McKnight

Rivers in Alaska are turning orange. The reason surprised even scientists (CNN)

Anonymous — Tue, 04 Jun 2024 21:24:27 +0000

Rivers in Alaska are turning orange. The reason surprised even scientists (CNN) Anonymous (not verified) Tue, 06/04/2024 - 15:24

Fabiana Chaparro , CNN

A new paper by a team of USGS and CU �鶹ӰԺ scientists is mentioned in this news story on rivers and streams in Alaska changing color. The streams are turning from blue to rusty orange because of toxic metals released by thawing permafrost and leaching into stream water.

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Colorado's streams are being loaded with toxic heavy metals (Newsweek)

Anonymous — Wed, 22 May 2024 19:21:10 +0000

Colorado's streams are being loaded with toxic heavy metals (Newsweek) Anonymous (not verified) Wed, 05/22/2024 - 13:21

Robyn White , Newsweek

Colorado's mountain streams are facing a "real challenge" from a rising concentration of heavy metal levels. These rising levels are only worsening with climate change, a new study found.

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Warming climate is putting more metals into Colorado’s mountain streams

Anonymous — Tue, 23 Apr 2024 07:25:13 +0000

Warming climate is putting more metals into Colorado’s mountain streams Anonymous (not verified) Tue, 04/23/2024 - 01:25

Liza Lester (AGU)

Warming temperatures are causing a steady rise in copper, zinc and sulfate in the waters of Colorado mountain streams affected by acid rock drainage. Concentrations of these metals have roughly doubled in these alpine streams over the past 30 years, a new study finds, presenting a concern for ecosystems, downstream water quality and mining remediation.

Iron oxides stain the bed of Upper East Mancos River in southwestern Colorado, an alpine stream affected by acid rock drainage. Concentrations of zinc, copper and sulfate have doubled in Colorado’s high-altitude streams, like the Upper East Mancos, where groundwater flows through bedrock rich in metal sulfides, according to a study that links the trend to climate change. Photo by Andrew Manning.

Natural chemical weathering of bedrock is the source of the rising acidity and metals, but the ultimate driver of the trend is climate change, the report found.

“Heavy metals are a real challenge for ecosystems,” said lead author Andrew Manning, a geologist with the U.S. Geological Survey in Denver. “Some are quite toxic. We are seeing regional, statistically significant trends in copper and zinc, two key metals that are commonly a problem in Colorado. It’s not ambiguous and it’s not small.”

The study was published in Water Resources Research, AGU’s peer reviewed journal for original research on the movement and management of Earth’s water.

Although the mechanism coupling warming temperatures to increased sulfide weathering is still an open research question, the new results point to exposure of rock once sealed away by ice as a top suspect, Manning said. The sudden appearance of “rusting Arctic rivers” flowing out of regions of thawing permafrost in the last couple of years is likely the same process, magnified.

Colorado is riddled with patches of bedrock rich in metal sulfides. Shiny iron sulfide, familiar to many Coloradans as fool’s gold, or pyrite, is the most common of these sulfide minerals, but copper, zinc and other metal sulfides are also common.

Exposure to air oxidizes the metal sulfides in bedrock, releasing the metals into groundwater, which flows into surface streams. Rusty red deposits in streambeds are distinctive signs of iron sulfide oxidation. Sulfides also acidify the water, which can accelerate weathering. Some alpine streams sampled were found have a pH as low as 3 or 4.

The study drew on 40 years of water chemistry data, taking final samples from all sites in 2021, from 22 headwater streams in 17 watersheds that are naturally acidic and metal-rich enough to limit aquatic plants and animals. Sampling sites were above 3,000 meters (10,000 feet) elevation and included a mix of pristine, untouched areas and places that had been mined historically, but left alone for 50 to 100 years.

“The key point is no recent mining or remediation work has been done,” Manning said. “These watersheds have just been sitting there responding to nothing other than the climate.”

Warming, drying mountains

I have been studying these increases in zinc and decreases in pH in the upper Snake River near Dillon for more than three decades and have suspected that similar changes have been occurring across the Colorado Mineral Belt. It’s sobering to have found out that indeed this is the case.
- Diane McKnight

Mountain streams were sampled from mid-July to November, spanning the late summer and fall low-flow period. Long-term records of flow volume from nearby stream gauges show streamflows have been dwindling with warming temperatures and smaller snowpacks, suggesting smaller water volumes could explain the higher metal concentrations.

But Manning and his colleagues found less water could only account for half the effect they observed. To reach the concentrations they were seeing, the mountains had to be putting metals and sulfate into streams at a faster rate.

As these metal-rich mountain streams flow down into larger rivers, the effect of the extra metal load is diluted, the researchers noted.

“I don’t think this is a big red flag for major metropolitan or agriculture users way downstream at lower elevations,” Manning said, “but some of our mountain communities get their water only a short distance down from these mineralized streams.” To help mitigate the water quality risk, managers could benefit from advance knowledge of what metals are entering the stream, and where and how fast they are increasing, Manning said.

More metals and acidity in these mountain streams could also impact decisions about where to invest limited funds for remediation of those that have been altered by historical mining, and where to stock fish to benefit tourism.

Local case, global pattern

Colorado’s watersheds are a dramatic case because of the unusual abundance of bedrock metal sulfides, Manning said, but scientists are observing more subtle rising sulfate concentrations in mountain streams around the world. The new study is the first to statistically connect accelerated sulfide weathering to rising temperatures on a large scale across an entire region.

“I have been studying these increases in zinc and decreases in pH in the upper Snake River near Dillon for more than three decades and have suspected that similar changes have been occurring across the Colorado Mineral Belt," says study coauthor Diane McKnight, an INSTAAR fellow and Distinguished Professor in Engineering. "It’s sobering to have found out that indeed this is the case. But it is also important for understanding how to move forward with planning for remediation of abandoned mine sites and for protecting downstream ecosystems.”

The study found the biggest gains in metal loads in the highest, coldest mountain streams. Manning said this pattern points to thawing underground ice. Colorado’s highest elevations have annual average temperatures close to zero degrees Celsius (32 degrees Fahrenheit), putting them right at the boundary conditions for permafrost. Some peaks have warmed past the freezing threshold since 1980.

“Ice is like armor. Melt it and you create windows for groundwater to get into rock that has not seen water and oxygen for millennia, and it will begin to oxidize quite quickly,” Manning said.

Other possible mechanisms are falling water tables exposing fresh rock to air and melting rock glaciers releasing pockets of concentrated metals stored in the ice. Wetlands accumulate metals and may release a burst when water returns after dry periods. The study did not find a correlation between rates of rising metal concentrations and the presence of wetlands, rock glaciers or factors linked to falling water tables, although these could be playing a role in other regions. But all these possible mechanisms are consequences of climate change.

“There’s just no other logical explanation than this is a changing climate signal,” Manning said. “Nothing else would reach all these watersheds universally.”

See also:

AGU press release (includes institutional and researcher contacts)

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Research in the aftermath of the Camp Fire reveals the threat of wildfires on water quality (Chico State)

Anonymous — Thu, 08 Feb 2024 23:04:31 +0000

Research in the aftermath of the Camp Fire reveals the threat of wildfires on water quality (Chico State) Anonymous (not verified) Thu, 02/08/2024 - 16:04

A groundbreaking multi-year research initiative launched at Chico State in the aftermath of the Camp Fire examined the presence of contaminants, including metals, in nearby watersheds. Joined by researchers from CU �鶹ӰԺ and the USGS, the research, recently published in the prestigious Journal of Environmental Science: Processes and Impacts, sheds light on the alarming impact of wildfires on stormwater runoff.

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Diane McKnight reflects on the LTER (LTER Network)

Anonymous — Thu, 28 Sep 2023 23:56:29 +0000

Diane McKnight reflects on the LTER (LTER Network) Anonymous (not verified) Thu, 09/28/2023 - 17:56

Diane McKnight has been an integral figure in the Long-Term Ecological Research Program for decades. She was instrumental in launching the McMurdo LTER, spearheaded restructuring network coordination, and served as Chair of the LTER Network Executive Board. She’s mentored dozens of students and developed too many projects to count. The LTER Network Office sat down with Diane to chat about her life in the Network and her dreams for the LTER moving forward.

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The birds are all right

Anonymous — Tue, 20 Jun 2023 20:05:18 +0000

The birds are all right Anonymous (not verified) Tue, 06/20/2023 - 14:05

Shelly Sommer , INSTAAR

A researcher brought her love of birds to a watershed in Summit County, Colorado, affected by acid mine drainage. Recently published in the journal Diversity,the resulting research connects some dots between water quality, life in streams, and life on land in the granitic landscape of the West.

Former CU graduate student Kelly Watson is lead author of the study with Professor and INSTAAR Fellow Diane McKnight. Based on her master’s degree research, the study aimed to see if breeding birds were avoiding streams with high metal concentrations.

The study found that, despite an order of magnitude increase in metal concentrations in some streams, birds did not seem to be avoiding them.

A stream in the Snake River watershed flows over rocks with a red coating, the result of high metal concentrations in the stream.

Diane McKnight has led investigations of water quality and stream ecology in Colorado’s Snake River watershed for decades. The watershed has a section with pristine streams, and a section with streams impacted by acid mine drainage.

Acidic drainage can happen wherever geology puts sulfide-based minerals together with air and water. But this natural weathering process is greatly intensified by mining activities that expose more rock. As a result, sulfuric acid and dissolved metals, like iron, drain into streams, where the more acidic water can further dissolve heavy metals and rare earth elements. Warmer, earlier summers are causing longer, lower stream flows, making it easier for metals to leach into streams.

“Acid mine drainage is a source of water pollution in the Rocky Mountains and around the world,” said Watson. “We know it has a lot of impacts on organisms living in the stream.”

McKnight has conducted research on many aspects of water quality in affected streams, as well as how it affects life within streams. The acidity of the water controls which species can live in it. For instance, the nymphs and larvae of mayflies populate the pristine streams of the Snake River watershed, but only the acid-tolerant larvae of stoneflies live in streams affected by acid mine drainage. Streams with particularly high metal content may develop a coating on their beds that inhibits insect and other life.

Relatively little is known, however, about how elevated metals and rare earth elements may affect terrestrial species living near polluted streams.

Then Watson joined her research program. Watson “had studied birds as an undergraduate at the College of William & Mary,” said McKnight. “She wanted to work with birds for her master’s thesis.” It was an opportunity to investigate links between stream chemistry and terrestrial life in the Snake River watershed.

“Something to consider is, what should we be looking at when we remediate mine drainage sites?” said Watson. “We’ve known for a long time that benthic macroinvertebrates are indicators of stream health. What about species that live on land around the streams?”

McKnight and Watson designed a research project to look at water quality, insect and other life in the streams, and birds breeding in the watershed. Were birds avoiding sites next to streams affected by acid mine drainage?

Because the insects and other invertebrates living in acidic streams accumulate metals in their bodies, there is concern that birds or fish that use them as a food source might also start to accumulate metals. There was some evidence of concern from a previous study in the area, which found elevated metal concentrations in tree swallow nestlings. But little was known about potential effects on migratory birds that breed in the area.

“As an undergraduate, I was part of a bird monitoring program in Virginia,” said Watson, who is now the Principal Floodplain Planner for �鶹ӰԺ County. “I learned how to do point counts and run the occupancy models we used in this study.”

The takeaway is that that birds that live by the stream are probably fine even though metals in the water have gone up by an order of magnitude.
- Diane McKnight

Watson worked together with Stella Koliavas, a student in the Undergraduate Research Opportunities Program (UROP), to conduct bird counts at twenty study sites along the main streams of the Snake River watershed during breeding season. They observed robins, dark-eyed juncos, Wilson’s warblers, Lincoln’s sparrow, mountain chickadees, ruby-crowned kinglets, white-crowned sparrows, and yellow-rumped warblers at many of the sites.

She also took samples of the water and macroinvertebrates living in the stream and analyzed them for concentrations of trace metals and rare earth elements. She then used a computer model to relate the presence of birds to various types of habitat and conditions, and to the potential for trace metal and rare earth element exposure.

The most acidified stream was about the acidity of soda or grapefruit juice, and showed more dissolved metals and very little resident life. Stonefly larvae dominated the acidified streams, which were about as acid as a cup of black coffee; while mayflies were the most abundant macroinvertebrate in the pristine stream, with a neutral pH. Overall, the water quality was similar to that found in many prior studies of the same watershed, though quantities of metals and rare earth elements in the streams are generally increasing.

Watson found that birds were found throughout the watershed area. The only pattern in their residency seemed to be habitat—a few birds are “habitat specialists” who nest in shrubby environments rather than forest. Habitat, but not water quality or invertebrate prey quality, is an important factor for these species during the breeding season.

The study also showed that the relationship between the amount of metals in a stream and the amount of metals accumulated in the bodies of insects living in the stream is not straightforward. This may affect how many metals birds ingest if they prey on the insects. While the species present in the streams are controlled by the acidity of the water, insects’ metal accumulations seem more related to what they eat and whether those food sources originate in the stream or out of it.

Watson and McKnight recently adapted Watson’s master’s thesis into the journal article. “I have a full-time day job, so on nights and weekends, Diane and I would collaborate and work on revisions,” said Watson.

“The takeaway is that that birds that live by the stream are probably fine,” said McKnight, “even though metals in the water have gone up by an order of magnitude.”

“The reason that’s interesting is because the stream conditions are getting worse,” she said. While the study was not designed to show any possible negative effects of birds breeding near acidic streams, the birds may be an example of resilience in a changing climate.

Another aspect of the study was finding that the concentrations of some rare earth elements in invertebrates were high and aligned with concentrations of lead. There is little information about rare earth elements in aquatic organisms, and this finding might point the way to a need for further research on how metals and rare earth elements are transferred through ecosystems.

“This study indicates further inquiry on how metals may or may not be moving into terrestrial ecosystems is needed,” said Watson.

McKnight will give a free public talk on the study at the Mountain Research Station, near Nederland, Colorado, on Wednesday June 28. All are invited.

Birds continue to thrive in Colorado’s Snake River watershed, despite increasing heavy metals and rare earth elements in streams, finds a study by Kelly Watson and Diane McKnight.

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Art and climate science converge in new exhibit at the Colorado Capitol (KUNC)

Anonymous — Wed, 24 May 2023 21:46:29 +0000

Art and climate science converge in new exhibit at the Colorado Capitol (KUNC) Anonymous (not verified) Wed, 05/24/2023 - 15:46

Emma VandenEinde

An exhibit that just opened in the Colorado capitol building's rotunda features artwork made in the process of partnerships between artists from around Colorado, their communities, and CU �鶹ӰԺ scientists. Called “Coloradans and our Shared Environment in Times of Challenge and Change,” the art grapples with the climate and environmental challenges that are part of Coloradoans' lives: drought, decreasing groundwater, acid mine drainage, wildfire, pine beetle tree mortality, and more.

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Coloradoans and our shared environment in times of challenge and change (CU OOE)

Anonymous — Thu, 18 May 2023 18:02:12 +0000

Coloradoans and our shared environment in times of challenge and change (CU OOE) Anonymous (not verified) Thu, 05/18/2023 - 12:02

CU Office for Outreach and Engagement

A collaborative exhibition tells the story of how Coloradans are experiencing interrelated challenges of fire, drought, and water and air quality in their communities. Artists (the CASE Fellows) partnered with scientists and communities to make visible the connections between Coloradans and their environment. Several INSTAARs acted as scientist partners. This website showcases the artwork, as well as quotes from the partners, explorations of the issues, and what you can do to act.

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Announcing the Colorado Art Science Environment Fellows and Colorado State Capitol Exhibition (CU �鶹ӰԺ Community Outreach and Engagement)

Anonymous — Tue, 20 Dec 2022 00:25:19 +0000

Announcing the Colorado Art Science Environment Fellows and Colorado State Capitol Exhibition (CU �鶹ӰԺ Community Outreach and Engagement) Anonymous (not verified) Mon, 12/19/2022 - 17:25

Gretchen Minekime , CU Office for Outreach and Engagement

The Office for Outreach and Engagement announces the CASE Fellows program. The program pairs Colorado artists with CU �鶹ӰԺ scientists to produce art that will be exhibited at the Colorado State Capitol in an exhibition about how Coloradans are experiencing interrelated challenges of fire, drought, and water and air quality. Lisa Schwartz from OOE is leading the program in partnership with Shelly Sommer at INSTAAR, �鶹ӰԺ County Arts Alliance and with exhibition and curatorial support from Amy Hoagland.

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These freeze-drying algae can awaken from cryostasis, could help spaceflights go farther (AGU)

Anonymous — Thu, 08 Dec 2022 21:10:05 +0000

These freeze-drying algae can awaken from cryostasis, could help spaceflights go farther (AGU) Anonymous (not verified) Thu, 12/08/2022 - 14:10

Liza Lester

Algal mats survive extreme conditions in Antarctica by entering a freeze-dried state. Led by Diane McKnight, researchers collected the green algae that survive there and grew them in the lab to assess their applications for spaceflight.

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