TOLERANCE OF NORTH-SEA ALGAE TO UV AND VISIBLE RADIATION

The tolerance of marine macroalgae from the coastal region of Helgolan d Island in the North Sea to ultraviolet and visible radiation was stu died as related to their habitat and the content of amino acids in the micosporine group. Littoral algae that contained UV-absorbing substan ces (micosporine-like amino acids), which act as biological screens, e xhibited high tolerance to UV radiation. The contents of MAAs in the s pecies studied correlated with the irradiance levels in their habitats . Increased MAAs levels were also found in algae growing under conditi ons of high UV irradiance. Deep-sea algae exhibited high sensitivity t o UV (particularly, to UV-B, 280-320 nm) radiation. Most sublittoral s pecies that did not occur in the drying zone (on the littoral) had no protective pigments. It is supposed that, during their evolution, thes e species permanently inhabited deep waters or lost their protective m echanisms. The tolerance of macroalgae to UV radiation depended on the ir age, germinating spores being the most sensitive growth phase.