Ian Snape

Impacts of local human activities on the Antarctic environment.

Abstract We review the scientific literature, especially from the past decade, on the impacts of human activities on the Antarctic environment. A range of impacts has been identified at a variety of spatial and temporal scales. Chemical contamination and sewage disposal on the continent have been found to be long-lived. Contemporary sewage management practices at many coastal stations are insufficient to prevent local contamination but no introduction of non-indigenous organisms through this route has yet been demonstrated. Human activities, particularly construction and transport, have led to disturbances of flora and fauna. A small number of non-indigenous plant and animal species has become established, mostly on the northern Antarctic Peninsula and southern archipelagos of the Scotia Arc. There is little indication of recovery of overexploited fish stocks, and ramifications of fishing activity on bycatch species and the ecosystem could also be far-reaching. The Antarctic Treaty System and its instruments, in particular the Convention for the Conservation of Antarctic Marine Living Resources and the Environmental Protocol, provide a framework within which management of human activities take place. In the face of the continuing expansion of human activities in Antarctica, a more effective implementation of a wide range of measures is essential, in order to ensure comprehensive protection of the Antarctic environment, including its intrinsic, wilderness and scientific values which remains a fundamental principle of the Antarctic Treaty System. These measures include effective environmental impact assessments, long-term monitoring, mitigation measures for non-indigenous species, ecosystem-based management of living resources, and increased regulation of National Antarctic Programmes and tourism activities.

Management and remediation of contaminated sites at Casey Station, Antarctica

The Protocol on Environmental Protection to the Antarctic Treaty requires that past and present work sites be cleaned up unless removal would result in greater adverse environmental impact than leaving the contaminant in its existing location. In the early 1990s Australia began the documentation of contaminated sites associated with its research stations, which resulted in an extensive record of contamination at abandoned stations and waste-disposal sites. Currently the technical capability to remediate these sites does not exist because of environmental challenges that are unique to the cold regions. Investigations indicate that clean-up operations in the past have proceeded without adequate precautions and without effective monitoring. To address these problems, three research priorities have been identified to assist meeting international and national obligations to clean up these sites. They are: understanding contaminant mobilisation processes; development of ecological risk assessment for use in monitoring and setting priorities; and development of clean-up and remediation procedures. This study provides sufficient information to guide the completion of a clean-up at Casey Station and to indicate how other similar sites should be managed. The next stage is to develop the theory into an operational plan to include detailed protocols for clean-up, monitoring, site remediation, and management of the waste stream from site to final repository. To achieve this, the Australian Antarctic Division has established a contaminated sites taskforce to facilitate the transition from research and development of techniques to implementation of suitable clean-up options.

Microbial community variation in pristine and polluted nearshore Antarctic sediments

Abstract Two molecular methods were used to investigate the microbial population of Antarctic marine sediments to determine the effects of petroleum and heavy metal pollution. Sediment samples were collected in a nested design from impacted and non-impacted locations. A detailed description of the diversity of the microbial population in two samples was obtained using 16S ribosomal DNA clone libraries constructed from an impacted and a non-impacted location. The clone libraries were very similar with the exception of two sequence clusters containing clones from only the impacted location. All samples were analysed by denaturing gradient gel electrophoresis. The band patterns generated were transformed into a presence/absence matrix and a multivariate approach was used to test for differences in the locations. Statistically significant differences were observed both between and within locations. Impacted locations showed a greater variability within themselves than the control locations. Correlations between the community patterns and environmental variables suggested that pollution was one of a number of factors affecting the microbial community composition.

Community fingerprinting in a sequencing world

Despite decreasing costs, generating large-scale, well-replicated and multivariate microbial ecology investigations with sequencing remains an expensive and time-consuming option. As a result, many microbial ecology investigations continue to suffer from a lack of appropriate replication. We evaluated two fingerprinting approaches - terminal restriction fragment length polymorphism (T-RFLP) and automated ribosomal intergenic spacer analysis (ARISA) against 454 pyrosequencing, by applying them to 225 polar soil samples from East Antarctica and the high Arctic. By incorporating local and global spatial scales into the dataset, our aim was to determine whether various approaches differed in their ability and hence utility, to identify ecological patterns. Through the reduction in the 454 sequencing data to the most dominant OTUs, we revealed that a surprisingly small proportion of abundant OTUs (< 0.25%) was driving the biological patterns observed. Overall, ARISA and T-RFLP had a similar capacity as sequencing to separate samples according to distance at a local scale, and to correlate environmental variables with microbial community structure. Pyrosequencing had a greater resolution at the global scale but all methods were capable of significantly differentiating the polar sites. We conclude fingerprinting remains a legitimate approach to generating large datasets as well as a cost-effective rapid method to identify samples for elucidating taxonomic information or diversity estimates with sequencing methods.

Using Real-Time PCR to Assess Changes in the Hydrocarbon-Degrading Microbial Community in Antarctic Soil During Bioremediation

A real-time polymerase chain reaction (PCR) method to quantify the proportion of microorganisms containing alkane monooxygenase was developed and used to follow changes in the microbial community in hydrocarbon-contaminated Antarctic soil during a bioremediation field trial. Assays for the alkB and rpoB genes were validated and found to be both sensitive and reproducible (less than 2% intrarun variation and 25–38% interrun variation). Results from the real-time PCR analysis were compared to analysis of the microbial population by a culture-based technique [most probable number (MPN) counts]. Both types of analysis indicated that fertilizer addition to hydrocarbon-contaminated soil stimulated the indigenous bacterial population within 1 year. The proportion of alkB containing microorganisms was positively correlated to the concentration of n-alkanes in the soil. After the concentration of n-alkanes in the soil decreased, the proportion of alkane-degrading microorganisms decreased, but the proportion of total hydrocarbon-degrading microorganisms increased, indicating another shift in the microbial community structure and ongoing biodegradation.

The effects of nitrogen and water on mineralisation of hydrocarbons in diesel-contaminated terrestrial Antarctic soils

Bioremediation of petroleum-contaminated soil in the Antarctic will be logistically and technically difficult and will cost more than similar treatment in temperate regions or the Arctic because of the remote location and unfavourable environmental conditions. To optimise nutrient amendments for the remediation of a long-term hydrocarbon-contaminated site at Old Casey Station in Antarctica, we investigated the effects of nitrogen (and phosphorus) amendments on microbial mineralisation using radiometric microcosm experiments and gas chromatography. Hydrocarbon mineralisation at nine different inorganic nitrogen concentrations (ranging from 85 to over 27,000 mg N kg-soil-H2O−1) was monitored over 95-day incubation at 10 °C. Total 14C-octadecane mineralisation increased with increasing nutrient concentration peaking in the range 1000–1600 mg N kg-soil-H2O−1. The microcosms with the lowest and highest concentrations of N had extended lag phases of over 12.5 days prior to significant mineralisation. Gas chromatographic analysis of the aliphatic components of Special Antarctic Blend (SAB) diesel in the contaminated soil showed good agreement with the 14C-octadecane mineralisation outcomes. Ratios of n-C17/pristane and n-C18/phytane indicated that low nutrient concentrations rather than water were the main limiting factor for biodegradation of hydrocarbons in the soil collected from Old Casey Station when incubated at 10 °C. However, because the soils from this site are characterised by low water holding capacities, it would be difficult to maintain optimal nutrient concentrations during full-scale treatment, and thus the use of a controlled release nutrient is being considered as a nutrient source in the bioremediation of SAB-contaminated Antarctic soils.

Human impacts in Antartic marine soft-sediment assemblages: correlations between multivariate biological patterns and environmental variables at Casey Station

Abstract Correlations between the spatial distribution of soft-sediment assemblages and environmental variables were evaluated at a number of control and potentially impacted locations (waste dumps, a sewage outfall and a wharf) at Casey Station, East Antarctica. Patterns of assemblage composition were compared with patterns of environmental variables using univariate and multivariate techniques. The utility of these methods, however, is uncertain in areas of significant habitat heterogeneity (at scales

The use of permeable reactive barriers to control contaminant dispersal during site remediation in Antarctica

When used as part of an integrated contaminated sites remediation program, permeable reactive barriers are a valuable technological application that can remove, retain or treat contaminated waters in seasonally frozen ground in remote areas. The main advantages of permeable reactive barriers for application in remote cold regions are that they are passive low-technology systems that do not require power to operate; they can be left at short notice during extreme weather events; and most importantly, they have a minimal impact on the environment as they can be completely removed at the end of site operations. However, barrier technology was originally developed for use in temperate regions and site-specific adaptations are required to ensure effective deployment and recovery from seasonally frozen ground. Experience gained from testing a variety of fill materials on site at Casey Station, Antarctica, indicates that fine-grained reactive materials are less suitable than coarse-grained (free-draining) materials. Preliminary results from simple field trials using granular activated carbon indicate that a significant improvement in water quality is possible for waters that contain high concentrations of petroleum hydrocarbons and heavy metals. For remote area deployment, barriers are best pre-assembled in modular form to allow rapid emplacement in frozen ground before seasonal melting begins. Future developments that are needed for efficient application in cold regions include the need to quantify reaction/adsorption rates at low temperatures for fill media and to establish breakthrough curves for promising materials.

The effects of cold temperature on copper ion exchange by natural zeolite for use in a permeable reactive barrier in Antarctica

Abstract Permeable reactive barriers (PRBs) are an in-situ passive treatment technology that removes dissolved contaminants from polluted waters through the subsurface emplacement of reactive materials such as natural zeolite. While significant work has been achieved using PRBs in temperate climates, adaptations to existing PRB technology and reactive material characteristics will be necessary for the successful treatment of heavy metal contaminated waters in cold regions. This study investigates the effects of cold temperature on the ion exchange equilibria of copper with clinoptilolite, a common natural zeolite, in natural and pretreated sodium forms. Batch tests were conducted at 22 and 2 °C in both simple binary systems and more complex multi-component systems. Results show that cold temperatures decrease copper uptake by clinoptilolite and appear to slow reaction kinetics. The ion exchange of copper in slightly saline waters is decreased at both 22 and 2 °C compared to uptake in simple binary systems. These results will have significant implications on cold region barrier design.

Bioremediation of petroleum hydrocarbons in cold regions

1. Contamination, regulation and remediation: an introduction to bioremediation of petroleum hydrocarbons in cold regions Ian Snape, Larry Acomb, David L. Barnes, Steve Bainbridge, Robert Eno, Dennis M. Filler, Natalie Plato, John S. Poland, Tania C. Raymond, John L. Rayner, Martin J. Riddle, Anne G. Rike, Allison Rutter, Alexis N.Schafer, Steven D. Siciliano, and James L. Walworth 2. Freezing and frozen soils Walter Fourie and Yuri Shur 3. Movement of petroleum through freezing and frozen soils David L. Barnes and Kevin Biggar 4. Hydrocarbon-degrading bacteria in contaminated cold soils Jackie Aislabie and Julia Foght 5. Temperature effects on biodegradation of petroleum contaminants in cold soils Anne Gunn Rike, Silke Schiewer, and Dennis M. Filler 6. Analytical methods for petroleum in cold region soils Daniel M. White, D. Sarah Garland, and Craig R. Woolard 7. Treatability studies: microcosms, mesocosms and field trials Ian Snape, C. Mike Reynolds, James L. Walworth, and Susan Ferguson 8. Nutritional requirements for bioremediation James L. Walworth and Susan Ferguson 9. Landfarming James L. Walworth, C. Mike Reynolds, Allison Rutter, and Ian Snape 10. Thermally-enhanced bioremediation and integrated systems Dennis M. Filler, David L. Barnes, Ronald A. Johnson, and Ian Snape 11. Emerging technologies Dale Van Stempvoort, Kevin Biggar, Dennis M. Filler, Ronald A. Johnson, Ian Snape, Kate Mumford, William Schnabel, and Steve Bainbridge Bibliography Glossary Index.