The relationship between sea surface temperature and population change of Great Cormorants Phalacrocorax carbo breeding near Disko Bay,Greenland

Arctic seas have warmed and sea ice has retreated. This has resulted in range contraction and population declines in some species, but it could potentially be a boon for others. Great Cormorants Phalacrocorax carbo have a partially wettable plumage and seem poorly suited to foraging in Arctic waters. We show that rates of population change of Cormorant colonies around Disko Bay, Greenland, are positively correlated with sea surface temperature, suggesting that they may benefit from a warming Arctic. However, although Cormorant populations may increase in response to Arctic warming, the extent of expansion of their winter range may ultimately be limited by other factors, such as sensory constraints on foraging behaviour during long Arctic nights.     

Physiological characterization of Mycobacterium sp. strain 1B isolated from a bacterial culture able to degrade high-molecular-weight polycyclic aromatic hydrocarbons

AIM: The aim of this study was to further characterize a bacterial culture (VUN 10,010) capable of benzo[a]pyrene cometabolism. METHODS AND RESULTS: The bacterial culture, previously characterized as a pure culture of Stenotrophomonas maltophilia (VUN 10,010), was found to also contain another bacterial species (Mycobacterium sp. strain 1B), capable of degrading a similar range of PAH substrates. Analysis of its 16S rRNA gene sequence and growth characteristics revealed the strain to be a fast-growing Mycobacterium sp., closely related to other previously isolated PAH and xenobiotic-degrading mycobacterial strains. Comparison of the PAH-degrading characteristics of Mycobacterium sp. strain 1B with those of S. maltophilia indicated some similarities (ability to degrade phenanthrene and pyrene), but some differences were also noted (S. maltophilia able to degrade fluorene, but not fluoranthene, whereas Mycobacterium sp. strain 1B can degrade fluoranthene, but not fluorene). Unlike the S. maltophilia culture, there was no evidence of benzo[a]pyrene degradation by Mycobacterium sp. strain 1B, even in the presence of other PAHs (ie pyrene) as co-metabolic substrates. Growth of Mycobacterium sp. strain 1B on other organic carbon sources was also limited compared with the S. maltophilia culture. CONCLUSIONS: This study isolated a Mycobacterium strain from a bacterial culture capable of benzo[a]pyrene cometabolism. The Mycobacterium strain displays different PAH-degrading characteristics to those described previously for the PAH-degrading bacterial culture. It is unclear what role the two bacterial strains play in benzo[a]pyrene cometabolism, as the Mycobacterium strain does not appear to have endogenous benzo[a]pyrene degrading ability. SIGNIFICANCE AND IMPACT OF THE STUDY: This study describes the isolation and characterization of a novel PAH-degrading Mycobacterium strain from a PAH-degrading culture. Further studies utilizing this strain alone, and in combination with other members of the consortium, will provide insight into the diverse roles different bacteria may play in PAH degradation in mixed cultures and in the environment.     

Hydrocarbon phytoremediation in the family Fabaceae--a review

Currently, studies often focus on the use of Poaceae species (grasses) for phytoremediation of hydrocarbon-contaminated soils. Research into the use of Fabaceae species (legumes) to remediate hydrocarbons in soils has been conducted, but these plants are commonly overlooked due to slower recorded rates of degradation compared with many grass species. Evidence in the literature suggests that in some cases Fabaceae species may increase total degradation of hydrocarbons and stimulate degradative capacity of the soil microbial community, particularly for contaminants which are normally more recalcitrant to degradation. As many recalcitrant hydrocarbons have negative impacts on human and ecosystem health, development of remediation options is crucial. Reconsideration of Fabaceae species for removal of such contaminants may lead to environmentally and economically sustainable technologies for remediation of contaminated sites.     

Environmental temperatures and the incidence of food poisoning in England and Wales

The incidence of food poisoning in England and Wales has been increasing for many years and it is now a major public health problem. Superimposed on this general rising trend is a well-established tendency for the number of cases of food poisoning to rise during the summer when warm weather favours the multiplication of pathogenic micro-organisms. This paper shows that weekly notifications of food poisoning in England and Wales are strongly associated with environmental temperatures, but that there are some important time lags in this relationship. The number of cases of food poisoning in a given week was only weakly correlated with the temperature of that week and the one preceding it. This suggests that factors operating close to the point of consumption within or outside the home are not the principal cause of the rise in food poisoning associated with warm summer conditions. There was a much stronger association with temperatures 2–5 weeks earlier, pointing to the importance of factors operating earlier in the food production or distribution system. The results of this study suggest that the food poisoning problem requires action by food producers and distributors as well as by consumers. Received: 15 May 2000 / Revised: 17 October 2000 / Accepted: 18 October 2000     

Methane production and microbial community structure in single-stage batch and sequential batch systems anaerobically co-digesting food waste and biosolids

Anaerobic co-digestion of food waste and biosolids was carried out in sequential batch and single-stage batch systems in four treatments. Methane yield, which was used as a functional process parameter, differed between treatments, with the single-stage batch system generating lower volumes than the sequential batch systems. Volatile fatty acid (VFA) concentrations and pH in the leachate also differed between treatments. VFA concentrations were highest and methane generation yields lowest in the single-stage batch system in comparison to the sequential batch systems. The anaerobic microbial community structure of the domains Archaea and Bacteria, determined by denaturing gradient gel electrophoresis, differed between treatments and was correlated to a number of environmental parameters such as pH, VFA concentration and methane generation rate. Methane generation rate was significantly correlated to the community structure of Bacteria but not Archaea. This indicated that the substrates that are produced by acetogens (Bacteria) are important for the growth and community structure of the methanogens (Archaea). Community structure of Archaea changed over time, but this had no observable effect on functional ability based on methane yields. Microbial diversity (H′) was shown to be not important in developing a functionally successful anaerobic microbial community.     

Rhizoremediation of residual sulfonylurea herbicides in agricultural soils using Lens culinaris and a commercial supplement

Sulfonylureas (SU) are a popular herbicide used today for controlling weeds. While beneficial for this purpose they present a persistent problem in agricultural treated areas, with this treatment proving detrimental for successive crops. This study assessed the phytoremediative properties of lentils (Lens culinaris) grown in uncontaminated and chlorsulfuron-contaminated soil, with and without the addition of a growth supplement, PulseAider?. The results show that in the presence of lentils the degradation of chlorsulfuron is enhanced and this degradation rate is significantly increased when the PulseAider? supplement was included during seed sowing. The supplement PulseAider? also significantly increased shoot and root biomass, root branching, and nodule number under control conditions. While this was not so for plants grown in contaminated soils, the PulseAider? supplement seemed to alter root branching and morphology. Most Probable Number (MPN) assays showed increased numbers of potential chlorsulfuron-degrading bacteria in soil treated with PulseAider?, although this was found to be significant only in the control soil. Sequencing of the 16S ribosomal gene showed the presence of Pseudomonas fluorescens bacterial species which is a known chlorsulfuron-degrading bacterium. This study is one of the first to address the remediation of residual SU herbicides and offers an economically feasible solution that may have an impact on global food security.     

Screening of Australian Native Grasses for Rhizoremediation of Aliphatic Hydrocarbon-Contaminated Soil

Rhizoremediation involves the breakdown of contaminants in soil resulting from microbial activity that is enhanced in the plant root zone. The objective of this study was to identify Australian native grass species as suitable candidates for rhizoremediation application. Seeds of nine perennial Australian native grasses were sown in soil from a mine site and artificially contaminated with a 60:40 diesel/oil mixture at concentrations of 1% (w/w), 0.5% (w/w), and 0% (control). Seedling emergence was not adversely affected by the presence of hydrocarbon contamination for all but one grass species. Three promising species (Brachiaria decumbens, Cymbopogon ambiguus, and Microlaena stipoides var. Griffin) were assessed for growth characterization in contaminated and uncontaminated soils. The evaluated species survived for 120 days in the contaminated soil and, in some instances, produced considerably more root biomass in the presence of contamination. C. ambiguus showed growth stimulation in the presence of contamination (1% and 0.5% w/w) with significantly increased root biomass production compared with the control (p = 0.0001). B. decumbens and M. stipoides showed tolerance, without adverse growth effects in the presence of diesel/oil at the exposed concentrations. Stimulation of the rhizosphere microbial population that is capable of degrading diesel/oil was found for all of the species tested, using a most probable number method for enumeration. This investigation has identified suitable candidates for further investigation of their rhizoremediation potential.