Iron travels "hitchhiking"

Nanocomplexes from bogs transport the trace element into the sea

Algae blooms in the sea © NASA GSFC
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No life without iron. In particular, seaweed, which is so important for global CO2 depletion, uses the trace element for its photosynthesis. The origin of the iron dissolved in seawater was previously unclear, but now a research team has gone on the search for clues and found what they are looking for: in bogs.

Whether or not the much-discussed climate change is to be halted ultimately determines the functionality of those regulatory mechanisms that control the global carbon cycle. An important element in this cycle is diatoms, which account for 20 percent of global photosynthesis and thus contribute significantly to CO2 degradation. In order to absorb CO2, the algae need the trace element iron. However, this is in short supply in the sea.

How does the iron get into the sea?

Seawater contains a little bit of iron, but not enough. "So we ask ourselves: how does the iron get into the sea?", Explains Professor Regina Krachler from the University of Vienna, head of the biogeochemical research project. Investigations showed that the iron enters the sea naturally either through rain or through river water.

Rivers more important than expected

"So far, it has been assumed that rivers do not play a role in the iron supply of the sea, because the iron particles that are washed out of the ground and float in the river water, flocculate as soon as they come into contact with seawater and settle in the estuary" explains Krachler. But researchers from the US recently found complex-bound iron in the open sea, which must come from riverine waters. "Moors with peat moss are particularly suitable for the production of such complex molecules that strongly bind iron, " says Krachler.

Nanoparticles piggyback on iron

A team from the Institute of Inorganic Chemistry then set out to investigate Moore in Scotland in this regard. In the bogs, the scientists discovered that bioinorganic substances involved in weathering processes have such highly complex structures that they bind the trace element iron and transport it to the sea. display

"Our project proves that moors play a major role in climate regulation and that we need to quickly protect these critically endangered habitats, " explains the researcher. Now, Krachler and her team are collecting samples of various bog waters in Austria to find out exactly which particles are capable of carrying the iron out into the sea. The research team hopes to be able to make an important contribution to climate protection. However, the chemist does not think much of the artificial release of the trace element, which is discussed in connection with climate change, because such interventions severely disrupt the natural cycles.

(University of Vienna, 12.07.2007 - NPO)