Editing IPCC:AR6/SROCC/Chapter-4 (section)

===== 4.3.3.5.3 Seagrasses =====

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Due to their natural capacity to enhance accretion and in the absence of mechanical or chemical destruction by human activities, seagrasses are not expected to be severely affected by SLR, except indirectly through the increase of the impacts of extreme weather events and waves on coastal morphology (i.e., erosion) as well as through changes in light levels and through effects on adjacent ecosystems (Saunders et al., 2013 <sup>[[#fn:r1313|1313]]</sup> ). Extreme ﬂooding events have also been shown to cause large-scale losses of seagrass habitats (Bandeira and Gell, 2003 <sup>[[#fn:r1314|1314]]</sup> ), for example seagrasses in Queensland, Australia, were lost in a disastrous ﬂooding event (Campbell and McKenzie, 2004 <sup>[[#fn:r1315|1315]]</sup> ). Changes in ocean currents can have either positive or negative effects on seagrasses, creating new space for seagrasses to grow or eroding seagrass beds (Bjork et al., 2008 <sup>[[#fn:r1316|1316]]</sup> ). But overall, seagrass will primarily be negatively affected by the direct effects of increased sea temperature on growth rates and the occurrence of disease (Marba and Duarte, 2010 <sup>[[#fn:r1317|1317]]</sup> ; Burge et al., 2013 <sup>[[#fn:r1318|1318]]</sup> ; Koch et al., 2013 <sup>[[#fn:r1319|1319]]</sup> ; Thompson et al., 2015 <sup>[[#fn:r1320|1320]]</sup> ; Chefaoui et al., 2018 <sup>[[#fn:r1321|1321]]</sup> ; Gattuso et al., 2018 <sup>[[#fn:r1322|1322]]</sup> ; Section 5.3.2) as well as by heavy rains that may dilute the seawater to a lower salinity. Such impacts will be exacerbated by major causes of seagrass decline including coastal eutrophication, siltation and coastal development (Waycott et al., 2009 <sup>[[#fn:r1323|1323]]</sup> ). Noteworthy is that some positive impacts are expected, as ocean acidification is expected to benefit photosynthesis and growth rates of seagrass (Repolho et al., 2017 <sup>[[#fn:r1324|1324]]</sup> ).

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