Sediment and Soil Dynamics In Mangrove Ecosystems of Florida.

Mangrove ecosystems are among the most well-described tidal forest communities in the world.  Their position at the ocean’s rim suggests they are vulnerable to sea-level rise and persistent storms.  While mangroves are impacted by both types of stressors, they are also highly resistant to natural stress under many circumstances.  The largest real threats to mangrove persistence are deforestation and anything that can compromise the integrity of underlying soils.  Indeed, because decomposition of organic matter in mangrove soils can proceed so slowly, these systems often serve as long-term sinks for organic carbon; carbon market prospectors have sought to develop business opportunities from the carbon sink nature of these habitats even as scientists try to unravel the underlying processes.  Mangrove soils develop in a number of contrasting ways, from expanding atop deposited sediments in true “floodplain” fashion to building successive generations of highly organic peat soils that pace sea-level rise.  In this talk, we will provide a general overview of mangrove sediment and soil dynamics accumulated from current studies.  To provide context, we will describe specific mangrove communities developing on different geomorphic settings in Florida that are subjected to a variety of controls over soil and surface elevation change (e.g., Ten Thousand Islands, Rookery Bay, Everglades National Park).  We will close by describing a study in Tampa Bay that examines soil development and elevation change at nine restored mangrove sites that vary in age from 3-20 years.  Overall, this talk will provide an overview of several processes (e.g., sedimentation, groundwater dynamics, root growth) that control soil and surface elevation change in mangroves of Florida while providing some insight into which substrates and hydrological regimes have good future potential for sequestering carbon in soils.