How Mangroves Respond to Hypersaline Condition? Preparedness for Predicted Sea Level Rise

TLDR: In this article, the authors highlighted a case study of adaptation of five different mangrove species to increasing salinity in the tiger dominated Indian Sundarbans of lower Gangetic region.

Abstract: Climate change has several components of varied nature and scale that influences the coastal vegetation. For mangroves, however, the most relevant components include changes in sea level, high water events, stormi- ness, precipitation, temperature, atmospheric CO2 concentration, ocean circulation patterns, health of functionally linked neighbour- ing ecosystems, as well as human responses to climate change. Of all the outcomes from changes in the atmosphere's composition and alterations to land surfaces, relative sea level rise is the greatest threat to mangroves. The adverse effect gets much more magnified if the mangrove flora is freshwater loving in nature like Heritiera fomes, Sonneratia apetala or Nypa fruticans. The rising sea level in- creases the salinity of the ambient water and soil, which poses a negative impact on the growth and physiological set-up of mangroves. The present paper highlights a case study of adaptation of five different mangrove species to increasing salinity in the tiger dominated Indian Sundarbans of lower Gangetic region. Along with the growth rate of the species in natural conditions, their pigment systems have also been analysed with respect to changing salinity levels. The results of the present study can be extrapolated to predict the effect of climate change induced sea level rise in Indian Sundarbans region on mangrove vegetation. The ecological value of the system in terms of carbon sequestration has also been highlighted since salt marshes, mangroves, and seagrasses store ten times more car- bon in their soils per hectare than temperate forests and fifty times more than tropical forests. Some management action plans (like regular dredging of the accumulated silt, interlinking of rivers etc.) have also been discussed to restore the mangrove system from the adverse impact of hypersalinization.