Researchers have found a way to chart changes in the speed of deep-ocean currents using the most modest of materials – mud. The approach, reported in the journal Deep-Sea Research Part I, could provide scientists with a better basis for understanding the behaviour of ancient ocean currents and, in an age of mounting apprehension over climate change, could help them to judge what level of fluctuation can be considered cause for concern.
(From Phys.org) — Acting like giant conveyor belts, ocean currents transport water warmed by the sun’s powerful rays over the equator towards the poles. As the water cools and releases its warmth into the atmosphere, areas in the North and South benefit from the warm air. In turn, currents regulate temperatures along the equator by offering an escape route for some of the heat.
The speed of ocean currents is hugely variable, but scientists are increasingly concerned that man-made climate change is altering their natural flow. If rising sea temperatures and increased levels of fresh water from melting ice caps slow down currents, this could wreak havoc on global weather systems and impede the vital role they play in counteracting the uneven distribution of solar radiation that reaches the Earth’s surface.
In order to fully understand what is happening to currents today and whether it is extraordinary, researchers need to build a picture of how they have behaved over time.
Modern current meters made from steel and plastic have only been widely used to track currents far beneath the surface since the 1960s, so to get a sense of how currents naturally fluctuate over long periods, scientists rely on proxies – such as changes over time in the natural radioactivity of particles.
Now, new research led by Professor Nick McCave, Fellow at St John’s College and Emeritus Professor at the Department of Earth Sciences, University of Cambridge, has found a way to use the size of mud particles deposited on the ocean floor to measure changes in the speed at which ocean currents flow, offering another means for scientists to identify patterns in ancient current speeds.
Read the full article here: https://phys.org/news/2017-09-deep-ocean-currents-modest-materialsmud.html#jCp