This is the penultimate week of our second 10-week collaboration. We challenged our volunteers to guess how long different types of litter take to decompose.
A lively debate ensued.
How long do you think it would take for these items to degrade?
Plastic bottle, tin can, plastic bag, nylon clothing, cigarette stubs, and glass (approximate answers at the end of this post)
Litter isn’t just unsightly; it pollutes our terrestrial and marine ecosystems.
If you visit the beach following a storm all manner of junk and debris is washed up by the tide. Unfortunately not all of the rubbish from our seas gets washed up.
Where does the litter go?
You may have heard of the floating rubbish islands a called ‘gyres’ which are formed from swirling vortexes of our rubbish. The map below shows the locations of the 5 largest gyres. The majority of floating rubbish not washed up on our coast lines ends up in one of these gyres.
Map showing locations of the 5 largest rubbish gyres (taken from http://5gyres.org/see_global_research/)
How does this link to our project?
Our reliance on all things plastic poses an invisible threat our marine ecosystems. Although Bryozans will happily colonise floating plastics, they pose a hidden threat to bryozoans and other marine-organisms. Plastics photo-degrade (are broken down by sunlight) into small particles called microplastics.
Image of fibrous microplastics found in deep ocean sediment (taken from http://www.nhm.ac.uk/about-us/news/2014/dec/deep-sea-littered-with-plastic-debris134005.html)
Filter feeders like our beloved bryozoans ingest these particles of plastic, instead of the tasty plankton that form their normal diet, they are not selective in their feeding ingesting anything the ocean current brings them. Ingestion of this non-nutritive bulk could starve or poison bryozoan colonies.
It's not just bryozoans that are at risk of harm, microplastics could also be entering the human food chain via seafood!
Glass 1-2 million years
Wan to know more?
5Gyres project set up by scientists to study the oceanic rubbish islands:
National Geographic article ‘Great Pacific Garbage patch’:
Paper published by Natural History Museum scientist Professor Lucy Woodall and team:
Woodal, L.C., Sanchez-Vidal, A., Canals, M., Paterson, G.L.P., Coppock, R., Sleight, V., Calafat, A., Rogers, A.D., Naravanaswamy, B.E., Thompsom, R.C., (2014) ‘The deep sea is a major sink for microplastic debris’ Royal Society Open Science [Online]. Availiable from: http://rsos.royalsocietypublishing.org/content/1/4/140317 (accessed 09/03/2015)