R.P. Bartholomeus, J.P.M. Witte, P.M. van Bodegom, J.C. van Dam, P. de Becker and R. Aerts recently published ‘Process-based proxy of oxygen stress surpasses indirect ones in predicting vegetation characteristics’ in: Ecohydrology, DOI: 10.1002/eco.261.

Robust relationships among soil, water, atmosphere and plants are needed to reliably forecast the plant species composition. In this paper, we show the need for, and the application of, a process-based relationship between soil moisture conditions and vegetation characteristics. We considered 366 groundwater-dependent sites, where oxygen stress, caused by a surplus of soil moisture, codetermines plant performance. We compared two existing indirect proxies for the soil oxygen status – namely mean spring groundwater level (MSL) and sum exceedence value (SEV) – with our newly developed process-based proxy, viz. root respiration stress (RS). The two indirect proxies and the process-based proxy for oxygen stress performed equally well in describing vegetation characteristics for the Netherlands under the current climate. However, relationships based on MSL and SEV appeared to produce systematic prediction errors when applied outside their calibration range, in contrast to the relationship based on RS. Hence, the two indirect proxies cannot be used in projections, such as in predicting effects of climate change on vegetation composition, all the more because they – unlike RS – do not account for essential parameters that determine oxygen stress (e.g. temperature and extreme rainfall events in the growing season). We advocate using RS for estimating vegetation impacts in climate projections to increase the reliability and effectiveness of adaptive strategies. Copyright © 2011 John Wiley & Sons, Ltd. More >>

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Today was the second day of the WQTC, and the final day of the exhibition. I attended a session on the impact of climate change. The first presentation showed the consequences of sea level rise on southeast Florida. The first consequences can already be noticed, but not everyone understands their impact. Some parts of the country will disappear within the next 50 years! Of course, this also has its consequences for the water availability in Florida, especially as the water sources tend to become salty.

The second presentation showed the first consequences of global warming for Alaska, where houses are collapsing as a result of the melting permafrost. As the water in Alaska is becoming warmer, the number of larves increases, which e.g. causes problems in the filters that are used to purify drinking water. Another presentation showed the problems that can be expected in the southwest part of the US. It was estimated that until the year 2050 the adaptations required for drinking water facilities in the US will cost between 326 and 692 billion dollars, whereas the costs for wastewater treatment plants adaptation will be between 123 and 252 billion dollars (these figures do not include the 500 billion required for maintenance of the present infrastructure).

In a session on endocrine disruptors, it was shown that the use of cocaine in a certain area can be estimated from the amount of its degradation product benzoylecgonine. Even in a creek in the Swiss mountains a notable amount of benzoylecgonine was detected!

Furthermore I attended several presentations on adsorption of NOM, mainly on activated carbon.At the end of the day there was a boat trip on the river. Unfortunately, it was too dark to see anything J.

Roberta Hofman-Caris