[{"command":"openDialog","selector":"#drupal-modal","settings":null,"data":"\u003Cdiv id=\u0022republish_modal_form\u0022\u003E\u003Cform class=\u0022modal-form-example-modal-form ecl-form\u0022 data-drupal-selector=\u0022modal-form-example-modal-form\u0022 action=\u0022\/en\/article\/modal\/6790\u0022 method=\u0022post\u0022 id=\u0022modal-form-example-modal-form\u0022 accept-charset=\u0022UTF-8\u0022\u003E\u003Cp\u003EHorizon articles can be republished for free under the Creative Commons Attribution 4.0 International (CC BY 4.0) licence.\u003C\/p\u003E\n \u003Cp\u003EYou must give appropriate credit. We ask you to do this by:\u003Cbr \/\u003E\n 1) Using the original journalist\u0027s byline\u003Cbr \/\u003E\n 2) Linking back to our original story\u003Cbr \/\u003E\n 3) Using the following text in the footer: This article was originally published in \u003Ca href=\u0027#\u0027\u003EHorizon, the EU Research and Innovation magazine\u003C\/a\u003E\u003C\/p\u003E\n \u003Cp\u003ESee our full republication guidelines \u003Ca href=\u0027\/horizon-magazine\/republish-our-stories\u0027\u003Ehere\u003C\/a\u003E\u003C\/p\u003E\n \u003Cp\u003EHTML for this article, including the attribution and page view counter, is below:\u003C\/p\u003E\u003Cdiv class=\u0022js-form-item form-item js-form-type-textarea form-item-body-content js-form-item-body-content ecl-form-group ecl-form-group--text-area form-no-label ecl-u-mv-m\u0022\u003E\n \n\u003Cdiv\u003E\n \u003Ctextarea data-drupal-selector=\u0022edit-body-content\u0022 aria-describedby=\u0022edit-body-content--description\u0022 id=\u0022edit-body-content\u0022 name=\u0022body_content\u0022 rows=\u00225\u0022 cols=\u002260\u0022 class=\u0022form-textarea ecl-text-area\u0022\u003E\u003Ch2\u003EWarmer, saltier polar water could change global ocean currents\u003C\/h2\u003E\u003Cp\u003EAt the North and South Poles, cold dense water sinks, powering the so-called \u003Ca href=\u0022https:\/\/horizon-magazine.eu\/article\/new-alliance-ocean-scientists-reveal-climate-change-impacts_en.html\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003Eglobal ocean conveyor belt\u003C\/a\u003E, a complex system reliant on heat transfer and density that drives ocean currents throughout the world.\u003C\/p\u003E\u003Cp\u003EThis system regulates regional climates but is threatened when large amounts of freshwater \u2013 such as glacial ice \u2013 fall into the sea. Ice shelf melt means that more\u0026nbsp;glacial ice will be dumped into the ocean, and this\u0026nbsp;risks switching off the conveyor belt, because\u0026nbsp;diluted, less dense\u0026nbsp;saltwater\u0026nbsp;is less likely to sink.\u003C\/p\u003E\u003Cp\u003EIn the Antarctic, at depths between 500 and 2000 metres, a surprisingly warm salty water mass can be found, called Circumpolar Deep Water. At certain points under Antarctica, this warm water comes into contact with the underside of the ice shelves and melts the ice. If more warm salty water is reaching the bottom of the ice shelves than in previous years, this could fuel an increase in ice-shelf melt.\u003C\/p\u003E\u003Cp\u003EDr Laura Herraiz Borreguero of the University of Southampton, UK, and coordinator of the OCEANIS project, is tracking the movements of this warm salty current, to see if there are any fluctuations or changes compared to previous years.\u003C\/p\u003E\u003Cp\u003EBy analysing and comparing data collected by other researchers, she has discovered that in the last 20 years, the warm salty water current has become more commonly found. The effects are even more pronounced in the inhospitable East Antarctica region, a part of the continent that is generally less well-researched than West Antarctica, as it\u2019s much more difficult to access.\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ESpeed bumps\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EBecause ice shelves act as speed bumps for glacial ice flow and slow down the rate at which Antarctic glaciers reach the sea, an increase in ice-shelf melt would mean that glaciers could dump vast amounts of freshwater ice into the ocean unchecked.\u003C\/p\u003E\u003Cp\u003E\u2018If we lose (the ice shelves), the speed of the glaciers could be four to five times faster,\u2019 said Dr Herraiz Borreguero.\u003C\/p\u003E\u003Cp\u003EHer next challenge is to determine precisely what impact the change in circumpolar deep water will have. \u2018What I\u2019m looking at now is how this alters the properties of the water around Antarctica, also in relation to the Southern Ocean circulation,\u2019 she said. \u2018Improving our knowledge of ice shelf-ocean interactions is a critical step toward reducing uncertainty in projections of future sea level rise.\u2019\u003C\/p\u003E\u003Cp\u003EOcean circulation is also being studied by Dr Melanie Grenier of the Centre National de la Recherche Scientifique (CNRS), France, who coordinates the GCP-GEOTARCTIC project. The project is part of a multinational collaborative effort called GEOTRACES that aims to better understand global ocean circulation and marine cycles by examining the distribution of dissolved and particulate chemical elements suspended in the water column.\u003C\/p\u003E\u003Cp\u003E\u003Cblockquote class=\u0022tw-text-center tw-text-blue tw-font-bold tw-text-2xl lg:tw-w-1\/2 tw-border-2 tw-border-blue tw-p-12 tw-my-8 lg:tw-m-12 lg:tw--ml-16 tw-float-left\u0022\u003E\n \u003Cspan class=\u0022tw-text-5xl tw-rotate-180\u0022\u003E\u201c\u003C\/span\u003E\n \u003Cp class=\u0022tw-font-serif tw-italic\u0022\u003E\u2018If we lose (the ice shelves), the speed of the glaciers could be four to five times faster.\u0026#039;\u003C\/p\u003E\n \u003Cfooter\u003E\n \u003Ccite class=\u0022tw-not-italic tw-font-normal tw-text-sm tw-text-black\u0022\u003EDr Laura Herraiz Borreguero, University of Southampton, UK\u003C\/cite\u003E\n \u003C\/footer\u003E\n\u003C\/blockquote\u003E\n\u003C\/p\u003E\u003Cp\u003EParticle concentrations, distributions and exchanges can tell scientists a lot about what\u2019s going on in the water column. Certain water masses have distinct properties, for example being nutrient-rich, or nutrient-poor, warm, cold, salty or fresh.\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EThorium-230\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EDr Grenier uses a chemical tracer called thorium-230 to monitor the volume of particles and has found that the composition of water at the North Pole is changing. \u2018The Amerasian Arctic exhibits lower concentrations of this geochemical tracer than in the past, consistent with the increasing trend of sea ice retreat and a subsequent increase of particle concentrations.\u2019\u003C\/p\u003E\u003Cp\u003EOne of the reasons for this is a decrease in ice cover. Less ice means that more light can enter the ocean and that more life can develop, leading to an increase of marine particles. Less ice also means more interaction with the atmosphere, notably with the wind, which can increase the mixing in the ocean, and so particles lying in the sediment are re-suspended into the water column.\u003C\/p\u003E\u003Cp\u003EWhile this is not necessarily damaging by itself, it is indicative of changes in ocean circulation and could affect the global ocean conveyor belt. However, it\u2019s not known how sensitive that system might be to change, so scientists will have to continue to monitor the situation.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EBoth OCEANIS and GCP-GEOTARCTIC intend to create maps based on their research \u2013 for OCEANIS, detailing the points where warm water reaches Antarctic ice shelves, and for GCP-GEOTARCTIC, a map of global thorium-230 distribution, with input from other GEOTRACES scientists.\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EModels\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EThese will be used to develop better-informed models to predict how the planet should react to changes in climate. The models are also being enhanced by researchers who are aligning climate records from marine sediments and ice by using fine particles of volcanic ash as a common thread.\u003C\/p\u003E\u003Cp\u003EVertical cylinders of marine sediment and ice, known as cores, are used by geologists to determine what past climates were like. As ice freezes or sediment settles, they trap air, particles and fossils that provide clues to the climate at that time. But, it can be difficult to match a particular piece of a marine sediment core to the corresponding time period of an ice core.\u003C\/p\u003E\u003Cp\u003EDr Peter Abbott of Cardiff University, UK, and the University of Bern, Switzerland, runs a project called SHARP to develop a method of doing just that.\u003C\/p\u003E\u003Cp\u003E\u003Cfigure role=\u0022group\u0022 class=\u0022@alignleft@\u0022\u003E\n\u003Cimg alt=\u0022Particles of ash from ancient volcanic eruptions are helping tie together climate records from different sources. Image Credit -\u0026nbsp;National Science Foundation\/Josh Landis\u0026nbsp;\u0022 height=\u0022656\u0022 src=\u0022https:\/\/horizon-magazine.eu\/research-and-innovation\/sites\/default\/files\/hm\/Mount%20Erebus_0.jpg\u0022 title=\u0022Particles of ash from ancient volcanic eruptions are helping tie together climate records from different sources. Image Credit -\u0026nbsp;National Science Foundation\/Josh Landis\u0026nbsp;\u0022 width=\u00221000\u0022\u003E\n\u003Cfigcaption class=\u0022tw-italic tw-mb-4\u0022\u003EParticles of ash from ancient volcanic eruptions are helping tie together climate records from different sources. Image Credit -\u0026nbsp;National Science Foundation\/Josh Landis\u0026nbsp;\u003C\/figcaption\u003E\n\u003C\/figure\u003E\n\u003C\/p\u003E\u003Cp\u003E\u2018The technique that I\u2019m using is called tephrochronology,\u2019 he said. \u2018We trace particles from past volcanic eruptions between the ice and the marine cores. If you can find the same eruption, then it can act as a tie-line between those records as the particles were deposited at the same time in both environments.\u2019\u003C\/p\u003E\u003Cp\u003EDr Abbott uses laboratory methods and optical microscopy to scan the cores and identify ash layers hidden within the ice and marine cores. Each individual volcanic event leaves a unique chemical fingerprint on the material it expels, which means researchers can use the ash to correctly match up the ice cores and the sediment cores, giving scientists more accurate information about past climates, and consequently improving the predictive models.\u003C\/p\u003E\u003Cp\u003E\u2018If we can explain how the climate has changed in the past, it gives us a better understanding of how it might be forced in the future,\u2019 said Dr Abbott.\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EAll research in this article is funded by the EU. 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