Chengwang Wang

The temporal variation of dissolved iron and its linkage with Fe cycling in the North Pacific Subtropical gyre

Name: Chengwang Wang
Primary Supervisor: Prof Alessandro Tagliabue
Year: 2
Discipline: Ocean Sciences
Presentation type: Poster
Project Title: The temporal variation of dissolved iron and its linkage with Fe cycling in the North Pacific Subtropical gyre

Abstract:

Abstract: Iron (Fe) is important for modulating the ocean carbon cycle but displays a short residence time.  We lack large-scale regional constraints from observations on how the Fe cycle fluctuates temporally which would better constrain predictions of how Fe limitation may alter. Here, we present a novel seasonal and interannual dataset from GEOTRACES sections in the western North Pacific Subtropical Gyre (along 10ºN and 155ºE), supported by insights from a global ocean biogeochemical model. Surface Fe and P inventory changes along 10ºN are consistent with aerosol deposition, while internal regeneration–scavenging processes appear more important elsewhere. Unexpected temporal variability in mesopelagic DFe is not linked to changes in hydrography or water masses but can be reproduced in the model by altering the internal Fe cycle. Our results highlight the critical role of internal processes—regeneration, scavenging, colloidal shunt and authigenic phases—in driving regional Fe variability. Repeat or seasonal sampling may reveal similar patterns elsewhere, offering key constraints for improving model projections of internal Fe cycling under environmental change.