Geographical distribution of fish catches and temperature variations in the northeast Atlantic since 1945     

Rögnvaldur Hannesson 《Marine Policy》2007

Warming of the northeast Atlantic is expected to affect the location and productivity of fish stocks. It is examined whether variations in catches of cod, herring, mackerel, anchovy and sardines in the ICES statistical areas are related to variations in ocean temperature. Temperatures at certain locations along the Norwegian coast are taken as proxies for temperatures in the Norwegian Sea and the North Sea. It is found that the catches of cod in the North Sea are inversely correlated with temperature and that recruitment and catches of cod in the Norwegian Sea and the Barents Sea are positively related to temperature. There is also some indication of a positive correlation between temperature and the catches of mackerel in the North Sea and the Norwegian Sea, and between temperature and the catches of sardines in the North Sea.  相似文献   

北极海冰减少的气候效应研究   总被引：2，自引：0，他引：2  

魏立新  张海影 《海洋预报》2005,22(Z1):56-61

本文采用了OSU两层大气环流模式对特定的北极海冰进行数值模拟,研究北极海冰减少的气候效应.试验中海温一律取为气候平均值,北极海冰作为外强迫源影响大气,大气响应完全是环流内部调整的结果.本文对北极海冰减少后的大气环流特征进行了分析,特别是与中国的气温和降水之间的关系.  相似文献   

呼伦湖的近期扩张及其与全球气候变化的关系   总被引：10，自引：0，他引：10  

秦伯强  王苏民 《海洋与湖沼》1994,25(3):280-287

通过近２０多年湖泊水量平衡分析发现，湖泊水位变化主要由湖盆内径流补给量的丰枯决定。进一步分析揭示，呼伦湖地区乃至整个东北地区，本世纪以来随气温升高，随水有增加的趋势。降水增加导致入湖径流量，湖水位上升，呼伦湖本世纪以来的扩张与内蒙古东部地区其他内陆湖泊的变化一致，但这在我国乃至整个亚洲内陆干旱或半干旱区是独一无二的，为此成为这一地区气候变化的指示器。  相似文献   

Spatial Modeling and Analysis for Shoreline Change Detection and Coastal Erosion Monitoring   总被引：3，自引：0，他引：3  

Rongxing Li  Jung-Kuan Liu  Yaron Felus 《Marine Geodesy》2001,24(1):1-12

Coastal erosion presents a serious problem throughout U.S. coastal areas. The Ohio Geological Survey estimates that more than 3,200 acres of Ohio's Lake Erie shore have been lost to erosion since the 1870s, resulting in economic losses exceeding tens of millions of dollars per year. This article presents research results of a project that monitors shoreline erosion using high-resolution imagery and examines erosion causes. Spatial modeling and analysis methods are applied to the project area along the south shore of Lake Erie. The shoreline is represented as a dynamically-segmented linear model that is linked to a large amount of data describing shoreline changes. A new method computes an instantaneous shoreline using a digital water level model, a coastal terrain model, and bathymetric data. This method provides an algorithm for deriving the Mean-Lower Low Water (MLLW) and the Mean High Water (MHW) shorelines that are essential to navigation charts. The results describe a part of our effort towards a coastal spatial information infrastructure to support management and decision-making in the dynamic coastal environment.  相似文献   

Variability in oceanographic and ecological processes in the Canadian Arctic Archipelago     

C. Michel  R.G. Ingram  L.R. Harris 《Progress in Oceanography》2006,71(2-4):379

This paper brings together unpublished historical data sets and published literature to review the role of climatic, oceanographic and ecological processes in the marine ecosystem of the eastern Canadian Archipelago. Physical data include characteristics of the water masses, circulation patterns, sea ice conditions, and climatic records from 1950s onward. Biological data include unpublished data sets on nutrients, primary and secondary production, and sedimentation, which were collected during the 1980–1990s in the eastern Canadian Archipelago. These results show high year-to-year variability in nutrient inventories and ratios, the magnitude of the ice algae and phytoplankton bloom, the timing of ice algae sedimentation in the spring, and the composition of the zooplankton community. The significance of this high interannual variability and its effect on pelagic–benthic coupling processes is discussed in the context of climatic and oceanographic forcing, with emphasis on recent (past decade) Arctic changes. An estimate of total primary production in the Archipelago is also presented, along with published production estimates for other Arctic shelves, showing that the Archipelago may support up to 32% of the total primary production of Arctic shelves. The high year-to-year variability in production and carbon transfer pathways (e.g. pelagic versus benthic) in the Archipelago suggest that the system might be resilient to the increased variability in climatic conditions occurring in the past decade. However, this increased variability combined with directional change in climatic and oceanographic conditions might also modify the existing balance of ecological processes. For example, shifts in the timing of events appear to have already occurred in the past decade, with potential cascading effects throughout the ecosystem.  相似文献   

The regime shift of the 1920s and 1930s in the North Atlantic   总被引：6，自引：3，他引：6  

Kenneth F. Drinkwater   《Progress in Oceanography》2006,68(2-4):134

During the 1920s and 1930s, there was a dramatic warming of the northern North Atlantic Ocean. Warmer-than-normal sea temperatures, reduced sea ice conditions and enhanced Atlantic inflow in northern regions continued through to the 1950s and 1960s, with the timing of the decline to colder temperatures varying with location. Ecosystem changes associated with the warm period included a general northward movement of fish. Boreal species of fish such as cod, haddock and herring expanded farther north while colder-water species such as capelin and polar cod retreated northward. The maximum recorded movement involved cod, which spread approximately 1200 km northward along West Greenland. Migration patterns of “warmer water” species also changed with earlier arrivals and later departures. New spawning sites were observed farther north for several species or stocks while for others the relative contribution from northern spawning sites increased. Some southern species of fish that were unknown in northern areas prior to the warming event became occasional, and in some cases, frequent visitors. Higher recruitment and growth led to increased biomass of important commercial species such as cod and herring in many regions of the northern North Atlantic. Benthos associated with Atlantic waters spread northward off Western Svalbard and eastward into the eastern Barents Sea. Based on increased phytoplankton and zooplankton production in several areas, it is argued that bottom-up processes were the primary cause of these changes. The warming in the 1920s and 1930s is considered to constitute the most significant regime shift experienced in the North Atlantic in the 20th century.  相似文献   

Use of Continuous Plankton Recorder information in support of marine management: applications in fisheries, environmental protection, and in the study of ecosystem response to environmental change   总被引：2，自引：0，他引：2  

K. M. Brander  R. R. Dickson  M. Edwards 《Progress in Oceanography》2003,58(2-4):175

The Continuous Plankton Recorder (CPR) survey was conceived from the outset as a programme of applied research designed to assist the fishing industry. Its survival and continuing vigour after 70 years is a testament to its utility, which has been achieved in spite of great changes in our understanding of the marine environment and in our concerns over how to manage it. The CPR has been superseded in several respects by other technologies, such as acoustics and remote sensing, but it continues to provide unrivalled seasonal and geographic information about a wide range of zooplankton and phytoplankton taxa. The value of this coverage increases with time and provides the basis for placing recent observations into the context of long-term, large-scale variability and thus suggesting what the causes are likely to be. Information from the CPR is used extensively in judging environmental impacts and producing quality status reports (QSR); it has shown the distributions of fish stocks, which had not previously been exploited; it has pointed to the extent of ungrazed phytoplankton production in the North Atlantic, which was a vital element in establishing the importance of carbon sequestration by phytoplankton.The CPR continues to be the principal source of large-scale, long-term information about the plankton ecosystem of the North Atlantic. It has recently provided extensive information about the biodiversity of the plankton and about the distribution of introduced species. It serves as a valuable example for the design of future monitoring of the marine environment and it has been essential to the design and implementation of most North Atlantic plankton research.  相似文献   

SeagrassNet monitoring across the Americas: case studies of seagrass decline   总被引：2，自引：0，他引：2  

Frederick T. Short  Evamaria W. Koch  Joel C. Creed  Karine M. Magalhães  Eric Fernandez  & Jeffrey L. Gaeckle 《Marine Ecology》2006,27(4):277-289

Seagrasses are an important coastal habitat worldwide and are indicative of environmental health at the critical land–sea interface. In many parts of the world, seagrasses are not well known, although they provide crucial functions and values to the world's oceans and to human populations dwelling along the coast. Established in 2001, SeagrassNet, a monitoring program for seagrasses worldwide, uses a standardized protocol for detecting change in seagrass habitat to capture both seagrass parameters and environmental variables. SeagrassNet is designed to statistically detect change over a relatively short time frame (1–2 years) through quarterly monitoring of permanent plots. Currently, SeagrassNet operates in 18 countries at 48 sites; at each site, a permanent transect is established and a team of people from the area collects data which is sent to the SeagrassNet database for analysis. We present five case studies based on SeagrassNet data from across the Americas (two sites in the USA, one in Belize, and two in Brazil) which have a common theme of seagrass decline; the study represents a first latitudinal comparison across a hemisphere using a common methodology. In two cases, rapid loss of seagrass was related to eutrophication, in two cases losses related to climate change, and in one case, the loss is attributed to a complex trophic interaction resulting from the presence of a marine protected area. SeagrassNet results provide documentation of seagrass change over time and allow us to make scientifically supported statements about the status of seagrass habitat and the extent of need for management action.  相似文献   

The Aleutian Low, storm tracks, and winter climate variability in the Bering Sea     

S.N. Rodionov  N.A. Bond  J.E. Overland 《Deep Sea Research Part II: Topical Studies in Oceanography》2007,54(23-26):2560

Previous studies have found inconsistent results regarding how wintertime conditions in the Bering Sea relate to variations in the North Pacific climate system. This problem is addressed through analysis of data from the NCEP/NCAR Reanalysis for the period 1950–2003. Composite patterns of sea-level pressure, 500 hPa geopotential heights, storm tracks and surface air temperature are presented for four situations: periods of strong Aleutian Low, weak Aleutian Low, warm Bering Sea air temperatures, and cold Bering Sea air temperatures. Winter temperatures in the Bering Sea are only marginally related to the strength of the Aleutian Low, and are much more sensitive to the position of the Aleutian Low and to variations in storm tracks. In particular, relatively warm temperatures are associated with either an enhanced storm track off the coast of Siberia, and hence anomalous southerly low-level flow, or an enhanced storm track entering the eastern Bering Sea from the southeast. These latter storms do not systematically affect the mean meridional winds, but rather serve to transport mild air of maritime origin over the Bering Sea. The leading indices for the North Pacific, such as the NP and PNA, are more representative of the patterns of tropospheric circulation and storm track anomalies associated with the strength of the Aleutian Low than patterns associated with warm and cold wintertime conditions in the Bering Sea.  相似文献   

Understanding El Niño — The importance of Grey Literature in Coastal Ecosystem Research and Management     

Sven Thatje  Jürgen Laudien  Olaf Heilmayer  Cornelia E. Nauen 《Marine Policy》2007

Access to information about past states of the environment and social systems is fundamental to understand, and cope with, the challenges of climate change and over-exploitation of natural resources at the onset of the 21st century. The loss of (old) data is a major threat to understanding better and mitigating long-term effects of human activities and anthropogenic changes to the environment. Although this is intuitively evident for old and local literature of any kind, even present-day international publishing of papers without the underlying raw data makes access to basic information a crucial issue. Here, we summarise experience resulting from a EU-funded International Science & Technology Cooperation (INCO) project (CENSOR) addressing Coastal Ecosystem Research and Management in the El Niño Southern Oscillation (ENSO) context. We show that indeed “Grey Literature” is still one of the most important sources of knowledge about natural science research and management of natural resource systems in Latin American countries. We argue that public archiving of original data of present-day research and old (Grey) Literature and easy public access are important for appreciating today's global environmental challenges caused by human activities, both past and present.  相似文献