Abstract:A major assumption in palaeoclimatic studies using speleothems is that cave-seepage waters are homogenized as they pass through the bedrock, so that they record the average annual isotopic signal of precipitation. A year-long study during 2001-02 was conducted at Indian Oven Cave in eastern New York State, USA, to investigate how cave-seepage water isotopic signals relate to those of precipitation. Samples were collected biweekly and analysed for stable isotopes of oxygen and hydrogen. Our study shows that, for this cave, homogenization did not occur, as seepage waters had the same seasonal variability as precipitation. However, mean seepage water isotopic values were very close to those of the mean values for precipitation. Rapid flow-through times of seepage water show that the speleothems can record climate conditions above the cave contemporaneously. At one location, flow ceased during the winter; therefore, isotopes measured in cave drip waters reflected only the enriched summer isotopes. Under certain circumstances, the analysis of calcite sampled from those drip waters may then lead to a false conclusion of a warming during that period, instead of the fact that it was merely a drier winter period.
This paper proposes a novel approach to measuring the progress of Small Island Developing States (SIDS) towards sustainable development (SD) as set by the UN Sustainable Development Goals 2030. Currently, these goals do not provide adequate guidance on how countries might measure their progress towards sustainability. We use these goals and a subset of their targets to develop an index with concrete targets, through the use of pertinent sustainability indicators, that SIDS should aim to achieve a sustainable society. In addition to the three categorical pillars of sustainable development (social, economic, and environmental), we included the category Climate Change and Disaster Management (incorporating Disaster Risk Reduction). The basis of our decision is that the UN and the Intergovernmental Panel on Climate Change have both recognized the vulnerability of SIDS to both environmental hazards. Our index scores a total 70 individual indicators for the four categories to track the progress of a SIDS towards a sustainable society. Using the Caribbean nation, Republic of Trinidad and Tobago, as our SIDS case study, we report the average of the scores for each category to illustrate its progress towards sustainability. Overall Trinidad and Tobago is slowly progressing towards a more sustainably developed society. Our results show that the nation is only moderately successful regarding progress in three traditional pillars of SD, social, economic and environmental. However, Trinidad and Tobago scores poorly in the Climate Change and Disaster Management category and needs to improve in this area especially due to its vulnerability.
Abstract:A calibration study of oxygen and hydrogen isotopic composition from precipitation and cave dripwater was conducted in westcentral Florida at Legend Cave during 2007. This study was performed to better understand how modern precipitation patterns can be discerned through examination of cave dripwater and speleothem calcite for paleoclimate reconstruction. The 'amount effect' was shown to be a dominant control on the oxygen isotopic composition of precipitation for the study area. A meteoric water line with a slope of 6Ð7 suggests evaporative effects occur either during precipitation or subsequent hydrological processes. However, υ18 O values of cave dripwater averaged near the mean annual amount-weighted average of precipitation, suggesting that the isotopic composition of dripwater tracks the long-term average of rainfall. An observed weak seasonal influence occurred in the d-excess values, with summer precipitation being more enriched due to increased evaporative effects.
Comparison of precipitation υ18 O values to synoptic weather data shows the dominant amount effect influence occurs due to strong convective storms producing highly 18 O-depleted rainfall at greater amounts during the year. Constant υ 18 O values of the dripwater indicate that paleoclimate reconstructions using speleothems from this area would record changes in annual to interannual shifts in precipitation amount above the cave.
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