Tag Archives: wetlands

Algae outbreaks (dead zones) in wetlands and waterways

It’s been over seven years since I first started writing about Duke University’s  Center for the Environmental Implications of Nanotechnology and mesocosms (miniature ecosystems) and the impact that nanoparticles may have on plants and water (see August 11, 2011 posting). Since then, their focus has shifted from silver nanoparticles and their impact on plants, fish, bacteria, etc. to a more general examination of metallic nanoparticles and water. A June 25, 2018 news item on ScienceDaily announces some of their latest work,

The last 10 years have seen a surge in the use of tiny substances called nanomaterials in agrochemicals like pesticides and fungicides. The idea is to provide more disease protection and better yields for crops, while decreasing the amount of toxins sprayed on agricultural fields.

But when combined with nutrient runoff from fertilized cropland and manure-filled pastures, these “nanopesticides” could also mean more toxic algae outbreaks for nearby streams, lakes and wetlands, a new study finds.

A June 25, 2018 Duke University news release (also on EurekAlert) by Robin A. Smith, which originated the news item, provides more detail,

Too small to see with all but the most powerful microscopes, engineered nanomaterials are substances manufactured to be less than 100 nanometers in diameter, many times smaller than a hair’s breadth.

Their nano-scale gives them different chemical and physical properties from their bulk counterparts, including more surface area for reactions and interactions.

Those interactions could intensify harmful algal blooms in wetlands, according to experiments led by Marie Simonin, a postdoctoral associate with biology professor Emily Bernhardt at Duke University.

Carbon nanotubes and teeny tiny particles of silver, titanium dioxide and other metals are already added to hundreds of commercial products to make everything from faster, lighter electronics, self-cleaning fabrics, and smarter food packaging that can monitor food for spoilage. They are also used on farms for slow- or controlled-release plant fertilizers and pesticides and more targeted delivery, and because they are effective at lower doses than conventional products.

These and other applications have generated tremendous interest and investment in nanomaterials. However the potential risks to human health or the environment aren’t fully understood, Simonin said.

Most of the 260,000 to 309,000 metric tons of nanomaterials produced worldwide each year are eventually disposed in landfills, according to a previous study. But of the remainder, up to 80,400 metric tons per year are released into soils, and up to 29,200 metric tons end up in natural bodies of water.

“And these emerging contaminants don’t end up in water bodies alone,” Simonin said. “They probably co-occur with nutrient runoff. There are likely multiple stressors interacting.”

Algae outbreaks already plague polluted waters worldwide, said Steven Anderson, a research analyst in the Bernhardt Lab at Duke and one of the authors of the research.

Nitrogen and phosphorous pollution makes its way into wetlands and waterways in the form of agricultural runoff and untreated wastewater. The excessive nutrients cause algae to grow out of control, creating a thick mat of green scum or slime on the surface of the water that blocks sunlight from reaching other plants.

These nutrient-fueled “blooms” eventually reduce oxygen levels to the point where fish and other organisms can’t survive, creating dead zones in the water. Some algal blooms also release toxins that can make pets and people who swallow them sick.

To find out how the combined effects of nutrient runoff and nanoparticle contamination would affect this process, called eutrophication, the researchers set up 18 separate 250-liter tanks with sandy sloped bottoms to mimic small wetlands.

Each open-air tank was filled with water, soil and a variety of wetland plants and animals such as waterweed and mosquitofish.

Over the course of the nine-month experiment, some tanks got a weekly dose of algae-promoting nitrates and phosphates like those found in fertilizers, some tanks got nanoparticles — either copper or gold — and some tanks got both.

Along the way the researchers monitored water chemistry, plant and algae growth and metabolism, and nanoparticle accumulation in plant tissues.

“The results were surprising,” Simonin said. The nanoparticles had tiny effects individually, but when added together with nutrients, even low concentrations of gold and copper nanoparticles used in fungicides and other products turned the once-clear water a murky pea soup color, its surface covered with bright green smelly mats of floating algae.

Over the course of the experiment, big algal blooms were more than three times more frequent and more persistent in tanks where nanoparticles and nutrients were added together than where nutrients were added alone. The algae overgrowths also reduced dissolved oxygen in the water.

It’s not clear yet how nanoparticle exposure shifts the delicate balance between plants and algae as they compete for nutrients and other resources. But the results suggest that nanoparticles and other “metal-based synthetic chemicals may be playing an under-appreciated role in the global trends of increasing eutrophication,” the researchers said.

Here’s a link to and a citation for the paper,

Engineered nanoparticles interact with nutrients to intensify eutrophication in a wetland ecosystem experiment by Marie Simonin, Benjamin P. Colman, Steven M. Anderson, Ryan S. King, Matthew T. Ruis, Astrid Avellan, Christina M. Bergemann, Brittany G. Perrotta, Nicholas K. Geitner, Mengchi Ho, Belen de la Barrera, Jason M. Unrine, Gregory V. Lowry, Curtis J. Richardson, Mark R. Wiesner, Emily S. Bernhardt. Ecological Applications, 2018; DOI: 10.1002/eap.1742 First published: 25 June 2018

This paper is behind a paywall.

Investigating nanoparticles and their environmental impact for industry?

It seems the Center for the Environmental Implications of Nanotechnology (CEINT) at Duke University (North Carolina, US) is making an adjustment to its focus and opening the door to industry, as well as, government research. It has for some years (my first post about the CEINT at Duke University is an Aug. 15, 2011 post about its mesocosms) been focused on examining the impact of nanoparticles (also called nanomaterials) on plant life and aquatic systems. This Jan. 9, 2017 US National Science Foundation (NSF) news release (h/t Jan. 9, 2017 Nanotechnology Now news item) provides a general description of the work,

We can’t see them, but nanomaterials, both natural and manmade, are literally everywhere, from our personal care products to our building materials–we’re even eating and drinking them.

At the NSF-funded Center for Environmental Implications of Nanotechnology (CEINT), headquartered at Duke University, scientists and engineers are researching how some of these nanoscale materials affect living things. One of CEINT’s main goals is to develop tools that can help assess possible risks to human health and the environment. A key aspect of this research happens in mesocosms, which are outdoor experiments that simulate the natural environment – in this case, wetlands. These simulated wetlands in Duke Forest serve as a testbed for exploring how nanomaterials move through an ecosystem and impact living things.

CEINT is a collaborative effort bringing together researchers from Duke, Carnegie Mellon University, Howard University, Virginia Tech, University of Kentucky, Stanford University, and Baylor University. CEINT academic collaborations include on-going activities coordinated with faculty at Clemson, North Carolina State and North Carolina Central universities, with researchers at the National Institute of Standards and Technology and the Environmental Protection Agency labs, and with key international partners.

The research in this episode was supported by NSF award #1266252, Center for the Environmental Implications of NanoTechnology.

The mention of industry is in this video by O’Brien and Kellan, which describes CEINT’s latest work ,

Somewhat similar in approach although without a direction reference to industry, Canada’s Experimental Lakes Area (ELA) is being used as a test site for silver nanoparticles. Here’s more from the Distilling Science at the Experimental Lakes Area: Nanosilver project page,

Water researchers are interested in nanotechnology, and one of its most commonplace applications: nanosilver. Today these tiny particles with anti-microbial properties are being used in a wide range of consumer products. The problem with nanoparticles is that we don’t fully understand what happens when they are released into the environment.

The research at the IISD-ELA [International Institute for Sustainable Development Experimental Lakes Area] will look at the impacts of nanosilver on ecosystems. What happens when it gets into the food chain? And how does it affect plants and animals?

Here’s a video describing the Nanosilver project at the ELA,

You may have noticed a certain tone to the video and it is due to some political shenanigans, which are described in this Aug. 8, 2016 article by Bartley Kives for the Canadian Broadcasting Corporation’s (CBC) online news.

Oil in the Gulf of Mexico, science, and not taking sides

Linda Hooper-Bui is a professor in Louisiana who studies insects.She’s also one of the scientists who’s been denied access to freely available (usually) areas in the Gulf of Mexico wetlands. She and her students want to gather data for examination about the impact that the oil spill has had on the insect populations. BP Oil and the US federal government are going court over the oil spill and both sides want scientific evidence to buttress their respective cases. Scientists wanting access to areas controlled by either of the parties are required to sign nondisclosure agreements (NDAs) by either BP Oil or the Natural Resource Damage Assessment federal agency. The NDA’s extend not just to the publication of data but also to informal sharing.

From the article by Hooper-Bui in The Scientist,

The ants, crickets, flies, bees, dragon flies, and spiders I study are important components of the coastal food web. They function as soil aerators, seed dispersers, pollinators, and food sources in complex ecosystems of the Gulf.

Insects were not a primary concern when oil was gushing into the Gulf, but now they may be the best indicator of stressor effects on the coastal northern Gulf of Mexico. Those stressors include oil, dispersants, and cleanup activities. If insect populations survive, then frogs, fish, and birds will survive. If frogs, fish, and birds are there, the fishermen and the birdwatchers will be there. The Gulf’s coastal communities will survive. But if the bugs suffer, so too will the people of the Gulf Coast.

This is why my continued research is important: to give us an idea of just how badly the health of the Gulf Coast ecosystems has been damaged and what, if anything, we can do to stave off a full-blown ecological collapse. But I am having trouble conducting my research without signing confidentiality agreements or agreeing to other conditions that restrict my ability to tell a robust and truthful scientific story.

I want to collect data to answer scientific questions absent a corporate or governmental agenda. I won’t collect data specifically to support the government’s lawsuit against BP nor will I collect data only to be used in BP’s defense. Whereas I think damage assessment is important, it’s my job to be independent — to tell an accurate, unbiased story. But because I choose not to work for BP’s consultants or NRDA, my job is difficult and access to study sites is limited.

Hooper-Bui goes on to describe a situation where she and her students had to surrender samples to a US Fish and Wildlife officer because their project (on public lands therefore they should have been freely accessible) had not been approved. Do read the article before it disappears behind a paywall but if you prefer. you can listen to a panel discussion with her and colleagues Christopher D’Elia and Cary Nelson on the US National Public Radio (NPR) website, here. One of the people who calls in to the show is another professor, this one from Texas, who has the same problem collecting data. He too refused to sign any NDAs. One group of nonaligned scientists has been able to get access and that’s largely because they acted before the bureaucracy snapped into place. They got permission (without having to sign NDAs) while the federal bureaucracy was still organizing itself in the early days of the spill.

These practices are antithetical to the practice of science. Meanwhile, the contrast between this situation and the move to increase access and make peer review a more open process (in my August 20, 2010 posting) could not be more glaring. Very simply, the institutions want more control while the grassroots science practitioners want a more open environment in which to work.

Hooper-Bui comments on NPR that she views her work as public service. It’s all that and more; it’s global public service.

What happens in the Gulf over the next decades will have a global impact. For example, there’s a huge colony of birds that make their way from the Gulf of Mexico to the Gaspé Peninsula in Québec for the summer returning to the Gulf in the winter.  They should start making their way back in the next few months. Who knows what’s going to happen to that colony and the impact this will have on other ecosystems?

We need policies that protect scientists and ensure, as much as possible, that their work be conducted in the public interest.