The role of particulate matter in the productivity of surface waters

Abstract

Except for the special cases of upwelled water and the spring blooms in temperate and boreal waters, the productivity of the oceans is largely governed by the rate of nutrient regeneration in surface waters. This rate of regeneration is a function of the number of actively metabolizing bacteria present, which in turn appears to be a function of the particle content of the water. Thus, particle content may be the basic control on the productivity of the open oceans. The possibility of increasing productivity by artificially increasing the particle content of the water should be considered for regions characterized by low particle count, such as the Sargasso Sea. Since silicate can only be resupplied by re-solution of diatom tests, a process taking place at depth, plankton blooms following regeneration kinetics will typically be dinoflagellate rather than diatom blooms.

Microorganisms and Detritus in the Water Column of a Subtidal Reef of Natal

“…This activity of free bacteria 1s in contrast to the proposal of Wangersky (1977) to the effect that the small size of bacteria means that in the free state they are l~m i t e d by Brownian movement to a small envelope of water which they impoverish before entering a dormant state, then needing up to six to twelve hours incubation at high nutrient levels for induction to activity. Turbulence on the OR1 Reef is l~k e l y to preclude such dormancy.…”

“…In the same paper, only slight pleomorphic changes are reported as accompanying natural bacterial proliferation in an eight hour study, indicating l~t t l e change from the predominant 'dormant' form. Wangersky (1977) and Stevenson (1978) also contend that bacteria attached to particles are more active, because they live in a micro-environment richer in nutrients than surrounding water by virtue of nutrition intrinsic to particles or adsorbed to them. On a numerical pro rata basis, uptake of labelled substrates by attached bacteria was only slightly lower than uptake by their unattached counterpart in the antibiotic and differential flltrat~on studies.…”

Effects of flocculated humic matter on free and attached pelagic microorganisms

“…The former may occur due to several proposed mechanisms whereby attachment stimulates bacterial production, i.e. adsorption of dissolved organics to the particles (Fletcher and Marshall 1982), enhanced speed of movement of the bacteria through the water and thereby breakage of diffusion barriers when attached to particles (Wangersky 1977), or conversely a positive effect of the boundary layer surrounding the aggregates that allows exoenzymes to act more efficiently (ZoBell ,1943). The cultures were grown on a rotary shaker, adjusted to keep all particles in suspension.…”

Photosynthesis and fish production: Hypothetical effects of climatic change and pollution

“…Communities predominated by small flagellates and others predominated by larger phytoplankton have been discussed in recent papers by Semina (1972), Parsons & Takahashi (1973) and Wangersky (1977). The reason for the predominance of different sizes of phytoplankton cells has been generally related to hydrographic conditions -including depth of mixing, nutrient concentration and the availability of light, as well as to biological conditions, such as the effect of zooplankton grazing (Malone, 1971).…”