Particulate matter was analyzed for carbohydrates off the coast of West Africa during a period of upwelling. Samples were analyzed for total, or dilute-acid soluble, dilute-alkali soluble and residual carbohydrate by the phenol-sulphuric acid technique. Concentrations of total carbohydrate in the area were intermediate between those previously reported for estuarine and open-ocean regions. Except for nearshore areas, where windblown sand discolored in the seawater, total carbohydrate in surface waters was directly proportional to chlorophyll a concentrations. Thus, living phytoplankton contributed a significant part of the carbohydrate. Dilute-acid fractions were generally 30 to 50% of the total carbohydrate in the surface waters along a transect offshore; in the deepest samples taken this fraction accounded for 15 to 25% of total carbohydrate. The dilute-alkali fraction was less than the dilute-acid fraction, accounting for ca 30% of the total carbohydrate in surface waters and usually 15% in deeper samples. The residual fraction generally increased with depth and accounted for more than 50% of the total carbohydrate in surface and deepest samples. The proportion of carbohydrate in living phytoplankton is discussed in relation to other analyses in upwelling areas and open ocean regions.
ASJC Scopus subject areas
- Environmental Science(all)
- Earth and Planetary Sciences(all)