Evolutionary Ecotoxicology

Chief Investigators: Emma Johnston, Bill Ballard, Rob Brooks, Alistair Poore, Ross Hyne
Pollution is a potentially powerful agent of selection acting on aquatic organisms. Evolutionary ecotoxicology is a new research program at UNSW combining quantitative and molecular genetics with field and laboratory-based ecotoxicology.

Pollution tolerant populations of marine invertebrates have been found in highly industrialised ports and harbours such as Port Kembla, NSW pictured on the right (Piola & Johnston 2006a, 2006b).

 
 
Evolutionary ecotoxicology at UNSW examines the response of marine invertebrates to heavy metal contaminants that are common in ports, harbours and marinas. These heavy metals include lead, zinc and copper. Much of our field research is conducted sub-tidally while laboratory selection studies are conducted in marine mesocosms.

Further reading

Piola RF, Johnston EL (2006) Differential resistance to extended copper exposure in four introduced bryozoans. Marine Ecology Progress Series 311: 103-114.


Piola RF, Johnston EL (2006) Differential tolerance to metals among populations of the introduced bryozoan Bugula neritina. Marine Biology 148: 997-1010.

 

PhD student Richard Piola conducts ecotoxicological research on SCUBA.

Risk Assessment


Anthropogenic changes to genetic diversity are a potentially important tool for risk assessment and environmental management. Perturbations in population genetics can represent an early warning of other more dramatic effects such as loss of species and alterations of dispersal. Collaborative research including field surveys and selection studies will test the hypothesis that the deleterious effects of heavy metal contaminants increase the frequency of metal-resistant genotypes.

  Melitid amphipods are abundant in marine sediments. The locally occuring Melita plumulosa (not illustrated) is a sensitive bio-indicator and our model organism for the studies described immediately above and below.

Standardised Tests


Conventional toxicity tests usually use individuals from a standard cultured population in order to minimise variability in response to a toxicant. In order to extrapolate from the effects observed in laboratory tests to impacts that will occur in the field, it is essential to know how natural populations may vary in their response to contaminants and the extent to which this is driven by genetic and/or environmental variability. Our collaborative research will determine whether genetic variation influences the survival and fecundity of a sensitive amphipod (Melita plumulosa) exposed to reference contaminants.

 

Ecological Consequences


Numerous studies have reported differential toxicant sensitivity between populations of the same species. Our research has identified that pollution tolerance increases the dominance of non-indigenous sessile marine organisms such as the bryozoan Watersipora subtorqata. Quantitative genetics experiments will establish the genetic basis for elevated tolerance.

 

Pollution tolerance invasive bryozoan Watersipora subtorquata (red) competes for space with a pollution-sensitive native Fenestrulina mutabilis (cream).

Ecological consequences of pollution tolerance. Increasing pollution load increases invader dominance (% cover) in marine invertebrate communities at three out of four sites surveyed. A fourth site (Wollomoloo) is already highly impacted and dominated by non-indigenous species (Piola and Johnston, unpublished data).