An apparatus for measuring microbial growth or survival in the marine environment

The apparatus consists of a glass tube closed at the top and with a bacteria-proof sinter-glass filter at the lower end. This is moored below the surface of the sea after inoculation with the organism under examination. Water enters and leaves the tube due to the hydrostatic pressure differential created by tides and waves; this gives a desirable rate of exchange of sea water withouth allowing the entry of any foreign organisms. After the period of immersion, the amount of growth or survival of the organism is estimated.