My Research Part II: Elemental Imbalances

I discussed previously the rather important Law of the Minimum. Essentially, that law states that growth is controlled not by the total of resources available, but by the scarcest resource (limiting factor). As with most biological principles, this law was derived from agriculture. Those raising crops all over the world were in the habit of shifting huge amounts of manure from feedlots to crop fields with the hope that whatever they were adding would cause the crops to grow more. In fact, in most cases, the crops would grow quite a bit more if just a single nutrient were added. And that's why the history of industrial fertilizers is really a history of how people can add nitrogen and phosphorus to soils.

At the same time that farmers and other agricultural experts were discovering that adding a few pounds of ammonia had the same effect as adding a hundred pounds of manure, ecologists were going around and trying to figure out what the limiting factor was for a whole bunch of plants and animals living in the wild. Over time a number of trends began to emerge and embed themselves into the background of ecological thinking: Autotrophs tended to be limited by nitrogen in terrestrial systems and phosphorus in aquatic systems, large mammals tended to be limited by food energy more than nutrients, etc. And so people tended to focus on particular elements because of their 'obvious' importance to particular processes.

In fact, some quite prominent research looking at how ecosystems function was done by looking pretty much entirely at a single element. One of the most famous and fascinating researchers of the early 1900s was Ray Lindeman, who spent his entire, short career studying how just 1 element (Carbon) was cycled in a bog. And this was and is somewhat interesting, but a little bit of common sense should cut in at some point and begin to wonder: Why just carbon? Is carbon being cycled in a form that is only carbon? The answer, of course, is that materials that contain carbon (like leaves and bugs and soils) also contain lots of other elements. All those elements are being cycled at once, in far more complex and interacting dynamics than you would ever even understand existed if you considered only one element.

(Side Note: Why was Ray Lindeman so interesting? Well, he was the first person to do anything like this, his papers essentialy began the field of ecosystem ecology, and he died tragically young before he even completed a postdoc. I'm sure I'm not the only ecologist to have read other papers from his lifetime, read his papers, and wondered in a somewhat dumbstruck amazement as to whether the entire science of ecology was set back a solid 20-25 years by his premature death.)

Let's imagine the biological parts of the carbon cycle for a moment. Atmospheric CO2 is taken up by plants, which are eaten by herbivores, who are eaten by predators. Along the way some plant material falls off and turns into soil, as does the feces and bodies of the animals. Within the soil, bacteria burn all that carbon for energy, releasing CO2 into the atmosphere, which goes back to the plants again. But what determines the amount of CO2 a plant takes in? If CO2 is the limiting factor, then the amount of CO2 taken in will be related to the maximum growth rate of the plant. But what if the amount of nitrogen in the soil is the limiting factor? Does the plant keep taking in more CO2 than it can use? Or does it taken in just as much CO2 as it can use with the amount of available nitrogen? Do different plants do different things?

The underlying problem here is that sometimes (probably most times) the resources available to an organism are not the ones that are optimum for its growth. To go back to the Liebig's barrel analogy from two weeks ago (here), organisms have no reason to build a long stave out of CO2, when they can only build a short one out of nitrogen. When an organism is faced with resources that do not match its elemental demands, we refer to it as an elemental imbalance. A big chunk of ecological stoichiometry is determining how elemental imbalances come to be, how organisms react to them, and how they influence the cycling of elements.

Let's explain some of the possibilities a little here. Let's go back to our hypothetical plant, and let's give it a name. Let's call it a mustard plant. Our hypothetical mustard plant is growth-limited by nitrogen in the soil, but has enough of everything else, and has a huge abundance of CO2 (because the atmosphere is essentially a limitless source of the stuff).

The first question is: Why? Why did the mustard plant evolve to need more nitrogen than was available here? There are lots of possible explanations for this, but one of the key issues is that chemical processes that make life alive are fundamentally constrained. It simply isn't possible to create a protein molecule without using some nitrogen. In many cases, the nutritional needs of an organism are determined not by evolution or biology, per se, but by the fundamental nature of the universe. These fundmental constraints make living organisms relatively homeostatic (that is, their body elemental composition doesn't change), at least compared to non-living materials.

The next question is: So what is this little mustard plant going to do about it? The answers to this depend a lot on the context of how they are asked. For instance, a continued shortage of nitrogen over evolutionary time scales might result in mustard plants evolving to minimize their nitrogen demands or possibly mustard plants will develop ways to extract more nitrogen from the soil. Alternatively, mustard plants might use that extra CO2 in other ways. For instance, many plants create secondary defensive compounds that consist of carbon compounds with little or no other nutrients. These defensive compounds may make the plant poisonious or unpalatable.

Finally, we might wonder: What is controlling the amount of carbon moving up the food change from this plant? If, for instance, nitrogen is limiting growth, then it may be directly linking to the amount of carbon being pulled out of the atmosphere. However, if the plants are producing the secondary defensive compounds with excess carbon, there may be a non-linear response. Plants begin to get starved for nitrogen and stop their basic growth process, but continue to produce new mass in the form of secondary defensive compounds, which deter herbivores from consuming, and therefore further reduce the amount of carbon moving up the food chain.

And all this is going on in the context of multiple plant and animal species competing for the same resources as well! Needless to say, this is an incredibly complicated process that will probably continue to keep ecologists occupied for, oh, say, the next ten thousand or so years.

And this is only the tip of the iceberg!

Coal Plants in Kansas: Ashtray of the Midwest

Well, as everyone suspected, legislators in Kansas have taken up the gauntlet on behalf of Sunflower Electric Power Corp. to build a pair of new coal mines in Holcomb, KS (previous posts on this here and here). From the Lawrence Journal World:

Bills addressing the top environmental issue of the legislative session were written in secret by those who support construction of two coal-burning power plants in western Kansas.

Energy bills written in secret? No input from environmental groups or stakeholders outside of the companies that will be directly profiting? Doesn't this sound like a certain presidential administration's Energy Task Force?

The bill that has been written is being described by intelligent people as a poor excuse for a compromise between the coal industry and environmental concerns. Diane Silver (from In This Moment) quotes Gov. Sebelius's press release:

Under the current bill, any coal plant, from anywhere in the country, applying for a permit and meeting the very minimum standards established by the EPA would have to be given a permit. It wouldn’t matter whether Kansas needed the energy or not. All the coal plants that have been denied permits or withdrawn applications in other states would be knocking at our door.

As the Sierra Club's Bruce Nilles puts it, this would make Kansas the ashtray of the midwest:

“Kansas is the first state that we know that is proposing to accelerate global warming,” Nilles said. “That is a real black eye for Kansas to be the one state right now proposing to accelerate global warming.”

Ok, that's what is happening, but what does this all mean? Well, basically it means that the Kansas legislators are not interested in listening to the interests of Kansas citizens. Earlier polls have indicated Kansans are heavily opposed to the construction of the coal plants, so why do elected officials continue to push an idea that is clearly unpopular? The reason is, of course, money. These legislators are guided only by the unholy dollar. Anything that is perceived, real or imagined, to be financially beneficial is going to be ram-rodded through the legislature.

Kansans need to let the legislature know how they feel about this issue. Here is the website where you can find your state representatives. Send them a letter.

[Hat tip: In this Moment]

Wind Farms

I'm a big proponent of alternative energy solutions. On a broad scale, I think producing energy that doesn't rely on simply burning fossil fuels, combined with a reduced consumption, is the only long-term solution to global climate change issues.

However, global climate change is only one step of the environmental issues we're facing as a society. We're also threatening the healthy functioning of ecosystems by eliminating species through habitat destruction, introducing new species, etc.

Wind power is one of the most cost-effective alternatives to coal available today. The physics are simple, the mechanics are well-understood, and the supply of wind is abundant in many locations. Indeed, wind power is growing so fast the suppliers of turbines are having a hard time keeping up. The overall picture is that wind power is going to become an increasingly important part of our energy budget.

The downside? Like just about everything else we push up into the sky, wind turbines may take a pretty heavy toll on the bird populations. This paper suggests that most of the birds killed by a Minnesota wind farm were migrants, and in case anyone forgot, we have a treaty that covers migrants. Overall though, I haven't been able to find a lot of hard data on the magnitude of effects on birds, but as I've mentioned before, I have terrible journal access here. I'll be at the library later this week and I'll have to see if I can find out more then.

There seems to be some inherent reason to believe that this might be similar to what happens with bird-kills around cell and radio towers. The basic idea with the towers is that lights on the towers reflect off clouds, creating a "false dawn" that the birds respond to en-masse. The response? Flying around in circles while waiting for the sun to come up. Unfortunately, flying around a 400 foot tower supported by guyed wires isn't a great idea, even for birds with as much dexterity as a sparrow. Of course, the wind turbines don't have wires supporting them (at least, not as many), but the swinging blades might pose a similar hazard.

I mention this because a battle over the environmental impacts of wind is raging down in Texas. Essentially, the use of wind is going to lead to whole new areas of land being given over to energy production that were previously being used for something else. I think the large-scale, long-term benefits of increasing wind production and subsequently decreasing coal/petroleum use probably outweigh the impacts on migratory birds, but I'm not sure. I'm not sure enough information about the effect of wind turbines on bird populations is even known to answer that question.

Any thoughts?

Kansans = Awesome

Not only did the Kansas Department of Health and the Environment make Kansas the first state to deny the construction of a new power plant based solely on greenhouse emissions, it turns out Kansans are totally on-board. From a poll paid for by the Land Institute out of Salina:

By a 2:1 margin (62% agree, 31% disagree), Kansas voters agree with the Kansas Department of Health and Environment's decision to block constrcution of the two new coal burning plants near Holcomb, Kansas. [cite]

Predictably, the Kansas State legislators from the Western district are unwilling to believe the results.

"I just can’t imagine that would be an accurate poll,” [Senate President Steve Morris, a Hugoton Republican] said. “Virtually everyone I’ve talked to has been concerned about the decision.” [cite]

Yes, well when you're only talking to Sunflower Electric and other entities with a financial stake in the issue, I suppose you might get that impression. Note the key here, Mr. Morris is solely saying that by virtue of the result the poll must be inaccurate. I know the Bush Administration has always taken the position that facts which contradict them are inherently suspect. I am disappointed to learn that philosophy is trickling down to local politicians.

For the record, the people of Kansas are seeing right through the non-sense that has been thrown at them from the various agencies who have a political or financial stake in building an unnecessary coal power plant.

Greenhouse Gas Emissions

This is hard to believe. The EPA has denied California the opportunity to set tougher emission standards than the federal government. Here's what EPA head Stephen Johnson said:

"The Bush administration is moving forward with a clear national solution — not a confusing patchwork of state rules," Mr. Johnson told reporters on a conference call. "I believe this is a better approach than if individual states were to act alone."

Um. What? What 'clear national solution' is he talking about? I've been watching the environmental idiocies of this presidency for the past 7 years, and I haven't seen a "clear national solution" for anything this administration has done. Is the solution "Do nothing."?

I can't help but wonder if this is the beginning of an attempt by the Bush administration to override the KDHE's decision to deny a permit for a new coal plant. I mean, really, isn't the KDHE's rejection of the permit on the basis of CO2 emissions essentially the same thing as California independently reducing car emissions?

The actions of the EPA and the government on this issue have, over the past 7 years, bordered on absolute lunacy. This appears to be a continuation of that trend.

Some more fallout from the coal plant denial

My thoughts on the KDHE denial of the coal plant near Holcomb have been previously identified. Hell, I even got into it with Greg Laden when he criticized Kansas without mentioning the denial.

Well, one of the big idiocies the pro-coal plant advocates have been promoting is the idea that without the coal plant all other alternative energy strategies in the region will be stymied. They've made this claim based on the understanding that without the coal plant investment money, there will be no attempt to build the high-energy wires that are needed to get wind power hooked into the grid.

I think this is a bogus argument on a number of fronts.

1. If the electricity is needed, the power lines will get built. The approval for their construction has already gone through state agencies, so one of the big hurdles is cleared already.

2. The power lines are/were being built by a consortia of power producers, government agencies, and other entities. I'm not convinced all those organizations are going to shut it down just because the coal plant won't be built (I could be wrong about that).

3. In Sunflower's own documentation on this plant, they cite a 15% increase in the power consumption over the next 25-50 years in SW Kansas. Even without high power transmission lines, it would appear the best way for SW Kansas to meet that increasing demand is through wind farms.

In conclusion, I don't think there's any way wind and solar power won't continue to grow within Kansas. If anything, I think the coal plant would have stymied the further development of wind power. Apparently that was the conclusion at the Dole Institute of Politics for the Kansas Electric Transmission Summit (what a name!) as reported by the Lawrence Journal World and Salina.com. In fact, the members of that conference pointed out that wind farms are increasing exponentially. If that continues, the power lines will be built, coal plant or not.

(Hat tip to Diane Silver's excellent blog In this Moment)

Cool Journal Articles: CO2 Enrichment and Crayfish

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