Processes Governing Coastal Marsh Stability

The major processes involved in marsh stability dynamics within Louisiana coastal wetlands are 

Eustatic sea-level rise, or global changes in the sea level because of changes in the mass of water in oceans, ocean volumes, and temperature changes. 

Compaction of deep sediments (except Holocene sediments) includes both tectonic downwarping of basement sediments and compaction of Tertiary, Pleistocene, and older sediments. Tectonic downwarping is probably the only factor in major depositional areas such as large deltas, where the loads from massive amounts of sediments cause the bottom of the sedimentary basin to warp. In most studies of modern sediments, very little is known about this factor, so it is often treated as an unknown or something outside of the system. 

Compaction of Holocene sediments includes dewatering of sediments (primary consolidation), rearrangement of mineral structure of the sediment and subsequent loss of volume (secondary consolidation), and the decomposition of organic matter in the sediment. This is the most important process affecting subsidence in Louisiana coastal areas however, it is a very difficult process to evaluate. 

Marsh accretion is the vertical accumulation of material (organic matter and mineral sediment) on the surface of a marsh. 

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List the main processes governing coastal marsh stability. 

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