eGEOTRACES

Factsheet #11: Protactinium

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

Atlas

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3D scenes showing the distribution of dissolved iron in the Atlantic and the Pacific, the Arctic Oceans. In warm colours (red, orange, etc.) you can view high concentrations of dissolved protactinium-231.

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 protactinium research:

Protactinium-231 budget of the Atlantic sector of Southern Ocean

Levier and colleagues analysed dissolved and particulate protactinium-231 in samples collected in a section in the Southern Ocean…

Intense benthic nepheloid layers in the Northwest Atlantic Ocean lead to unexpected distributions of dissolved and particulate thorium-230 and protactinium-231

Chen and colleagues explore the behaviour of thorium-230 and protactinium-231 in the benthic nepheloid layers…

Measuring actinium-227 by mass spectrometry is feasible, sensitive and reliable!

Levier and co-authors have developed a new protocol measurement of the dissolved actinium in seawater.

Thorium-Protactinium fate across the tropical Atlantic Ocean: what reveals the water column-sediment coupling

Twenty seawater profiles and twenty core-top 231-protactinium and 230-thorium analyses were realised by Ng and colleagues along five depth transects across the northern tropical Atlantic open ocean.

Isopycnal mixing controls protactinium and thorium distributions in the Pacific Southern Ocean

Pavia and co-workers determined the physical and chemical speciation as well as the vertical distribution of Protactinium-231 and Thorium-230 at 12 stations across the Southern Pacific Antarctic Circumpolar Current…

More realistic oceanic particle field improved the thorium-230 and protactinium-231 modeling

Thorium-230 (230Th) and protactinium-231 (231Pa) are two geochemical tracers extensively used for investigating particle transport in the ocean and reconstructing past ocean circulation. A key feature in reproducing their distributions by […]

List of publications

Scroll down to view the list of GEOTRACES publications on protactinium-231:

31.05.2022

Factsheet #10: Thorium

In the marine environment, the different elements of the natural radioactive families of uranium (U)and thorium (Th) can be classified into two groups: those that are soluble in seawater and those that are particle-reactive, extracted from the water column by chemical and biological processes (adsorption, aggregation, precipitation).

Thorium isotopes are very reactive toward particles in the marine environment. In seawater, thorium is present as Th(OH)4 oxide and adsorbs on all solid surfaces.

Thorium isotopes have different half-lives:
234Th: T1/2 = 24.1 days
232Th: T1/2 = 1.4 1010 years
230Th: T1/2 = 7.5 104 years

Thorium-232 (232Th) is the most abundant and is brought to the ocean in detrital form by rivers and the atmosphere. 232Th, coming from terrigenous dust, is directly associated with particles in the ocean. It is mostly transported by detrital matter. In the earth’s crust its concentration is of the order of 10.7 ppm but in sea water it is less than 0.7 ppt Thus, this isotope is used in marine geochemistry to quantify the so-called lithogenic contributions (from the erosion of rocks).

Thorium-234 (234Th) and Thorium-230 (230Th) are produced in situ (in dissolved form) by radioactive decay of Uranium-238 (238U) and Uranium-234(234U) by alpha emission. The concentrations of 238U and 234U are constant in the ocean, these nuclides represent homogeneous sources of 234Th and 230Th in the water column. These thorium isotopes, produced in situ, rapidly leave the seawater by attaching to marine particles. In this form, they become tracers of particulate matter. Therefore, the use of U/Th imbalances allows the study of:

  • Particle fall rate and calibration of particle traps
  • Estimation of exported production
  • Interaction processes between solution and marine particles
  • Ventilation of intermediate and deep waters

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

Atlas

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Thorium-230

Thorium-232

Thorium-234

3D scenes showing the distribution of 230Th, 232Th and 234th in the Atlantic, the Pacific and the Arctic Oceans. In warm colours (red, orange, etc.) you can view high concentrations of dissolved thorium.

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 thorium research:

Protactinium-231 budget of the Atlantic sector of Southern Ocean

Levier and colleagues analysed dissolved and particulate protactinium-231 in samples collected in a section in the Southern Ocean…

Intense benthic nepheloid layers in the Northwest Atlantic Ocean lead to unexpected distributions of dissolved and particulate thorium-230 and protactinium-231

Chen and colleagues explore the behaviour of thorium-230 and protactinium-231 in the benthic nepheloid layers…

Measuring actinium-227 by mass spectrometry is feasible, sensitive and reliable!

Levier and co-authors have developed a new protocol measurement of the dissolved actinium in seawater.

Thorium-Protactinium fate across the tropical Atlantic Ocean: what reveals the water column-sediment coupling

Twenty seawater profiles and twenty core-top 231-protactinium and 230-thorium analyses were realised by Ng and colleagues along five depth transects across the northern tropical Atlantic open ocean.

Isopycnal mixing controls protactinium and thorium distributions in the Pacific Southern Ocean

Pavia and co-workers determined the physical and chemical speciation as well as the vertical distribution of Protactinium-231 and Thorium-230 at 12 stations across the Southern Pacific Antarctic Circumpolar Current…

More realistic oceanic particle field improved the thorium-230 and protactinium-231 modeling

Thorium-230 (230Th) and protactinium-231 (231Pa) are two geochemical tracers extensively used for investigating particle transport in the ocean and reconstructing past ocean circulation. A key feature in reproducing their distributions by […]

List of publications

Scroll down to view the list of GEOTRACES publications on dissolved thorium:

31.05.2022

Factsheet #9: Neodymium

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

Atlas

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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 neodymium.

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 neodymium research:

A thorough estimate of the hydrothermal plumes on neodymium concentration and isotope oceanic cycles

Basak and co-workers investigated the influence of particulate matter on neodymium distributions in the Southern East Pacific Rise Hydrothermal Plume.

The development of the modern Antarctic Circumpolar Current occurred much later than previously thought!

This study is challenging the belief that the onset of the Antarctic Circumpolar Current was solely triggered by the opening and deepening of Southern Ocean Gateways.

Overlooked riverine contributions of dissolved neodymium and hafnium to the Amazon estuary and oceans

Xu and colleagues investigated the isotopic composition of dissolved neodymium and hafnium along the entire salinity gradient of the Amazon estuary.

Exhaustive modelling study of the oceanic neodymium parameters

The conclusion of this study reinforces the important role of the solid particles in driving the neodymium oceanic cycle.

Updated compilation of the global continental and marine lithogenic neodymium isotopic measurements

This new compilation and gridded datasets offer a concrete way forward to improve the application of neodymium isotopes as a useful tracer of ocean circulation.

Rare Earth Elements and neodymium isotopes as tracers in the Mediterranean Sea

Garcia-Solsona and co-workers analysed 9 seawater stations around the central Mediterranean Sea

List of publications

Scroll down to view the list of GEOTRACES publications on dissolved neodymium:

31.05.2022

Factsheet #8: Dissolved Nickel

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

Atlas

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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 nickel.

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 nickel research:

What are the drivers of the distributions of cadmium, nickel, zinc, copper and cobalt, manganese and aluminium in the Atlantic Ocean? Two papers are tackling this issue

Chen and co-authors reveal that the distributions of dissolved tracers at depth in the South Atlantic are predominantly controlled by the mixing of North Atlantic Deep Water and waters of Antarctic origin…

Shelf sediments in the Benguela Upwelling System as a major source of trace metals to the shelf and eastern South Atlantic Ocean

Liu and her colleagues investigated dissolved trace metals distributions within the Benguela Upwelling System sampled from GEOTRACES GA08 cruise.

Debate on the dissolved nickel bioavailibility in surface waters

John and co-authors tackle one of the known paradoxes regarding trace metal cycles in the ocean…

Nickel bioactive role in the oceans assessed by its isotopes

Lemaitre and her colleagues realized the simultaneous analysis of the dissolved nickel isotopes and concentrations in the North Atlantic.

Contrasting distributions of dissolved manganese, nickel, cadmium and zinc in the Mediterranean Sea

Extensive trace metal clean sampling during the Dutch GEOTRACES cruise in the Mediterranean Sea allowed Middag and his colleagues to establish the basin scale distribution of these trace metals.

Icebergs as sources of trace metals to the ocean: which impact?

Earth’s Ice Sheets are known to release significant quantities of lithogenic particles into the ocean every year, but how does this material affect trace metal availability in the ocean?

List of publications

Scroll down to view the list of GEOTRACES publications on dissolved nickel:

31.05.2022

Factsheet #7: Dissolved Manganese

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

Atlas

(The images below may not show if you are using Safari. Please change your browser if necessary).

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 manganese.

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 manganese research:

Protactinium-231 budget of the Atlantic sector of Southern Ocean

Levier and colleagues analysed dissolved and particulate protactinium-231 in samples collected in a section in the Southern Ocean…

Intense benthic nepheloid layers in the Northwest Atlantic Ocean lead to unexpected distributions of dissolved and particulate thorium-230 and protactinium-231

Chen and colleagues explore the behaviour of thorium-230 and protactinium-231 in the benthic nepheloid layers…

Measuring actinium-227 by mass spectrometry is feasible, sensitive and reliable!

Levier and co-authors have developed a new protocol measurement of the dissolved actinium in seawater.

Thorium-Protactinium fate across the tropical Atlantic Ocean: what reveals the water column-sediment coupling

Twenty seawater profiles and twenty core-top 231-protactinium and 230-thorium analyses were realised by Ng and colleagues along five depth transects across the northern tropical Atlantic open ocean.

Isopycnal mixing controls protactinium and thorium distributions in the Pacific Southern Ocean

Pavia and co-workers determined the physical and chemical speciation as well as the vertical distribution of Protactinium-231 and Thorium-230 at 12 stations across the Southern Pacific Antarctic Circumpolar Current…

More realistic oceanic particle field improved the thorium-230 and protactinium-231 modeling

Thorium-230 (230Th) and protactinium-231 (231Pa) are two geochemical tracers extensively used for investigating particle transport in the ocean and reconstructing past ocean circulation. A key feature in reproducing their distributions by […]

List of publications

Scroll down to view the list of GEOTRACES publications on dissolved manganese:

31.05.2022

Factsheet #6: Dissolved Cobalt

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

Atlas

(The images below may not show if you are using Safari. Please change your browser if necessary).

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 cobalt.

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 cobalt research:

Protactinium-231 budget of the Atlantic sector of Southern Ocean

Levier and colleagues analysed dissolved and particulate protactinium-231 in samples collected in a section in the Southern Ocean…

Intense benthic nepheloid layers in the Northwest Atlantic Ocean lead to unexpected distributions of dissolved and particulate thorium-230 and protactinium-231

Chen and colleagues explore the behaviour of thorium-230 and protactinium-231 in the benthic nepheloid layers…

Measuring actinium-227 by mass spectrometry is feasible, sensitive and reliable!

Levier and co-authors have developed a new protocol measurement of the dissolved actinium in seawater.

Thorium-Protactinium fate across the tropical Atlantic Ocean: what reveals the water column-sediment coupling

Twenty seawater profiles and twenty core-top 231-protactinium and 230-thorium analyses were realised by Ng and colleagues along five depth transects across the northern tropical Atlantic open ocean.

Isopycnal mixing controls protactinium and thorium distributions in the Pacific Southern Ocean

Pavia and co-workers determined the physical and chemical speciation as well as the vertical distribution of Protactinium-231 and Thorium-230 at 12 stations across the Southern Pacific Antarctic Circumpolar Current…

More realistic oceanic particle field improved the thorium-230 and protactinium-231 modeling

Thorium-230 (230Th) and protactinium-231 (231Pa) are two geochemical tracers extensively used for investigating particle transport in the ocean and reconstructing past ocean circulation. A key feature in reproducing their distributions by […]

List of publications

Scroll down to view the list of GEOTRACES publications on dissolved cobalt:

31.05.2022

Factsheet #5: Dissolved Zinc

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

Atlas

(The images below may not show if you are using Safari. Please change your browser if necessary).

3D scenes showing the distribution of dissolved zinc in the Atlantic and the Pacific. In warm colours (red, orange, etc.) you can view high concentrations of dissolved zinc.

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 zinc research:

Protactinium-231 budget of the Atlantic sector of Southern Ocean

Levier and colleagues analysed dissolved and particulate protactinium-231 in samples collected in a section in the Southern Ocean…

Intense benthic nepheloid layers in the Northwest Atlantic Ocean lead to unexpected distributions of dissolved and particulate thorium-230 and protactinium-231

Chen and colleagues explore the behaviour of thorium-230 and protactinium-231 in the benthic nepheloid layers…

Measuring actinium-227 by mass spectrometry is feasible, sensitive and reliable!

Levier and co-authors have developed a new protocol measurement of the dissolved actinium in seawater.

Thorium-Protactinium fate across the tropical Atlantic Ocean: what reveals the water column-sediment coupling

Twenty seawater profiles and twenty core-top 231-protactinium and 230-thorium analyses were realised by Ng and colleagues along five depth transects across the northern tropical Atlantic open ocean.

Isopycnal mixing controls protactinium and thorium distributions in the Pacific Southern Ocean

Pavia and co-workers determined the physical and chemical speciation as well as the vertical distribution of Protactinium-231 and Thorium-230 at 12 stations across the Southern Pacific Antarctic Circumpolar Current…

More realistic oceanic particle field improved the thorium-230 and protactinium-231 modeling

Thorium-230 (230Th) and protactinium-231 (231Pa) are two geochemical tracers extensively used for investigating particle transport in the ocean and reconstructing past ocean circulation. A key feature in reproducing their distributions by […]

List of publications

Scroll down to view the list of GEOTRACES publications on dissolved iron:

31.05.2022

Factsheet #4: Dissolved Cadmium

Atlas

(The images below may not show if you are using Safari. Please change your browser if necessary).

3D scenes showing the distribution of dissolved cadmium in the Atlantic, Pacific Indian and Arctic Oceans. In warm colours (red, orange, etc.) you can view high concentrations of dissolved Cadium.

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 cadmium research:

What are the drivers of the distributions of cadmium, nickel, zinc, copper and cobalt, manganese and aluminium in the Atlantic Ocean? Two papers are tackling this issue

Chen and co-authors reveal that the distributions of dissolved tracers at depth in the South Atlantic are predominantly controlled by the mixing of North Atlantic Deep Water and waters of Antarctic origin…

Trace metal fluxes of cadmium, copper, lead and zinc from the Congo River into the South Atlantic Ocean are supplemented by atmospheric inputs

Liu and colleagues show that rainfall augments some fluxes of trace metals from the Congo River.

Disentangling what controls the cadmium distribution in the Pacific Ocean

Sieber and his colleagues established the distribution of dissolved cadmium concentrations and isotopes in a section extending from Alaska to Tahiti.

Shelf sediments in the Benguela Upwelling System as a major source of trace metals to the shelf and eastern South Atlantic Ocean

Liu and her colleagues investigated dissolved trace metals distributions within the Benguela Upwelling System sampled from GEOTRACES GA08 cruise.

Contrasting distributions of dissolved manganese, nickel, cadmium and zinc in the Mediterranean Sea

Extensive trace metal clean sampling during the Dutch GEOTRACES cruise in the Mediterranean Sea allowed Middag and his colleagues to establish the basin scale distribution of these trace metals.

Unique winter dataset of particulate and dissolved cadmium in the Indian sector of the Southern Ocean

Cloete and collaborators analysed particulate and dissolved cadmium at 7 stations in austral winter along a North South section off South Africa.

List of publications

Scroll down to view the list of GEOTRACES publications on dissolved cadmium:

30.05.2022

Factsheet #12: Radium isotopes

Naturally occurring radium isotopes allow the study of short and long term processes in the ocean. Radium is produced by the decay of thorium mainly in the sediments but also in the water column. In the ocean, thorium is produced by the decay of uranium directly present in the water column. Thorium have a strong affinity for particles and is adsorbed on the particles. Then thorium is transported to the bottom and slowly accumulates in the sediments. Having an affinity for the dissolved phase, radium, produced in the sediments, diffuses to the water column at the margins and into the deep ocean. Therefore, radium concentrations are generally high near the sediments, in freshwater discharges to the ocean and in circulating waters through the sediments, and are low in the open ocean. Water masses in contact with sediments become enriched in radium. Radium isotopes can be used to trade different processes.

The isotopes radium-224 (224Ra) and radium-223 (223Ra), because of their short half-lives, remain in the ocean about 2 or 3 weeks and 2 months, respectively. They are detected mainly at the interfaces (sediment, surface, margins. . .) and in the first 100 km offshore in the mixed layer. These two isotopes can be used to quantify freshwater discharge fluxes at sea and circulation waters through sediments, to estimate the residence time in the coastal zone, horizontal transports from the coast to the open sea gradient.

Radium-228 (228Ra) has a longer half-life which allows it to reach the open ocean. 228Ra can be measured up to about 30 years after its release from the sediments. The highest activities of 228Ra are observed at the surface due to surface transport from continental margins, rivers, freshwater discharges, and recirculating water in the sediments. Fluxes of 228Ra from springs and, more generally, from continental margins to the open ocean can be converted to fluxes of trace elements such as iron.

Radium-226 (226Ra) has the longest half-life. 226Ra activities increase with depth, which is mainly explained by diffusion from deep sediments. 226Ra activities vary from one basin to another depending on the water masses and their origins. Bottom waters get enriched with 226Ra along the path of the thermohaline circulation between the North Atlantic and the North Pacific. The transit time of water from the North Atlantic to the North Pacific is about 1000 years. This transit time is similar to the half-life of 226Ra and makes it a potential tracer of this global circulation and water masses.

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

Atlas

North Atlantic Ocean:

Pacific Ocean:

3D scenes showing the distribution of dissolved radium-226 and radium-228 in the North Atlantic and the Pacific. In warm colours (red, orange, etc.) you can view high activities of dissolved radium.

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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 radium research:

North-South radium-228 section in the Pacific Ocean

Moore and colleagues present results from radium-228 along the U.S. GEOTRACES Pacific Meridional Transect (GP15).

First direct measurement of actinium (but also radium and thorium) distribution coefficient values in marine sediments

Actinium-227, radium-226 and radium-228 profiles in sediments were measured and modeled at 5 stations in the Northeast Pacific…

A detailed study of the land-ocean input of dissolved iron, manganese and cobalt in the Northeast Atlantic Ocean

Chen and co-authors propose a detailed study of the spatial and seasonal distributions of dissolved iron, manganese and cobalt in the Northeast Atlantic continental margin.

Radium-224 and radium-223: powerful chronometers to estimate the residence time of Amazon waters on the Brazilian continental shelf

In this study, radium is used as a tracer for the waters of the Amazon that mix with those of the Atlantic Ocean.

List of publications

Scroll down to view the list of GEOTRACES publications on radium isotopes:

19.05.2022

Rechercher