Two distinct microtidal estuarine systems were assessed to advance the understanding of the coastal dynamics of sea level rise in salt marshes. A coupled hydrodynamic-marsh model (Hydro-MEM) was applied to both a marine-dominated (Grand Bay, Mississippi) and a mixed fluvial/marine (Weeks Bay, Alabama) system to compute marsh productivity, marsh migration, and potential tidal inundation from the year 2000 to 2100 under four sea level rise scenarios. Characteristics of the estuaries such as geometry, sediment availability, and topography, were compared to understand their role in the dynamic response to sea level rise. The results show that the low sea level rise scenario (20 cm) approximately doubled high-productivity marsh coverage in the marine-dominated estuary by the year 2100 due to an equilibrium between the rates of sea level rise and marsh platform accretion. Under intermediate-low sea level rise (50 cm), high-productivity marsh coverage in the year 2100 increased (doubled in the marine-dominated estuary and a seven-fold increase in the mixed estuary) by expanding into higher lands followed by the creation of interior ponds. The results also indicate that marine-dominated estuaries are vulnerable to collapse as a result of low, relatively uniform topography and lack of sediment sources, whereas mixed estuaries are able to expand due to higher elevations and sediment inputs. The results from the higher sea level rise scenarios (the intermediate-high (120 cm) and high (200 cm)) showed expansion of the bays along with marsh migration to higher land, producing a five-fold increase in wetland coverage for the mixed estuary and virtually no net change for the marine-dominated estuary. Additionally, hurricane storm surge simulations showed that under higher sea level rise scenarios, the marine-dominated estuary demonstrated weaker peak stage attenuation indicating that the marsh’s ability to dissipate storm surge is sensitive to productivity changes and bay expansion / marsh loss.

The Indo-Pacific lionfish Pterois volitans has invaded western Atlantic Ocean coastal habitats over the past 2 decades and has the potential to cause major ecological changes in reef fish communities. While many aspects of lionfish ecology in their invaded range have been examined, there is a paucity of information on movements of lionfish, particularly adults. We surgically implanted ultrasonic transmitters into 25 lionfish at a natural hard bottom area off North Carolina (USA) in December 2008 and February 2009, and used an array of remote underwater receivers to monitor movements in the study area for up to 6 mo. We also affixed a control transmitter in the study area to assess changes in transmitter detection rate as a function of multiple variables, and used a generalized additive model to show that the control transmitter detection rate declined with time, increasing water temperature, and increasing wave period. Despite variable detection probabilities, we found that telemetered lionfish remaining in the study area displayed high site fidelity to areas no broader than 400 m in diameter; daily movements were nearly always <150 m. By estimating variable detection rates of transmitters and lionfish movements, we provided information that can be useful in understanding the spatial scale of lionfish impact and developing management or mitigation strategies for this invasive species.

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