Chemical Sensor Program
Monterey Bay Iron

MBARI has maintained a time series at three stations in the Monterey Bay region of the California Current System since 1988. The stations are visited by ship at approximately three-week intervals and moorings are maintained at two of the stations. A broad suite of biogeochemical measurements are made. Dissolved and dissolvable iron have been measured in this coastal observing system over nearly four annual cycles (44 months; ~21 day resolution) at these stations.  A large pulse of dissolvable iron consistently occurs during the first spring upwelling event of each year that is derived from resuspended sediment. Iron concentrations then drop rapidly at all three stations.  During the summer months, only the most inshore station (C1) maintains iron concentrations in excess of nitrate.  Offshore however (M2),  phytoplankton biomass,  primary production and community structure appear to be controlled by low iron concentrations during this time.  The station at the mouth of the bay (M1) receives periodic iron injections during the summer months from upwelling events originating just north of the bay.

An initial description of the data is found in:

Johnson, K.S., F.P. Chavez, V.A. Elrod, S.E. Fitzwater, J.T. Pennington, K.R. Buck and P.M. Waltz (2001) The annual cycle of iron and the biological response in central California coastal waters. Geophysical Research Letters, 28, 1247-1250.

Iron Time Series: (Excel Spreadsheet)                        

(Tab Delimited Text File: C1,  M1,  M2, glossary, methods)

Global Iron Distribution

More information on the distribution of iron throughout the world ocean can be found in:

Johnson, K.S., R.M. Gordon and K.H. Coale (1997) What controls dissolved iron concentrations in the world ocean? Marine Chemistry, 57, 137-161.

and at:

Other iron data sets produced by this lab are available at:

MBARI Surface Ocean Lower Atmosphere Study