Primary productivity in the Gulf of California, calculated from the relationship between superficial irradiance and chlorophyll in the euphotic zone

Abstract

The vertical distribution of chlorophyll a in the Gulf of California during the spring of 1992 showed a subsurface maxima between 10 and 50 m of depth. The average surface chlorophyll concentration was 0.71 mg m–3. It was linearly related to the integrated chlorophyll of the euphotic zone (r2 = 0.3 1, p < 0.001) and in the first optical depth (r2 = 0.56, p < 0.00l), estimated from a spectral model. The highest values of the integrated chlorophyll of the euphotic zone were found at the region of the large islands (62.76 mg m–2). The calculated values of integrated chlorophyll and incident irradiance were used to estimate primary productivity in the water column of the Gulf of California, throughout the parameter Ψ*. The predictions obtained with different values of this parameter were compared with measurements of primary productivity made in situ with the 14C method and estimated with natural fluorescente. Productivity increased to the north, reaching maximum values at the large islands region. Ψ*p = 0.039 + 0.017 m2 (gCla)–1 is proposed for spring in the Gulf of California.

Keywords

• chlorophyll
• primary productivity
• Gulf of California