Contamination in estuaries: detecting ecological impacts Allyson O’Brien, Gigi Woods, Liz Morris & Mick Keough School of BioSciences University of Melbourne Centre for Aquatic Pollution Identification and Management

Cause-effect relationships Fundamental to environmental guidelines Reliable risk assessments We know they are variable We know less about: Levels of biological organisation Ecological processes

n = 13 Linked individual responses to population or community changes Marine experiments O’Brien & Keough 2014 (Environmental Pollution)

Estuarine toxicity tests Gammaropsis sp. Simplesetia aequistis Individual endpoints Survival Behaviour – Gigi Woods Metabolomics – Sara Long (CAPIM, Bio21 Institute) Population-level endpoints Population growth Size-class structure Community-level endpoints Microbial functional diversity – Liz Morris

Laboratory experiment – April 2015 Cu-dosed estuarine sediment O, 100, 200, 300 mg/kg Amphipods and microbial communities 2 week experiment

Endpoints Individual – Survival ✔ – Behaviour ✔ – Metabolomics Population-level endpoints – Population growth – Size-class structure Community-level – Microbial functional diversity ✔

Results – survival & behaviour Number of amphipods/beaker (range) Control0 – mg/kg1 – mg/kg0 – mg/kg1 – 3 These were all from the largest size class Different rates of burrowing

Microbial functional diversity Biolog Ecoplates TM Measures metabolism of 31 carbon sources per assay Distinguishes spatial and temporal changes in microbial communities Used in Melbourne Water Western Treatment Plant monitoring program

Where to from here? Did the spiking work? Improve survival in laboratory populations Amphipod behaviour could be a sensitive indicator. Also using polychaetes. Microbial functional diversity (ecoplates) worth pursuing Metabolomics with Sara Long & Metabolomics Australia (Bio21 Institute)

Field mesocosms Aim: To develop an experimental approach that could be used to detect causality Mesocosm = experimental unit Easily transported deployed sampled

Field mesocosms Translocation experiments using whole sediments Defaunated by freezing Deployed in intertidal sediments Multiple estuary experiments

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O’Brien & Keough 2013 (Environmental Pollution)

Where to from here? – field mesocosms Field dosing experiments Incorporate DNA metabarcoding – ARC Linkage project & collaboration with CSIRO

Overcome study bias – Lab experiments = individual responses – Field experiments = community responses How do we link responses at the individual- level to populations and communities? Where to from here? – more broadly

Co-authors and collaborators: – Liz Morris – Gigi Woods – Sara Long – Anthony Chariton – Mick Keough Acknowledgements