An audio postcard

J. and I were sitting by Lake Rotoiti admiring this patch of forest over lunch. We were astounded by how loud the birds were, even in the middle of the day. (I'm used to hearing a flurry of activity at dawn and dusk.)

Here's a quick video recording to give you a glimpse of a genuine New Zealand beech forest, complete with native sights *and* native sounds.

Most of what you're hearing are native bellbirds; we saw a few flitting around in the canopy, but they were too fast and tiny to be captured with my little point-and-shoot camera's video function.  Apparently -- at least, judging by the signs forbidding entry to dogs -- there are also kiwis poking around in the forest's leaf litter, though they're only active at night.

Two-Month Summary

Obviously I've been rather lax in posting these summary statistics, but with two months down and two weeks to go, here are some entertaining figures drawn mostly from J. and my trip to Nelson Lakes in search of more field sites.

Distance driven on the "wrong side" of the road in the last three days: 1200 km (~750 miles)
Number of American-style (i.e. counter-clockwise) "open space U-turns" (i.e., in parking lots or grassy areas): 2
Number of Kiwi (i.e. clockwise) U-turns: 3
Number of mp3 files that will fit on a standard CD: 140
Do two such mp3-packed CDs fill a 1200 km journey: No

Lake temperature in St. Arnaud: 45 F
Number of eels seen post-swim: 8
Length of largest eel observed: 4 ft
Number of one-legged ducks spotted: 2 (out of 30+)
Number of stories about ducklings being eaten by eels heard: 1

Ocean temperature in Kaikoura: 60 F
Number of frightening creatures seen in ocean: 0
Moral of this story: Salty >>> Fresh

Number of insect bites currently being ignored: 13 (plus the 3 I won't feel until I wake up scratching them)
Number of field sites obtained and sampled: 2
Number of field sites expected: 5

Desire to do future work in insect-free, ocean-full Antarctic: 50,000,000
Relative scale of this desire: Unknown

Where the Wild Things Are

Everyone knows I love microbes. In general, I have very little patience for multicellular things -- they're just adding unnecessary complexity to the metabolic magic that a single-celled bacterium or protist can do.  In fact, the only thing that saves tress for me is the fact that they can photosynthesize: Photosynthesis is my absolute most favorite metabolic process.

But in spite of my preference for things visible only through a microscope, I've still enjoyed a few very special wildlife encounters over the last few weeks.

The first was in Akaroa last month (it's taken me a lamentably long time to post about it), when my friend Elise was in the country following her research cruise to Antarctica. (Elise, like many of my most awesome friends, studies microbes: She works on marine phytoplankton, the free-floating algae responsible for half of Earth's photosynthesis.)  Elise's Dad treated us to a wonderful boat trip out of Akaroa Harbor.

Akaroa Harbor sits in the crater of an ancient, sunken volcano.

The 190th Hole (Anatomy of Soil Sampling)

The past week -- and the week to come -- are all about digging.  More precisely, they're about hammering a short segment of PVC pipe into the ground, and then digging.

K. and J. extracting samples from a grassland. You can see a
pine plantation in the background, and a wilding Douglas-fir
just behind K. (in the purple shirt). The white tube in J.'s hands
is a newly-extracted soil core.

Together with the help of K. (who knows all the best ice cream spots on the South Island) and J. (who's generously loaning her strong arms and back in the name of seeing more of New Zealand), I'm collecting soil samples for a greenhouse bioassay (a glasshouse-based experiment using living organisms to test the properties of an environment).

This experiment is the natural complement to my survey of fungi infecting existing seedlings. In this case, I'm collecting soil from the same three canopy types (grassland, native beech forest, and Douglas-fir forest) at sites spread across the South Island of New Zealand (rather than the few local sites at which I collected my seedlings).  I'll plant Douglas-fir seeds in these soils, allow them to grow in the greenhouse for 6 to 9 months under the watchful eye of some helpful Landcare folks who will keep them happy and watered for me, and then harvest them to find out what fungi from the soils colonized the seedlings.

I need your help!

The National Science Foundation has asked me to write an abstract of one segment of my Ph.D. research.  In 350 words or less, I need to describe a project I'm working on back home, also using Douglas-fir, but with fungi from its native range.  Because the National Science Foundation is funded through our tax dollars, they -- and I -- want this abstract to be really readable.

Unfortunately, having buried my head in science for the past four years (and having been nose-deep in it for four years before that), I'm not the best at catching all my technical jargon.  Have a look at what I've written below, and let me know what you think.  What don't you understand?  What's missing?  What's unnecessary?

Thanks!

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Metabolic Bet Hedging as an Explanation for Maintenance of Diverse Tree-Ectomycorrhizal Mutualisms*

Trees are a critical part of many terrestrial ecosystems, providing both physical structure and chemical energy through the process of photosynthesis.  In order to conduct photosynthesis efficiently, many trees rely on mutually-beneficial interactions with below-ground fungi called mycorrhizae, which gather nutrients, supply water, and defend against pests in exchange for energy provided by the tree.  One group of these fungi, the ectomycorrhizae, is particularly diverse, having a large number of species, each with its own suite of metabolic abilities which determine its value as a trading partner to its host tree.

Intriguingly, an individual tree may host dozens of different species of ectomycorrhizae simultaneously, including species which appear to be of little to no benefit, or may even be harmful to the tree.  Presumably, rather than limiting its interactions to the subset of most useful fungi, the tree is incurring fitness costs by supporting a larger fungal community. Why hasn't natural selection produced a tree that can perfectly control its suite of fungal partners, so that it maintains only those that are most beneficial to it at any given time?

One possible explanation is metabolic bet hedging.  Trees are long-lived organisms that experience seasonal and interannual environmental variation. Therefore, their nutrient requirements also vary over time, potentially altering the relative value of each fungal partner. So, much as human investors maintain a portfolio of stocks to compensate for economic variation, trees may passively maintain a range of ectomycorrhizae in response to changing environments. 

This project tests the metabolic bet hedging hypothesis using laboratory (greenhouse experiments that control trees, fungi, and environmental conditions) and mathematical (economic models that test tree fitness as a function of fungal mutualisms) approaches. Results, in addition to their broader theoretical value to scientific understanding of mutualisms, will be of specific value to the management of Douglas-fir (the tree model used in this study), which is both a commercially important forestry species, and an aggressive invader in some foreign locales.


*Sorry, I can't do anything about the title.  Otherwise, I'd have tried to think of something more witty, like this week's ozone hole column, "All that's holey".