Rl. France et al., ADJUSTING CHLOROPHYLL-A ESTIMATES THROUGH TEMPORAL WEIGHTING BASED ONTHE SEASONAL DEVELOPMENT OF PHYTOBIOMASS, Aquatic sciences, 56(2), 1994, pp. 106-114
Citations number
35
Categorie Soggetti
Water Resources",Limnology,"Marine & Freshwater Biology
North-temperate lakes have been shown to progress through a general cy
cle of chlorophyll-a Phenology. Because estimates of seasonal means ar
e often based on only a few samples collected against this variable ba
ckground, these estimates can be biased or uncertain. Our goal was to
reduce the seasonal uncertainty and thereby produce more accurate esti
mates of chlorophyll concentration by defining a correction for phenol
ogical development. Time-series data from 149 lake-years were used to
develop equations from which chlorophyll values could be ''corrected''
to the seasonal mean in relation to their particular date of measurem
ent. However, we found the seasonal correction to be ineffectual in re
ducing uncertainty about nutrient-response regressions. After reviewin
g a number of hypotheses, we conclude that the correction derived from
the average response for many lakes will be inadequate to adjust for
the seasonal pattern occurring within any particular lake. This occurs
because the temporal weighting correction, generated through repeated
averaging, underestimates the seasonal variability which exists among
individual lakes. An effective correction, if it is developed will ha
ve to be based on patterns within single lakes or possibly different l
akes within a single region.