Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > How do green algae react to carbon nanotubes? Nanotubes «rob» green algae of space and light

Carbon nanotubes are not poisonous to green algae, but they do slow the growth of these organisms at high concentrations because they cause clumping which leads to the algae receiving less light. Left: intact algae (green) in a clump of carbon nanotubes (black). Right: "normal" photosynthetic activity of the algae (red) made visible by fluorescence.
Carbon nanotubes are not poisonous to green algae, but they do slow the growth of these organisms at high concentrations because they cause clumping which leads to the algae receiving less light. Left: intact algae (green) in a clump of carbon nanotubes (black). Right: "normal" photosynthetic activity of the algae (red) made visible by fluorescence.

Abstract:
Nanoparticles such as carbon nanotubes (CNT), which are found in an ever-increasing number of products, are ending up more and more frequently in our surroundings. If and how they affect aquatic ecosystems are questions which are still unanswered. An Empa study shows that while CNTs do not have toxic effects on green algae they do inhibit its growth by depriving the plant of light and space.

How do green algae react to carbon nanotubes? Nanotubes «rob» green algae of space and light

Switzerland | Posted on November 4th, 2011

Carbon nanotubes (CNTs) are up to 100,000 times thinner than a human hair and as light as plastic. Despite this they have a higher tensile strength than steel, are harder than diamond and conduct electricity better than copper. These properties make CNTs a raw material with a very promising future. All over the world possible applications are being investigated, including use in solar cells, plastics, batteries, medical technology and the purification of drinking water.

With the increasing industrial production of CNTs now reaching the level of hundreds of tons per year, the quantity of these particles which could be released into the environment has also risen. Certain studies have raised the possibility that CNTs lodged in the lungs might cause similar health effects as do asbestos fibers. An interdisciplinary team of scientists from Empa and the Agroscope Reckenholz-Taenikon (ART) Research Station have now begun investigating the fundamentals of how CNTs behave when they are deposited in waterways and lakes.

Algae remain healthy but grow slower
In the course of the project, which is financed by the Swiss National Funds, researchers further developed a standard chemical method in order to measure the growth and photosynthetic activity of green algae exposed to CNTs. They discovered that even in the presence of high concentrations of CNTs the algae retain normal levels of photosynthesis, although growth rates are reduced. Also noticeable was that when CNTs are added to the algae suspension, its color darkens and the algae forms clumps with the nanotubes. Despite this there is no evidence that the nanotubes are absorbed by the plants.

The investigators came to the conclusion, therefore, that the algae grow more slowly because they stick together as a result of the presence of CNTs and therefore receive less light. To prove this, they developed two further tests which allowed them to measure quantitatively the shadowing and agglomeration effects the nanotubes had on the algae. The results show that the slower growth of the organisms is in actual fact primarily due to these two factors. The conclusion is therefore that CNTs are not directly toxic to green algae, as earlier studies indicated. In the presence of CNTs, algae simply do not enjoy ideal growth conditions because, like land plants, they need sufficient room and light to do so.The clumping and shadowing effects which were observed only manifest themselves at elevated CNT concentrations of more than one milligram per liter, however. These levels of carbon nanotubes concentrations are currently unlikely to be met in the environment.

«Our study shows how difficult is to understand in detail the effect of nanomaterials on organisms», says Empa and ART researcher Fabienne Schwab. The results will help to test other nanoparticles to ensure that the safety of humans and their environment is guaranteed. Empa researcher Bernd Nowack advises that until comprehensive, long term results are available for complex organisms such as green algae, nanoparticles (particularly unbound nanoparticles) should not be released into our environment.

####

For more information, please click here

Contacts:
Further information

Dr. Bernd Nowack
Empa, Technology and Society Laboratory
Tel. +41 58 765 76 92


Fabienne Schwab
Agroscope ART
Tel. +41 44 377 7197


Editor/Media Contact

Rémy Nideröst
Empa, Communication Dept.
Tel. +41 58 765 45 98

Copyright © Empa

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

ANU invention to inspire new night-vision specs December 7th, 2016

Arrowhead Pharmaceuticals to Webcast Fiscal 2016 Year End Results December 7th, 2016

Journal Nanotechnology Progress International (JONPI), newest edition out December 7th, 2016

In IEDM 2016 Keynote, Leti CEO Says ‘Hyperconnectivity’, Human-focused Research and the IOT Promise Profound, Positive Changes December 7th, 2016

Nanotubes/Buckyballs/Fullerenes

Infrared instrumentation leader secures exclusive use of Vantablack coating December 5th, 2016

Novel Electrode Structure Provides New Promise for Lithium-Sulfur Batteries December 3rd, 2016

Cutting-edge nanotechnologies are breaking into industries November 18th, 2016

Hybrid nanostructures hold hydrogen well: Rice University scientists say boron nitride-graphene hybrid may be right for next-gen green cars October 25th, 2016

Discoveries

ANU invention to inspire new night-vision specs December 7th, 2016

Leti IEDM 2016 Paper Clarifies Correlation between Endurance, Window Margin and Retention in RRAM for First Time: Paper Presented at IEDM 2016 Offers Ways to Reconcile High-cycling Requirements and Instability at High Temperatures in Resistive RAM December 6th, 2016

Tokyo Institute of Technology research: 3D solutions to energy savings in silicon power transistors December 6th, 2016

Physicists decipher electronic properties of materials in work that may change transistors December 6th, 2016

Announcements

ANU invention to inspire new night-vision specs December 7th, 2016

Arrowhead Pharmaceuticals to Webcast Fiscal 2016 Year End Results December 7th, 2016

Journal Nanotechnology Progress International (JONPI), newest edition out December 7th, 2016

In IEDM 2016 Keynote, Leti CEO Says ‘Hyperconnectivity’, Human-focused Research and the IOT Promise Profound, Positive Changes December 7th, 2016

Environment

Semiconductor-free microelectronics are now possible, thanks to metamaterials November 9th, 2016

First time physicists observed and quantified tiny nanoparticle crossing lipid membrane November 7th, 2016

Nanosensors on the alert for terrorist threats: Scientists interested in the prospects of gas sensors based on binary metal oxide nanocomposites November 5th, 2016

Marsden minds: Amazing projects revealed November 3rd, 2016

Safety-Nanoparticles/Risk management

First time physicists observed and quantified tiny nanoparticle crossing lipid membrane November 7th, 2016

SUN shares its latest achievements during the 3rd Annual Project Meeting November 1st, 2016

The Sustainable Nanotechnologies Project’s Final Events: Bringing Nano Environmental Health and Safety Assessment to the Wider Discussion on Risk Governance of Key Enabling Technologies November 1st, 2016

Exploding smartphones: What's the silent danger lurking in our rechargeable devices? New research identifies toxic emissions released by lithium-ion batteries October 21st, 2016

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project