Recently sampled locations on the SEALS expedition.
Follow R/V Roger Revelle on Marine Traffic.
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Trace elements in the ocean serve a variety of critical functions: some act as essential micronutrients for marine life, others serve as indicators of oceanic processes, and some are harmful pollutants that can endanger ecosystems and human health. Understanding the factors that govern the large-scale distribution and internal cycling of these trace elements is therefore vital. In this expedition we will be quantifying and characterizing flux of iron and Rare Earth Elements (REEs) from the Labrador and Greenland coasts. |
Map showing planned cruise path - Woods Hole, USA to Reykjavík, Iceland
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Why North Atlantic?
The North Atlantic plays a critical role in global climate through the Atlantic Meridional Overturning Circulation (AMOC). The AMOC is a key part of the large-scale system of interconnected ocean currents that circulate water, heat, nutrients, carbon and oxygen throughout the world's oceans. It is driven by heat exchange with the atmosphere—as warm surface water moves northward, the ocean cools and the atmosphere warms. This causes cold, dense surface water in the Labrador Sea and other areas of the North Atlantic to sink and form deep water that flows southward. In addition to physically driving global oceanic circulation, this deep water controls climate and marine biogeochemistry by sequestering carbon from the atmosphere and oxygenating the deep ocean. Therefore, what happens in the North Atlantic does not stay in the North Atlantic and this region has global significance for Earth’s climate.
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Primary research objectives
1. Explore sources and sinks of Rare Earth Elements in the North Atlantic
The REEs are comprised of 15 elements on the periodic table ranging from atomic number 57 to 71, plus Yttrium and Scandium, and are referred to as the “lanthanides.” REEs or ‘technology metals’ are becoming increasingly important due to their use in modern-day technology, including uses in healthcare, telecommunication, and defense. Yet, the sources and sinks of REEs in the global ocean is relatively understudied. Marine sediments at the bottom of the ocean are often explored as a potential REE resource. During this expedition we will collect sediment cores along the cruise transect to extract porewaters to estimate REE flux form the sediment. We will also collect water column, suspended particulates, and aerosol samples to estimate all probable sources and sinks of REEs to the North Atlantic.
Neodymium (Nd) is one of REEs that has gained significant attention due to its use in manufacturing powerful magnets. However, Nd has other important applications as well—for example, isotopes of Nd measured in marine archives (such as fossil fish teeth found in marine sediments) can provide insights into how deep ocean circulation has changed over geological time. As we evaluate new sources and sinks of REEs, we will revisit and refine our current understanding of how Nd isotopes are used to study past deep ocean circulation.
2. Investigate fluxes of nutrient iron from continental shelf sediments to the Labrador Sea
The ocean is one of the largest sinks of atmospheric carbon dioxide in the Earth system and therefore plays a critical role in influencing global climate. In regions of deep water formation like the Labrador Sea, phytoplankton photosynthesis in the surface water can lead to long-term sequestration of carbon as newly formed deep water flows south and becomes isolated from the atmosphere. The deep wintertime mixing in this area also provides a route for nutrients like iron (Fe) from the seafloor to reach the surface and fertilize phytoplankton growth. In certain regions and seasons in the Labrador Sea, the availability of Fe is thought to be an important control on phytoplankton growth; therefore, even small changes in Fe sources or sinks can have significant impacts on primary productivity. Despite past evidence that shelf sediments are a source of iron to the Labrador Sea system, the biogeochemical cycling of iron in the sediments and associated benthic fluxes have not been investigated in this area. In this expedition, we aim to quantify fluxes of iron from the seafloor to the water column and explore the biogeochemical and physical controls on the release and transport of benthic iron in the Labrador Sea.
The REEs are comprised of 15 elements on the periodic table ranging from atomic number 57 to 71, plus Yttrium and Scandium, and are referred to as the “lanthanides.” REEs or ‘technology metals’ are becoming increasingly important due to their use in modern-day technology, including uses in healthcare, telecommunication, and defense. Yet, the sources and sinks of REEs in the global ocean is relatively understudied. Marine sediments at the bottom of the ocean are often explored as a potential REE resource. During this expedition we will collect sediment cores along the cruise transect to extract porewaters to estimate REE flux form the sediment. We will also collect water column, suspended particulates, and aerosol samples to estimate all probable sources and sinks of REEs to the North Atlantic.
Neodymium (Nd) is one of REEs that has gained significant attention due to its use in manufacturing powerful magnets. However, Nd has other important applications as well—for example, isotopes of Nd measured in marine archives (such as fossil fish teeth found in marine sediments) can provide insights into how deep ocean circulation has changed over geological time. As we evaluate new sources and sinks of REEs, we will revisit and refine our current understanding of how Nd isotopes are used to study past deep ocean circulation.
2. Investigate fluxes of nutrient iron from continental shelf sediments to the Labrador Sea
The ocean is one of the largest sinks of atmospheric carbon dioxide in the Earth system and therefore plays a critical role in influencing global climate. In regions of deep water formation like the Labrador Sea, phytoplankton photosynthesis in the surface water can lead to long-term sequestration of carbon as newly formed deep water flows south and becomes isolated from the atmosphere. The deep wintertime mixing in this area also provides a route for nutrients like iron (Fe) from the seafloor to reach the surface and fertilize phytoplankton growth. In certain regions and seasons in the Labrador Sea, the availability of Fe is thought to be an important control on phytoplankton growth; therefore, even small changes in Fe sources or sinks can have significant impacts on primary productivity. Despite past evidence that shelf sediments are a source of iron to the Labrador Sea system, the biogeochemical cycling of iron in the sediments and associated benthic fluxes have not been investigated in this area. In this expedition, we aim to quantify fluxes of iron from the seafloor to the water column and explore the biogeochemical and physical controls on the release and transport of benthic iron in the Labrador Sea.