Spectrophotometric determination of chlorophylls and total carotenoids

We have not included any calculations for astacin or animal pigments as suggested initially by Richards. In our e rience artifacts are possible when using these calculatidns with a phytoplankton crop rich in dinoilagellates and the relationship between the apparent astacin content of the water and the planktonic invertebrate population is too tenuous for much useful ecological application. 

The sensitivity of the method described below is adequate except where sample volumes are restricted or where the chlorophyll content of the water is below about 0.2 mg/m . The precision decreases appreciably with concentrations below this level, becoming very poor if less than 0.1 mg/m is present In these circumstances a fiuorimetric determination is recommended. Such a method requires a sensitive fluorimeter and a suitable technique is described in Sections IV.3.IV and V. 

The limit of detection of plant pigments in sea water cannot be simply stated. An unlimited volume of water may be filtered for analysis however, in practice, the volume filtered will rarely exceed 10 liters. The lower limit of detection for the filtration of 10 liters has not been statistically determined but appears to be of the 

CHLOROPHYLL a PRECISION AT THE 5 fiG LEVEL The correct value lies in the range  

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