STUDIES ON THE BIOLOGY AND CHEMISTRY OF THE GULF OF MAINE

Abstract

Quantitative studies in the deeper part of the Gulf of Maine showed a marked stratification in hydrographical conditions and in vertical distribution of plankton. Transition layers at depths of 20-30 m. were more saturated with O (thus indicating greater photosynthetic activity) and had a greater maximum of phytoplankton than surface layers. Some spp. had their maximal frequency at depths of 40-50 m. where 0 content was low. Sim.il.ar sampling from the shallower Georges Bank revealcd the same spp. but a different quantitative and vertical distribution. On the Bank the spp. were evenly distributed from surface to bottom, due to vertical mixing of waters. Some culture experiments reaffirmed the importance of nitrates and phosphates in stimulating phytoplankton productivity. No positive evidence was secured for the hypothesis that quantities of soluble Fe present in sea water may be insufficient to support a rapld growth of neritic diatoms. Notes on local distribution of the more abundant spp. are given.