Application of vertically integrated sampling approach to study of new production via ²³⁴Th-²³⁸U disequilibria

The spatial and temporal distributions of new production vary largely in different sea area.To understand the level of new production in the sea area studied better,an estimate of new production must be obtained in large spatial and temporal scales.The ²³⁴Th-²³⁸U disequilibrium is an effective method for the study of new production.Two sampling strategies,vertically integrated sampling approach based on trapewidal integration principle and discrete layer sampling approach,Two compared in the studies of the Xiamen Bay and the northern South China Sea.The scavenging fluxes and removal fluxes of ²³⁴Th and the residence times for dissolved and particulate ²³⁴Th were calculated.The coincident results from two sampling approach suggest that vertically integrated sampling approach is not only effective and reliable,but also significantly reduces the number and volume of samples.It allows us to study new production by ²³⁴Th-²³⁸U disequiiibria in large spatial scale.