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Message: <blockquote data-quote="ibnanv" data-source="post: 21753537" data-attributes="member: 218596">Mangrove forests could play a crucial role in  protecting coastal areas from sea level rise caused by climate change,  according to new research involving the University of Southampton.A joint study between researchers at the University of Southampton  along with colleagues from the Universities of Auckland and Waikato in  New Zealand used leading-edge mathematical simulations to study how  mangrove forests respond to elevated sea levels.  Taking New Zealand mangrove data as the basis of a new modelling  system, the team were able to predict what will happen to different  types of estuaries and river deltas when sea levels rise.  They found areas without mangroves are likely to widen from erosion  and more water will encroach inwards, whereas mangrove regions prevent  this effect -- which is likely due to soil building up around their  mesh-like roots and acting to reduce energy from waves and tidal  currents.  Coastal estuaries and recesses in coastlines that form bays receive  the run-off from erosion on steep catchments, which give them the  tendency to fill in over time. As they infill, the movement of the tidal  currents over the shallow areas create networks of sandbanks and  channels. The sand banks grow upward to keep pace with water-level  changes, while the channels get deeper to efficiently drain the excess  water out to sea.  The researchers' latest work shows that mangroves can facilitate this  process, by adding leaf and root structures into the accumulating  sediment, which increase the elevation while enhancing the trapping of  new sediment arriving from the catchment. Dr Barend van Maanen from the University of Southampton explains: "As  a mangrove forest begins to develop, the creation of a network of  channels is relatively fast. Tidal currents, sediment transport and  mangroves significantly modify the estuarine environment, creating a  dense channel network. "Within the mangrove forest, these channels become shallower through  organic matter from the trees, reduced sediment resuspensions (caused by  the mangroves) and sediment trapping (also caused by the mangroves) and  the sea bed begins to rise, with bed elevation increasing a few  millimetres per year until the area is no longer inundated by the tide." In modelling of sea level rise in the study, the ability of mangrove  forest to gradually create a buffer between sea and land occurs even  when the area is subjected to potential sea level rises of up to 0.5mm  per year. Even after sea level rise, the mangroves showed an enhanced  ability to maintain an elevation in the upper intertidal zone. Associate Professor Karin Bryan, from the University of Waikato, says  the spread of mangroves is changing the New Zealand coastal landscape.  "In New Zealand, mangroves have been traditionally viewed as undesirable  as they take over areas where there were once sandy beaches. In other  countries, this is not the case as they are seen as a buffer for climate  change in low level areas."  "Now we know that they also could play a critical role in buffering  our coastal land from the effects of sea-level rise. Although the study  is on Avicennia marina (the only species of mangrove that occurs in New  Zealand), Avicennia occurs in every major mangrove habitat in the  world."  Overseas studies have shown mangroves have the ability to remove  carbon from the atmosphere and protect people from hazards such as  tsunami. The research team hopes that this work will enhance the case  for protecting global fringing wetlands from the threats of drainage and  clearance caused by development and aquaculture pressures. "These findings show that mangrove forests play a central role in  estuarine and salt marsh environments," Associate Professor Giovanni  Coco from the University of Auckland says. "As we anticipate changes  caused by climate change, it's important to know the effect sea level  rise might have, particularly around our coasts."Mangroves appear to be resilient to sea level rise and are likely to  be able to sustain such climatic change. The implications for the New  Zealand coastline are considerable and will require new thinking in  terms of sediment budgets and response to climatic changes."<a href="https://www.sciencedaily.com/releases/2015/07/150723083855.htm" target="_blank">https://www.sciencedaily.com/releases/2015/07/150723083855.htm</a></blockquote>

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