Abstract:Coastal margin habitats are globally significant in terms of their capacity to sequester and store carbon, but their continuing decline, due to environmental change and human land use decisions, is reducing their capacity to provide this ecosystem service. In this paper the UK is used as a case study area to develop methodologies to quantify and calculate a monetary value for the service of carbon sequestration and storage in coastal margin habitats. Specific changes in UK coastal habitat area between 1900 and 2060 are documented, the long term stocks of carbon stored by these habitats are calculated, and the capacity of these habitats to sequester CO 2 is outlined. Changes in value of the carbon sequestration and storage service of coastal habitats were then projected for under two scenarios, the maintenance of the current state of the habitat and the continuation of current trends of habitat loss. If coastal habitats were to be maintained at their current extent, their sequestration capacity over the period 2000-2060 is valued to be in the region of £1-3 billion UK sterling. However, if current trends of habitat loss continue, the capacity of the coastal habitats both to sequester and store CO 2 will be significantly reduced, with a reduction in value of around £0.25 -1 billion . If loss-trends due to sea level rise or land reclamation worsen, this loss in value will be greater. This case study provides valuable site specific information, but also highlights global issues regarding the quantification and valuation of carbon sequestration and storage. Whilst our ability to value ecosystem services is improving, considerable uncertainty remains. If such ecosystem valuations are to be incorporated with confidence into national and global policy and legislative frameworks, it is necessary to further address this uncertainty. Recommendations on achieving this are outlined.3

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Abstract. The relationship between reflectance and suspended sediment concentration (SSC) is depcndent upon the wavebands sensed and the vicwing geometry of the sensor. The laboratory experiment reported in this paper investigatcd thesc dependenecs. The retlectance in four wavebands (two visible and two near-infrared) of a large water-filled and wave-free tank were recorded as three variables were changed, namely SSC. sensor viewing angle and relative sensor azimuth. The strength of the positive relationship between reflectance and SSC was shown to vary with (i) wavelength, as the maximum reflectance and SSC class separability occurred at the longer visible wavelengths, and (ii) viewing geometry, as the reflectance/SSC asymptote was dependent upon both the angle and azimuth of the sensor. The optimum conditions for the sensing of SSC ~c concluded to be nadir in visible (0-55 and 0.65 pm) and ne,ar-infrared (0-75pm) wavelengths.