title: Ecosystem impacts of three sequential hurricanes (Dennis, Floyd, and Irene) on the United States' largest lagoonal estuary, Pamlico Sound, NC.
abstract: Three sequential hurricanes, Dennis, Floyd, and Irene, affected coastal North Carolina in September and October 1999. These hurricanes inundated the region with up to 1 m of rainfall, causing 50- to 500-year flooding in the watershed of the Pamlico Sound, the largest lagoonal estuary in the United States and a key West Atlantic fisheries nursery. We investigated the ecosystem-level impacts on and responses of the Sound to the floodwater discharge. Floodwaters displaced three-fourths of the volume of the Sound, depressed salinity by a similar amount, and delivered at least half of the typical annual nitrogen load to this nitrogen-sensitive ecosystem. Organic carbon concentrations in floodwaters entering Pamlico Sound via a major tributary (the Neuse River Estuary) were at least 2-fold higher than concentrations under prefloodwater conditions. A cascading set of physical, chemical, and ecological impacts followed, including strong vertical stratification, bottom water hypoxia, a sustained increase in algal biomass, displacement of many marine organisms, and a rise in fish disease. Because of the Sound's long residence time ( approximately 1 year), we hypothesize that the effects of the short-term nutrient enrichment could prove to be multiannual. A predicted increase in the frequency of hurricane activity over the next few decades may cause longer-term biogeochemical and trophic changes in this and other estuarine and coastal habitats.
authors.affiliation: University of North Carolina at Chapel Hill, Institute of Marine Sciences, Morehead City, NC 28557, USA. hans_paerl@unc.edu
authors.forename: H W
authors.initials: HW
authors.lastname: Paerl
authors.forename: J D
authors.initials: JD
authors.lastname: Bales
authors.forename: L W
authors.initials: LW
authors.lastname: Ausley
authors.forename: C P
authors.initials: CP
authors.lastname: Buzzelli
authors.forename: L B
authors.initials: LB
authors.lastname: Crowder
authors.forename: L A
authors.initials: LA
authors.lastname: Eby
authors.forename: J M
authors.initials: JM
authors.lastname: Fear
authors.forename: M
authors.initials: M
authors.lastname: Go
authors.forename: B L
authors.initials: BL
authors.lastname: Peierls
authors.forename: T L
authors.initials: TL
authors.lastname: Richardson
authors.forename: J S
authors.initials: JS
authors.lastname: Ramus
mesh_terms: D000818:Animals; D004190:Disasters; D017753:Ecosystem; D005618:Fresh Water; D008386:Marine Biology; D009657:North Carolina; D013045:Species Specificity