SS3.06 Large Scale Change in Prominent Ecosystems
Date: Wednesday, June 12, 2002
Time: 11:45:00 AM
Location: Lecture Theatre
 
PaerlHW, Univ. of North Carolina at Chapel Hill, Instit. of Marine Sciences, Morehead City, NC 28557, USA, hans_paerl@unc.edu
Peierls, B, L, Univ. of North Carolina at Chapel Hill, Instit. of Marine Sciences, Morehead City, NC 28557, USA, peierls@email.unc.edu
Fear, J, , Univ. of North Carolina at Chapel Hill, Instit. of Marine Sciences, Morehead City, NC 28557, USA, jfear@sph.unc.edu
Twomey, L, J, Univ. of North Carolina at Chapel Hill, Instit. of Marine Sciences, Morehead City, NC 28557, USA, twomeyluke@hotmail.com
Bales, J, D, US Geological Survey, Raleigh, NC 27607, USA, jdbales@usgs.gov
 
ECOLOGICAL RESPONSE OF PAMLICO SOUND, NC TO 3 SEQUENTIAL HURRICANES IN 1999: A GLIMPSE INTO POTENTIAL IMPACTS OF CLIMATE CHANGE ON LARGE ESTUARIES
image
Three major hurricanes, Dennis, Floyd and Irene, struck the USA’s second largest estuary and largest lagoonal ecosystem, Pamlico Sound, NC in a 6-week period during Sept.-Oct., 1999. This caused a 50-500 year flood (depending on location) in the Sound’s watershed. Floodwater inputs reduced the Sound’s water residence time from 1 year to 6 weeks and supplied more than the annual N load. Hydrologic, nutrient (C, N, P), oxygen, phytoplankton community growth and composition responses were examined and compared to non-hurricane years. Short-term (weeks) and longer-term (months) observations revealed an immediate 4-fold increase in phytoplankton biomass accompanied by longer-term compositional shifts. These alterations have lasted at least a year and appear linked to long-term biogeochemical and trophic changes under investigation. Freshwater discharge strongly influenced the location, magnitude and duration of phytoplankton blooms and hypoxia events. These large-scale responses are discussed in the context of efforts to distinguish impacts of acute, catastrophic storm events from chronic anthropogenic nutrient enrichment and hydrological modifications. Assessments of causes and effects of ecological change must include a predicted 10-40 year rise in Atlantic Ocean tropical storms.