Ocean chlorophyll fluorescence in-situ monitor

The invention discloses a small-size chlorophyll fluorescence in-situ monitor capable of being used in water depth of 3000m. According to the small-size chlorophyll fluorescence in-situ monitor, an exciting light modulation and synchronous detection technology is adopted, a system light path is optimized and a low-power-consumption circuit design is adopted, so that the small-size chlorophyll fluorescence in-situ monitor has the advantages of high detection precision, low power consumption, ambient light interference resistance and the like. The small-size chlorophyll fluorescence in-situ monitor can be connected with an underwater battery to carry out long-time self-contained type work or is mounted into a towed body to carry out underwater towing and vertical section investigation; the small-size chlorophyll fluorescence in-situ monitor can be integrated to third party platforms including a multi-parameter system, an ocean buoy/a subsurface buoy, a seabed observational network and the like in a modularized manner to carry out in-situ continuous monitoring. The small-size chlorophyll fluorescence in-situ monitor can be used for conveniently and rapidly determining vertical and horizontal distribution of chlorophyll concentrations of different sea areas from off-shore areas to the ocean.