data exist to provide initial, forcing and validational data for the simulations with the 130-box setup (ND130) of the ecosystem model ERSEM. The annual cycles presented give a clear picture for the whole of the North Sea. The highest concentrations occur at the continental coasts as a result of continued river input, which is added to the ongoing atmospheric input over the North Sea. Also, from the Atlantic Ocean water with relatively high nutrient concentrations enters the North Sea via the northern boundary. In the productive areas on and around the Dogger Bank nutrient concentrations are lower than in the other parts of the North Sea, even in winter. The areas with seasonal stratification have very different annual cycles in the upper (0–30 m) and lower layers (30 m-bottom). The shallow boxes are fully mixed and exhibit a relatively fast increase of nutrient concentrations caused by summer regeneration of nutrients. 相似文献
14.
Grgory Beaugrand 《Progress in Oceanography》2004,60(2-4):245
This paper focuses on the ecosystem regime shift in the North Sea that occurred during the period 1982–1988. The evidence for the change is seen from individual species to key ecosystem parameters such as diversity and from phytoplankton to fish. Although many biological/ecosystem parameters and individual species exhibited a stepwise change during the period 1983–1988, some indicators show no evidence of change. The cause of the regime shift is likely to be related to pronounced changes in large-scale hydro-meteorological forcing. This involved activating of complex intermediate physical mechanisms which explains why the exact timing of the shift can vary from 1982 to 1988 (centred around two periods: 1982–1985 and 1987–1988) according to the species or taxonomic group. Increased sea surface temperature and possibly change in wind intensity and direction at the end of the 1970s in the west European basin triggered a change in the location of an oceanic biogeographical boundary along the European continental shelf. This affected both the stable and substrate biotope components of North Sea marine ecosystems (i.e. components related to the water masses and components which are geographically stable) circa 1984. Large-scale hydro-climatic forcing also modified local hydro-meteorological parameters around the North Sea after 1987 affecting the stable biotope components of North Sea ecosystems. Problems related to the detection and quantification of an ecosystem regime shift are discussed. 相似文献
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将伴随同化方法用于渤、黄海NPZD三维浮游生态动力学模型的研究中,利用1998年～2006年的SeaWiFS叶绿素资料作为观测数据进行同化实验,优化难以确定的生态参数.文中对参数在整个计算区域取常数时进行了优化,同时尝试了一种新的参数化方案,即在海区中选取一些点作为独立参数点,其它点的参数由独立参数点的值经过线性插值得到,优化独立点的参数后得到所有计算格点的参数.针对这两种不同的参数化方案做了一系列对比实验,结果表明利用伴随同化方法反演空间分布的参数能有效地提高数值模拟的精度. 相似文献
17.
M.R. Heath J. Rasmussen J. Allen A.S. Brierley A. Bunker R. Davidson W.S.C. Gurney S. Hay A.G. Hirst A. Ingvarsdottir P. Lindeque D. Montagnes R. Pollard R.A. Saunders G. Smerdon P. Walsham L. Webster 《Progress in Oceanography》2008,76(1):39-88
Continuous Plankton Recorder data suggest that the Irminger Sea supports a major proportion of the surface-living population of the copepod Calanus finmarchicus in the northern North Atlantic, but there have been few studies of its population dynamics in the region. In this paper, we document the seasonal changes in the demographic structure of C. finmarchicus in the Irminger Sea from a field programme during 2001/2002, and the associations between its developmental stages and various apparent bio-physical zones. Overwintering stages were found widely at depth (>500 m) across the Irminger Sea, and surviving females were widely distributed in the surface waters the following spring. However, recruitment of the subsequent generation was concentrated around the fringes of the Irminger Sea basin, along the edges of the Irminger and East Greenland Currents, and not in the central basin. In late summer animals were found descending back to overwintering depths in the Central Irminger Sea. The key factors dictating this pattern of recruitment appear to be (a) the general circulation regime, (b) predation on eggs in the spring, possibly by the surviving G0 stock, and (c) mortality of first feeding naupliar stages in the central basin where food concentrations appear to be low throughout the year.We compared the demographic patterns in 2001/2002 with observations from the only previous major survey in 1963 and with data from the Continuous Plankton Recorder (CPR) surveys. In both previous data sets, the basic structure of G0 ascent from the central basin and G1 recruitment around the fringes was a robust feature, suggesting that it is a recurrent phenomenon. The Irminger Sea is a complex mixing zone between polar and Atlantic water masses, and it has also been identified as a site of sporadic deep convection. The physical oceanographic characteristics of the region are therefore potentially sensitive to climate fluctuations. Despite this, the abundance of C. finmarchicus in the region, as measured by the CPR surveys, appears not to have responded to climate factors linked to the North Atlantic Oscillation Index, in contrast with the stocks in eastern Atlantic areas. We speculate that this may because biological factors (production and mortality), rather than transport processes are the key factors affecting the population dynamics in the Irminger Sea. 相似文献
18.
Frdric Gazeau Stephen V. Smith Bernard Gentili Michel Frankignoulle Jean-Pierre Gattuso 《Estuarine, Coastal and Shelf Science》2004,60(4):673-694
The geomorphic, oceanographic, terrestrial and anthropogenic attributes of the European coastal zone are described and published data on ecosystem function (primary production and respiration) are reviewed. Four regions are considered: the Baltic Sea, Mediterranean Sea, Black Sea and the European Atlantic coast including the North Sea. The metabolic database (194 papers) suffers from a non-homogeneous geographical coverage with no usable data for the Black Sea which was therefore excluded from this part of our study. Pelagic gross primary production in European open shelves is, by far, the most documented parameter with an estimated mean of 41 mmol C m−2 d−1, the lowest value is reported in the Mediterranean Sea (21 mmol C m−2 d−1) and the highest one in the Atlantic/North Sea area (51 mmol C m−2 d−1). Microphytobenthic primary production, mostly measured in shallow areas, is extrapolated to the entire 0–200 m depth range. Its contribution to total primary production is low in all regions (mean: 1.5 mmol C m−2 d−1). Although macrophyte beds are very productive, a regional production estimate is not provided in this study because their geographical distribution along the European coastline remains unknown. Measurements of pelagic community respiration are clearly too sparse, especially below the euphotic zone, to yield an accurate picture of the fate of organic matter produced in the water column. With a mean value of 17 mmol C m−2 d−1, benthic community respiration consumes approximately 40% of the pelagic organic matter production. Estuaries generally exhibit high metabolic rates and a large range of variation in all parameters, except microphytobenthic primary production. Finally, the problem of eutrophication in Europe is discussed and the metabolic data obtained in the framework of the Land–Ocean Interactions in the Coastal Zone (LOICZ) project are compared with available direct measurements of net ecosystem production. 相似文献
19.
At interannual to multidecadal time scales, much of the oceanographic and climatic variability in the North Atlantic Ocean can be associated with the North Atlantic Oscillation (NAO). While evidence suggests that there is a relationship between the NAO and zooplankton dynamics in the North Atlantic Ocean, the phytoplankton response to NAO-induced changes in the environment is less clear. Time series of monthly mean phytoplankton colour values, as compiled by the Continuous Plankton Recorder (CPR) survey, are analysed to infer relationships between the NAO and phytoplankton dynamics throughout the North Atlantic Ocean. While a few areas display highly significant (p < 0.05) trends in the CPR colour time series during the period 1948–2000, nominally significant (p < 0.20) positive trends are widespread across the basin, particularly on the continental shelves and in a transition zone stretching across the Central North Atlantic. When long-term trends are removed from both the NAO index and CPR colour time series, the correlation between them ceases to be significant. Several hypotheses are proposed to explain the observed variability in the CPR colour and its relationship with climate in the North Atlantic. 相似文献
20.
Warm eddy movements in the eastern Japan Sea 总被引：1，自引：0，他引：1
Yutaka Isoda 《Journal of Oceanography》1994,50(1):1-15
Warm eddy movements and their areal extent in the eastern Japan Sea were described by presenting space-time diagrams for the warm eddy locations and magnitudes. The analyzed data were compiled from Japan Maritime Safety Agency thermal maps at 200 m depth from 1985 to 1992. Two to four warm eddies always existed in the eastern Japan Sea and exhibited both internnual and annual signals. We found that warm eddies were generated in spring around Oki Spur at least three times during the analyzed period of eight years, moved eastward, and interacted with neighboring warm eddies, which were involved in coalescences or separations. The warm eddy distributions off Noto Peninsula have clear seasonal preference. Warm eddies moved eastward from Noto Peninsula in winter-spring to North Japan in the next winter, with mean translation speeds of 0.5–2 cm s–1. Warm eddies reaching North Japan typically decayed during a few month after splitting into two or three mesoscale warm eddies. 相似文献