ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Publication Date: 2007-05-10
    Print ISSN: 1468-2702
    Electronic ISSN: 1468-2710
    Topics: Geography , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2009-11-11
    Description: Global warming is predicted to alter the ocean's biological productivity. But how will we recognise the impacts of climate change on ocean productivity? The most comprehensive information available on the global distribution of ocean productivity comes from satellite ocean colour data. Now that over ten years of SeaWiFS data have accumulated, can we begin to detect and attribute global warming trends in productivity? Here we compare recent trends in SeaWiFS data to longer-term records from three biogeochemical models (GFDL, IPSL and NCAR). We find that detection of real trends in the satellite data is confounded by the relatively short time series and large interannual and decadal variability in productivity. Thus, recent observed changes in chlorophyll, primary production and the size of the oligotrophic gyres cannot be unequivocally attributed to the impact of global warming. Instead, our analyses suggest that a time series of ~40 yr length is needed to distinguish a global warming trend from natural variability. Analysis of modelled chlorophyll and primary production from 2001–2100 suggests that, on average, the global warming trend will not be unambiguously separable from decadal variability until ~2055. Because the magnitude of natural variability in chlorophyll and primary production is larger than, or similar to, the global warming trend, a consistent, decades-long data record must be established if the impact of climate change on ocean productivity is to be definitively detected.
    Print ISSN: 1810-6277
    Electronic ISSN: 1810-6285
    Topics: Biology , Geosciences
    Published by Copernicus on behalf of European Geosciences Union.
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
  • 4
    Publication Date: 2015-09-22
    Description: The relationship between physical properties of the water column and spatial patchiness of phytoplankton spring bloom development on the Greenland shelf edge and in the Irminger Sea was investigated using data collected during a spring cruise (April and May 2002). The observations confirm a strong relationship between the onset and stage of bloom development and the stratification induced by freshwater input to the surface layer in the shelf region. Interestingly, at the shelf, in the region influenced by melting of the seasonal ice-cover, the vertical distribution of chlorophyll a showed a subsurface maximum at ca. 25 m depth at several stations. Since nutrients were not exhausted at these stations, such a pattern does not conform to the general picture of a spring bloom. In contrast, in the open ocean part of the Irminger Sea pre-bloom conditions and a retarded development of the phytoplankton population were observed with low, more uniform distribution of chlorophyll a. The nitrate drawdown was estimated at between 16.5 and 270 µm m–2 (mean 108.6 ± 82.2 µm m–2) and the new primary production was estimated to be between 1.3 and 21.4 g C m–2 (8.6 ± 6.5 g C m–2), corresponding to 0.42 g C m–2 d–1. The phytoplankton community in the melting ice zone consisted of Phaeocystis sp., small flagellates (〈 4 µm) and picoplankton, while diatoms were less abundant. Phaeocystis sp. contributed up to 15 g C m–2 to the carbon biomass (70% of total carbon measured), whereas the contribution of diatoms and flagellates to carbon biomass was relatively low, with up to 1.2 g C m–2 (5.7%) and up to 2.5 g C m–2 (11.7%), respectively. On the shelf the bloom starts at the very beginning of stabilisation (elevated N2 values) which results solely from the release of meltwater. The locally restricted water stability leads to a patchy phytoplankton distribution in the Irminger Sea.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2015-09-22
    Description: 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.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2021-05-19
    Description: Over the past decade, exports of fish and fishery products from developing countries have increased rapidly. However, one of the major challenges facing developing countries in seeking to maintain and expand their share of global markets is stricter food safety requirements in industrial countries. Kenyan exports of Nile perch to the European Union provide a notable example of efforts to comply with such requirements, overlaid with the necessity to overcome restrictions on trade relating to immediate food safety concerns. Although food safety requirements were evolving in their major markets, most notably the EU, most Kenyan exporters had made little attempt to upgrade their hygiene standards. Likewise, the legislative framework of food safety controls and facilities at landing sites remained largely unchanged. Both exporters and the Kenyan government were forced to take action when a series of restrictions were applied to exports by the EU over the period 1997 to 2000. Processors responded by upgrading their hygiene controls, although a number of facilities closed, reflecting significant costs of compliance within the context of excess capacity in the sector. Remaining facilities upgraded their hygiene controls and made efforts to diversify their export base away from the EU. Legislation and control mechanisms were also enhanced. Hygiene facilities at landing beaches were improved, but remain the major area of weakness. The Kenyan case illustrates the significant impact that stricter food safety requirements can have on export-oriented supply chains. It also demonstrates how such requirements can exacerbate existing pressures for restructuring and reform, while prevailing supply and capacity issues constrain the manner in which the supply chain is able to respond. In Kenya most of the concerted effort to comply with these requirements was stimulated by the sudden loss of market access in very much a “crisis management” mode of operation, illustrating the importance of responding to emerging food safety requirements in a proactive and effective manner. This paper - a product of the International Trade Department, Poverty Reduction and Economic Management Network - is part of a larger effort in the network to understand the challenges and opportunities facing developing countries associated with evolving international standards for food and other products.
    Description: Published
    Keywords: Development economics ; Private sector ; Public Policy Fishing Industry ; Environmental economics & policies ; Fisheries ; Agricultural Knowledge & Information Systems ; Agribusiness & Markets ; Coastal and marine resources ; Fishery management ; Fishery products ; Fishery resources ; Food availability ; Aquaculture development ; Aquaculture economics ; Fishery economics ; Fishery management ; Fishery products ; Food availability
    Repository Name: AquaDocs
    Type: Working Paper , Non-Refereed
    Format: 857035 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...