Day 50, Friday, July 13, 2012
Dear Family and Friends,
On March 24, 1989, the oil tanker Exxon Valdez hit a reef in Prince William Sound, Alaska and released an estimated 11 million gallons of oil into the water. It was the largest oil spill in U.S. waters. Despite the disaster, little research was done on the impact on whales beyond the immediate acute toll of whale deaths due to being covered in oil. Twenty three years later, the longer term consequences are now emerging as a pod of killer whales in the area, once healthy and strong, will soon be completely wiped out and gone. No one studied the effects of that crisis on whale DNA.
On April 20th, 2010, this Deepwater Horizon accident occurred and dramatically eclipsed the Exxon Valdez accident is size and concern. In fact, it is estimated that the an amount of oil equivalent to the Exxon Valdez accident gushed from the well head in the Gulf of Mexico every 3-4 days. The spill lasted at least 85 days or 21-28 Exxon Valdez equivalents. It was so large – you could see it from space (NASA satellite photo attached). A large follow-up spill was seen in 2011 covering several square miles and was a confirmed chemical match for the oil from Deepwater Horizon (that was the one Iain). This past March revealed a persistent leak (aka “seep”) near the epicenter. Again the major focus was on how many whales died. But, this time we are on the case and seeking to learn the lessons about oils spills and their effects on whale DNA.
I am often asked what we are finding in the Gulf. It’s a straightforward question, but the answer is more complex and subtle. I think the real question behind it is something more like- how bad is it down there? or Are the whales going to be ok? Still the answers to even those questions are hard to provide and figure out. I worry too that since the answers are not simple and dramatic the meaning of them may be downplayed in an economically troubled time. It seems some think we should only worry about losing whales if they have significant economic value. That seems entirely shortsighted and simply wrong to me, but yes I can ascribe an economic value to why we need to worry about whales.
We were all troubled by the images of birds, dolphins and turtles bathed in crude oil, while the oil continued to gush in the Gulf. The images were dramatic as were the health consequences to many of those individuals. But, with the removal of the oil from the surface, those dramatic images, where the affliction is obvious to everyone, cease to be shown. I mean everyone knows a bird cloaked from head to tail in oil is not a good thing. But, the only thing that ceases for the health concerns are that they are no longer obvious to all. They are still very real and problematic, but they become very hard to see.
Furthermore, the default expectation is that with the oil gone from view some other environmental stressor must be the cause of any observed ill effects. It seems that the explanation that oil caused the effect has become the least likely possible cause, only suggested after all others have been exhausted. For example, the past 2 years have seen a huge spike in the number of dolphin deaths in the Gulf. I have heard government officials present the data and attribute it to global warming or a virus or perhaps global warming and a virus, but never as a consequence of 210 million gallons of oil and 2 million gallons of chemical dispersants being suddenly released into the Gulf. Perhaps, it is because they are not allowed to speak of measurements they surely must have made to rule in or out the effects of the spill. I am not sure. But, I’d like to know. Maybe someday, we finally will.
So goes the challenge for our data. Our focus is on DNA and could the oil, or dispersants applied to the oil or the metals within the oil damage DNA in the whales. DNA is on the material upon which all life depends, whether bacteria, plant or animal, whether human or whale. DNA codes the information that gives up the bodies we have and the features we are known by. Each species DNA contains all the instructions needed to create a person, a whale, a turtle a fish and so on. It is our genetic blueprint. Each cell in our body contains these instructions and uses the information in them to carry out its particular specific function. Damaging DNA in those cells alter those instructions and alters the fate of those affected cells.
Sometimes the cells can repair the damage and recover. Sometimes they cannot. Sometimes the fate of the damaged cell is to simply die. Sometimes the fate is to more dire and the cell becomes the foundation of a tumor or other health aberration. If the damage occurs in a sperm or egg cell or in a cell in a growing embryo, the consequences can include infertility, spontaneous abortions, birth defects and developmental abnormalities. None are good for people. None are good for whales. It’s just not a good thing to damage DNA.
To do this work definitively and say specifically it was the oil from the spill that caused the effects, the experiment would involve different tanks of sperm whales in the laboratory that would be exposed to varying levels of crude oil from the spill, dispersed oil from the spill, dispersants used in the spill and metals from the oil in the spill. The whales would be watched for a period of years to see what toxic outcome occurred. That approach is clearly not possible as there are no tanks of whales in the laboratory and insufficient quantities of oil and dispersed oil available from the spill if there were. Thus, we have to consider a less definitive study and instead recreate conditions in the laboratory that mimic the chemicals from the spill. Instead of exposing whole whales, we treat whale cells.
Our measures in the whales themselves are limited to what we can reliably tell from a skin biopsy. We have no access to lung, or liver or kidney or testes or ovary tissues in these living whales. In other words, we will have to learn what we can from a small piece of skin and blubber and infer from there.
Accordingly, we have collected these biopsies and used the skin to tell us the levels of oil-related metals like chromium and nickel. We will use the blubber to tell us the levels of oil and dispersants. We will grow cells from the small razor thin area where the skin and blubber meet to tell us if there is DNA damage in the whales, themselves. These data will then be combined with our laboratory studies dosing whale cells with the oil-related chemicals to present a picture of what an oil spill could do to whales and their DNA.
What we cannot do is definitively tie these exposures and these outcomes to this specific spill. The reason – there is no way to definitively show the chemicals we find came from this spill. If the oil enters the whale, the body will metabolize the oil into another form and irradicate it’s unique chemical signature. Hence any evidence of oil in the whale will be dismissed by critics as merely a part of life in the Gulf and due to natural seeps on the bottom of the Gulf or perhaps another spill. Similarly it goes for the dispersants, though with them so little is known that the possible metabolism and the things to measure are poorly understood. The metals have a yet different confounder as it’s not so much their metabolism that is an issue, but rather they are elemental in nature and have no unique signature. Chromium and nickel are basic elements. We can measure them, but we cannot identify their original source.
Thus, when all of our data is in. We will have a clear picture of what an oil spill can do to whales and their DNA. We will know that an oil spill occurred here in the Gulf that was the worst marine accidental spill in the world’s history. But, it will have to be up to each person to decide if the outcomes we find were due to this unprecedented, mammoth release of oil into the Gulf and its subsequent release from surface burns into the marine air (which the whales breathe) or merely a product of the small natural seeps of oil on the bottom of the Gulf and is just how life is in the Gulf. The evidence will tell us about oil spills and whales, but only you can decide if it is due to this oil spill affecting these whales. I imagine some will still conclude our outcomes are due to global warming or a virus or perhaps global warming causing a virus. I know, absurd, but it will be said.
So what are we finding?
Well, we started by focusing on oil-related metals. Specifically, chromium and nickel. Why these and not the oil and dispersants? Its two parts really – one part science and one part budget. The simplest reason is budget. Analyzing for organic chemicals like crude oil and dispersants are much more expensive than analyzing for metals. With a very limited budget, we would get more samples done by focusing on the metals. But, more important than budget was the science. Currently, the best measures for oil and dispersants in whale tissues have not been determined. By contrast, the best measures for metals are known. Thus, while we wait for the chemistry of what to measure to be better defined, we have focused on metals in the whale tissue.
Thus, we have started with chromium and nickel. Both are known to be present in oil. Both are known to damage DNA and chromosomes in humans and experimental animals. We first measured them in oil from the spill. We measured chromium and nickel in tarballs collected on Gulf beaches at the start of the spill, and in oil collected from the Deepwater Horizon riser and found them to be present, well above trace levels, in the several part-per-million (ppm) range. We confirmed that chromium and nickel were in the oil from this particular oil spill. Next up were the whales.
Biological systems like whales are known to concentrate chemicals found in their environment. It is a consequence of the physiology of complex organisms and the biochemistry of the interaction of the specific chemicals and that physiology and underlying cell biology. We measured chromium and nickel levels in the whales we sampled in 2010. We found them to be high, very high. In fact some of the whales had some of the highest levels of chromium and nickel in the world.
How do we know they are among the highest in the world? Well, from 2000-2005, Ocean Alliance collected sperm whale biopsies from around the world. We used those samples to determine a global baseline for chromium and nickel levels in sperm whales. Gulf animals were not included in that study, which was conducted 5 years before the accident. When we compared the Gulf whales to the whales from the rest of the world, the average chromium levels were in the Gulf whales were 1.4-times higher that the rest of the world and nickel levels were 6.5 times higher in the Gulf whales that the rest of the world. Both increases were statistically significant.
As I mentioned both chromium and nickel can damage DNA leading to health effects in humans and experimental animals. We find that chromium can damage DNA in sperm whale cells. We are testing nickel now. We have found elevated DNA problems in both Bryde’s and sperm whales.
Thus, phase 1 of our testing finds elevated chromium and nickel in the oil from the spill and elevated chromium and nickel in the whales. We find elevated DNA problems in the whales. We find that chromium can damage DNA in sperm whale cells. Nickel data are pending. The dots are not hard to connect. We are working to connect them further.
There is still more work to do. We are working hard to do it. I worry about these whales and what this spill means for them and other whales and marine life affected by future spills. I hope you do too.
It was a quiet day on the boat. One biopsy taken before scattered thunderstorms forced us all into a much needed day of rest. The sunset was spectacular orange against a blue sea (the Wise Lab colors!) and we had a lovely dinner under the stars.
P.S. If you want to see our location on Google Maps we are at:
just paste in the coordinates and click search
If you want to read the previous days of these messages- they are
posted at www.usm.maine.edu/toxicology/gulf and click on “read logs
John Pierce Wise, Sr., Ph.D.