eGEOTRACES

Factsheet #3: Mercury

The UNEP Minamata Convention was ratified in August 2017 and aims to protect human health from mercury exposure by reducing anthropogenic, inorganic, mercury emissions. The most toxic and biomagnifying mercury species, methylmercury, is not emitted from anthropogenic or natural sources, but produced in the ocean from inorganic mercury.

A 3D scene showing the distribution of dissolved mercury in the Atlantic. In warm colours (red, orange, etc.) you can view high concentrations of dissolved mercury.

Data

Data is available to download after registration here: https://geotraces.webodv.awi.de/login

Discoveries include:

Loss of old Arctic sea ice increases methylmercury concentrations

Researchers from the SCRIPPS, the Stockholm Natural Museum and the Mediterranean Institute of Oceanography show the importance of sea ice composition on methylmercury budgets

Precise estimate of the mercury export from the Arctic to the Atlantic Ocean

Using new observations acquired during GEOTRACES Arctic cruises, a refined arctic mercury budget has been established

Arctic mercury export flux with marine particles higher than anticipated

In the ocean, the residence time of mercury (Hg), is largely driven by two removal mechanisms: evasion to the atmosphere and downward export flux with settling particles. The later was […]

Who produces methylmercury in the global ocean?

The UNEP Minamata Convention was ratified in August 2017 and aims to protect human health from mercury exposure by reducing anthropogenic, inorganic, mercury emissions. The most toxic and biomagnifying mercury […]

Methylmercury subsurface maxima explain mercury accumulation in Canadian Arctic marine mammals

Mercury (Hg) concentrations in Canadian Arctic marine mammals were monitored during the last four decades and found to be highly elevated, frequently exceeding toxicity thresholds. Mercury concentrations in marine biota […]

High production of methylmercury in the anoxic waters of the Black Sea

As part of the GEOTRACES MedBlack cruise, the research vessel Pelagia occupied 12 full-depth stations in the Black Sea along an East-West transect between July 13th and 25th, 2013. In […]

Want to learn more?

Watch the talk of Dr. Katlin Bowman “Mercury biogeochemistry in the Arctic Ocean” given as part of the webinar series “Breaking the Ice Ceiling” organized by a coalition of institutions including The Arctic Institute, Women in Polar Sciences, and Women of the Arctic:

Factsheet #2: Dissolved lead

3D scenes showing the distribution of dissolved iron in the Atlantic, the Pacific and the Indian. This tracer is of anthropogenic origin. In warm colours (red, orange, etc.) you can view high concentrations of dissolved lead. The dominant input into the North Atlantic and spreading with the main deep water masses are clearly visible on the Atlantic Ocean map.

Increased usage and then phasing-out of leaded-petrol since the mid-70’s yielded a decrease of this contamination. By measuring lead concentrations and isotopes GEOTRACES scientists reveal for the first time that natural lead can be detected again in the surface water of the North Atlantic. Indeed, significant proportions of up to 30–50% of natural Pb, derived from mineral dust, are observed in Atlantic surface waters off the Sahara. This clearly reflects the success of the global effort to reduce anthropogenic Pb emissions.

Atlantic Ocean:

Indian Ocean:

Pacific Ocean:

South Pacific Ocean:

Data

Data is available to download after registration here: https://geotraces.webodv.awi.de/login

Discoveries include:

Loss of old Arctic sea ice increases methylmercury concentrations

Researchers from the SCRIPPS, the Stockholm Natural Museum and the Mediterranean Institute of Oceanography show the importance of sea ice composition on methylmercury budgets

Precise estimate of the mercury export from the Arctic to the Atlantic Ocean

Using new observations acquired during GEOTRACES Arctic cruises, a refined arctic mercury budget has been established

Arctic mercury export flux with marine particles higher than anticipated

In the ocean, the residence time of mercury (Hg), is largely driven by two removal mechanisms: evasion to the atmosphere and downward export flux with settling particles. The later was […]

Who produces methylmercury in the global ocean?

The UNEP Minamata Convention was ratified in August 2017 and aims to protect human health from mercury exposure by reducing anthropogenic, inorganic, mercury emissions. The most toxic and biomagnifying mercury […]

Methylmercury subsurface maxima explain mercury accumulation in Canadian Arctic marine mammals

Mercury (Hg) concentrations in Canadian Arctic marine mammals were monitored during the last four decades and found to be highly elevated, frequently exceeding toxicity thresholds. Mercury concentrations in marine biota […]

High production of methylmercury in the anoxic waters of the Black Sea

As part of the GEOTRACES MedBlack cruise, the research vessel Pelagia occupied 12 full-depth stations in the Black Sea along an East-West transect between July 13th and 25th, 2013. In […]

Factsheet #1: Dissolved Iron

Phytoplankton who lives at the surface of the oceans is the responsible of half of the Earth oxygen production, through photosynthesis. In addition, it is fixing dissolved carbon (CO2) of atmospheric origin as solid particles which, when dying, are falling as detritus in the abyss and the sediment. This mechanism called the “Biological Carbon Pump” is an important sink for the anthropogenic CO2. Understanding the processes leading to the phytoplankton development is thus a major issue for the present-day climate modelling and the prediction of our future climate.

Iron (as other trace metals) is essential for the photosynthesis success of most of the phytoplanktonic species. However, its abundance in the marine waters is extremely low and its absence is limiting the phytoplankton development in roughly half of the world’s oceans. This led to the development of studies of artificial ocean iron fertilization, the hypothesis being that stimulating the photosynthesis will improve the capacity of the ocean to absorb CO2. However, thanks to studies on iron distribution and fate it is now proved that artificial ocean iron fertilization will never produce the expected result as photosynthesis continues to be limited due to the complexity of processes at play in surface waters. Such results prevent wasting money in useless operations.

Thus, to understand the carbon pump functioning or to test geoengineer’s hypothesis, studying the oceanic iron cycle is essential. This includes: understanding the iron sources to the ocean, its sinks, its distribution, etc. GEOTRACES is elucidating these questions, as well as, producing high quality data and representing it on an electronic Atlas that helps to easily convey the information.

Find below a summary of main GEOTRACES findings and products on iron research:

Atlas

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Atlantic Ocean:

Pacific Ocean:

3D scenes showing the distribution of dissolved iron in the Atlantic and the Pacific. In warm colours (red, orange, etc.) you can view high concentrations of dissolved iron. The diversity of hydrothermal iron inputs is identified along Mid Oceanic Ridges in the two basins. Important release of dissolved iron from the sediments are indicated along the African, South American, Asian and Peruvian coasts.

Data

Data is available to download after registration here: https://geotraces.webodv.awi.de/login

Discoveries include:

Below you can find a list of science highlights of main GEOTRACES discoveries on iron research:

Loss of old Arctic sea ice increases methylmercury concentrations

Researchers from the SCRIPPS, the Stockholm Natural Museum and the Mediterranean Institute of Oceanography show the importance of sea ice composition on methylmercury budgets

Precise estimate of the mercury export from the Arctic to the Atlantic Ocean

Using new observations acquired during GEOTRACES Arctic cruises, a refined arctic mercury budget has been established

Arctic mercury export flux with marine particles higher than anticipated

In the ocean, the residence time of mercury (Hg), is largely driven by two removal mechanisms: evasion to the atmosphere and downward export flux with settling particles. The later was […]

Who produces methylmercury in the global ocean?

The UNEP Minamata Convention was ratified in August 2017 and aims to protect human health from mercury exposure by reducing anthropogenic, inorganic, mercury emissions. The most toxic and biomagnifying mercury […]

Methylmercury subsurface maxima explain mercury accumulation in Canadian Arctic marine mammals

Mercury (Hg) concentrations in Canadian Arctic marine mammals were monitored during the last four decades and found to be highly elevated, frequently exceeding toxicity thresholds. Mercury concentrations in marine biota […]

High production of methylmercury in the anoxic waters of the Black Sea

As part of the GEOTRACES MedBlack cruise, the research vessel Pelagia occupied 12 full-depth stations in the Black Sea along an East-West transect between July 13th and 25th, 2013. In […]

List of publications

Scroll down to view the list of GEOTRACES publications on dissolved iron: (Not updated — IN CONSTRUCTION!!!)

Rechercher