Planktonic organisms

NOTE Compare this with similar problems in CW systems—those of easily and accurately (and at low-cost) determining levels of microbiological contamination. In most CW systems, apart from a general maintenance quality indicator, the levels of bulk water planktonic organisms tend to have little relevance to sessile organism-biofilm reactions occurring at the metal-water interface. 

Although reaction-diffusion limitation and the presence of nutritionally restricted phenotypes are obviously important determinants of biofilm drug resistance, neither, either separately or in combination, provides a complete explanation of the phenomena. Cells on the periphery of the biofilm, subject to nutrient fluxes similar to planktonic organisms would succumb to antibacterial concentrations that are effective against the planktonic cells. Cell-death at the periphery would lead to increased nutrient availability for deeper-lying cells. These would, in turn, grow faster and adopt a more susceptible... 

Only a few studies on defined chemical defense metabolites from non-phyto-plankton organisms that spend their entire life history in the water column have been reported to date [81]. 

Picard V, Lair N (2005) Spatio-temporal investigations on the planktonic organisms of the Middle Loire (France), during the low water period biodiversity and community dynamics. Hydrobiologia 551 69-86... 

Heterotrophic microbes consume organic matter to fuel respiration metabolisms that provide energy. Aerobic respiration of the Redfield-Richards planktonic organic matter can be represented stoichiometrically as... 

Plankton Organisms that drift passively or are weak swimmers. Includes mostly microscopic plants (phytoplankton) and protozoans, as well as larval animals and small filter feeders (zooplankton). 

Collier, A., Fatty Acids in Certain Plankton Organisms, in Estuaries, ... 

Typically, we will undertake serious action if the level of live planktonic organisms found in a cooling system reaches between 1 x 105 and 1 x 106 aerobic colony-forming units per milliliter (CFU/ml). When we compare this with a potable water supply that may contain only 20 to 200 CFU/ml, it appears to be a large number however, on a weight basis, this still represents an incredibly small amount of contamination, probably much less than the daily contaminant load from air-blown dust and soil. 

High planktonic (CFU/ml) levels within the cooling system indicate that suitable conditions for rapid reproductive growth exist and thus planktonic organisms may further rapidly proliferate, adding greatly to the source of biofoulant load. 

Matrices are primarily composed of polysaccharide slimes exuded by immobilized sessile bacteria. Planktonic organisms that become trapped can adapt to the new environment within minutes, and produce copious amounts of adherent and protective slime. 

The natural organic matter suspended in the oceans at sites far from land consists of altered and linked biomolecules such as amino acids, sugars, and triglycerides that have been linked together. In large lakes and estuaries, the natural organic material in sediments and suspended sediments is derived from a mixture of the remains of terrestrial and planktonic organisms. 

FIGURE 5.2 Chemical structures of deterrents from planktonic organisms. 

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