Primary Production off Kuwait, an Arid Zone Environment, Arabian Gulf

Kuwait Bay, surrounded by arid lands, is shallow (<30m), eutrophic, well mixed and with a high degree of anthropogenic pollution but not well studied. In this unique environment distribution of surface phytoplankton biomass measured as chlorophyll-a concentration, and primary production were studied at six stations during March 1997 through April 1998 in relation to the environmental factors: temperature, salinity, pH, dissolved Oxygen, turbidity, NO₃⁻, NO₂⁻, NH₃, PO₄⁻ and Si(OH)₃⁻. Chlorophyll-a concentration and primary production ranged from 0.12 to 23.66 μg l⁻¹ and 31.67 to 653.31 μg C l⁻¹ d⁻¹, respectively. Phytoplankton biomass and primary production were significantly lower in the southern waters (1.5 μg l⁻¹, 42.2 μg C l⁻¹ d⁻¹, respectively), which are further away from the river runoff than the northern waters off Kuwait (4.4 μg l⁻¹, and 453.4 μg C l⁻¹ d⁻¹, respectively) based on the Wilcoxon-Rank test. Potential photosynthetic efficiency was high [15 - <25 μg C (μg chl-a) ⁻¹ h⁻¹] at most stations with lower values [<10 μg C (μg chl-a) ⁻¹ h⁻¹] observed in the highly stressed Kuwait Bay waters [0.4–8.0 μg C (μg chl-a) ⁻¹ h⁻¹ at stations K6 and K10]. Southern waters also had low potential photosynthetic efficiency [0.4–10.2 μg C (μg chl-a) ⁻¹ h⁻¹]. Levels of phytoplankton biomass, primary production and the potential photosynthetic efficiency are comparable to some of the coastal areas in the world. Temporal and spatial variations for the last two variables are reported here for the first time for the subtidal waters of Kuwait. Principal component analysis (PCA) revealed that underlying hydrodynamic regime might influence phytoplankton primary production in Kuwait's waters.