Restoring Saltwater Flats

A recent study from the University of Queensland in Australia, released through the online scientific journal PLOSone, has analyzed the most effective methods for restoring near shore marine environments that have been affected by various human caused — or, anthropogenic — activities. In the wake of massive weather events like Hurricanes Harvey in Houston and Irma impacting South Florida and the Upper Keys, the findings are particularly timely.

Near shore saltwater habitats in subtropical latitudes typically include both flats — prime playing fields for Florida anglers pursuing Bonefish — and brackish water estuaries, which are populated with Redfish and Sea Trout that are now a focus for fly fisherman on the Texas Gulf Coast. In more temperate climates such as the Pacific Northwest and New England, estuaries of moderate salinity provide rearing grounds for juvenile sport fish such as salmon and striped bass. In all cases, the presence of seagrass is an indicator of environmental health and has been identified as a crucial element in the purification of water through its metabolisis of sulfur dioxide, a potent and naturally occurring biotoxin.

While an effective seawater purifier itself, Seagrass is sensitive to toxin loads expelled from onshore agricultural and urban runoff, particularly herbicides. When Seagrasses die, they drive a feedback loop of sulfur dioxide increase through rotting vegetable matter being broken down by bacteria and fungi. As reported by the Washington Post, water in these "Dead Zones" becomes discolored and turbid, and can create conditions for toxic algae blooms as have been increasingly seen on the southern Florida Gulf Coast, which presents a direct threat to humans in addition to marine life.

The massive volume of water that was recently dumped on south Texas and Florida will undoubtedly carry huge amounts of chemicals, herbicides, pesticides and other agents that will increase mortality of near shore marine vegetation. The University of Queensland study has identified the most effective means for restoring seagrass biologies, with four main strategies being outlined that are dependent on subjective conditions.

The study states, "We propose that integrated land--sea planning must compare the cost-effectiveness of 4 broad conservation actions: protect habitat on the land, protect habitat in the ocean, restore habitat on the land, and restore habitat in the ocean. Here, we develop a repeatable and transferable approach to determine which of those 4 actions maximises the extent of intact marine habitat for a given budget and project timeframe"

A proposed budget of $50 million USD per year over a multi-decade timeframe was applied to the study results, which were intended to address the needs of near shore environments of specific and limited area. This represents a significant and probably shockingly large expenditure for local economies.

With a conservative estimate of the value of sport fishing economy in south Florida representing $1.8 Billion, this type of analysis is a valuable tool for policy makers both at the state and federal level. However, while the cost-benefit analysis of the study seems to be straightforward and well considered, the realistic expenditures for these types of efforts would appear to be on a governmental scale, and would require significant political will to enact legislation.

With increasing evidence of more and larger weather events driving environmental disruptions, localized responses to these types of events eventually will have to be considered on balance relative to the cost of addressing the root causes of climate change.