The Ecological Role of Water-Column Microbes in the Sea
Marine Ecology Progress Series, January 1983
This article gives some insight into the ecology we are missing when we try to control algae blooms with carbon dosing.
It’s not even close to a simple bacteria vs algae contest, or bacteria-to-skimmer export that gets reported in hobby literature.
A few quotes:
There is evidence that bacteria show kinesis [movement] in a field 10 to 100 µm from algal cells, close enough to take advantage of DOM (Azam, in press). Under laboratory conditions in natural sea- water, bacteria were observed to remain at distances of the order of 10 pm from algal cells, possibly being repelled by antibiotics produced by healthy algae. They attach mainly to moribund algae.
[…]it follows that the supply of either carbon for energy, or other nutrients may limit bacterial growth. However, in phytoplankton blooms DOM is often produced, and bacteria with their large surface:volume ratio are adapted to scavenging nutrients from the water at very low concentrations. The difficulties experienced in quantifying the release of DOM by algae are almost certainly due to its rapid uptake by bacteria. The same argument applies to nutrient cycling. If bacteria are so well adapted to
scavenging DOM and nutrients at low concentrations, what limits their population size to the biomass levels given in Table I ? Fenchel (1982a,b, c, d, in press) has shown that heterotrophic microflagellates in the size range 3 to 10 pm are effective bacteriovores in the sea, capable of filtering 12 to 67 % of the water column per day (see also Sorokin, 1979; Sieburth, 1982).These are principally choanoflagellates and colourless chry- somonads[…]