The Nature Conservancy has deep scientific and conservation expertise in the globally significant habitats of the Gulf of Mexico. To get more perspective on what the oil spill could do to these habitats — and how the Conservancy’s data will help in restoration assessment and restoration efforts — we talked with Mike Beck, a senior scientist with the Conservancy’s Global Marine Team and an expert in, among many other things, the conservation and restoration of nearshore habitats including shellfish reefs and beds.
Q: What’s at stake ecologically in the Gulf from this spill?
Mike Beck: The Gulf has incredibly important coastal habitats: salt marshes, seagrass meadows, tidal freshwater marshes.
In particular, the Gulf is critically important for oyster reefs. Our global research at the Conservancy shows that oyster reefs are the single most impacted ecosystem globally — 85% have been lost. The northern Gulf presently supports the world largest remaining harvest of native, wild oysters. And the Gulf of Mexico is the best and perhaps only place left in the world for large-scale oyster reef conservation and sustainable fisheries.
But we have lost more than 50% of reefs there are already. The spill is going to make their conservation harder and hurt fisheries.
Q: For those who know nothing about shellfish, salt marshes and seagrass — what might this oil slick do to them?
Mike Beck: For oysters, the worst thing will be for those reefs that are intertidal — that are breaking the surface — where most of the oil will show up. And as the oil hits those reefs, some of the subtidal oysters will also be affected as oil sinks. Anything above light oil levels will have direct mortality on those oysters.
For those oysters that don’t die in those areas, we expect lots of toxins to be accumulated in their tissues, and we expect that to slow their growth. We also expect oil to sink and get into the sand and sediments — and when storms come through and churn up the sand, those toxins will get re-suspended in the water, and we’ll get another spike in toxins for quite some time after the storms. All this knowledge is based on data from two recent oil spills off of Europe’s Galician coast.
The habitats that will be hit the hardest are, again, those that are intertidal. Salt marshes will be affected greatly. We also have great concern for some of the interior, estuary freshwater tidal grasses and marshes — these are even more sensitive to oil. Some of the saltmarsh grasses can be relatively hardy to light oil if the oil just coats the bottom part of the plant and the oil can be broken down biologically.
Finally, we also have serious concerns about whether the oil slick will become entrained in the Gulf loop current, which comes up from the south, loops around near the Mississippi River outlet, and heads down and east by the Florida Keys area.
We’re lucky right now if the slick keeps getting pushed away from shore — but if that keeps happening, it’s then getting pushed into the Gulf loop current, and that will carry it relatively quickly out down to the Keys. And if it goes out through the Keys, it gets caught up through the Gulf Stream and will affect the east coast of the United States.
Q: What kinds of baseline data has the Conservancy helped gather about the gulf, and how is that going to help in restoration efforts?
Mike Beck: Starting back about 12 years ago, the Conservancy put together a Gulf of Mexico regional conservation plan and published that in a scientific journal — it was the first published marine regional conservation plan of any sort.
That effort created a lot of our base data for the Gulf — it pulled together all available habitat data at that time for seagrass, oyster reefs, salt grass marshes, etc. — and that’s now online on our interactive map. A lot of that data is still the best data available on these habitats. In addition, we did a Florida regional marine conservation plan about 5 years ago for the Florida Wildlife Conservation Commission, and published that in the journal Aquatic Conservation as well.
So we’ve got a lot of large regional data. The other primary source of Gulf ecological data that’s been collected by the Conservancy is from the more than 20 habitat restoration projects we’ve been working on as part of our partnership with the NOAA Community-Based Restoration Program in the Gulf. All of those involve pre- and post-restoration monitoring of sites for ecological condition.
At the regional level, we’ll be expecting to use that information to look at where the oil spill is reaching at a very broad geographical level — we have the very latest maps about the distribution of the oil overlaid on our regional maps to understand broadly the scale of sea grass, salt marsh and oyster reefs that are being impacted.
We’ll also be working closely with NOAA to make our site-based data is available for any post-impact studies and measurements. This pre-impact data is the kind that was missing from the studies of the ecological impacts of the Exxon Valdez spill. In that case, there were lots of post-spill measurements, but very little pre-spill data.
It’s hard to know impacts unless you have the pre-spill data. And that data is going to be extremely important in understanding what the scale and costs of restoration will be.
So, I think the first and primary use of the data will be understanding just how much was really lost. You need to know exactly what kinds of changes in species diversity you’re seeing after the spill is over and what is the overall rate of loss of habitats and species.
Now, I should mention that, even before the spill, we knew there had been huge habitat loss issues in the Gulf, and this baseline data was feeding into restoration goals for salt marshes, seagrasses, and oyster reefs in the Gulf. All of that goal setting requires knowledge on how much habitat there used to be, how much there is now, and how much there will be six months from now.
Q: Will we be studying the effects as the oil hits, or mostly afterwards?
Mike Beck: There will be some near-term monitoring as it comes ashore, but the primary post-spill reckoning will be after all the oil hits — after the majority of the oil has gone where it’s going, either onto shore or sinking into the sediment or (with any luck) a bit of it is collected. That’s when you have the first major post-impact assessment.
You can expect those assessments to happen at the very least quarterly over the next year and then at least yearly for some time — that’s the minimum frequency. Keep in mind that we’re still doing studies 20 years on after the Valdez spill.
(Image: Oil spill in Gulf, May 4, 2010. Image credit: NASA Goddard Photo and Video/Flickr through a Creative Commons license.)
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