AUTOCOMPACTION RATES OF THE HOLOCENE STRATUM OF THE PEARL RIVER MARSH

The Louisiana gulf coast is losing acres of valuable coastal land every day. In the last 70 years, Louisiana has lost more than 1.2million acres of coastal wetlands and the U.S. Geological Survey predicts that another 448,000 acres will vanish over next 50 years. Many complex and inter-related factors and processes contribute to the loss of Louisiana marsh and wetlands, including sea level rise, sediment starvation, natural resource harvesting, and fluid withdrawal. An important, but poorly constrained, contributing factor is the natural process of autocompaction of Holocene stratum. Focusing on shallow sediment compaction of the Holocene stratum, physical soil parameters will be both measured and calculated to determine the major factor or factors driving autocompaction on a site specific basis. My hypothesis is autocompaction rates in the Pearl River Marsh can be determined by iterative measurements on a centimeter by centimeter scale yielding high resolution compaction rates of the upper Holocene stratum. This method does not require a common datum to be shared by all cores and instead will utilize fall out isotopes for dating of sediments. An empirical formula will be developed to identify those locations where autocompaction rates are highest, lowest, and static by analyses of bulk density, initial porosity, soil texture, organic matter content, and water content. These results can be applied to wider areas to ascertain the overall autocompaction of the Pearl River Marsh with the collection of more cores.