Catherine K. King

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.

Combined effects of two ocean change stressors, warming and acidification, on fertilization and early development of the Antarctic echinoid Sterechinus neumayeri

The effects of concurrent ocean warming and acidification on Antarctic marine benthos warrant investigation as little is known about potential synergies between these climate change stressors. We examined the interactive effects of warming and acidification on fertilization and embryonic development of the ecologically important sea urchin Sterechinus neumayeri reared from fertilization in elevated temperature (+1.5°C and 3°C) and decreased pH (−0.3 and −0.5 pH units) treatments. Fertilization using gametes from multiple males and females, to represent populations of spawners, was resilient to acidification at ambient temperature (0°C). At elevated temperatures, there was a negative interactive effect of temperature and pH on percentage of fertilization (11% reduction at 3°C). For cleavage stage embryos, there was a significant, but small reduction (6%) in the percentage of normal embryos at pH 7.5. For blastulae, a 10–11% decrease in normal development occurred in the +3°C treatments across all pH levels. Our results highlight the importance of considering the impacts of both temperature and pH in assessing the life history response of S. neumayeri in a changing polar ocean. While fertilization and development to the blastula stage were robust to levels of temperature and pH change predicted over coming decades, deleterious interactive effects were evident between these stressors at levels projected to occur by 2100 and beyond.

CHRONIC SUBLETHAL SEDIMENT TOXICITY TESTING USING THE ESTUARINE AMPHIPOD, MELITA PLUMULOSA(ZEIDLER): EVALUATION USING METAL-SPIKED AND FIELD-CONTAMINATED SEDIMENTS

The present study describes the development of a 42-d chronic sublethal sediment toxicity test using the estuarine amphipod Melita plumulosa (Zeilder). This test was shown to predict the toxicity of metal-contaminated sediments previously found to adversely affect benthic community structure. Metals initially were tested individually by spiking reference sediment under conditions that ensured low metal concentrations in pore waters. Fertility was the most sensitive sublethal endpoint for copper- and zinc-spiked sediments, whereas cadmium-spiked sediments were not toxic to M. plumulosa, despite their high bioaccumulation of cadmium. The 42-d chronic sediment test was reproducible; however, variation between reference sediments collected from the same field location over time or from different locations did affect the reproduction of M. plumulosa. Sensitivity of M. plumulosa to metal-spiked sediments suggested that the interim sediment-quality guidelines (ISQGs) were too conservative. However, toxicity testing of sediments collected from field sites known to affect community assemblages significantly (p < 0.001) reduced the fertility of M. plumulosa, reflecting benthic community survey results and supporting the ISQGs. Bioaccumulation of cadmium and copper by M. plumulosa was elevated following chronic exposure to both laboratory and field-contaminated sediments; however, zinc bioaccumulation could be measured only in M. plumulosa exposed to field-contaminated sediments.

An Antarctic Research Station as a Source of Brominated and Perfluorinated Persistent Organic Pollutants to the Local Environment

This study investigated the role of a permanently manned Australian Antarctic research station (Casey Station) as a source of contemporary persistent organic pollutants (POPs) to the local environment. Polybrominated diphenyl ethers (PBDEs) and poly- and perfluoroalkylated substances (PFASs) were found in indoor dust and treated wastewater effluent of the station. PBDE (e.g., BDE-209 26-820 ng g(-1) dry weight (dw)) and PFAS levels (e.g., PFOS 3.8-2400 ng g(-1) (dw)) in dust were consistent with those previously reported in homes and offices from Australia, reflecting consumer products and materials of the host nation. The levels of PBDEs and PFASs in wastewater (e.g., BDE-209 71-400 ng L(-1)) were in the upper range of concentrations reported for secondary treatment plants in other parts of the world. The chemical profiles of some PFAS samples were, however, different from domestic profiles. Dispersal of chemicals into the immediate marine and terrestrial environments was investigated by analysis of abiotic and biotic matrices. Analytes showed decreasing concentrations with increasing distance from the station. This study provides the first evidence of PFAS input to Polar regions via local research stations and demonstrates the introduction of POPs recently listed under the Stockholm Convention into the Antarctic environment through local human activities.

Laboratory culture and life-cycle experiments with the benthic amphipod melita plumulosa (zeidler)

In Australia, the collection of estuarine invertebrates from the field for whole-sediment toxicity tests is hindered because of temporal variability in their population densities and distributions. The present study aimed to develop culturing procedures for Melita plumulosa (Zeidler), an epibenthic and intertidal, deposit-feeding amphipod that is native to the southeastern coast of Australia. During a 28-d chronic exposure, the species was tested under a range of salinities (5-35 per thousand), temperatures (14-25 degrees C), and sediment particle sizes (sand to silt). Optimal culture conditions with respect to salinity, temperature, sediment particle size, feeding, and light regimes were determined. Compared to survival, amphipod growth and fertility were better predictors of optimal culture conditions. A life-history experiment was undertaken at the initial culture conditions of 22 degrees C and 35 per thousand salinity to establish the age at maturity, length of reproductive cycle, and life span for each sex. Under these test conditions, posthatch female M. plumulosa released their first offspring at seven weeks, after which each female produced an average of nine juveniles every 16 d. Male M. plumulosa had an average life span of eight months, whereas females had an average life span of 11 months. Optimal culturing conditions established in the present study have been incorporated into toxicity test procedures with this species and are being used to maximize reproductive output of this species in laboratory cultures to provide a supply of juveniles for routine use in whole-sediment toxicity tests.

Contaminated suspended sediments toxic to an Antarctic filter feeder: Aqueous‐ and particulate‐phase effects

Disturbances such as dredging, storms, and bioturbation result in the resuspension of sediments. This may affect sessile organisms that live on hard substrates directly above the sediment. Localized sediment contamination exists around many Antarctic research stations, often resulting in elevated contamination loads in marine sediments. To our knowledge, the potential impact of resuspended contaminated sediments on sessile fauna has not been considered, so in the present study, we assessed the sensitivity of Antarctic spirorbid polychaetes to aqueous metals and to metal-contaminated sediments that had been experimentally resuspended. Worms were first exposed to aqueous metals, both singly and in combination, over 10 d. Spirorbid mortality was tolerant to copper (median lethal concentration [LC50], 570 microg/L), zinc (LC50, > 4,910 microg/L), and lead (LC50, > 2,905 microg/L); however, spirorbid behavior responded to copper concentrations as low as 20 microg/L. When in combination, zinc significantly reduced mortality caused by copper. A novel technique was used to resuspend sediments spiked with four concentrations of three metals (up to 450 microg/g dry wt of copper, 525 micro/g dry wt of lead, and 2,035 microg/g dry wt of zinc). The response of spirorbids to unfiltered suspended sediment solutions and filtered solutions (aqueous metal exposure) was measured. Suspended sediments were toxic to filter-feeding spirorbids at concentrations approximating those found in contaminated Antarctica areas. Toxicity resulted both from aqueous metals and from metals associated with the suspended sediments, although suspended clean sediments had no impact. To our knowledge, the present study is the first to show that resuspension of contaminated sediments can be an important pathway for toxicity to Antarctic hard substrate organisms. Based on the present results, current sediment-quality guidelines used in the evaluation of Australian sediments may be applicable to Antarctic ecosystems.

Phytoremediation of hydrocarbon contaminants in subantarctic soils: An effective management option

Accidental fuel spills on world heritage subantarctic Macquarie Island have caused considerable contamination. Due to the islands high latitude position, its climate, and its fragile ecosystem, traditional methods of remediation are unsuitable for on-site clean up. We investigated the tolerance of a subantarctic native tussock grass, Poa foliosa (Hook. f.), to Special Antarctic Blend (SAB) diesel fuel and its potential to reduce SAB fuel contamination via phytoremediation. Toxicity of SAB fuel to P. foliosa was assessed in an 8 month laboratory growth trial under growth conditions which simulated the islands environment. Single seedlings were planted into 1 L pots of soil spiked with SAB fuel at concentrations of 1000, 5 000, 10,000, 2000 and 40,000 mg/kg (plus control). Plants were harvested at 0, 2, 4 and 8 months and a range of plant productivity endpoints were measured (biomass production, plant morphology and photosynthetic efficiency). Poa foliosa was highly tolerant across all SAB fuel concentrations tested with respect to biomass, although higher concentrations of 20,000 and 40,000 mg SAB/kg soil caused slight reductions in leaf length, width and area. To assess the phytoremediation potential of P. foliosa (to 10 000 mg/kg), soil from the planted pots was compared with that from paired unplanted pots at each SAB fuel concentration. The effect of the plant on SAB fuel concentrations and the associated microbial communities found within the soil (total heterotrophs and hydrocarbon degraders) were compared between planted and unplanted treatments at the 0, 2, 4 and 8 month harvest periods. The presence of plants resulted in significantly less SAB fuel in soils at 2 months and a return to background concentration by 8 months. Microbes did not appear to be the sole driving force behind the observed hydrocarbon loss. This study provides evidence that phytoremediation using P. foliosa is a valuable remediation option for use at Macquarie Island, and may be applicable to the management of fuel spills in other cold climate regions.

Sensitivity and response time of three common Antarctic marine copepods to metal exposure.

Understanding the sensitivity of Antarctic marine organisms to metals is essential in order to manage environmental contamination risks. To date toxicity studies conducted on Antarctic marine species are limited. This study is the first to examine the acute effects of copper and cadmium on three common coastal Antarctic copepods: the calanoids Paralabidocera antarctica and Stephos longipes, and the cyclopoid Oncaea curvata. These copepods responded slowly to metal exposure (4-7d) emphasising that the exposure period of 48-96 h commonly used in toxicity tests with temperate and tropical species is not appropriate for polar organisms. We found that a longer 7 d exposure period was the minimum duration appropriate for Antarctic copepods. Although sensitivity to metal exposure varied between species, copper was more toxic than cadmium in all three species. P.antarctica was the most sensitive with 7d LC50 values for copper and cadmium of 20 μg L(-1) and 237 μg L(-1) respectively. Sensitivities to copper were similar for both O. curvata (LC50=64 μg L(-1)) and S. longipes (LC50=56 μg L(-1)), while O. curvata was more sensitive to cadmium (LC50=901 μg L(-1)) than S. longipes (LC50=1250 μg L(-1)). In comparison to copepods from lower latitudes, Antarctic copepods were more sensitive to copper and of similar sensitivity or less sensitive to cadmium. This study highlights the need for longer exposure periods in toxicity tests with slow responding Antarctic biota in order to generate relevant sensitivity data for inclusion in site-specific environmental quality guidelines for Antarctica.

Temporal changes in the sensitivity of coastal Antarctic zooplankton communities to diesel fuel: A comparison between single- and multi-species toxicity tests

Despite increasing human activity and risk of fuel spills in Antarctica, little is known about the impact of fuel on Antarctic marine fauna. The authors performed both single- and multi-species (whole community) acute toxicity tests to assess the sensitivity of an Antarctic coastal zooplankton community to the water-accommodated fraction of Special Antarctic Blend diesel. Single-species tests using abundant copepods Oncaea curvata, Oithona similis, and Stephos longipes allowed comparisons of sensitivity of key taxa and of sensitivity estimates obtained from traditional single-species and more novel multi-species tests. Special Antarctic Blend diesel caused significant mortality and species compositional change in the zooplankton community within 4 d to 7 d. The sensitivity of the community also increased across the summer sampling period, with decreasing 7-d median lethal concentration (LC50) values for total petroleum hydrocarbons (TPH): 1091 µg TPH/L in early January 2011, 353 µg TPH/L in mid January 2011, and 186 µg TPH/L in early February 2011. Copepods showed similar sensitivities to Special Antarctic Blend diesel in single-species tests (7-d LC50s: O. curvata, 158 µg TPH/L; O. similis, 176 µg TPH/L; S. longipes, 188 µg TPH/L). The combined use of single- and multi-species toxicity tests is a holistic approach to assessing the sensitivity of key species and the interactions and interdependence between species, enabling a broader understanding of the effects of fuel exposure on the whole zooplankton community.

Effects of ocean warming and acidification on fertilization in the Antarctic echinoid Sterechinus neumayeri across a range of sperm concentrations

The gametes of marine invertebrates are being spawned into an ocean that is simultaneously warming and decreasing in pH. Predicting the potential for interactive effects of these stressors on fertilization is difficult, especially for stenothermal polar invertebrates adapted to fertilization in cold, viscous water and, when decreased sperm availability may be an additional stressor. The impact of increased temperature (2-4 °C above ambient) and decreased pH (0.2-0.4 pH units below ambient) on fertilization in the Antarctic echinoid Sterechinus neumayeri across a range of sperm concentrations was investigated in cross-factorial experiments in context with near future ocean change projections. The high temperature treatment (+4 °C) was also used to assess thermal tolerance. Gametes from multiple males and females in replicate experiments were used to reflect the multiple spawner scenario in nature. For fertilization at low sperm density we tested three hypotheses, 1) increased temperature enhances fertilization success, 2) low pH reduces fertilization and, 3) due to the cold stenothermal physiology of S. neumayeri, temperature would be the more significant stressor. Temperature and sperm levels had a significant effect on fertilization, but decreased pH did not affect fertilization. Warming enhanced fertilization at the lowest sperm concentration tested likely through stimulation of sperm motility and reduced water viscosity. Our results indicate that fertilization in S. neumayeri, even at low sperm levels potentially found in nature, is resilient to near-future ocean warming and acidification.