Engineering and design of the Lightning Point Shoreline Restoration Project in Bayou La Batre, Alabama

Lightning Point, located in Alabama at the confluence of the Bayou La Batre navigation channel and Mississippi Sound, is a culturally and ecologically valuable site with an extensive history of shoreline erosion. Between 1916 and 2019, the shoreline experienced approximately 750 to 1,000 ft of shoreline retreat as a result of severe weather events and anthropogenic causes such as shoreline modification and response efforts related to the Deepwater Horizon oil spill. Moffatt & Nichol worked with The Nature Conservancy to restore the lost habitat and resources through ecology-based engineering and design. The Lightning Point Shoreline Restoration Project is a 1-milelong living shoreline that includes approximately 4,700 ft of segmented, overlapping breakwaters, 40 acres of marsh and upland habitat creation, and 10,000 linear feet of tidal creeks. The project was designed to include a diversity of habitat types (subtidal, intertidal, higher scrub-shrub) and to serve as a resilient restoration solution capable of adapting in the face of sea level rise and increasing storm activity.

Occurrence of Microplastic Pollution at Oyster Reefs and Other Coastal Sites in the Mississippi Sound, USA: Impacts of Freshwater Inflows from Flooding

Much of the seafood that humans consume comes from estuaries and coastal areas where microplastics (MPs) accumulate, due in part to continual input and degradation of plastic litter from rivers and runoff. As filter feeders, oysters (Crassostrea virginica) are especially vulnerable to MP pollution. In this study, we assessed MP pollution in water at oyster reefs along the Mississippi Gulf Coast when: (1) historic flooding of the Mississippi River caused the Bonnet Carré Spillway to remain open for a record period of time causing major freshwater intrusion to the area and deleterious impacts on the species and (2) the spillway was closed, and normal salinity conditions resumed. Microplastics (~25 µm–5 mm) were isolated using a single-pot method, preparing samples in the same vessel (Mason jars) used for their collection right up until the MPs were transferred onto filters for analyses. The MPs were quantified using Nile Red fluorescence detection and identified using laser direct infrared (LDIR) analysis. Concentrations ranged from ~12 to 381 particles/L and tended to decrease at sites impacted by major freshwater intrusion. With the spillway open, average MP concentrations were positively correlated with salinity (r = 0.87, p = 0.05) for sites with three or more samples examined. However, the dilution effect on MP abundances was temporary, and oyster yields suffered from the extended periods of lower salinity. There were no significant changes in the relative distribution of MPs during freshwater intrusions; most of the MPs (>50%) were in the lower size fraction (~25–90 µm) and consisted mostly of fragments (~84%), followed by fibers (~11%) and beads (~5%). The most prevalent plastic was polyester, followed by acrylates/polyurethanes, polyamide, polypropylene, polyethylene, and polyacetal. Overall, this work provides much-needed empirical data on the abundances, morphologies, and types of MPs that oysters are exposed to in the Mississippi Sound, although how much of these MPs are ingested and their impacts on the organisms deserves further scrutiny. This paper is believed to be the first major application of LDIR to the analysis of MPs in natural waters.

Field of dreams: Restoring estuarine habitat and structure in Mississippi after the Deepwater Horizon oil spill

This paper presents a Mississippi Department of Marine Resources (MDMR), Office of Coastal Restoration and Resiliency, perspective on adaptation and innovation in restoration permitting, collaboration, and design in an era shaped by the Deepwater Horizon oil spill (DWH). These adaptations and innovations lay groundwork to support Mississippi’s future address of challenges stemming from its ongoing geomorphic evolution and loss of primary landforms. The Round Island project in Jackson County, Mississippi (MS), will serve as a principal example. Completed through the efforts of four agencies via a Memorandum of Understanding (MOU) and funded by the National Fish and Wildlife Foundation (NFWF) this project helped break a long-standing practice of dumping large quantities of federal navigation channel dredged materials in an Offshore Dredged Material Disposal Site (ODMDS). Not only were 220 acres of new island and marsh habitat created in the Mississippi Sound, the Round Island project saved millions in federal navigation dollars because it could be more efficiently accessed than the ODMDS site. The Round Island project represents a collective, multi-agency step toward strategic scale, nature-based approaches more capable of managing Mississippi’s burgeoning restoration and resource needs.