We Finally Know Why Florida's Coral Reefs Are Dying, and It's Not Just Climate Change

[Neoalchemist]

We Finally Know Why Florida's Coral Reefs Are Dying, and It's Not Just Climate Change

Hot water is killing Florida's coral reefs. But it's not the only factor bleaching them white.

www.livescience.com

 

[29bonsaireef]

Sad to say, but the keys were doomed the day Henry Flagler started construction. IMHO, there's always been a lot more to it then just climate change if that is really a damaging cause to Florida reefs. I'm not a scientist though, so cannot say with certainty.

Coincidentally, during the summer, when it's the hottest.. is also the rainy season around the everglades, s/sw Florida region. SO at the same time they're blaming temps is also the same time the most runoff is washing into the gulf/ocean down here. Now I know people who've been going to the keys since the 50's and 60's. 88-90 degree surface temp was not super rare back then either, it happened in the summers, and the reefs thrived through the 70's.

Only MAJOR change is development, agricultural expansion, more people. I'm not saying warming temps do not have some negative effect on the corals, but I don't really believe it is the main factor in die-off/loss of stony corals here in the keys.

 

[TexasReefer82]

I completely agree! The coral reefs of the Florida reef track are pretty far north - not formally in the tropics - and have always been subject to seasonal temperature extremes of both hot and cold (and both can cause bleaching). The temperature extremes aren't anything new and they have likely been worse in past decades/centuries.

The initial white band disease that killed off the Acropora cervicornis and palmata was determined to be the direct result of human fecal bacteria released from so many leaky septic systems in the keys. The keys were then entirely placed on municipal sewer systems and white band disease is no longer a major issue. Hence, in the 20-teens Ted Nedimeyer and the Coral Restoration Foundation can out-plant over 100,000 acropora frags with ~70% survival rate - this wouldn't have been possible in the early 1980's.

The Comprehensive Everglades Restoration Plan (CERP) aims to redirect large scale water flow south through the everglades and into Florida Bay in a needed effort to replenish water to the Glades. Much of this redirected water is agricultural runoff that currently is shunted straight to the Atlantic ocean and the Gulf of Mexico from central Florida. They're far from done with the CERP but have already made some major progress. I just wonder if the CERP is responsible for this recent coral disease problem. There's also a problem of large areas in the Northern Glades being overtaken by cattails from the high nutrient runoff.

What's more... In personal communication with Dr Martin Moe about his efforts to restore the diadema urchin to Florida Keys and Caribbean... Florida Bay is significantly contaminated with heavy metals and endocrine disruptors from agricultural runoff and municipal wastewater. It is known that this pollution inhibits restoration of the diadema in Florida Bay and I wouldn't be the least bit surprised if it disrupts the Keys reef track as well.

Another issue proportional to tourism and population: Sunscreen. It will be very interesting to see if Hawaii observes any noticeable improvement in reef health after their sunscreen ban.

All this blithering talk about global warming completely misses and distracts from the root causes of reef decline. It's almost like the AGW campaign is supported on purpose as a cover for parties that release real pollution.

 

[EmdeReef]

Thread and article titles are misleading. Read the original study and it’s about a very specific area and specific causes which may or may not apply to any other regions, so even extending it to the entire Florida coast is a stretch let alone another region in the world.

I find it beyond incredible that reefers would blindly dismiss the severe impact of temperature on corals.

Here’s an experiment for those who don’t believe extremely well documented bleaching events are primarily caused by high temperatures.

Set your controller to ~90 degrees 24/7 (90 is directionally an average of daily and nightly temperatures as in some regions the temperatures ran well into a hundred for days) and run your tank for a 14-30 days, come back and report “other” causes that melt your corals

There have been bleaching events in the past, but in the last 20 years there’s been a record number lasting significantly longer thus effectively killing entire colonies and not allowing surviving colonies to recover.

 

[twotangs]

Using the same argument, try rainwater run off from a farm to mix your salt with and do a few water changes that way and report the results. This is not a problem that has a one size fits all answer. Just my thoughts.

 

[TexasReefer82]

EmdeReef,
No one here is blindly dismissing the impact of temperature on corals. Instead we are recognizing the exacerbating effect of nutrients (particularly phosphorous limitation) on the sensitivity of corals to temperature and solar radiation.

Contemporary with the Keys bleaching events of the past decades is a tremendous increase of population in Florida. And in the decades prior to that Florida was turned from a native wilderness into a vast agricultural region with hugely altered hydrology. All of these changes have made a substantial impact on the water quality of the Keys, including Looe Key.

That we may be able to control nutrient runoff as an exacerbating factor to prevent future bleaching would be a tremendous improvement for these reefs.

 

[Neoalchemist]

Arguing for or against which human influenced causes are to blame is like detonating four different explosives in someone's living room and then arguing over which one killed the guy.
We as aquarist know first hand that in most cases many factors are often responsible for the weakened condition that allows for infection and mass coral death to take hold.

 

[Brad Miller]

I think the latest issue of Coral Magazine explained it a little better.
Temps appear to never have been the cause, as was thought....

 

[DuckSlayer627]

I was just in the Cayman Islands(Grand Cayman&Cayman Brac) in August and the water was 86-87 degrees down to at least 130ft. and all corals appeared to be thriving, even the 2 Acropora sp. I was diving with shorts and no wetsuit. It felt like bath water. Saw many large thriving colonies of both Acro. sp. as well as all the other stony and soft corals of the Caribbean. So to believe that temperature is the issue just doesn't line up with what I saw with my own eyes.

 

[Graffiti Spot]

I think it’s been proven that temperature certainly is the cause for many reefs bleaching events. Also proven that runoff effects the reefs in a similar way. Not sure what everyone is debating. I am also really suprised at the amount of reefkeepers I have seen that don’t believe in global warming at all.

Duckslayer, I wonder what the reefs would look like with a few weeks of temps at 90+? I haven’t heard of bleaching events on reefs with 86 degree temps so I don’t think you should let that sway your opinion on wether or not temp bleaches reefs.

 

[TexasReefer82]

I am also really suprised at the amount of reefkeepers I have seen that don’t believe in global warming at all.

Why are you so surprised?

I'm sure that those who believe and those who do not have their reasons.

That we use the word "believe" in this context is indicative of the nature of this issue.

 

[PatW]

At Little Cayman, there was a large bleaching event that wiped out the corals at the outer wall at the Jackson Bight section about 12 years ago. That was attributed to an episode of elevated temperatures. There are uninhabitated islands in the pacific with dead reefs.

Now if you dive Cozumel, you will see that the reefs at the southern part of the island are in really good shape. The currents come in from the open ocean from the south. As you go progressively north, the corals get into increasingly bad shape. There are large resorts on the island. They might use large septic systems but I bet they dump all those nutrients right out into the reefs. The reefs become increasingly covered with algae as you go north. Any reefer would suspect that the problem there is from nitrates and phosphates. And many cruise ships tie up at Cozumel and I bet they pump out their bilges as they approach. I often see blighted reefs right where I would suspect that there are large discharges of nutrient laden waste water.

Another possible issue is the removal of predators. I have heard that the damsel fish tend their own algae gardens which can damage corals. If you have some groupers around, there is less of a problem but that is just hearsay. But it would hardly be surprising that massive over fishing adversely affects corals by disrupting food webs.

And then you have an increase of carbon dioxide in the water making it more acid and that cannot be good.

Many reefs experience a combination of the above: high temperatures, elevated nutrients, removal of predators, and increased acidity. It can hardly be a surprise that corals are not doing well.

 

[Justfebreezeit]

Plus not to mention here in florida recreational and commercial diving. I see countless divers grabbing onto corals (brains, seafans, sponges etcc.) Something that took a few years to grow is gone in seconds and happens daily on a large scale here.

Not to mention fisherman anchoring right on the reef.

Between physical destruction and sub par water quality for whatever reason, coral really doesn't stand a chance.

 

[Daniel@R2R]

This is an interesting discussion to follow. I believe the decline in reef health is more nuanced than relegating it to any 1 issue.