Physico-chemical characteristics and circulation of waters in the Mauritius-Seychelles ridge zone, southwest Indian Ocean

184-191Influence of north-south oriented Mauritius-Seychelles ridge on flow patterns in the southwest Indian Ocean has been studied using IIOE data. The ridge affects the zonal flow by causing divergence (upwelling) with a consequent increase in nutrient levels in its leeward side especially during winter. Distributions of physico-chemical parameters together with geostrophic flow patterns for both austral winter (June to August) and summer (December to February) seasons are also presented. The occurrence of 2 general gyres - clockwise and anticlockwise rotations with centres around 12ᵒ S and 22ᵒ S respectively - is a general characteristic feature of the surface circulation in the southwest Indian Ocea

Epipelagic mesozooplankton dynamics around the Mascarene Plateau and Basin, Southwest Indian Ocean

It has been suggested that the obstruction of the South Equatorial Current by the Mascarene Plateau might cause upwelling, nutrient enrichment and enhanced chlorophyll and secondary production levels downstream. A study conducted in April and May 2001 showed variability in biomass and community structure which appeared to support this hypothesis but, in the absence of supporting physical and biochemical measurements, we were unable to confirm it. In June and July 2002 the sampling was repeated with the supporting environmental measurements available from a large research vessel. In this paper we present the results from this sampling programme, compare them with the 2001 results, and examine both datasets in the light of physical and other environmental data gathered during the 2002 programme in order to evaluate the evidence for significant upwelling around the Mascarene Plateau. The evidence is inconclusive: the 2002 dataset shows only a little evidence of topographic upwelling. However, the mesozooplankton and other physical and biochemical data from the 2002 sampling programme indicate support for the theory of an open-ocean upwelling between 5 and 10° S across the central and western Indian Ocean from 50 to 90° E, due to Ekman divergence along the northern edge of the South Equatorial Current. It is possible that these two separate sources of upwelling may coexist and combine at times, producing the very high levels of biomass found during 2001

Coastal systems and low-lying areas

Since the IPCC Third Assessment Report (TAR), our understanding of the implications of climate change for coastal systems and low-lying areas (henceforth referred to as ‘coasts’) has increased substantially and six important policy-relevant messages have emerged. Coasts are experiencing the adverse consequences of hazards related to climate and sea level (very high confidence). Coasts are highly vulnerable to extreme events, such as storms, which impose substantial costs on coastal societies [6.2.1, 6.2.2, 6.5.2]. Annually, about 120 million people are exposed to tropical cyclone hazards, which killed 250,000 people from 1980 to 2000 [6.5.2]. Through the 20th century, global rise of sea level contributed to increased coastal inundation, erosion and ecosystem losses, but with considerable local and regional variation due to other factors [6.2.5, 6.4.1]. Late 20th century effects of rising temperature include loss of sea ice, thawing of permafrost and associated coastal retreat, and more frequent coral bleaching and mortality [6.2.5]. Coasts will be exposed to increasing risks, including coastal erosion, over coming decades due to climate change and sea-level rise (very high confidence). Anticipated climate-related changes include: an accelerated rise in sea level of up to 0.6 m or more by 2100; a further rise in sea surface temperatures by up to 3°C; an intensification of tropical and extra-tropical cyclones; larger extreme waves and storm surges; altered precipitation/run-off; and ocean acidification [6.3.2]. These phenomena will vary considerably at regional and local scales, but the impacts are virtually certain to be overwhelmingly negative [6.4, 6.5.3]

The experience of collaborative assessment in e-learning.

ABSTRACT This paper examines the various ways in which students talk about their experience and perceptions of collaborative review and assessment as it occurs in e-learning environments. Collaborative review and assessment involves the student, their peers and tutor in thoughtful and critical examination of each student’s course work. The process involves two stages: review and discussion of the student’s work with a view to bringing different critical yet supportive perspectives to the work. This is followed by the use of two sets of criteria to make judgements on the student’s work: one set provided by the student, the other by the tutor. The purpose of collaborative assessment is to foster a learning approach to assessment and to develop a shared power relationship with students. From analysis of face-to-face interviews, examination of e-learning discussions and student-completed questionnaires, a set of analytic categories was built describing the learners’ experiences of collaborative e-assessment. These categories are: (1) the appropriateness of collaborative assessment; (2) collaborative assessment as a learning event; and (3) the focus for assessment. The paper focuses on analysing and discussing these categories of experience. The research shows that a positive social climate is necessary in developing and sustaining collaborative assessment and that this form of assessment helps students to reduce depen-dence on lecturers as the only or major source of judgement about the quality of learning. Students develop skill and know-how about self- and peer assessment and see themselves as competent in making judgements about their own and each other’s work, which are surely good lifelong learning skills