Climate Change, Nature, Science

Climate Change Speeds Up Snowmelt and Drought Risk Grows in West

Snow melts on Mount Rainier and water runs off the Wilson Glacier and disappears under the NIsqually Glacier.
Snow melts on Mount Rainier and water runs off the Wilson Glacier and disappears under the NIsqually Glacier. Photo: Jim Culp | FlickrCC.

In the Western parts of North America, mountains play a big part in the water cycle. Colorado and Washington snowmelt contributes to how much water is captured in the ground, used by plants, or makes its way into groundwater.

It also joins streams and flows downhill to cities and rural areas. Climate change can have a big impact on snowmelt as global average temperatures rise.

Water on mountains deposited in the form or rain or snow either evaporates or flows downhill. The way that water collects on the mountains has an impact on water flow. Rainwater tends to disappear more quickly, while snow takes longer to melt and allows for a more consistent, and longer, addition of water to streams and so watersheds.

The result is that, as we saw in Washington in 2015, if it doesn’t snow enough, you don’t get as much water coming down from the mountains in the spring and summer, and you end up with a drought.

According to a study performed by researchers in Colorado, rising temperatures can have a hug impact on how much water makes it from the mountains to the lowlands. Higher temperatures generally mean less snow, though not always less precipitation. But as we’ve already seen, snowmelt has a more gradual effect, and if water isn’t running downhill, it needs to be brought from reservoirs and other sites.

The key take away from the study is that water resource managers need to know how different forms of precipitation interact with their local environments, in order to best budget for water consumption during growing seasons.

Although the researchers have more work to do on the subject, this initial study should help western states and provinces deal with potential droughts a little better.

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Nature, Science

Why Are Swiss Stickelback Fish Evolving So Fast?

A population of stickleback fish is rapidly splitting into two distinct species in Switzerland’s Lake Constance.
A population of stickleback fish is rapidly splitting into two distinct species in Switzerland’s Lake Constance. Photo: EAWAG | David Alexander Marques.

There is a concept in evolutionary biology called sympatry, in which two interbreeding populations develop unique genetics and evolve into two species.

Sympatry is a rare biological event. Conventional biology has assumed that speciation only occurs when a mountain range or some other type of geographical or geological feature separates two populations. Increasingly though, sympatry has been gaining ground as more and more researchers seem to be finding it among their subjects.

Most recently, researchers in Switzerland have discovered that two populations of three-spined sticklebacks in Lake Constance and its watershed streams are evolving along these lines.

Basically, one group favors the streams, and another favors the lakes. They show marked differences in size and armor, which could be chalked up to lifestyle differences, but there are specific genetic differences between the two groups.

The most interesting part though, is that they not only both breed in the same streams, but also continue to interbreed. This clear example of sympatry could tell us quite a lot about evolution.

The general assumption is that evolution requires significant periods of time to occur. However, the three-spined stickleback has only lived in those waters for about 150 years, which is the blink of an eye compared to evolutionary timelines. This isn’t the first example of evolution on this kind of timescale though.

Apple maggots evolved in North America within two centuries of apples being first introduced to the continent. Cancers become resistant to drugs. Insects develop resistance to pesticides. Bacteria develop resistance to antibiotics.

A major factor contributing to this process may be the average lifespan of such organisms, but it doesn’t change the fact that we’re finding, more and more, that evolution is capable of a wide variety of timescales.