Dr Mark Anthony
School of Biology & Environmental Science
Testing the ecological relevance of biomarkers in predicting the impacts of pollution on the structure and functioning of marine ecosystems
My current project is investigating whether we can detect the subtle influences of environmental impacts using ‘biomarkers’ - responses to environmental insults by organisms. Our current understanding is hampered because most biomarkers have been studied in isolation at different levels of biological response. For biomarkers to be effective in programmes of monitoring they must differentiate between different types of chemical disturbance and reflect environmental stresses over time in a quantitative way. When a contaminant causes a disturbance of sufficient magnitude to elicit a response in a particular level of organisation it is termed a pollutant. For this to occur, the disturbance caused by the contaminant must be large enough to overcome the inertia in that level of biological organisation. The size of the disturbance will not just depend upon the concentration (magnitude), but will also depend upon the number of contaminants present (identity), the duration they are present in their toxic form (timing and variance) and the sensitivity of the organism(s). The use of biomarkers is, however, largely based on single-compound exposures, carried out in the laboratory and over short-time scales. These compounds are assumed to have additive or independent effects in habitats with mixtures of contaminants. Consequently, before biomarkers can be used in programmes of monitoring, experiments are needed which combine all of these elements, particularly the notion of spanning a range of levels of organisation.
To achieve this I am using field experiments with patches of mussels (Mytilus edulis) to examine direct and indirect consequences of metal and biocides in habitats. Patches of mussels are an ideal experimental system for assessing the ecological relevance of biomarkers. The physical structure of the shells provide secondary habitat for a wide range of organisms, their filter-feeding removes particulates and organisms from the water-column, and their faeces is a source of nutrients for organisms. Mussels have a global distribution, are used in many programmes of monitoring and there is a well-established hierarchy of methodologies to provide integrated measures of sub-lethal stresses. Using this I am testing the value of different biomarkers integrated across a range of levels of organisation from biochemical, cell to organism, population, assemblage and ecosystem. My experiments are manipulating the magnitude, timing, variance and identity of the contaminants in patches of mussels. This allows me to evaluate the performance of the techniques under different scenarios and determine whether:
(i) biomarkers of exposure predict the quantity of contaminants in the tissues of animals,
(ii) biomarkers of effect predict changes in the structure of assemblages before they occur,
(iii) there are differences in the rate of impact and recovery across levels of biological organisation,
(iv) assessments made at lower levels of organisation indicate the progress of impact and recovery processes at higher levels,
(v) effects of the individual contaminants are smaller or greater than the mixtures,
(vi) statistical tests of equivalence can be used to asses the ecological status of habitats.
This work is important because direct discharges and run-off from mining, agriculture, fish-farming, the treatment of sewage and shipping contaminate marine habitats with metal and biocides, which accumulate in great concentrations in water, sediment and the tissues of animals. Mussels in Ireland have combined concentrations of mercury, lead and cadmium up to 1.22 µg g-1 and concentrations of copper up to 32 µg g-1 wet weight of tissue. Ireland uses more than 2840 tonnes of pesticides each year for agriculture and climatic change is predicted to increase their use further. Warmer temperatures are expected to increase the abundance of disease and pest species, and greater rain-fall during the winter is predicted to increase the erosion of soil and run-off, resulting in greater concentrations of metals and biocides reaching marine habitats through storm-water. As such metals and biocides represent 50 % of the contaminants monitored, yet the relationship between localised impacts from these and marine biodiversity is poorly understood.
My work is providing the first direct experimental evidence about whether biomarkers are sensitive enough to predict changes in the structure and functioning of marine ecosystems due to contaminants. This research is providing the crucial information to allow environmental managers to choose the best techniques to protect and enhance the environment, in line with the European Water and Marine Strategy Framework Directives, and the Convention for the Protection of the Marine Environment of the North-East Atlantic.
This work is funded by an Irish Research Council for Science, Engineering and Technology (IRCSET) post-doctoral fellowship. It is being done in collaboration with Tasman Crowe, Paul Brooks (University College Dublin), Tony Underwood, Gee Chapman (University of Sydney), and Emma Jonhston (University of New South Wales).
1. Browne, M. A., Galloway, T. S., Thompson, R. C. (2010) Spatial patterns of plastic debris along estuarine shore lines. Environmental Science and Technology. In press.
2. Browne, M. A. (2010) Characterisation of microplastic debris in terrestrial, freshwater and marine estuarine habitats within the Hornsby Shire Catchment area. Final Report.
3. Moreira, F. T. Browne, M. A., Coleman, R. A. (2010) An ecological experimental framework for investigating and managing discharges from buildings using seawater as a coolant. Human and Ecological Risk Assessment. In press.
4. Browne, M. A., Dissanayake, A., Galloway, T. S., Lowe, D. M., Thompson, R. C. (2008) Ingested microscopic plastic translocates to the circulatory system of the mussel, Mytilus edulis (L.). Environmental Science and Technology. 42:5026–5031
5. Browne, M. A., Galloway, T. S., Thompson, R. C. (2007) Microplastic – An emerging contaminant of potential concern? Human and Ecological Risk Assessment. 3:559-561
6. Cartwright, S. R., Coleman, R. A., Browne, M. A. (2006) Ecologically relevant effects of pulse application of copper on the limpet Patella vulgata (L). Marine Ecology Progress Series. 236:187-194
7. Galloway, T. S., Brown, R. J., Dissanayake, A., Browne, M. A., Lowe, D. M., Cheung, V., Depledge, M. H., Jones, M. B. (2006) The ECOMAN project: a novel approach to sustainable ecosystem function. Marine Pollution Bulletin. 53:186-194
8. Coleman, R. A., Browne, M. A., Theobalds, T. (2004) Aggregation as a defence: Limpet tenacity changes in response to simulated predator attack. Ecology. 85:1153-1159
9. Bonacci, S., Browne, M. A., Dissanayake, A., Hagger, J. A., Corsi, I., Focardi, S., Galloway, T. S. (2004) Esterase activities in the bivalve mollusc Adamussium colbecki as a biomarker for pollution monitoring in the Antarctic marine environment. Marine Pollution Bulletin. 49:445-455
10. Brown, R. J., Galloway, T. S., Lowe, D., Browne, M. A., Dissanayake, A., Jones, M. B., Depledge, M. H. (2004) Differential sensitivity of three marine invertebrates to copper assessed using multiple biomarkers. Aquatic Toxicology. 66:267-278
11. Galloway, T. S., Brown, R. J., Browne, M.A., Dissanayake, A., Lowe, D., Jones, M. B. and Depledge, M. H. (2004) A multi-biomarker approach to ecosystem management. Environmental Science and Technology. 38:1723-1731
12. Galloway, T. S., Brown, R. J., Browne, M. A., Dissanayake, A., Lowe, D., Jones, M. B., Depledge, M. H. (2004) Ecosystem management bioindicators: the ECOMAN project - a multi-biomarker approach to ecosystem management. Marine Environmental Research. 58:233-237
13. O'Neill, A. J., Galloway, T. S., Browne, M. A., Dissanayake, A., Depledge, M. H. (2004) Evaluation of toxicity in tributaries of the Mersey estuary using the isopod Asellus aquaticus (L.). Marine Environmental Research 58:327-331.
14. Bloxham, M. J., Jones, M. B., Galloway, T. S., Lowe, D. M., Browne, M. A., Depledge, M. H. (2004) Ecosystem management bio-indicators. Final Report, DEFRA CDEP 84/5/292.
15. Galloway, T. S., Millward, N., Browne, M. A., Depledge, M. H. (2002) Rapid assessment of organophosphorous/carbamate exposure in the bivalve mollusc Mytilus edulis using combined esterase activities as biomarkers. Aquatic Toxicology 61:169-180.
1. Browne, M. A. Tenacity of limpets. (2010) World Congress of Malacology, Phuket, Thailand.
2. Browne, M. A., Galloway, T. S., Thompson, R. C. (2010) Spatial patterns of plastic debris along estuarine shore lines. European Meeting of the Society of Environmental Toxicology & Chemistry, Seville, Spain.
3. Browne M. A. (2009) Using flower pots to improve biodiversity on seawalls. Sydney Royal Botanical Gardens, Australia
4. Browne, M. A. (2009) Managing the problem of microplastic debris in oyster fisheries in NSW, Australia. Broken Bay Oyster Association and Hornsby Shire Council, Australia.
5. Browne, M. A. (2009) Unravelling the environmental consequences of microscopic plastic debris in natural habitats. Royal Zoological Society Forum, Sydney, Australia.
6. Browne, M. A., Dissanayake, A., Lowe, D. M., Galloway, T. S., Thompson, R. C. (2008) Environmental and biological consequences of microplastic debris in marine habitats. NSW DPI, Australia.
7. Browne, M. A., Dissanayake, A., Lowe, D. M., Galloway, T. S., Thompson, R. C. (2008) The big problem of small particles of plastic. University of New South Wales, Australia.
8. Browne, M. A., (2008) Environmental consequences of microscopic plastic debris in marine habitats. University of Sydney, Australia.
9. Browne, M. A., Dissanayake, A., Lowe, D. M., Galloway, T. S., Thompson, R. C. (2008) Environmental consequences of microscopic plastic debris in marine habitats. Tokyo University of Agriculture and Technology, Japan.
10. Browne, M. A., Thompson, R, C., Lowe, D, M., Dissanayake A., Galloway, T, S. (2005) Consequences of microplastic in the mussel, Mytilus edulis (L.). University College Dublin, Ireland.
11. Browne, M. A. (2009) Blooming marvellous: using flower pots as rock-pools on existing seawalls to sustain greater levels of biodiversity. British Ecological Society Meeting. University of Hertfordshire, UK.
12. Browne, M. A. (2009) Effect of slope and substratum on the tenacity of limpets on seawalls and rocky shores. Temperate Reef Symposium, Adelaide, Australia.
13. Browne, M. A., Chapman, M. G., Underwood A. J., Echavarri, B. (2009) Effect of slope and substratum on the tenacity of limpets on seawalls and rocky shores. Ecological Society of Australia, Sydney.
14. Browne, M. A., Thompson, R. C., Lowe, D. M., Dissanayake, A., Galloway, T. S. (2005) Consequences of microplastic in the mussel, Mytilus edulis (L.). Ingestion, translocation & biological effects. Society of Environmental Toxicology & Chemistry North America, Montreal, Canada.
15. Browne, M. A., Aspden, R. J. (2000) Deposition of sediment in two monopolising intertidal assemblages. ESCA Conference, Germany.
16. Aspden, R. J., Browne, M. A. (2000) Species diversity patterns in sediment accumulating rocky shore mussels. ESCA Conference, Germany.
Some media clips on attaching flower pots on seawalls