PRIMARY PRODUCTION PROCESS grazing gain In light + Co2 10.40% biomass 1040% 02 oxygen Net C02 Primary (respiration) Production detrital (NPP) losses A(decompos ition 40-10 autotro phs self-feeders) need Co2 heterotrophs (oth er feeders) 50 need 02 root roots nutrients losses structural >2 mm returned 20-40% fine <2mm