The effects of beach renourishment on benthic microalgae

UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
Erin S. Carey (Creator)
The University of North Carolina Wilmington (UNCW )
Web Site:
Lawrence Cahoon

Abstract: Coastal erosion threatens hundreds of miles of beach every year making beach renourishment in the southeastern United States essential to the economic health of coastal communities. Governments often fail to consider the possibility of ecological damage associated with renourishment projects and the potential for negative impacts on local fisheries through damage to benthic microalgae, the base of the food web. This study set out to determine what impact beach renourishment had on the benthic microalgal communities by measuring and comparing chlorophyll a concentrations before and after renourishment at Kure Beach and Carolina Beach in southeastern North Carolina. The final data set contained 4260 chlorophyll a measurements that covered two beaches, 8 sites, 16 transects, and 3 elevations per treatment with 6 samples collected at each elevation. Sediment samples were also analyzed for mean grain size. Sampling design considered effects of site elevation, renourishment, and seasonality and was completed 15 times for each beach for a total of 30 sampling trips. Up-current and down current controls were included in the experimental design Chlorophyll a measurements ranged from 0.00 mg/m2 to 14.88mg/m2 with an overall mean of 3.53 mg/m2 (s = 2.22). Results show no significant impact from renourishment on benthic microalgal communities at either beach. Paired comparisons between beaches, and between treatment and control sites at each elevation were made using a mixed model ANOVA (SAS) with no significant results observed. Data indicated a negative relationship between chlorophyll a concentrations and grain size but the source sediment for these projects was well suited for the renourished beaches. No significant change in grain size after renourishment was observed and no drop in chlorophyll a could be detected.

Additional Information

A Thesis Submitted to the University of North Carolina Wilmington in Partial Fulfillment Of the Requirements for the Degree of Master of Science
Language: English
Date: 2009
Beach erosion--North Carolina--Carolina Beach, Beach erosion--North Carolina--Kure Beach, Beach nourishment--Environmental aspects--North Carolina--Carolina Beach, Beach nourishment--Environmental aspects--North Carolina--Kure Beach, Benthos--North Carolina--Carolina Beach--Effect of habitat modification on, Biotic communities--North Carolina--Carolina Beach, Biotic communities--North Carolina--Kure Beach, Chlorophyll--North Carolina--Carolina Beach, Chlorophyll--North Carolina--Kure Beach, Microalgae--North Carolina--Carolina Beach, Microalgae--North Carolina--Kure Beach, Primary productivity (Biology)--Measurement, Shore protection--North Carolina--Carolina Beach, Shore protection--North Carolina--Kure Beach
Beach nourishment -- Environmental aspects -- North Carolina -- Carolina Beach
Beach nourishment -- Environmental aspects -- North Carolina -- Kure Beach
Beach erosion -- North Carolina -- Carolina Beach
Beach erosion -- North Carolina -- Kure Beach
Shore protection -- North Carolina -- Carolina Beach
Shore protection -- North Carolina -- Kure Beach
Biotic communities -- North Carolina -- Carolina Beach
Biotic communities -- North Carolina -- Kure Beach
Primary productivity (Biology) -- Measurement
Chlorophyll -- North Carolina -- Carolina Beach
Chlorophyll -- North Carolina -- Kure Beach
Benthos -- North Carolina -- Kure Beach -- Effect of habitat modifcation on
Benthos -- North Carolina -- Carolina Beach -- Effect of habitat modification on
Microalgae -- North Carolina -- Kure Beach
Microalgae -- North Carolina -- Carolina Beach

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