(A and B) Two Paramuricea sp. from MC344 in November 2011 with
apparently healthy and visibly unhealthy and dead portions of the colonies apparent.
New
research by scientists at Pennsylvania State University has found two more reefs that were negatively affected by the 2010
Deepwater Horizon oil well blowout. The 87-day gusher spread an estimated 210 million gallons of oil into the Gulf of Mexico.
Impacts on sea creatures and birds were extensive. But the lead PSU researcher, Charles Fisher,
said:
"The footprint of the impact of the spill on coral communities is both deeper and wider than previous data indicated. [...] This study very clearly shows that multiple coral communities, up to 22 kilometers from the spill site and at depths over 1800 meters, were impacted by the spill."
The oil from the spill in the Gulf of Mexico has largely dissipated, so other clues now are needed to identify marine species impacted by the spill. Fisher's team used the current conditions at a coral community known to have been impacted by the spill in 2010 as a model "fingerprint" for gauging the spill's impact in newly discovered coral communities. [...]
Unlike other species impacted by the spill whose remains quickly disappeared from the ocean floor, corals form a mineralized skeleton that can last for years after the organism has died. "One of the keys to coral's usefulness as an indicator species is that the coral skeleton retains evidence of the damage long after the oil that caused the damage is gone," said Fisher.
According to the researchers:
Here we describe the discovery of five previously unknown coral communities near Macondo wellhead and show that at least two additional coral communities were impacted by the spill. Although the oil-containing flocullent material that was present on corals when the first impacted community was discovered was largely gone, a characteristic patchy covering of hydrozoans on dead portions of the skeleton allowed recognition of impacted colonies at the more recently discovered sites. One of these communities was 6 km south of the Macondo wellhead and over 90% of the coral present showed the characteristic signs of recent impact. The other community, 22 km southeast of the wellhead between 1,850 and 1,950 m depth, was more lightly impacted. However, the discovery of this site considerably extends the distance from Macondo and depth range of significant impact to benthic macrofaunal communities. We also show that most known deep-water coral communities of the Gulf of Mexico do not appear to have been acutely impacted by the spill, although two of the newly discovered communities near the wellhead apparently not impacted by the spill have been impacted by deep-sea fishing operations.
There is more below the fold.
Emily Atkin at ThinkProgress interviewed Fisher. Here's a key part of their exchange:
Think Progress: So because of the mystery of the deep sea, we don’t know how ecologically important this is. What are the implications of the fact that we don’t know these impacts?
Fisher: What we’ve demonstrated here are what I would call acute impact to corals. In other words, corals that were impacted so hard that parts of the colony immediately died and then were colonizes by these hydroids. Things are starting to break off.
Corals are a great indicator species … they are an indicator that this impact from the oil spill reached that far away.
What we still don’t know, and what we need to all keep in mind, is that there’s the potential for sub-acute impact. In other words, things that might have happened to the corals’ reproductive system—slower acting cancers, changes in the fitness of the animal.
These are very hard to detect and they’ll take a long time for us to see whats going on.
It seems like its been along time [since the spill], but the deep sea is a slow-moving environment. the water temperature down there is 4 degrees Celsius. These corals, some of them are 500 years old. Things change slowly. So it could be a while before things are fully recognized in the wider Gulf.
TP: Are you worried?
Fisher: About the deep sea? Sure I am.
There are many different stressers being applied to the oceans right now. In addition to energy extraction and metal extraction that’s coming upon us very quickly with people wanting to mine deep sea metals, there’s increased fishing pressure. We’ve got climate change and the effects of that, runoff and everything else.
The ocean is under a lot of pressure, and the shallows have already felt it very seriously, with a serious decline in coral all over the world. And the deep sea is starting to feel it as well. So yes, I’m concerned.
As we all should be.