How plastic is making coral reefs sick

We've all heard about the threats of climate change and bleaching to coral reefs, but there's one issue that has only just come to light - the plastic problem.

There has been a surge in interest and campaigning about this issue following it's feature in Blue Planet, and the UK is making big changes to begin the fight against plastic.

A recent study in the journal Science has now found that plastic rubbish intensifies disease in corals.

"Plastics make ideal vessels for colonising microscopic organisms that could trigger disease if they come into contact with corals", said the study's lead author, Joleah Lamb from Cornell University.

"Plastic items, such as bottle caps and toothbrushes, have been shown to become heavily inhabited by bacteria. "This is associated with the globally devastating group of coral diseases, known as white syndromes".

The likelihood of disease increases from 4 to 89% when plastic debris meets coral, and current estimates state around 11.1 billion plastic items to be entangled in reefs across the Asia-Pacific region. It is also anticipated that this figure will increase by 40% over the next 7 years.

What is coral?

Coral are tiny marine invertebrates (they don't have a spinal column or backbone) that cling to one another to build up colonies or 'reefs'.

"Coral reefs are productive habitats in the middle of nutrient-poor water", said Drew Harvell, Professor of ecology and evolutionary biology. They are the greatest foundation for biodiversity in the ocean, and are also critical for fisheries.

Back to plastic

The bacteria that reside on plastic rubbish can disturb the delicate coral tissues.

"What's disturbing about coral disease is that once the coral tissue loss occurs, it's not coming back', said Lamb.

As a result of their study, which looked at 159 coral reefs in Indonesia, Australia, Myanmar and Thailand, the scientists forecast that by 2025, plastic going into the marine environment and on to coral reefs will increase to 15.7 billion items.

References

Page: Cornell University. "A 'marine motorhome for microbes': Oceanic plastic trash conveys disease to coral reefs." ScienceDaily. ScienceDaily, 25 January 2018. <www.sciencedaily.com/releases/2018/01/180125140848.htm>.

Journal: Joleah B. Lamb, Bette L. Willis, Evan A. Fiorenza, Courtney S. Couch, Robert Howard, Douglas N. Rader, James D. True, Lisa A. Kelly, Awaludinnoer Ahmad, Jamaluddin Jompa, C. Drew Harvell. Plastic waste associated with disease on coral reefs. Science, 2018 DOI: 10.1126/science.aar3320

Image: "https://www.freepik.com/free-photo/coral-reefs-below-the-surface-of-an-island_1115947.htm