Chlorophyll production, degradation, and sedimentation: implications for paleolimnology.

Chlorophyll production and pigment resuspension were both major sources of water column pigments. Photodegradation rates were rapid and indicated that detritus particles that remained in the epilimnion for periods > 3 days lost nearly all detectable pigments. Therefore, only rapidly sinking detrital particles or those produced in deep layers at low light intensity could make appreciable contributions to sedimentary chlorophyll degradation products. Pheophorbide a, a grazing indicator, was the dominant chlorophyll a degradation product found in sediment traps. Pigment sedimentation increased significantly with mean size of cladocerans and omnivorous copepods. In contrast, sedimentation rates of chlorophyll degradation products did not increase with primary production. In these lakes, deposition of chlorophyll degradation products in sediments depended primarily on size and biomass of grazers. -from Authors