Effective international knowledge exchange to rehabilitate rivers in urban delta’s: case study Metropolitan Manilla

In coastal and low-lying vulnerable delta cities, such as the Rotterdam Metropolitan region and Metropolitan Manila, there has been an increase in vulnerability of urban flooding and water quality problems. New approaches address the current and future effects of climate change and increase urban quality, reduce vulnerability and increase water quality. New arrangements for international cooperation are set up in order to address these problems in the project ‘IWASTO’ (‘to correct and to prevent’) where several organisations from the Philippines and The Netherlands join forces to rehabilitate rivers and introduce new innovations for water quality monitoring and waste collection using the ‘Research Design and Manufacaturing (RDM)’ approach. One of the concrete results from this RDM approach in 2016 is the development and implementation of the ‘Longganisa’, a waste collection tool that was designed by a Dutch-Philippine team. In addition, the waterquality was measured and mapped with innovating methods using apps in order to locate and prioritize highly polluted areas. In the near future measures will be implemented to rehabilitate the rivers in Manila and a knowledge exchange forum will be set up to share the best management practices on international scale in countries as Indonesia, India and China

Environmental Signals in Coral Tissue and Skeleton: Examples from the Caribbean and Indo-Pacific

Coral tissue and skeleton contain physical and chemical proxy signatures of the surrounding environment. The purpose of this thesis is to broaden or refine the use of corals as environmental recorders/tracers by examining the fidelity of both new and existing techniques. Corals from the Caribbean and Indo-Pacific are utilised, with primary reference to samples from Jamaica and Indonesia. Coral skeletons from Banda Api, Indonesia, contain evidence of a short term pulse of volcanic ash and hydrothermal fluids which affected the surrounding reef during a May, 1988 eruption. Partial burial of corals by volcanic ash led to the formation of highly bioeroded death surfaces and the incorporation of ash into underlying skeletal pores. Subsequent recovery of the coral resulted in preservation of these features as death/regrowth surfaces. Hydrothermal activity is preserved in the skeleton as a distinct orange layer of iron hydroxide which has been termed the "Banda Band". X-radiography confirms that the location of these features within the coral skeletons coincides with the timing of the eruption. Preservation of an environmental pulse lasting only a few days demonstrates the fine scale resolution that can be obtained from coral skeletal records. Coral tissues from Jamaica and Zanzibar, collected along depth/light gradients, were analysed for δ¹⁵N. Coral tissue δ¹⁵N was found to decrease with decreasing light availability. A conceptual steady state model has been developed to explain this relationship. In higher light conditions, corals and/or their symbiotic algae significantly deplete the internal pool of dissolved inorganic nitrogen, resulting in minimal fractionation during uptake. Under lower light conditions, however, less dissolved nitrogen is assimilated and fractionation is more fully expressed, with the light isotope of nitrogen being taken up preferentially. These results suggest corals are not conservative tracers of nitrogen. It is proposed, however, that shallow water ( δ¹⁵N and δ¹³C signals of shallow water corals collected from seven different reefs were compiled. Significant inter-reef variability in δ¹⁵N was found. Both light availability and the isotopic composition of source nitrogen are thought to contribute to the variation between reefs. Other factors such as nutrient concentration may also be important. δ¹³C variability was much less significant in the data set, with most reefs having enriched coral tissue signals, consistent with a primarily autotrophic diet. The tissue and underlying skeleton of Jamaica and Zanzibar corals were also analysed for δ¹³C. Tissue δ¹³C was found to decrease with decreasing light availability. Skeletal δ¹³C, however, shows no relationship with depth/light availability. It is proposed that strong kinetic isotope effects associated with the rate of calcification mask any such relationship. A simple data transformation is applied to account for the presence of kinetic isotope effects, the result of which is a much clearer relationship between skeletal δ¹³C and light availability. These results suggest that it is possible to correct for the presence of kinetic isotope effects associated with the rate of skeletogenesis and to resolve meaningful environmental/metabolic information from skeletal carbon isotopic records.Doctor of Philosophy (PhD

Se Isotopes as Groundwater Redox Indicators:Detecting Natural Attenuation of Se at an in Situ Recovery U Mine

One of the major ecological concerns associated with the in situ recovery (ISR) of uranium (U) is the environmental release of soluble, toxic selenium (Se) oxyanions generated by mining. Post-mining natural attenuation by the residual reductants in the ore body and reduced down-gradient sediments should mitigate the risk of Se contamination in groundwater. In this work, we investigate the Se concentrations and Se isotope systematics of groundwater and of U ore bearing sediments from an ISR site at Rosita, TX, USA. Our results show that selenate (Se­(VI)) is the dominant Se species in Rosita groundwater, and while several up-gradient wells have elevated Se­(VI), the majority of the ore zone and down-gradient wells have little or no Se oxyanions. In addition, the δ⁸²Se_VI of Rosita groundwater is generally elevated relative to the U ore up to +6.14‰, with the most enriched values observed in the ore-zone wells. Increasing δ⁸²Se with decreasing Se­(VI) conforms to a Rayleigh type distillation model with an ε of −2.25‰ ± 0.61‰, suggesting natural Se­(VI) reduction occurring along the hydraulic gradient at the Rosita ISR site. Furthermore, our results show that Se isotopes are excellent sensors for detecting and monitoring post-mining natural attenuation of Se oxyanions at ISR sites

Evidence of Longshore Drift in Beach Sediment: Manzanillo, Costa Rica

The beach at Manzanillo, Costa Rica, is composed of a mixture of terrigenous siliciclastic and marine calcareous sediment. The most abundant siliclastic grains are magnetite and diopside. The most abundant calcareous grains are red algae and molluscan fragments. These grains are found in much greater abundance in the beach sediment then in their source areas as a result of their resistance to breakdown. The distribution of the siliclastic minerals on the beach shows longshore drift to be from east to west. The main source of siliclastic sediment is the Rio Sixaola. Local rivers provide small inputs of sediment. The trace element chemistry of the beach indicates the possibility that some elements may be absorbed on the surfaces of grains as opposed to being substituted for other elements in mineral lattices.ThesisBachelor of Science (BSc