Stuck between a rock and a tar ball

Last month Kalamazoo River watchdogs presented startling stories that the river is loaded with tar balls, resulting from the oil spill back in 2010.  As testimonial, videos, and photos emerged online, several fact-checking reporters turned to professor of ecosystem ecology and biogeochemistry, Dr. Stephen K. Hamilton of the Kellogg Biological Station, Michigan State University (and, full disclosure, he’s my graduate advisor).  Faster than I can say “biogeochemistry”, some of Steve’s comments were picked up and mis-quoted on other web sites.  While Steve explained to me how these events unfolded, I was struck by the perplexing conundrum he was in, and what I could learn from it as a young scientist interested in controversial environmental issues.  So in this post I’m going to explore that conundrum, discuss the role of science and scientists in this type of situation, and explain a little about Michigan geology.

The play-by-play

First, watch this quick video to set the stage:

These citizens also sent samples to a lab for analysis, the results of which were interpreted as evidence that Enbridge (the oil company responsible for the spill) secretly used “Corexit”, a paint-thinner-like dispersant to make the floating oil sink to the bottom.  (You may remember the controversy over BP’s use of Corexit in the Deepwater Horizon oil spill).  The thinking for the Kalamazoo River was that this might explain why millions of dollars and several years later, clean up efforts continue to uncover oil submerged in sediments.  This was reported in the Vancouver Observer and The Tyee.

When reporters (including NPR) need a second opinion on anything related to the environmental impacts of the Kalamazoo oil spill, they turn to Steve Hamilton.  He served on the EPA’s science advisory team for the Enbridge cleanup; in fact he was the only independently-funded (non-government, non-Enbridge) scientist on the team.  Additionally, one of his graduate students did work looking at the health of the macro-invertebrate food web after the oil spill, and Steve led a crew studying the re-suspension of oil from disturbed sediments.  So reporters got in touch with Steve for the tar balls story, too.  He pointed out that what the stories call “tar balls” are naturally occurring calcium carbonate rocks (see below for explanation), and that the reported presence of a dispersant chemical was inferred from the presence of 2-Butoxyethanol.  This makes for a weak inference since this substance is commonly found in many household and industrial products, which all end up washed down the drain and eventually in our rivers (along with plenty of other substances like antibiotics, synthetic hormones, and caffeine).

Aye, there’s the rub

Even though the communication with the reporter was written out in an email, the initial version of the Tyee article mis-quoted Steve, saying he was “not surprised that an Alabama lab found compounds used in the oil dispersant Corexit on the carbonate rocks.”  When what he actually wrote was that he “would be incredibly surprised if evidence for dispersant use were found because I do not believe it was ever used on the river” (Steve Hamilton, personal communication).  What he was “not surprised” about was that the analysis indicated the presence of the diluted bitumen (tar sands oil) in these porous rocks, because the spilled oil coated everything it contacted including vegetation along the flooded banks–the river was unfortunately high at the time of the spill making cleanup even more difficult.

So, no tar balls and no Corexit (given the evidence).  When the mis-quoted version appeared online, Steve faced two sticky options:

Option 1 (rock): Clarify your position to set the record is straight.  But saying that there are no tar balls and that Enbridge did not use any secret chemicals (given the evidence) may be seen by some as defending the big oil company.

Option 2 (hard place): Don’t say anything, ruffle fewer feathers; but you would have to live with the face that you knew better and did not speak up.  While the record shows you were using poor judgment given the evidence.  This may come back to haunt you.

What’s a scientist to do?

Dr. Stephen K. Hamilton is a professor of ecosystem ecology and biogeochemistry at the MSU Kellogg Biological Station and a Michigan native. Photo:

As you may have already pieced together, Steve contacted the author of the Tyee story and clarified his statement–read the corrected version here.  The story was corrected within 12 hours of its initial posting, but several other websites picked up the original version and still carry it now.  Citizens’ observations and concerns are an important part of society’s conversation about environmental issues.  So scientists encourage people to keep an eye out and speak up when they notice something.  They are experts of their own lives, land, and nearby water bodies.  But in today’s age of blogs and YouTube, unsubstantiated evidence can “go viral” and be presented as fact in sloppy reporting (here is a particularly poor example of the tar ball story).  In this case, these people did send samples to a chemistry lab for analysis.  Unfortunately, not all chemistry labs were created equal, so just as we weigh a scientists’ statement by his or her apparent objectivity, the same is true for labs.

In the bigger picture, this story might make you wonder, “What is a scientists’ role in environmental controversies?”  Above I suggested that by taking Option 1, Steve might be seen as defending the big oil company.  Defending big oil companies is normally not something that an ecologist wakes up in the morning and hopes to do that day; but sometimes the truth ain’t pretty.  At the end of the day, it’s not appeal, but truth that is the golden rule for scientists.  In difficult situations that can mean putting aside both your personal views on big oil companies and your sympathies for environmentalism.

Michigan really is all it’s chalked up to be

Now let’s talk about how those (non-tar ball) rocks got to be in the Kalamazoo River–they can also be found in lots of other lakes and streams in the area.  Back in the day (that is, about 400 million years ago) before the Great Lakes, before Pangaea, when the equator crossed the Hudson Bay and bony fish were the new thing, what is now southern Ontario was marine sediment in the Panthalassic Ocean.  (Don’t worry, you won’t be quizzed on that.)  Over millions of years, these Ontario sediments built up vast quantities of calcium carbonate.  How?  Lots of marine organisms take calcium and bi-carbonate ions from sea water and form calcium carbonate, which they use to build hard structures like shells.  (We use calcium phosphate to make bones, our hard structures.)  For example:

Coccolithophore species: Emiliania huxleyi type A.  Photo:
Coccolithophore species: Emiliania huxleyi type A. Photo:

coral reefs, which would have thrived in these warm, equatorial waters,

–some mollusks (and most mollusk larvae) like the chambered nautilus and oysters,

coccolithophores–a group of super important marine phytoplankton (algae), and

tube-building marine annelid worms.

All of these calcium carbonate skeletons piled up, eventually forming limestone, and then during the last ice age (about 10,000 years ago) the glaciers moved these sediments around–delivering them to Michigan.  This is how Petoskey stones (fossil corals adored by Michigan beach combers) arrived.  So in Michigan, above our bedrock, we have a thick layer (~200 feet in places) of calcium carbonate mixed with glacial sediments (sand and gravel).  This limestone is the matrix for our groundwater and explains why groundwater is “hard”–a lot of calcium tends to build up on Michigander’s coffee pots.  This calcium carbonate gets carried into streams and rivers, where it falls out of solution, and can build up into layered, porous, chalky (literally) deposits.  Who knew those crusty rocks lying around the Kalamazoo River bed were so cool?  Oceans!  Corals!  Glaciers!  Oh my!

Below is a photo of a calcium carbonate rock found on the shore of Lake Michigan near Charlevoix.  It has been turned on it’s side and the black part was sitting in the black spot to its left.  The surprising black color is probably the indirect result of bacteria munching on organic material in the absence of oxygen, such as you might encounter underneath a rock.  As you and I breathe out CO2, some of these bacteria breathe out hydrogen sulfide.  When this gas meets reduced (ferrous) iron, iron sulfide (the black stuff) precipitates out of solution–sometimes this can be found inside water pipes.  I can’t do that, can you?  Microbes rule!

Photo by Steve Hamilton.
A naturally occurring calcium carbonate rock, with black iron sulfide precipitates resulting from microbial activity.  Photo by Steve Hamilton.

For more information on actual tar balls, check out this fact sheet from NOAA.


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