British coral reefs

When you think of coral reefs, your mind immediately transports you to The Red Sea, The Australian Coastline and the warm, blue waters of Indonesia. But did you know, they’re also found in the waters around Britain? Granted, these aren’t the colourful, tropical coral reefs we’re so used to seeing, but cold water corals do exist and can be found on the sloping sea beds of Western Scotland and even on the legs of Oil rigs in the North Sea.

But what about climate change, technological advances, human intervention and  accelerated evolution? Could we one day see these warmer climate counterparts around this relatively small island in the Northern Hemisphere?

Corals are currently grown in labs across the Britain as part of on-going research, as well as for retail. Whilst in these labs, many are undergoing experiments with the best intentions of hardening them to rising temperatures to prevent the coral bleaching events we’re unfortunately seeing more and more often. But what if this was turned on its head? What if the corals could be exposed to cooler temperatures to harden them towards colder environments?

One theory that could be utilised in acclimating corals to cooler water is ‘coral memory’

In 1994, Barbara Brown was a marine Biologist at Newcastle University (England) and she had noted that only the Eastern sides of the SPS Coelastrea aspera bleached during a high heat event at her field site in Phuket, Thailand.

In a study that was published in Nature Magazine several years later, she hypothesized that the Western sides of corals were more tolerant having previously been exposed to more sun. She took this theory and tested it in laboratory conditions using coral samples that she exposed to varying temperature and lighting schedules..

In 2000, the team returned to the site in Thailand and rotated several corals so that the assumed stress-tolerant West facing sides now faced East, and vice versa. Almost ten years would pass before the reef experienced another severe bleaching event, but when it did, the team discovered that the now Eastern sides of the corals, fared better than the Eastern sides of corals that had not been rotated. The team interpreted this as evidence that the corals had indeed recalled a ‘memory’ of their previous exposure even though this had happened some ten years prior. In December 2014 the team published the paper “Decadal environmental ‘memory’ in a reef coral?”

There are many innovative methods that scientists, marine biologists, field experts and even hobbyists are using to ensure the survival and protection of coral reefs around the world. Whilst this one is not related to temperature, it is one of my personal favourites, and that is the autonomous underwater Crown-of-Thorns-Starfish killing robot named RangerBot. Given that the population of this particular coral eating starfish is booming, a team in Australia has developed a robot which will seek out and provide a lethal dose to the starfish to try and aid in the survival of the reefs. Some may suggest that this is playing God, and why should man be trying to affect the ecosystem. The truth is, it’s humans have played a large part in causing this to happen by overfishing the natural predators of the starfish, as well as agricultural run-off providing an abundance of food for the young. Paired together with the starfish’s natural ability to grow and breed very quickly, this has caused explosions in the population.

NASA data suggests that around 90% of global warming is occurring in the oceans and that there’s been a rising trend in sea water temperatures since records began.

Sea surface temperature records have been collected for decades and the trends of these figures is what scientists are looking at closely. In the waters surrounding Britain, it is estimated that average temperatures have risen by 0.8°C since 1870, and have shown a consistent warming trend from the 1970’s onwards. Current trends predict that based on the current trajectory, we could see a rise in global sea surface temperature of 1.5°C by 2050, and 3.2°C by 2100.

Figures similar to this can be found from multiple sources which naturally all differ, however, even though each institution has its own data and hypothesis as to how things will unfold, they all show a common upward trend.

The term ‘poleward migration’ has been given to the corals that are actually migrating to cooler water in order to avoid the warming waters of specific areas, We’re now seeing corals colonising more temperate waters. 

Currently, the waters around Britain reach a high of around 18°C in the warmest months of July and August. A rise in this top temperature would also mean the lower temperatures would rise and it’s this rise that provides the possibility that this would create the necessary range in which tropical corals could exist. It will also be interesting to see how the current cold water corals adapt and evolve to deal with these temperatures. Could we see a hybrid of cold water corals becoming hardened to the warmer waters, alongside tropical corals which have adapted to the cooler environments? Something which would be truly unique to the world.