Kelp Ecklonia maxima and Laminaria pallida both undergo fragmentation from the tip and thus release structural components as particulate matter and a dissolved fraction from the cell contents into the water column. Analysis of the dissolved fraction released as mucilage from kelp during fragmentation yielded a 92-94 '10 gravimetric recovery comprising 4.74-5.27 "it, protein, 0.17-0.18 "/3 fat, 7.17-7.56 "/o sugar and polyols, 4.77-5.01 '/o alginate and 4.6-7. Energy released as dissolved organic components during kelp fragmentation amounts to approximately 34 '/Q of the total annual energy production of L. pallida and 16-17 O/O of that by E. maxima. Total particulate energy production from both species in a small kelp bed of 700 ha is estimated as 43.25 X 10'' kJ y-', whereas that released as dissolved organic matter amounts to 10.74 X 101° kJy-l. This is equivalent to 20.24 X 107 1 mucilage released year-' during fragmentation into the shallow water of the kelp bed, to which should be added undetermined losses of mucilage from the surface of the fronds. Studies of the concentration of dissolved organic matter in the water near a kelp bed suggest that the exudate released during fragmentation is rapidly utilised within 24 h by microheterotrophic organisms rather than by phytoplankton.