Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Diatom ooze sediments are a large marine mercury sink

27.07.2018

Mercury has been released by humans by multiple processes such as gold and silver mining and emissions to the atmosphere by coal burning, to name the most important ones. These processes have caused strong enrichment of mercury in the environment. The fate of mercury in the marine environment is barely understood. Scientists from Technical University of Braunschweig, Germany, investigated cores of biogenic sediments from marine Antarctica for accumulation of mercury in the past 8.000 years. They found out that microalgae accumulate high amounts of mercury in marine sediments and reveal onset and extent of global anthropogenic mercury emissions. Results have been published in SCIENCE.

Atmospheric derived mercury is transformed in the ocean to toxic methylmercury, which is enriched in fish. Large marine predators such as tuna are strongly affected and even humans through fish consumption.


Marine bottom sediments which consist mainly of diatom remains (diatom ooze).

Sara Zaferani/TU Braunschweig


Sampling of biogenic marine sediments.

Sara Zaferani/TU Braunschweig

Up to now, no data on mercury accumulation in deep sea sediments has been available. Scientists from TU Braunschweig have now investigated the role of microalgae for mercury accumulation in biogenic marine sediments.

The environmental geochemistry group at the Institute of Geoecology at TU Braunschweig under direction of Prof Harald Biester has investigated marine bottom sediments which consist mainly of diatom remains (diatom ooze) for the historical accumulation of mercury.

Those so called diatom ooze sediments are a result of algae blooms in the nutrient rich water of the Southern Ocean and form sediments of more than 100 m thickness with sedimentation rates of more than 1 cm per year.

With their analyses the scientists can show for the first time that diatom ooze accumulates large amounts of mercury in deep ocean sediments. Mercury accumulation rates derived from sediment cores from marine Antarctica are the highest ever reported for the marine environment.

Calculations based on the silicon/mercury ratio in the investigated sediment cores as well as literature data on global diatom ooze sedimentation reveal that between 9 and 20 percent of the annually emitted mercury from industrial sources could have been buried by diatoms alone. Moreover, diatom ooze could have been accumulated between 6,5 and 20 percent of all mercury emitted to the atmosphere during the industrial period. These results highlight the important role of algae for the accumulation of mercury in marine sediments.

The high resolution (10-40 years) historical mercury record (8.600 years) derived from Adélie Basin (marine Antarctica) sediments indicates that anthropogenic mercury pollution in Antarctica started with the beginning of the industrial period at around 1850 AD.

Earlier emissions, for example from colonial gold and silver mining in the 16th century where mercury was used for the extraction of the precious metals, could not be detected. Overall, the publication presents new important results for the global distribution of mercury emitted from anthropogenic sources and its enrichment in the marine food chain.

Wissenschaftliche Ansprechpartner:

Prof. Harald Biester
Leiter der Arbeitsgruppe Umweltgeochemie
Technische Universität Braunschweig
Institut für Geoökologie (IGÖ)
Langer Kamp 19c
38106 Braunschweig
Tel.: +49 (0) 531 391-7240
E-Mail: h.biester@tu-braunschweig.de
Web: https://www.tu-braunschweig.de/geooekologie/institut/geochemie

Originalpublikation:

Zaferani S, Pérez-Rodríguez M, Biester H (2018) Diatom ooze—A large marine mercury sink, Published Online 26 Jul 2018, DOI: https://doi.org/10.1126/science.aat2735

Janos Krüger | idw - Informationsdienst Wissenschaft

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: It’s All in the Mix: Jülich Researchers are Developing Fast-Charging Solid-State Batteries

There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.

The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

Quantum bugs, meet your new swatter

20.08.2018 | Information Technology

A novel synthetic antibody enables conditional “protein knockdown” in vertebrates

20.08.2018 | Life Sciences

Metamolds: Molding a mold

20.08.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>