P in streams

I work with some incredible grad students at the University of Alaska Fairbanks. Today, I’d like to highlight research led by Sophie Weaver, a student in the Biology & Wildlife department.

When asked about her research, Sophie likes to say she studies “P in streams.” Sophie is investigating how differences in nutrient availability might affect the growth of the organisms that make up the green scum, or microbial skins, that one slips on when crossing a stream. Besides phosphorus (the “P” in her descriptive quip), she also works with nitrate, ammonium, and acetate.

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Sophie with her little blue cups.

After adding various nutrients to little blue cups, she launches them in her research streams. Post-incubation, she collects the cups to measure the abundance of autotrophs (critters that produce their own energy) and heterotrophs (critters that, like us, consume delicious things to produce energy). The ratio of autotrophs to heterotrophs can tell her something about how nutrients impact green scum composition. This research is important because stream microorganisms directly influence water quality and ecosystem function.

Sophie conducts her research at the Caribou-Poker Creeks Research Watershed (CPCRW), a pristine watershed located about thirty-five miles northeast of Fairbanks. Rumor has it that Sophie and her labmates been known to pursue the other wonders of CPCRW besides what fuels green scum growth, from chilling ciders in wee arctic streams to stripping down, jumping in, and cooling off on a “hot” Alaskan summer day.

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A post on one of biology’s most confounding riddles: the latitudinal gradient in biodiversity.

A beautiful, but comparatively species poor forest in eastern Oregon

Explaining global patterns of biodiversity is a fundamental goal in biology. Understanding how the tens of millions of species on earth have arranged themselves into populations, communities, and ecosystems, is critical for conserving them in the face of a rapidly growing human population and global climate change.

ResearchBlogging.orgThe latitudinal gradient in species diversity is perhaps the most famous such pattern, and it has confounded biologists for decades. Almost invariably across taxonomic groups, hemispheres and continents, as one moves from polar regions towards the equator, species diversity increases (see the figure for a depiction of global bird diversity). The concept of diversity here can be broken down into three parts: “alpha diversity” or the diversity of species in a single location; “beta diversity”, or the turnover of species observed when moving among locations; and “gamma diversity” or the diversity of species found in an entire region. The latitudinal diversity gradient holds true for all three elements.
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