Project: Vertical Transport and Exchange

The Vertical Transport and Exchange (VERTEX) project was one of the early in situ iron research project lead by John Martin. A sampling program was conducted in the Gulf of Alaska (northeast Pacific) in order to test the carbon cycling hypothesis that iron deficiency was responsible for the phytoplankton's failure to remove major plant nutrients from these waters. Based on the results of phytoplankton Fe enrichment experiments and observed environmental Iron levels, researchers concluded that the Gulf of Alaska would be a good location to test their hypothesis. Free-floating particle interceptor traps (MULTITRAPS) were deployed at nine stations to measure the vertical fluxes of organic Carbon, Hydrogen and Nitrogen associated with passively sinking particles. With the exception of one station off Peru, all were located in the northeast Pacific (see Martin et al., 1989, Figure 1). Other pertinent information about time and place of sampling is summarized in Table 1 of Martin et al. (1989). During the field program, trap locations were monitored using the Argos satellite system.

Publication:
John H. Martin, R.Michael Gordon, Steve Fitzwater, William W. Broenkow, Vertex: phytoplankton/iron studies in the Gulf of Alaska, Deep Sea Research Part A. Oceanographic Research Papers, Volume 36, Issue 5, May 1989, Pages 649-680, ISSN 0198-0149, DOI: 10.1016/0198-0149(89)90144-1. (Martin et al., 1989 paper from Science Direct)

The VERTEX cruises:
1980	VERTEX I, (off Point Sur), RV Cayuse and RV Wecoma 
1981    VERTEX II (November, R/V Wecoma) - 18 deg N, 108 deg W 
1982    VERTEX III (November, R/V Wecoma) - 15 deg 10 min N, 107 deg 30 min W
1983	VERTEX-IV (July, RV Wecoma) - 155 deg 7 min W, 28 deg 15 min N
1984	VERTEX-V (May/June) R/V Thompson
        A - 139 deg 34 min W, 33 deg 6 min N
        B - 128 deg 31 min W, 34 deg 59 min N
        C - 122 deg 38 min W, 36 deg 6 min N
        D - 133 deg 15 min W, 34 deg 11 min N
1986-89	VERTEX-VI (seasonal study - 7 Sea 1-Sea 7,  Sept 86 - May 89) - 139 deg 0 min W, 33 deg 0 min N
1987	VERTEX-VII (July/Aug)
        T-4  139 deg 0 min W, 33 deg 0 min N
        T-5  140 deg 46 min W, 39 deg 36 min N
        T-6  142 deg 52 min W, 45 deg 0 min N
        T-7  145 deg 0 min W, 50 deg 0 min N  (Station P)
        T-8  147 deg 30 min W, 55 deg 30 min N

A complete list of VERTEX publications was compiled by Cindy Lee (SUNY Stonybrook) in 2010 (PDF document).