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Friday News: AGU; on Science News on Science Blogs;

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Hi folks, here are some of the thoughts that came to my mind over the last few days.

AGU — looking back

The AGU fall meeting happened a couple of weeks ago now. However, it’s still vividly in my mind and there are still thoughts popping up:

  • it was such a big meeting, so that it was impossible to see or hear everything. Hence it is a great thing for the people who attended the meeting, as well as for people who did not, that some of the lectures are available online. Here is a great example, the online version of of a presentation, the Bjerkens Lecture, given by Richard B. Alley from Penn State University. As it happens, the best live talk I have attended at the meeting was also by Richard B. Alley, when he talked about flying buttresses and ice shelves. The Bjerkens Lecture is on the role of CO2 in earth’s history. Here are a few of my thoughts:

    • for times when there are no more ice cores available, those earth scientists (that is the climate-earth-scientists as opposed to “us hydrogeologists”) need to do the same thing as we do — look for other sources of data that help them to infer what they were looking for in the first place. One example that Alley presents is that they look for the density of openings in ancient leafs. Leaves “have to decide” if they put many holes in their leaves, which allows them to take in a lot of CO2 which they need for breathing, but which also dries them out quicker – or if they put few holes in their leaves, allowing little CO2 to come in but at the same time allowing only little water to go out. If the atmosphere contains little CO2, plants need relatively more holes in their leaves. I think this is a great example of “complimentary independent data-sets“, a term coined by John Cherry. Call me a geek, but I do like this term!

    • Alley mentions snowball earth, and there is also a cool picture in his talk from Namibia, which can be found here

    Alternative Text

    Boulders dropped by icebergs into laminated marine sediment in late Precambrian time, Narachaampspos, Kaokoveld, Namibia. The chief proponent of the Snowball Earth hypothesis, Paul Hoffman, points to the transition to carbonate rocks which indicate the sudden termination of this frigid event. Photo M. J. Hambrey.

    • Alley mentions very briefly something along the lines that the mid-range models are right. Well, I don’t think that’s surprising. I would argue that the more important question is, if the extreme models get the extremes right…
  • There are two other blog-posts related to AGU which I want to point out:

Soil in the News

Two sites, “ScienceDaily” and “ScienceBlog” have the exact same story today, with exact the same heading: “Water hits and sticks: Findings challenge a century of assumptions about soil hydrology”. That sounds quite intriguing. Both articles stat that the research they write about is published on Nature Geoscience, but neither link to the paper. It is here. The “paper” is actually called in Nature Geoscience lingo a “letter”, and I am not sure what that implies.

Here is how I picture the process: it rains, some water enters the soil below the root zone, it continues it’s path towards the water table, some might flow laterally (towards a stream), some other part might be perched, and finally the rest makes it to the water table. On its way to the water table, it is commonly assumed, as the authors point out, that “water entering the soil as precipitation displaces the water that was present previously, pushing it deeper into the soil and eventually into the stream”, a concept referred to as “translatory flow”. Here is my first complaint, as stated above, I don’t think all the water below the root zone must go straight into a stream. But I agree with the (so far commonly used) concept of displacement.

The authors collected isotopic data, which suggests that “a pool of tightly bound water that is retained in the soil and used by trees does not participate in translatory flow, mix with mobile water or enter the stream.” And I think this is the key finding of this letter. Some water of the process I described above, might stay very close to the root zone.

This finding makes the authors suggest that their implications “are perhaps most profound for biogeochemical cycling and transport of nutrients to streams”. At the same time the authors concede that

“(t)his conceptual framework requires further testing to see if the underlying mechanisms are true, and if such separation of water resources holds for different climates and locations.”

I am wondering, how these two blog posts in ScienceDaily and ScienceBlog actually happened. Who wrote them? With what intentions?

More Water-Related News

  • WaterWired has put up a great list of “Well-Worn Water Words” in two parts (part 1, part 2). Here is my favourite:

Water is the new oil because whisky is for drinking and water is for fighting, unless you are already in a water war, in which case you are probably already in water-power nexus from which only integrating science and policy will begin to address the fish versus farmer conflict defeating all efforts toward sustainability.

Written by Claus

January 22nd, 2010 at 9:57 am