Identification of Algae-Nutrient Relationships

Abstract

Fundamental relationships are presented showing that the probability distribution of chlorophyll a (Chla) depends on both the distribution of Chla conditioned on TN and TP, and the distribution of TN conditioned on TP. It is further shown that simplified forms of these distributions can be identified using the non-parametric Spearman correlations between Chla, TN, and TP. Based on these fundamental relationships, a novel approach is presented for estimating Chla concen- trations that do not depend on a-priori assumptions of an analytic relationship between Chla, TN, and TP. The proposed approach is demonstrated by application to six subareas within an impaired segment of the Halifax River in Florida. Results from these analyses show that the relationship between Chla, TN, and TP exhibits significant spatial and temporal variability over length scales on the order of 1 mile, and that using the Redfield ratio as a basis for identifying the controlling nutrient is not reliable.