Replenishing California's aquifers

Water is a perennial topic in California. How much rain is falling, and where? How can we get cities and farmers to use less? How fast are we sucking it from underground aquifers? And, of course, how can we get more?

UC Santa Cruz professor Andy Fisher and his graduate student Sarah Beganskas are working on that last question. They’re building percolation ponds in the Pajaro Valley, on the central coast of California. Their goal is to replenish groundwater, which we’re using faster than nature alone can replace. The idea is to capture excess storm water before it gushes out to sea. (Recently, I wrote about their work for the San Jose Mercury News.) 

One problem with collecting storm water is that it can pick up fertilizers and pesticides as it cascades across the landscape. The UCSC scientists are trying to figure out how to deal with that issue; one idea is to enlist the help of bacteria. Adding a layer of microbe-harboring wood chips to infiltration basins might reduce pollutants before water soaks into the aquifer below. Early results from tests Beganskas and Fisher are running at Watsonville's Harkins Slough suggest that wood chips alone may not be enough, though. The microbes need time to work, so the researchers will experiment with slower infiltration rates in future trials.

When it rains, water collects in this infiltration basin at Harkins Slough, then percolates through the soil to recharge the groundwater below. (Image by USDA/Lance Cheung)

Badwater Basin

Earlier this month, I drove to Death Valley National Park to do some reporting for an on-going project. This was a few weeks before the current “superbloom” sprouted up, but we did see some pretty spectacular scenery while we were there. 

Badwater Basin, Death Valley National Park.

(Image by Emily Benson)

Badwater Basin, at about 280 feet below sea level, is the lowest point in North America. The water that collects there has nowhere to go except into the atmosphere. As it evaporates into the arid desert air, it leaves minerals and salts behind, forming salt flats in its wake.

A small pool of salty water sits at the edge of a boardwalk in the middle of the basin. A sign proclaims that the pool “is home to one of Death Valley’s rarest animals — the Badwater Snail. These tiny mollusks exist only in a few springs at the edge of Death Valley salt flats.”

And how did the snails get over the mountains that ring the bowl of the basin? A genetic analysis in 2008 suggested that the Badwater snails, based on the timing of their divergence from a coastal ancestor, likely hitchhiked a ride into Death Valley on migrating water birds.

A pool at the edge of the Badwater Basin salt flats.

(Image by Emily Benson)


Last weekend, I visited lovely Monterey, California to check out Whalefest Monterey, an annual celebration of marine science hosted by the town's Fisherman's Wharf Association

In the course of reporting a story about leatherback sea turtles that I wrote for the San Jose Mercury News, I learned that leatherback hatchlings, which start life small enough to fit in your palm, grow up into adult turtles that can weigh as much as a ton. Turns out leatherbacks are seasonal visitors to California's coast, which was news to me, though their numbers are dwindling rapidly and they're considered critically endangered

To learn why paying attention to the source of the swordfish you eat could help leatherbacks make a comeback, check out my newspaper story here

A leatherback hatchling makes its way to the ocean. 

(Image by Ken Clifton via Flickr; creative commons license)

Sea tomatoes

In the southwest corner of Greenland, where the tundra is dotted with small lakes, scientists spied something unusual beneath the surface of the ponds: Piles of giant colonies of toxin-producing Nostoc bacteria, each colony a jelly-like, spherical blob, some as big as softballs.

Greenlanders call them sea tomatoes.

“These are really slow growing,” biologist Jessica Trout-Haney of Dartmouth College told me. “Some of the big ones are 25 years old.”

Not much else can survive the harsh conditions of the lakes, Trout-Haney said, where organisms must contend with the annual cycle of freezing and thawing and periods of intense sunlight in summer and equally profound under-ice darkness in winter.

That lack of ecological competitors might explain why sea tomatoes can survive for so long in Greenland’s Arctic lakes, Trout-Haney said.

To read more about Trout-Haney’s research on sea tomatoes and Arctic lakes, check out the article I wrote for last week.

Lakes and ponds are scattered across the Arctic landscape near Kangerlussuaq, Greenland, where Trout-Haney and her colleagues spotted sea tomatoes growing on lake bottoms.   (Image by Miss Copenhagen via  Flickr ; creative commons license)

Lakes and ponds are scattered across the Arctic landscape near Kangerlussuaq, Greenland, where Trout-Haney and her colleagues spotted sea tomatoes growing on lake bottoms. 

(Image by Miss Copenhagen via Flickr; creative commons license)