Ocean Dead Zones are Spreading

(Originally appeared at TenthMil.com)

A new type of dead zone is growing off our coasts - low-oxygen regions that kill fish.

“In some spots off Washington state and Oregon , the almost complete absence of oxygen has left piles of Dungeness crab carcasses littering the ocean floor, killed off 25-year-old sea stars, crippled colonies of sea anemones and produced mats of potentially noxious bacteria that thrive in such conditions,” McClatchy news reports.

Dead zones aren’t new - one type of dead zone appears every year at the mouth of major rivers like the Mississippi, where nutrients from farm fertilizers that have been washed into the rivers reach the ocean and serve as food for algae blooms. In the feeding frenzy, the algae use up all the oxygen in the water, and any fish in the area literally suffocate and drown. And the isolated waters of the deep ocean has always been low in oxygen, but sea life in the depths has adapted.

The other type of dead zone is more troubling. These have been happening in places like the Pacific Northwest coast off Oregon and Washington, and until now scientists weren’t sure why they were occurring - they just knew they were growing from year to year. It looks like the deep-see dead zones are spreading, rising toward the surface and even coming close enough to the coastline to affect the fishing there. On the Southern California coast, oxygen levels have dropped 20 percent over the past 25 years.

“The real surprise is how this has become the new norm,” said Jack Barth, an oceanography professor at Oregon State University . “We are seeing it year after year.”

We’ve reported at TENTHMIL about the problem of ocean acidification - as CO2 levels in the atmosphere rise, more is absorbed in the upper levels of the ocean, where it turns to carbonic acid. The rise in acidity is bad for fish all up and down the food chain, but is particularly bad for plankton and shellfish, because it interferes with their shell formation. Barth and other scientists say this is all related - climate change, acidification, and dead zones.

“It’s a large disturbance in the ecosystem that could have huge biological changes,” said Steve Bograd , an oceanographer at NOAA’s Southwest Fisheries Science Center in Southern California .
Bograd has been studying oxygen levels in the California Current, which runs along the West Coast from the Canadian border to Baja California and, some scientists think, eventually could be affected by climate change.

Want even more fun news? Some ocean life is happy with the change - jellyfish, in particular, love it. This may have something to do with the abundance of jellyfish that have been plaguing beaches in the US, Europe and Japan. There’s a world to look forward to - no fish, no shellfish… just beaches that are ankle-deep in jellyfish and slimy algae.

Restoring Florida's Coral Reefs

Coral reefs are among the most productive ecosystems in the ocean, harboring thousands of species from plankton all the way up to fish like the grouper and snapper.

Covering less than a quarter of a percent of the ocean’s surface, coral reefs support twenty-five percent of all marine life!

Coral reefs also among the most beautiful ecosystems in the world – painted canyons of branching coral, waving kelp, and dazzling fish in rainbow colors. They remain a huge attraction to divers and other tourists, and are a mainstay of the economies of South Florida’s Keys and countless other destinations around the globe.

Coral reefs are also among the most threatened environments in the world today. Scientists estimate that 25 percent of the world’s reefs have already been destroyed or badly degraded.
What’s killing the reefs?

• Diseases: staghorn and elkhorn coral have been hit hard by diseases, possibly imported from the Pacific via the Panama canal; they hit corals whose immune systems are already weakened by the other factors. Both species are now listed as threatened.
• Algae: The green growth was kept in check by voracious sea urchins, but disease has wiped out the previously large populations of urchins, and the resulting algae explosion is creating huge problems for coral reefs.
• Cold – this winter’s unusual cold snap, which didn’t affect deep-sea coral, was devastating to corals in shallow waters along the coast.
• Human Damage – sometimes intentional, like when dredging for a shipping channel or building a jetty; or accidental, when a ship runs aground. In either scenario, the reef gets pulverized and takes years to recover.

Florida Aquarium’s Global Reef Institute, is doing something about it.

Coral may look like a plant, but it’s actually a tiny animal – a polyp – that builds a tree-like framework of calcium carbonate to protect itself. In the wild, corals reproduce by larvae, which swim freely until they find a good place to settle down. Then they anchor themselves, and grow. When a piece of coral is smashed to bits – say, in a ship grounding – it can take months or more for the pieces to get back to equilibrium, and if they don’t land in a suitable place, they may never recover.

That’s where the researchers step in.

“We got the idea that if we could grow them in mass, we could start doing restoration,” says Craig Watson, lab director at the University of Florida’s Tropical Aquaculture Laboratory in Ruskin, who is also on the board of the Florida Aquarium. “The concept is to take coral fragments, grow them up to a size where they would be stable and growing, and take them out to a reef that’s damaged and plant them there.” They gather those coral fragments and place them in a pond or tank, where they can be carefully nurtured for six months. Once they’re healthy, they can be taken back to the wild and glued to a reef. “We can get a huge jump on nature rather than waiting for spawning to occur and a single polyp to establish itself,” says Watson. “It’s like planting a seedling rather than a seed.”

The conventional wisdom was that if you grew coral in a land-based condition, it wouldn’t be able to survive when you transplanted it, but that after three years of experimentation they’ve got it down. “In fact,” says Allan Marshall, the aquarium’s vice president of biological operations, “the program proved that inland grown coral does even better – we’ve had a 70 percent success rate.”

Another concern, with transplanted coral, was the threat of diseases. Whenever you pen up a whole lot of organisms in an un-natural environment, there’s a risk that pathogens will run rampant through the population, and then spread to the wild (it’s a problem on big cattle feedlots and salmon farms). Wanting to make sure they could literally give their coral a clean bill of health, the aquarium has worked out a certification program. Having USDA veterinarians monitor the coral closely, then before any coral is released into the wild it is certified as disease-free.

Marshall says the reef ecosystem is a lot like the tropical rainforests: fragile, and feeling the pressure of changes big and small. The best targets for restoration, at least for now, are reefs with physical damage, usually from a boat grounding. There is also funding there, since the shipping companies responsible are supposed to pay for that restoration work. Money is also coming into the project from the Economic Stimulus, via the Nature Conservancy.

“We’re not looking at restoring reefs where [temperature change] is the problem,” notes Watson, “the reasoning being that those spots aren’t going to be good for coral now.”

Sadly, most of their work takes place in an area that’s already supposed to be a protected zone: the Florida Keys National Reef Sanctuary. “The reality is there are a lot of people in South Florida,” says Watson, “so even though the reefs are already protected there are a lot of impacts associated with all those people.” And he adds that they’re seeing good results with other species. For instance, research found that the grouper and snapper for much of the east coast spawned in one small area. “They’ve created a no-take zone right there,” he says, “so now spawning aggregations are taking place without harassment, so that’s going to help with recovery of those fisheries.”

What can you do?
The Nature Conservancy has an Adopt-a-Reef program that allows you to take part directly – this year, it’s a big part of their Earth Day campaign.
http://adopt.nature.org/coralreef/
http://earthday.nature.org/

(Originally appeared at TenthMil.com)