Tag Archives: Mussels

Signs of fracking water found in freshwater mussels

In Pennsylvania, the release of fracking water has been banned in 2011, but traces from before the ban are still visible in aquatic environments.

Frack the environment

Hydraulic fracturing (or fracking) is a process through which oil companies can retrieve otherwise inaccessible reserves of shale gas. As the name suggests, it involves using a high-pressure mixture of water and chemicals (called fracking fluid) to create a system of fractures which would allow the gas to escape towards the surface, where it can be captured.

Illustration of hydraulic fracturing and related activities. Image credits: US Environmental Protection Agency.

Fracking is controversial for several reasons. It uses massive quantities of water, it appears to cause increased seismicity, and, of course, the leaks. Creating a system of fissures a few kilometers beneath ground is challenging, but ensuring that the system is tight and doesn’t allow leaks is massively more difficult. Naturally, many people are concerned that the fracking fluid or the gas itself can leak towards the surface, seeping into the soil and water reserves — which has observed to be the case at some wells in the past.

But the release of used fracking water is also a major issue with long-lasting consequences.

“Freshwater pollution is a major concern for both ecological and human health,” said David Gillikin, professor of geology at Union College and co-author of a new study. “Developing ways to retroactively document this pollution is important to shed light on what’s happening in our streams.”

In their new paper, Gillikin and colleagues report finding high concentrations of strontium, an element associated with oil and gas wastewaters, in the shells of freshwater mussels downstream from fracking wastewater disposal sites.

A smoking gun

Image credits: Engbretson Eric, USFWS.

In a way, freshwater mussels are a bit like trees — they can offer a lot of information about the environmental quality of the water they live in, much like tree rings offer information about past climate events. Because they feed by filtering water, mussels hold a record of past water quality, which can be studied.

“Freshwater mussels filter water and when they grow a hard shell, the shell material records some of the water quality with time,” said Nathaniel Warner, assistant professor of environmental engineering at Penn State. “Like tree rings, you can count back the seasons and the years in their shell and get a good idea of the quality and chemical composition of the water during specific periods of time.”

After usage, fracking fluid is treated and cleaned — but this process is not perfect. In 2011, biologists noticed that despite this treatment, water and sediment downstream from fracking wastewater disposal sites still contained worrying amounts of fracking chemicals. The water was contaminated and in turn, affected aquatic life, causing widespread damage. After this was revealed, Pennsylvania banned all fracking wastewater treatment facilities from releasing the water back into the ecosystem. But the effect of the released water before the ban is still unclear.

To shed some light on it, researchers collected freshwater mussels from the Alleghany River, both upstream and downstream of a wastewater disposal facility in Warren, Pennsylvania. They also collected mussels from two other rivers — the Juniata and Delaware — that had no reported history of oil and gas discharge, for comparison.

They particularly looked at strontium isotopes, which in this context can be a smoking gun for fracking wastewater. They also analyzed the oxygen isotope, to identify the year and season. Not surprisingly, they found elevated concentrations of strontium in the shells of the freshwater mussels collected downstream of the facility, whereas all others showed no significant elevation. But not everything came as expected.

Despite the 2011 ban, strontium levels didn’t immediately drop sharply. Instead, it took a while before the decrease was visible, and the decrease was quite slow. This suggests that even years in which fracking water has not been released back into the ecosystem, the effects are still visible.

“We know that Marcellus development has impacted sediments downstream for tens of kilometers,” said Warner. “And it appears it still could be impacted for a long period of time. The short timeframe that we permitted the discharge of these wastes might leave a long legacy.”

Considering the large scale of modern fracking, this is particularly concerning. According to the U.S. Department of Energy, up to 95% of new wells drilled today are hydraulically fractured.

“The wells are getting bigger, and they’re using more water, and they’re producing more wastewater, and that water has got to go somewhere,” said Warner. “Making the proper choices about how to manage that water is going to be pretty vital.”

This study goes on to show that even a few years of the process could have long-lasting, damaging consequences. It also suggests that freshwater mussels can be used to study potential seepages at oil sites, since conventional oil drilling can also cause a similar type of pollution.

Journal Reference: Thomas J. Geeza, David P. Gillikin, Bonnie McDevitt, Katherine Van Sice, Nathaniel R. Warner. Accumulation of Marcellus Formation Oil and Gas Wastewater Metals in Freshwater Mussel Shells. Environmental Science & Technology, 2018; 52 (18): 10883 DOI: 10.1021/acs.est.8b02727

For the last 18 years, robotic mussels have been watching over our oceans

For the past 18 years, our oceans have been under the surveillance of silent, blinking guardians. Known as “robomussels”, these Northeastern University devices have been used to record decades of valuable data to marine life conservation efforts.

Robomussels were designed to have the same thermal proprieties as the un-robotic variety. They’re typically make of epoxy (as seen here), but smaller ones (under 4 cm) are also constructed from real shells filled with silicone.
Image credits Brian Helmuth et al., Scientific Data, 2016.

Every 10 or 15 minutes for the past 18 years, Professor Brian Helmuth of NU’s College of Science and the School of Public Policy and Urban Affairs and a team of 48 researchers have been informed of the internal temperatures of mussel beds all over the world. All this data was pooled from the robomussels, artificial constructs which have the shape, size, and color of actual mussels but carry built-in sensors to track water and atmospheric temperature and solar radiation levels — both of which play a part in heating up the little critters.

“They look exactly like mussels but they have little green blinking lights in them,” says Helmuth.

Northeastern’s Marine Science Center in Nahant, Massachusetts, houses the most extensive database of ocean temperatures around the world. It was built on the work of this team, which traveled the globe to place robomussels inside the beds of their biological counterparts. Over time, they’ve recorded staggering amounts of data, all of which is used to identify areas of unusual warming. Starting from it, scientists can intervene to protect vital marine ecosystems and develop conservation strategies to save species from extinction.

“You basically pluck out a mussel and then glue the device to the rock right inside the mussel bed. They enable us to link our field observations with the physiological impact of global climate change on these ecologically and economically important animals.”

But they don’t only track the effects of shifting climate. Using feedback from the robots, scientists can estimate the health of mussels in a particular area. Should they be in trouble or dying out because an area becomes unusally hot (areas called “hotspots”), local authorities can be informed to step in to relieve stressors such as erosion or water acidification before permanent damage is done.

Tiny things heralding big changes

The robots are already watching. Judging. Blinking.
Image credits Allison Smith.

Because they rely on external sources for heat, mussels act as a precise barometer of climate change for ecological forecasters such as Helmuth. Through a mix of fieldwork, mathematical, and computational models, he can estimate how mussels will grow, survive, or perish in inter-tidal zones. Throughout the years, the robomussels have revealed several surprising hotspots for the team. In 2002, they reported the existence of such areas not only at the mussels’ southernmost range (south California) but also up north, near Oregon and Washington state.

“Our expectations of where to look for the effects of climate change in nature are more complex than anticipated,” says Helmuth.

“These datasets tell us when and where to look for the effects of climate change. Without them we could miss early warning signs of trouble.”

It takes constant monitoring to determine which ecosystems are under stress. Thankfully, the robomussles blink away with stoicism, watching the oceans for any sign of over-heating.

“If we start to see sites where the animals are regularly getting to temperatures that are right below what kills them, we know that any slight increase is likely to send them over the edge, and we can act,” says Helmuth.

And since mussels underpin the food chains throughout their range, monitoring their health ensures a steady supply of food for everything else swimming about. The robomussels’ data can thus prove invaluable in maintaining coastal ecosystems. On a more human-centric note, they’re also good for pinpointing the best places for mussel farms.

“Losing mussel beds is essentially like clearing a forest,” says Helmuth. “If they go, everything that’s living in them will go. They are a major food supply for many species, including lobsters and crabs. They also function as filters along near-shore waters, clearing huge amounts of particulates. So losing them can affect everything from the growth of species we care about because we want to eat them to water clarity to biodiversity of all the tiny animals that live on the insides of the beds.”

The team published a paper describing their work with the robomussels under the title “Long-term, high frequency in situ measurements of intertidal mussel bed temperatures using biomimetic sensors” in the journal Scientific Data.