Ecological effects of mosquitofish

Last week I visited UC Santa Cruz’s Long Marine Lab for the first time. Perched on the edge of Monterey Bay and nestled against the edge of Younger Lagoon, the lab is perfectly situated for aquatic and coastal research.

I was there to talk with Eric Palkovacs and his graduate student David Fryxell about mosquitofish (a creature I’ve written about before on The Watershed), for a story that appeared in today’s Santa Cruz Sentinel.

The researchers recently published a paper on the ways in which mosquitofish populations dominated by males and females differ. Mosquitofish females grow to be about twice as big as males, and the scientists found that the females’ ecological effects are outsized, too.

The view of Monterey Bay from Long Marine Lab. 

(Image by Sara Stasi via Flickr: Creative Commons license)

Water on Mars

Usually posts on The Watershed focus on Earth-bound water. But water, it turns out, can be extraterrestrial, too. 

Last week I wrote a story for the Santa Cruz Sentinel on local elementary schoolers learning about NASA research on Mars. The students were excited to learn that liquid water exists on the Red Planet – according to NASA, a recent research paper offers "the strongest evidence yet" for water on Mars. 

Martian water is too salty to drink in its current form, the students learned. Still, it could be purified, and perhaps even used to support human exploration in the far-off future. As the authors of the paper wrote, "Water is essential to life as we know it."

Water also exists in the form of white clouds above the surface of Mars. (Image by NASA/JPL-Caltech/MSSS)

The future of The Watershed

The Watershed has been my weekly companion for over a year – during that time, I’ve researched and written about everything from mystery-solving fish DNA buried in 2,000-year-old sediment to aquatic creatures (both large and small) eating, breathing, vomiting, hitching a ride on other animals to get from place to place, and simply living their lives. For every paper, project, or place I covered, there were at least ten others, all equally engaging, that I could’ve chosen instead. Aquatic ecology is a thriving field, and I hope to continue to explore the issues surrounding our world’s water in the future – to that end, I’m about to begin a new adventure.

After five years spent watching the rolling hills of the Palouse change colors with the seasons, this fall I moved to coastal California to begin the Science Communication Program at U.C. Santa Cruz.

I suspect the rigors of graduate school will prevent me from continuing weekly posts on The Watershed, so as of this week I’m suspending regular contributions – I will, however, continue to post stories as they come up, as they’re sure to do.

In the meantime, thanks for reading – and don’t be afraid to get your feet wet!

A view of California's central coast. 

(Image by Emily Benson)

Scoops of seawater

The Great Barrier Reef World Heritage Area, off the northeast coast of Australia, is “one of the richest and most diverse natural ecosystems on Earth.” Thousands of species of mollusks, more than 1,500 species of fish, and 400 species of coral live within its waters.

There’s something else there, too – herbicides, washed into the ocean via rivers draining agricultural areas.

Herbicides can breakdown in nature (UV rays can degrade the molecules, or microbes can consume them), but it’s unclear how long that process might take under the conditions that occur around the Great Barrier Reef – many of the studies conducted in the past included unrealistic conditions, like unusually low temperatures or levels of herbicides 500 times higher than what researchers typically find there. A group of scientists working in Queensland, Australia, sought to detail the timing of herbicide persistence in seawater from the Great Barrier Reef lagoon kept under more natural conditions; they recently published the results of their study in the journal PLoS ONE.

Working with samples of water scooped up from off the coast of Queensland, the researchers added several different herbicides, then stored the flasks under different combinations of conditions: some in the dark, some under partially lit conditions, some at 77 degrees Fahrenheit (the average temperature of seawater around the Great Barrier Reef over the course of a year), and some at 88 degrees Fahrenheit (the summertime high temperature of seawater near the shore in part of the Great Barrier Reef lagoon). They took samples from the flasks every few weeks for a year to measure the herbicide concentrations, allowing them to estimate how quickly the herbicides broke down.

The estimated half-life of each herbicide – the time it takes for half of the initial amount of the chemical to degrade – ranged from about 150 days to more than 5,000 days. The light and temperature conditions the flasks were stored under didn’t lead to consistent patterns in how the herbicides broke down.

The scientists also added a chemical that stops microbial activity to some of the flasks, and no herbicide degradation occurred under those conditions, suggesting that it was the microbial community present in the seawater collected from the Great Barrier Reef lagoon that broke down the herbicides.

“Chronic exposure of [the Great Barrier Reef] and catchment biota to . . . herbicides (from microbial communities to macrophytes) remains largely unstudied,” the researchers note, “and should be a future focus for research and risk assessment.”

Australia's Great Barrier Reef World Heritage Area stretches over 1,000 miles along the coast of Queensland. 

(Image by Tchami via Flickr: Creative Commons license)