During the Ecocentre day out we ran a sediment sampling run, looking for microplastics in the sediment of the Maribynong River. Port Phillip Bay has had very few studies of this type and hopefully the work done over the last years by researchers and government agencies can be ramped up to discover the depth of the problem, literally.
We have teamed with Dr Mark Osborn and Dr Slobodanka Stojkovic from RMIT this year to analyse our samples which are collected daily during the Two Bays 2016 program. Last year we did the same and it emerged from those studies that the most abundant microplastic in our samples (from Port Phillip Bay) was from plastic fibres in clothes. The EPA has given a huge amount of in-kind support to our citizen science arm of the project and we were fortunate to have Dr Randall Lee on board to help with the sampling on this day.
We had two methods for sampling during this year's Two Bays. We daily ran a microplastics trawl and collected microplastics at the end of the day from 212 micron and 425 micron sieves, from water (from the water column about a meter beneath the vessel) pumped into Pelican 1. We also, as pictured above, did some sediment testing. The scientists are looking at the microplastics that may end up deposited in the sediment. There has not been a lot of study yet about the microplastics in marine sediment and interactions between these plastic particles and toxicants, which are known to fuse with the plastic. The tiny pieces also attract other organisms, who leap on the life-raft of plastic chance to create miniature ecologies. We hope to further this much needed field of investigation in our home embayment and develop more studies for Two Bays 2017.
Below is a photo of our Marine Educator Harry Breidahl, showing another sediment dweller- sea cucumbers. Unfortunately we did not study these little critters to see if they had ingested microplastics but we will endeavour to include them in our future studies.
The PDF below is from a talk given recently by Dr Mark Osborn about plastics in the aquatic environment.