PRIMARY PRODUCTION OF CAPE OF GOOD HOPE LITTORAL AND SUBLITTORAL SEAWEEDS

SUMMARY

The annual primary productivity of three littoral and three understorey sublittoral seaweed species has been calculated for the Cape of Good Hope, South Africa, between Cape Point and Yzerfontein using previously published photosynthesis and biomass data. The understorey species fix 68 t C.yr⁻¹ and the intertidal species 541 t C.yr ⁻¹ along this portion of coast compared to 36 220 t C.yr⁻¹ fixed by kelps. This confirms the kelps are the major macrophyte primary producers of the west coast inshore region. The littoral algae fix eight times as much carbon over the same distance of shore as the sublittoral algae. Owing to their higher rates of carbon fixation, the littoral species turn over between 13 and 33 times p.a., whilst the sublittoral seaweeds turn over between 8 and 13 times p.a.