Detrital production in Nova Scotian kelp beds: patterns and processes

摘要: Connectivity via the transport of detrital material from areas high to low productivity may be an important determinant secondary and biodiversity in receiving communi- ties. On Atlantic coast Nova Scotia, detritus exported subtidal kelp beds contributes food webs communities inhabiting deeper waters offshore. To estimate amount energy available this pathway, we measured rates production erosion blades at 5 sites varying wave exposure. Specifically, 2 dominant species kelp, Laminaria digitata Saccharina longicruris, over 16 mo. We also examined effect environmental biological factors on rates, including temperature, exposure, grazing by snails cover invasive bryozoan Membranipora membranacea. observed clear seasonal spatial patterns productivity, with highest spring. Erosion rate was highly variable across seasons, strongly related M. membranacea intensity snail distal end blades. Both cause tissue degradation, abrasions perforations that weaken positively water temperature site Annual increased linearly bed biomass, ranged 0.5 1.71 kg dry weight m -2 (150-513 g C ) sites. These equal or exceed annual phytoplankton off Scotia estimates seagrass North America.