Document: DAN-3-93-10

Spatial structure and predictive mapping of chlorophyll in a large estuarine system.

FISCUS, D.A.* ¹, W.R.BOYNTON ² and R.H.GARDNER ¹

University of Maryland , Frostburg, MD 21532 USA ¹
UMCES, Solomons, MD 20688 USA ²

Abstract:
Analysis of surface chlorophyll (CHL) from 107 transects of the Chesapeake Bay allows two questions to be examined: 1) Does knowledge of patchiness and scaling properties improve spatially-extrapolated estimates of total surface chlorophyll? 2) Will nutrient regimes (load, frequency and residence time), spatial variability and seasonality determine patchiness and scaling? Both questions are relevant to dynamics of secondary production in the Bay. Results of spectral and autocorrelation analysis of CHL, salinity and temperature from 1996 and 1997 transects showed that estimated correlation lengths agree with results from aerial photography. Slopes of variance spectra for CHL and salinity were similar, resembling the theoretical -5/3 Kolmogorov slope. ANOVA of slopes showed that variability between Bay sections was more important than seasonal or yearly patterns of variation. For predictive mapping, simple interpolation techniques did not preserve observed scaling properties. Mapped estimates of surface CHL should display the natural variance scaling characteristics resulting from the coupling of physical and biological processes as well as the uncertainties associated with the estimation procedures. The spectral analysis results can be used to constrain a mapping algorithm to preserve these effects.

Keywords: scale, estuary, phytoplankton, variance spectra

This abstract is being presented at: 11:15 AM in session:
Oral Session #37: Phytoplankton.