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In July of 1996 a transect study was conducted to evaluate regional variability in hydrographic and biogeochemical parameters between Station ALOHA and the historical Climax study area. The cruise was made from July 8-16, 1996 on the R/V Moana Wave and covered a cruise track that overlaid the Topex-Poseidon satellite track (Figure 33).

The primary purpose of the cruise was to:
  1. Determine the regional variability and gradients in selected biogeochemical and physical properties of the upper water column from Station ALOHA to the Climax Program study site.

  2. Assess upper water column characteristics at Climax using modern techniques for comparison to the historical data set.

  3. Compare depth specific phytoplankton and mesozooplankton communities with near synoptic resolution at ALOHA and Climax.

  4. Determine regional variability in phosphorus pool inventories and dynamics.

  5. Determine along-track variability in particle concentration, pCO2, Chlorophyll a, and hydrographic parameters.

Station coordinates are given in the Table below. Stations 1 to 5 were the originally planned, however, Stations 6 to 9 were added to document the development and extent of an algal bloom encountered during this cruise.


Station           Location                   Date          Comments

   1      21 29.04' N, 158 22.44' W       8 July 1997
   2      22 45.00' N, 158 00.00' W       9 July 1997      Station ALOHA
   3      24 34.20' N, 157 00.00' W      10 July 1997
   4      26 22.50' N, 156 10.02' W      11 July 1997
   5      28 00.00' N, 155 24.60' W      12 July 1997      Station Climax
   6      25 58.91' N, 156 17.62' W      14 July 1997
   7      24 50.22' N, 156 47.66' W      15 July 1997
   8      24 09.90' N, 157 05.45' W      15 July 1997
   9      22 45.00' N, 158 00.00' W      15 July 1997      Station ALOHA
  

Location of stations for ALOHA-Climax 1 cruise


Results (ftp View Data)


Thermosalinograph

Time-series of NST and NSS measured by the thermosalinograph during AC-1 are shown in Figure 34. Large temperature and salinity gradients were encountered during this cruise which covered a long transect. Overall, temperatures range from 24.5 to 27.4 Deg C and salinities range from 34.4 to 35.3.


Chlorophyll a Concentrations

Profiles of chlorophyll a are shown in Figure 35. From these profiles, it appears that Station ALOHA and Climax are quite similar. The stations in between them, however, appear different, showing a subsurface maximum at Station 3 and a subsurface minimum at Station.


Underway Surface Fluorescence

Underway fluorescence data at 45 meters from the towed instrument is shown in figure 46. This data shows large spatial variability along the cruise track.


Primary Production

Depth profiles of primary production at Station ALOHA and Climax are shown in figure 47a, figure 47b, figure 47c & figure 47d. Figure 47a shows a comparison of primary production vales using the standard HOT protocol and the Climax protocol, referred to as the Hayward protocol. A significant difference is evident from water samples collected at 100 meters. Figure 47c and figure 47d show the profiles at Station Climax. Again HOT and Hayward protocols appear to produce different results with the exception of the 5 m water samples. Using various types of filters with the Hayward protocol, it appears that Millipore filters produce higher values than GF/F or than Nuclepore filters.


Meteorological Observations

Meteorological data collected during are presented as time series in figure 48a & figure 48b.