Contamination in estuaries: detecting ecological impacts

Allyson O’Brien, Gigi Woods, Liz Morris & Mick Keough

School of BioSciencesUniversity of Melbourne

Centre for Aquatic PollutionIdentification 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

253

1442

n = 13Linked 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 & behaviourNumber of

amphipods/beaker (range)

Control 0 – 3

100 mg/kg 1 – 5

200 mg/kg 0 – 3

300 mg/kg 1 – 3

These were all from the largest size class

Different rates of burrowing

Microbial functional diversity• Biolog EcoplatesTM

• 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

010

020

030

0

Proc

Con0

1

2

3

4

5

Tota

l Wel

l Col

our

Dev

elop

men

t 620

nm

Amino acids

010

020

030

0

Proc

Con0

1

2

3

4

5

6

7Carbohydrates

Copper concentration (mg/kg)

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

✚

✚Watsons Creek

Lake Borrie

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