Wednesday, November 28, 2007

Cool Journal Articles: CO2 Enrichment and Crayfish

Blogging on Peer-Reviewed Research

I have a lot less time to read good journal articles than I used to, and KDWP has incredibly limited access to on-line journals, so I am just now getting to the latest issue of the Journal of the North American Benthological Society (JNABS; which is actually listed as December 2007). I feel like JNABS is a vastly underrated journal, but I have to admit that I’ve published two papers there, so I may not be entirely without bias.

At any rate, there are several very interesting articles in this issue, and I hope to highlight them all on this blog. The most interesting/amazing by far (in my mind) is one by John Kominoski and others (see full citation below #1). I just did a quick google-search, and apparently Kominoski has his own google-page (you can get a .pdf of this article from there).

Ok, so let’s talk about this paper a little. Oddly enough, this paper integrates subjects I find very interesting: dissolved organic matter (DOM), periphyton and crayfish. The basic premise of the paper is that as CO2 levels in the atmosphere rise, the organic chemistry of plants is going to change. This has lead to a widespread idea that herbivores feeding on these elevated CO2 plants will be less able to extract needed nutrients. My friend and collaborator Paul Frost has published one paper exploring the stoichiometry behind this, but he certainly isn’t the only one (see his citation below #2). The basic idea is that as you increase the CO2 in the atmosphere, you increase the amount of carbon in the leaves/tissues of plants. That seems great, since it means more productivity when measured in terms of energy.

Unfortunately, it also means less (by percent weight) of other essential elements (i.e., nitrogen or phosphorus). So more CO2 in the atmosphere means you have to eat more food to get the same amount of nutrients (as in a lower CO2 atmosphere). At least, that’s one theory with some support.

The kicker is that the additional C in those leaves in plants may not just be adding nutrient-poor bulk to the plant, it may be in the form of compounds that are actively toxic. That’s what Paul Frost found in the 2005 paper I mentioned earlier. His little bugs eating elevated-CO2 leaves were leaking essential nutrients.

So back to the Kominoski paper. Kominoski (or Nancy Tuchman or one of the authors) got the idea that these leaves aren’t just a direct food source to detritivores and herbivores, they are also an indirect food source to the base of the aquatic foodweb (the biofilms on rocks, often referred to as periphyton). Here’s where the DOM story comes into play. See, DOM is a fantastically important component of most aquatic ecosystems, controlling light penetration through the water column, the bioavailability of heavy metals and nutrients, has a huge effect on the pH of water, and is a ‘food’ source for bacteria and algae. DOM is just organic matter, which is a pretty broad category, and it comes from a lot of different places (animal excretion, algal release, bacterial release), but one of the biggest sources in temperate forested streams (and lakes) is leaves.

That’s right, leaves. Leaves falling into streams or lakes or wetlands leach organic compounds. You can probably imagine where this is going. Kominoski et al. found that the DOM leached out of his CO2 enriched leaves caused a different biofilm to develop than the DOM leached out of leaves raised in ambient conditions. That difference proved to be one that crayfish (a hugely important species in many aquatic ecosystems) could detect, and avoid. The implication that Kominoski et al. draw is that crayfish in a CO2 enriched world will possibly stop eating periphyton and start eating other, more nutrient-rich sources of food preferentially. Say goodbye to smaller macroinverts!

One key implication of this paper is that climate change isn’t just going to cause ecological havoc because of changes in temperature or rainfall; simply changing the CO2 content of the atmosphere will have dramatic and subtle effects on the biosphere.

Now, I don’t necessarily get everything in this paper. For example, the conclusion is somewhat tenuous. I’ve measured the grazing rate of crayfish on periphyton: For some species it is not much. Of the crayfish I’ve seen, it seems like they don’t eat periphyton unless they’re starving, but I’m no expert on that. (Hopefully some experts will email me a smarter reply about that.)

I’m also a little thrown off by a particular line in the abstract: “...cyanobacterial biovolume was higher in [elevated CO2] algal assemblages than in [ambient CO2] algal assemblages after 35 [days].” Yet in Figure 2, the differences in cyanobacterial biovolume don’t appear to be significant (visually or statistically), and leading up to the 35 day mark the different treatments appear to flip-flop in importance. So, I’m not sure I would have included that in the abstract, even though it is conceptually an appealing idea (cyanobacteria seem to be considered ‘poor quality’ food by most aquatic ecologists).

A few other notes:
- I’m curious to see on how many more posthumous papers the legendary Bob Wetzel will be a co-author. Will this be the last one? Is John Kominski (who seems pretty cool) the last first author with Wetzel as a co-author?

- I really thought this paper was Nature-worthy. That’s pretty much the holy grail of ecologists. However, after I read around a little, I realized that the implicit finding here (that CO2 enrichment will cause all kinds of weird and unexpected effects) is not that novel. Still, a great and complete story.

- I also saw a talk John Kominoski gave at NABS 2003 in Athens, GA. I talked to him at that conference, but I doubt he would remember me. I’m somewhat surprised that it has taken this long for the paper to come out. I wonder if it got rejected by a better journal, causing the delay. Formatting this thing for Nature would have been hard, and it would have been equally hard to re-format it for JNABS.

#1 Kominoski, J.S., P.A. Moore, R.G. Wetzel, and N.C. Tuchman. 2007. Elevated CO2 alters leaf-litter-derived dissolved organic carbon: effects on stream periphyton and crayfish feeding preferences. JNABS 26:663-680. DOI: 10.1899/07-002.1

#2 Frost, P.C. and N.C. Tuchman. 2005. Nutrient release rates and ratios by two stream detritivores fed leaf litter grown under elevated atmospheric CO2. Archiv für Hydrobiologie 163: 463-477

That's pretty cool.

So there have been grumblings that the Bush administration has consistently undermined the best science at federal agencies. Finally some action is being taken to correct those idiotic decisions. Let's just hope this keeps up.

Wednesday, November 21, 2007

The Society for Environmental Toxicology and Chemistry (SETAC)

Last week I attended SETAC's annual conference, which took place in Milwaukee. I gave a talk about toxistoichiometry, and attended the whole meeting.

There's a lot to talk about with SETAC, so I think I'm just going to hit the memorable stuff for now:

1. SETAC's annual conference is riddled with extremely poor talks. The 2nd talk of the Green Chemistry session was by an EPA scientist who didn't really give a talk at all. He simply recited a list of criteria for what makes a chemical 'environmentally friendly.' No justification, no explanation, nothing but a recitation of conditions. I wish this were unusual, but in fact, SETAC appears plagued by talks from people who don't really seem to care about producing a quality talk. That's extremely disappointing, especially when the titles and/or abstracts sound so promising. By comparison, the annual conference for the North American Benthological Society (NABS) typically contains a slew of extremely well-done talks.

2. The heavy metals story is overwhelming. There were multiple sessions and hundreds of posters detailing the toxicity and effects of heavy metals. This was encouraging to me, since I've been working to stop a project by an energy company to dump heavy metals into the Kansas river. The sheer volume of evidence in support of the hazards of heavy metals makes my job easier.

3. Ecotoxicologists at SETAC need to get better, and that's all there is to it. One speaker used a tennis-shoe metaphor/literary device to get her point across ( the "Just do it." approach or a "New Balance"), without ever explaining what either meant. Another speaker referred to a 24 hr toxicity test on crustaceans as 'Chronic.' A third speaker (actually the chair of my session) gave a talk that consisted entirely of him recounting an unsuccessful survey for hellbender salamanders and then showing us pictures he took while he was doing the survey.
These are unacceptable, and we should expect better from scientists giving talks at major conferences. If you don't have any results or data, don't try to amuse me by showing me your pretty underwater photographs of a bluegill. A talk at a scientific conference should include, at minimum, a complete story of some research, along with necessary background info and some kind of data.

4. The good talks: While the "Ecotoxicology" sessions were mostly awful, the "Wildlife Ecotoxicology" session was amazing. I didn't agree with all of the science (particularly one speaker's assumption-laden justification for his qualitative interpretation of his data) in almost every talk we got an introduction, a compelling methodology, and a insightful synthesis. This peaked with Nico van den Brink and Frouke Vermeulen's separate talks demonstrating the importance of taking into account foraging on heavy metal uptake from both a theoretical and experimental basis. That whole session was stellar, and has to rank as the overall highlight of the conference.

5. Tyrone Hayes. This guy gave the best scientific talk I have ever seen in my life. You can read about him online here, here, and here. He made a compelling case that Syngenta has bought out the integrity of several researchers and may be unfairly influencing the EPA. Apparently this fight has been going on for awhile, although I hadn't been fully aware of it. I do know that corporate interests certainly seem able to "buy" whatever results they want from unscrupulous researchers.

6. My talk. I thought my talk went fairly well. I had a lot of good questions, mostly on a more general front, but also a few that made me think. When people see this research, they start thinking up lots of intuitive ideas about how to go forward, and for some reason, a lot of these ideas are pretty obvious. I had multiple questions that paralleled my own thoughts, and the thoughts others have offered. One of my hopes during this conference was to interact with some profs who might be interested in doing some toxi-stoich research in their own labs. I don't know if that is going to happen.

There was a lot more that happened, and I'll try to recount some of it here, along with my thoughts on how to improve scientific conferences.

Tuesday, November 6, 2007

Explanations: Conservation Easements

Whenever a project will be destroying critical habitat for a state-listed species, the project sponsor is required to replace the lost habitat. This can be done in a number of ways, but one of the critical components is insuring that the replaced habitat will not just be torn down once KDWP isn’t looking. As a result, I’ve been running into projects where conservation easements are likely to be a critical component.

An easement is a legal document attached to a title/deed, specifying a certain condition or use of the property. A conservation easement is, obviously, used to specify conditions or usage that will accomplish conservation goals. The property is still owned by the deed-holder, but the owner must abide by the terms of the easement.

Existing habitat can actually be used as “replacement” of lost habitat if the existing habitat will be managed in a way that improves its quality. For example: Cattle grazing is detrimental to Broadhead Skinks. A conservation easement may require an area be fenced off and grazing stopped, which would greatly improve the habitat quality for the Skink.

The issues with easements start with their length. We at KDWP have a mandate to preserve habitat in perpetuity. Landowners in Kansas (especially Western Kansas for some reason), tend to get really nervous when you talk about perpetuity. In the past, we’ve done easements for various lengths of time: 100, 50, or even as little as 25 years. The difference between 100 years and perpetuity is significant, but sometimes 100 years is all you can get. Considering the statutes regulating T&E in Kansas have only been around ~30 years, preserving/enhancing habitat on the 100 year scale is probably pretty good.

However, all these inconsistencies in past easements have made my job difficult. See, project sponsors like to see consistently. “Why can’t I do a 25 year easement if my neighbor did?” This is an understandable concern, and on numerous issues in this job, I’ve tried to make a point of following the precedents we’ve set previously. I’ve done this because I wanted to get my feet wet before stirring things up. Finally, this week we’ve collectively made the decision that we’re just not going to accept easements for less than perpetuity.

Personally, I feel like this is the right thing to do. The KS statutes refer to perpetuity, and the habitats ought to be preserved indefinitely. Even beyond T&E species, Kansas and the U.S. has a need to maintain ecosystem integrity, and maintaining conservation easements in perpetuity also accomplishes that.