A study of the response of chlorophyll-a biomass to a winter upwelling event off Western Iberia using SeaWiFS and in situ data

Observations of a winter upwelling event off Western Iberia shelf/slope in the area of influence of the Western Iberia Buoyant Plume (WIBP) were conducted in February 2000. Spatial patterns and time evolution of the chlorophyll-a (chl-a) biomass are analysed, based on in situ and satellite data. SeaWiFS-derived chl-a concentration L2 products were used to track the chlorophyll front and estimate its westward migration velocity (maximum up to 29 km day⁻¹), as well as to characterize the frontal system and its evolution. A method associating the type of spectral signature of a pixel to the fraction of chlorophyll probed by SeaWiFS enabled the estimation of the chl-a biomass within error intervals. High chlorophyll concentrations (for wintertime) were observed over the shelf and slope, up to large distances to the coast. Due to the WIBP, a shallow Ekman layer developed, being nearly coincident with the stratified upper meters. The transport comprised westward advection and stretching of the plume, with little entrainment with the offshore deep mixed layer waters. The relative enlargement of the total area of the Inside-Front Zone (IFZ) during the upwelling event was roughly accompanied by the maintenance of the average biomass per unit of area, considering the water column up to depths of interest. This suggests that there was a net increase of chl-a biomass inside the water column associated with the IFZ, roughly proportional to the increase in the IFZ area. Retention of phytoplankton in the shallow stratified nutrient-rich waters of the WIBP was a key factor for this increase in chl-a biomass.     

The winter St. Helena climate index and extreme Benguela upwelling

Climate changes in the subtropical South-east Atlantic turn out to be well described by the St. Helena Island Climate Index (HIX) and observed fluctuations are in good agreement with inter-decadal variability of the entire South Atlantic Ocean. Year-to-year variations of the averaged austral winter HIX (July–September), representative of the main upwelling season, were compared with (i) corresponding averages of the geostrophic alongshore component of the south-east trade wind (SET) between St. Helena Island in the south-west and Luanda/Angola in the north-east, (ii) the meridional distribution of surface waters colder than 13 °C to characterise intense Benguela upwelling (IBU), and (iii) the meridional position of the Angola-Benguela Frontal Zone (ABFZ) determined by means of sea surface temperature images for offshore distances between 50 and 400 km. Temporal changes of these parameters were investigated and showed that the frequency of consecutive years of strong and relaxed Benguela upwelling is characterised by a quasi-cycle of about 11–14 years. It is proposed that the index of the winter HIX may be used as a ‘surveyor’s rod' to describe interannual changes in the Benguela upwelling regime as well as those of the embedded marine ecosystem.     

Evolution of the open-sea eddy ALGERS'98 in the Algerian Basin with Lagrangian trajectories and remote sensing observations

The westward evolution of an open-sea anticyclonic eddy along the western Algerian Basin is shown, for the first time, by means of 15 buoy trajectories and remote sensing observations. For 3 months, the buoy trajectories described several anticyclonic loops in periods of 4–21 days. The eddy's movement, translation, and rotation were separated with a kinematic model, resulting in a mean translation speed of 2 km/day, which fits the self-propulsion speed predicted on theoretical models for isolated eddies on a beta plane. Fluctuations in translation speed were associated with advection of the mean flow and topographic interactions. Both mechanisms changed the eddy's horizontal shape from circular to elliptical, inducing fluctuations in its swirl velocity and solid-body rotation. The initial stage of the eddy is an isolated asymmetric dipole, comprised by a small cyclone and a large anticyclone, the latter generated from a frontal instability, which under the Coriolis term acquires anticyclonic relative vorticity. During its first days of life, the anticyclonic eddy was shallow Ro=0.9 and small (diameter less than 50 km). Later on, it reached a diameter of 150 km and a vertical structure of 3 km (Ro=0.1). A retrospective analysis with infrared images shows that the eddy's generation took place at about 3–4°E. Then, the eddy completed a counterclockwise circuit never before reported in other studies and ended up at the entrance of the Algerian Basin, where the interaction with the topography and the coastal instability induced its decay. The eddy's life span was 10 months. Computations of the heating rate following clusters of buoy trajectories show fluctuations throughout the eddy's journey, induced by advection and a seasonal warming.     

航运与广州城市变迁

广州自古就是“青山半入城,六脉皆通海”的滨海城市。独特的海江联运网络推动了广州海上交通与贸易的发达,也促成了既中外兼容又具有浓烈地方特色的广府文化的形成。可以说,航运是广州城市化进程中的蓝色推动力。     

基于沿海开发背景的南通高职院校服务地方经济社会探析

文章分析了南通地区高职院校在服务南通地方经济方面的作用,指出了存在的问题,并从打造人才基地、提供人才培训与技术服务、提升技能培训的国际化水平等几方面提出了相应的解决措施,具有一定的指导价值。     

Catalyzing Coastal Management in Kenya and Zanzibar: Building Capacity and Commitment

Site-based projects were initiated in Chawka Bay-Paje, Zanzibar, and Nyali-Bamburi-Shanzu, Kenya, to demonstrate the benefits of an integrated coastal management (ICM) approach for addressing coastal issues such as tourism development and enhancement of resource-dependent village economies in eastern Africa. A two-year, multidonor project used three primary strategies to make rapid, but sustainable, progress toward ICM. These included using interagency government teams for ICM planning, adopting an internationally recognized framework for ICM as a project ''road map,'' and explicitly incorporating capacity-building strategies into all aspects of the project. Within two years, integrated ICM action strategies, prepared through participatory processes, were being implemented at both sites, and both teams were working to expand the scale and scope of ICM in their nation. More importantly, the project helped create committed, capable, interagency groups that continue to work together to address urgent ICM issues.     

Co-management of Tropical Coastal Zones: The Case of the Soufriere Marine Management Area,St. Lucia,WI

Centralized, top-down fisheries management models based on biological stock-recruitment have, at best, achieved limited success when adapted to Third World fisheries. Comanagement, a resource management approach oriented towards resource users and their communities, has been proposed as an alternative strategy for managing Third World fisheries. We examine the initial success and subsequent problems of one such collaborative coastal zone management project on St. Lucia's leeward coast. Factors that must be considered in the development, implementation, and maintenance of coastal comanagement systems operating in the contexts of tropical marine ecosystems in developing nations are identified and discussed.     

Extant Legal and Jurisdictional Constraints on Irish Coastal Management

The success of any coastal zone management policy is dependent on, among other things, effective legislation and its enforcement. This article examines some possible legal constraints on the implementation of an integrated coastal zone management policy in Ireland. An introduction to the existing legal framework is provided, and the inconsistencies and ambiguities related, in particular, to jurisdiction and area of responsibility are highlighted. In particular the effect of land ownership and property rights on coastal zone management are examined with reference to two popular resort beaches in County Donegal, Ireland. While a revision of the relevant legislation is desirable, it is probably unrealistic; however, powers are available to the various institutions involved in coastal management that are currently unused. These are reviewed and their potential to improve coastal zone management is discussed.     

Governing Coastal Spaces: The Case of Disappearing Science in Integrated Coastal Zone Management

Scientific knowledge is central to “good” governance of coastal spaces: developing methods through which the complexities of the coastal zone can be understood by stakeholders to improve the sustainable management of coastal systems. Enhancing our knowledge of the range of processes that shape coastal spaces and define the total behavioural environment of the system remains a primary challenge for the coastal research community. However, this article raises the argument that current approaches to Integrated Coastal Zone Management (ICZM)—the preferred governing framework for the coastal environment, do not give sufficient emphasis to this fundamental need. Improving the basic scientific knowledge that underpins policymaking at the coast is argued to be urgently needed. Issues such as that of developing a communality of the purpose and approach between stakeholders within the coastal zone (through conflict resolution and access to information, for example) seem to claim the rights of the integrated management research agenda. However, the very nature of ICZM as “worthwhile coastal management” requires that integrated management represents more than a governing framework. Successful integration in coastal management must also be underpinned by knowledge of the integrated behavior of the system. Science has an increasingly marginalized position within ICZM and as a result geographers, contributing knowledge of the patterns and processes of the human and environmental landscapes, are also becoming a disappearing breed in integrated coastal management.     

Marine and coastal protected areas in Latin America: A preliminary assessment

Abstract

One approach to the management of coastal and marine areas is the establishment of protected areas (e.g., reserves, parks, sanctuaries). Under the general rubric of “marine reserves,”; this paper examines the Latin American experience with this strategy. A comprehensive table lists most, if not all, national or state declared parks or reserves. The table is organized by country. All Latin American nations have, to a varying extent, declared marine parks and protected areas. The authors review the sources or uses which have been “managed”; by marine reserves, the management approaches, uses, and problem which have been identified in achieving management objectives. The authors conclude with observations about the potential future utility of marine reserves as a management approach for areas and resources of the coastal and littoral zones of Latin America.