Natural formation and degradation of chloroacetic acids and volatile organochlorines in forest soil--challenges to understanding

- DOI: http:/dx.doi.org/10.1065/espr2005.06.262 Goal, Scope and Background The anthropogenic environmental emissions of chloroacetic acids and volatile organochlorines have been under scrutiny in recent years because the two compound groups are suspected to contribute to forest dieback and stratospheric ozone destruction, respectively. The two organochlorine groups are linked because the atmospheric photochemical oxidation of some volatile organochlorine compounds is one source of phytotoxic chloroacetic acids in the environment. Moreover, both groups are produced in higher amounts by natural chlorination of organic matter, e.g. by soil microorganisms, marine macroalgae and salt lake bacteria, and show similar metabolism pathways. Elucidating the origin and fate of these organohalogens is necessary to implement actions to counteract environmental problems caused by these compounds. Main Features While the anthropogenic sources of chloroacetic acids and volatile organochlorines are relatively well-known and within human control, knowledge of relevant natural processes is scarce and fragmented. This article reviews current knowledge on natural formation and degradation processes of chloroacetic acids and volatile organochlorines in forest soils, with particular emphasis on processes in the rhizosphere, and discusses future studies necessary to understand the role of forest soils in the formation and degradation of these compounds. Results and Discussion Reviewing the present knowledge of the natural formation and degradation processes of chloroacetic acids and volatile organochlorines in forest soil has revealed gaps in knowledge regarding the actual mechanisms behind these processes. In particular, there remains insufficient quantification of reliable budgets and rates of formation and degradation of chloroacetic acids and volatile organochlorines in forest soil (both biotic and abiotic processes) to evaluate the strength of forest ecosystems regarding the emission and uptake of chloroacetic acids and volatile organochlorines, both on a regional scale and on a global scale. Conclusion It is concluded that the overall role of forest soil as a source and/or sink for chloroacetic acids and volatile organochlorines is still unclear; the available laboratory and field data reveal only bits of the puzzle. Detailed knowledge of the natural degradation and formation processes in forest soil is important to evaluate the strength of forest ecosystems for the emission and uptake of chloroacetic acids and volatile organochlorines, both on a regional scale and on a global scale. Recommendation and Perspective As the natural formation and degradation processes of chloroacetic acids and volatile organochlorines in forest soil can be influenced by human activities, evaluation of the extent of this influence will help to identify what future actions are needed to reduce human influences and thus prevent further damage to the environment and to human health caused by these compounds.     

The effect of residential and agricultural runoff on the microbiology of a Hawaiian ahupua'a.

The objective of this project was to study the relationship between environmental runoff and the incidence of antibiotic-resistant microorganisms (ARMO) in freshwater streams. Five water systems along the windward coast of the island of O'ahu were evaluated. Samples were collected from sites upstream of residential or agricultural areas, throughout these areas, and at sites of entrance into oceans or bays. It was hypothesized that the incidence of ARMO would increase as the stream received runoff from residential and agricultural areas. The percentage of ARMO did not increase as the streams passed through residential or agricultural areas. Surprisingly, pristine sites, well upstream from residential or agricultural areas, contained bacteria resistant to at least one antibiotic. Areas most affected by runoff did not show a significant increase in the incidence of antibiotic-resistant organisms, suggesting that the incidence of antibiotic resistance is not simply a function of contamination with agricultural or residential runoff. The correlation of antibiotic resistance with heavy metal resistance was evaluated, because others (Fasim et al., 1999; Lazar et al., 2002; Nies, 1999) have shown that antibiotic and heavy metal resistance are each carried on extrachromosomal plasmids. The vast majority of ARMO were also resistant to concentrations of heavy metals reported in the sediments of indicator streams (Waihee, system III), suggesting that an antibiotic-resistant bacterium has a high probability of having dual resistance to a heavy metal. A 3.2-kb plasmid (pSTAMP) was isolated from a bacterium with dual antibiotic and heavy metal resistance. Further analysis of the plasmid is currently in progress.     

The effects of temperature and salinity on egg production and hatching success of Baltic Acartia tonsa (Copepoda: Calanoida): a laboratory investigation

The functional response of the aspects of reproductive success of a southwestern Baltic population of Acartia tonsa (Copepoda: Calanoida) was quantified in the laboratory using wide ranges in temperatures and salinities. Specifically, daily egg production (EP, # female⁻¹ day⁻¹) was determined for 4 or 5 days at 18 different temperatures between 5 and 34°C and the time course and success of hatching were evaluated at 10 different temperatures between 5 and 23°C. The effect of salinity (0 to 34 psu) on egg hatching success was also examined. The highest mean rates of EP were observed between 22 and 23°C (46.8–50.9 eggs female⁻¹ day⁻¹). When studied at 18 psu, hatching success of eggs increased with increasing temperature and was highest (92.2%) at 23°C. No hatching was observed for eggs incubated at low temperatures (≤12°C) that were produced by females acclimated to temperatures ≤10°C indicating a possible thermal threshold between 10.0 and 13.0°C below which only the production of diapause (or low quality) eggs exists in this population. When tested at 18°C, the hatching success of eggs incubated at 15 different salinities increased asymptotically with increasing salinity and was maximal (81.4–84.5%) between 17 and 25 psu. The high reproductive success observed over wide ranges in temperatures and salinities in this Baltic population demonstrates one of the mechanisms responsible for the cosmopolitan distribution of this species within productive, estuarine and marine habitats.     

Territory and group sizes in Eurasian beavers (Castor fiber): echoes of settlement and reproduction?

According to current theories of territoriality, an animal is expected to defend the smallest area that can provide resources for maximisation of reproduction, known as the economically defendable area. In group territorial species however, the strategies behind resource defence are likely to be more complex with corporate territoriality, cooperative breeding, delayed dispersal and intra-group competition all potentially playing a role. Here we examined group territoriality in a social herbivorous rodent, the Eurasian beaver Castor fiber. Beavers in our study do not inhabit economically defendable territories. Instead the sequence of arrival of pairs into unoccupied areas seems to play a more important role in determining the size of the territory, whereas group size is determined by past reproductive success. We argue that the settlement pattern and reproductive history have a lasting impact in the territorial system of beavers due to a combination of the low adult mortality, high dispersal costs, and avoidance of resource depletion.R.D. Campbell and F. Rosell contributed equally to this work     

Competitive interactions between related clades: evolutionary implications of overgrowth interactions between encrustin cyclostome and cheilostome bryozoans

Overgrowth interactions between encrusting cyclostome (eight species) and cheilostome (over 50 species) colonies were examined in subtidal communities in the northern Adriatic Sea off Rovinj, Croatia, in May–June 1988 and September–October 1990. Cheilostome colonies occupied ca. 80% of the available substrate space, whereas the cyclostome colonies occupied <5%. Out of 210 recorded interactions, cheilostomes overlapped cyclostomes in 164, while cyclostomes overlapped cheilostomes in only 16; 30 encounters resulted in mutual overlap or at least temporary growth termination along the line of contact. Most of the recorded interactions were for the cyclostomes Diplosolen obelia (Johnston) and Plagioecia patina (Lamarck). Both species elevated their colony margins on contact with a cheilostome in some instances, but D. obelia only overgrew competing cheilostomes in 12/120 encounters, and P. patina never prevailed. I propose that the cheilostomes have a key evolutionary innovation, lacking in cyclostomes, consisting of more rapid ontogenetic development of zooids along colony margins so that encrusting cheilostomes have substantially higher colony margins. This results in an outflow of filtered water along the edge of encrusting cheilostome colonies, while cyclostomes take water in at colony margins. These contrasting feeding currents apparently give a competitive advantage to the cheilostomes where colony margins approach and make contact with those of cyclostomes.     

The Journal of Coastal Conservation, 1995–2004

This paper concludes the publication of theJournal of Coastal Conservation from 1995–2004 after the European Coastal Union and the Publishers decided to terminate the production of the journal. We look back at the 206 research papers published in this period while concentrating on Geographical and ecological variation, Focuses and trends, and Progress in European coastal conservation and management. Three indices are added: (1) a list of the 206 papers; (2) an Author Index; and (3) a Subject Index based on the titles, keywords and some additional important subjects found in the tables and figures.     

A new approach to quantifying and comparing vulnerability to drought

In this study we develop an “inference modeling” approach to compare and analyze how different disciplines (economics, political science, and behavioral science/environmental psychology) estimate vulnerability to drought. It is thought that a better understanding of these differences can lead to a synthesis of insights from the different disciplines and eventually to more comprehensive assessments of vulnerability. The new methodology consists of (1) developing inference models whose variables and assertions incorporate qualitative knowledge about vulnerability, (2) converting qualitative model variables into quantitative indicators by using fuzzy set theory, (3) collecting data on the values of the indicators from case study regions, (4) inputting the regional data to the models and computing quantitative values for susceptibility. The methodology was applied to three case study regions (in India, Portugal and Russia) having a range of socio-economic and water stress conditions. In some cases the estimates of susceptibility were surprisingly similar, in others not, depending on the factors included in the disciplinary models and their relative weights. A new approach was also taken to testing vulnerability parameters by comparing estimated water stress against a data set of drought occurrences based on media analysis. The new methodologies developed in this paper provide a consistent basis for comparing differences between disciplinary perspectives, and for identifying the importance of the differences.

Who is susceptible and why? An agent-based approach to assessing vulnerability to drought

In this paper, we specify susceptibility to drought from a psychology-based bottom-up perspective. On the basis of the protection motivation theory (Rippetoe and Rogers in J Pers Soc Psychol 52(3):596–604, 1987), we developed the protection-capacity model (Krömker and Mosler in Global environmental change in Alpine regions: impact, recognition, adaptation, and mitigation. Edward Elgar, Cheltenham, pp 93–112, 2002) to analyse the susceptibility with respect to the protection capacity of agents. The protection capacity is determined by the agents’ subjective assessment of the situation, which consists of the appraisal of threat, on the one hand, and the coping appraisal, on the other hand. Additionally, the protection-capacity model specifies several factors which influence the two central appraisal processes. Empirical data were collected in interviews with experts and with a total of 65 exemplarily selected households which are typical for the respective case study regions (Andhra Pradesh, India; Algarve and Alentejo, Portugal; Volgograd and Saratov, Russia). The data were analysed with the help of fuzzy set methodology. Results show that the households of the Indian region are the most susceptible when compared to those of the Russian region with ‘low’ and to households of the Portuguese region with a ‘very low’ degree of susceptibility. Moreover, we identified subgroups within the regions which are characterized by different degrees of susceptibility and a different profile of factors influencing susceptibility. Altogether, the agent-based perspective allows identifying relevant factors that need to be addressed to minimize susceptibility of the population and special subgroups. However, the results are not representative for the case study regions because of the small database. Additionally, more effort is needed to validate the findings.     

Electrochemical removal of metal ions from aqueous solution: a student workshop

An environmental electrochemistry workshop program on metal ion removal is described. The program was designed for undergraduate students in chemistry, chemical engineering or environmental science and teaches environmental electrochemistry through a combination of hands-on experiments, understanding of research concepts, completion of project reports and in class discussion. The students are encouraged to quantitatively describe the performance of the electrochemical cells (containing 2-D and 3-D carbon cathodes) and to consider the advantages and shortcomings of electrochemical routes to environmental treatment.