By Tim Mann
Why are coral reefs fragile ecosystems?
Any ecosystem is a fragile ecosystem! That is, if you apply the correct pressure to it. Coral reefs are usually robust, balanced, dynamic, self-regulating ecosystems that will have greater or lesser populations of all the species of plants and animals that live there, depending on the climate conditions: water temperature, amount of sunlight, salinity, etc.
But there are situations in which this balance can be quickly and easily thrown out of whack: it happened on my Big Island of Hawaii when the “crown of thorns” starfish invaded our reefs.
I moved to the Big Island before this population explosion started, and we rarely saw one when we dived the beautiful reefs of the west side of the island. But then they started to show up in numbers we’d never seen before; creatures that looked like this: (photo of COT)
There were always one or two of these scattered around the reef; but not the population explosion we saw in the late ‘70’s and early ‘80’s; thousands of them munching on coral, their favorite food. And whole swaths of reef were turning up dead and white, looking like the area to the right of the starfish in the photo below: (photo of bunch of COT’s munching on coral w/ big dead white coral area too)
At first, the marine biologists and scientists didn’t understand the problem, and had all the professional divers and scuba instructors telling people to harvest them and dump them on land somewhere, in an effort to control this threat.
Then someone made a connection between the bloom of starfish and the amount of fertilizer (nitrate) runoff from luxury golf courses and resorts on the island; they put controls in place to reduce this source of pollution, and now there are far, far fewer of them.
They couldn’t shut the golf courses down entirely…but there was a huge improvement; we’re almost back to where we were 40 years ago. And it only took 40 years!
This was written by Tim Mann, a commercial fisherman, “real world” marine biologist, and owner of a USDA organic-certified commercial aquaponics farm, Friendly Aquaponics. You can see the original post and more of Tim’s writing on Quora.
Copyright © 2017 by Marine Science Today, a publication of Marine Science Today LLC.