The Biology Laboratory conducts Algal
Growth Potential and Limiting Nutrient algal assays. Algal Growth Potential
(AGP) tests and Limiting-Nutrient assays are the most direct and effective ways
to determine the amount of nutrients available to organisms in surface waters,
and the eutrophication potential of an aquatic system. These methods provide
information on the biologically-available nutrients in the water. Few other
laboratories in Florida have the capacity or the staff able to perform these
highly useful tests.
Algal Growth Potential (AGP) assays
determine the maximum amount of algal growth that the nutrients in a water
sample can support. This test provides a better indication of the potential for
algal blooms than can be determined by chemical measurement of nutrient
concentrations, because all nutrients in the water are not in a form that can be
used by algal. Additionally, there may be substances present in the water that
inhibit algal growth. In nature, other factors than nutrient availability can
limit the growth of algae, such as the amount of light available, water
temperature, or the amount of algal being consumed by algae-eating organisms.
However, the AGP assay alerts officials to the potential for algal blooms.
Limiting Nutrient (LN) assays
determine what nutrient is preventing even more algal growth than is presently
possible. All plants, including algal, require various nutrients in different
amounts. Whichever of the required nutrients is used up first by the algal
prevents further growth regardless of how much of the other nutrients are
available. The LN assay helps officials to understand what nutrient is limiting
greater algal growth and to regulate discharges of that nutrient to help prevent
the occurrence of algal blooms.
Used with taxonomic identification and
chlorophyll measurements, these procedures produce a complete picture of the
trophic status of a system.
These algal assays require specialized
equipment and expertise not found in most laboratories.
The Standard Operating Procedures used
in preparation for and conducting Algal Assay and Limiting Nutrient tests can be
viewed or downloaded from the
Biology Section SOPs.