Chlorophyll



Chlorophyll is a component of photosynthesis. Chlorophyll-a is the most common pigment. It is found in plants, algae, and phytoplankton. A measurement of chlorophyll-a can give an idea of how much primary production is happening in the water column. How It Works

Fluorescence is the method used to measure chlorophyll. The sensor has a light emitting diode or LED that emits a specific wavelength of light, usually a wavelength of blue light (450–495 nm). The wavelength is absorbed by the chlorophyll, which then fluoresce at a specific wavelength. If the LED emits blue light, then the chlorophyll will fluoresce red. The sensor detects that return wavelength, allowing for a measurement of chlorophyll. Sensor Variations

Fluorometers or Chlorophyll sensors are a standard sensor attached to CTD rosettes. They can also be attached to other platforms and there are hand held models. The most basic fluorometers only measure chlorophyll-a. However, there are models such as the bbe FluoroProbe that are able to classifying algae. This is done by software recognizing the “fingerprints” of algal classes based on chlorophyll-a interacting with other pigments giving off wavelengths unique to different types of marine primary producers.

The NASA Sea-viewing Wide Field-of-view Sensor (SeaWiFs) project uses the same technology at a larger scale to collect global composite data on chlorophyll in the oceans.