Submitted and accepted for the Symposium of Contemporary Conservation (SCCP) 2016. Nominated for the KZN Premier's Award 2016.

1. Why count Bacteria: quickly, easily and accurately?
Kunnen, T.H., Moodley, G.K. Robertson-Andersson, D.V
University of KwaZulu-Natal
Abstract
The microbial loop conceptualizes the pathways of nutrients and energy flow between the
microscopic organisms within aquatic ecosystems and primarily revolves around the
recycling of organic nutrients into inorganic nutrients by the heterotrophic bacteria. This
cycling of nutrients enables ecosystems to function at a relatively stable rate in the absence of
allochthonous sources of nutrients, which although essential, are heavily dependent on rain
and wind driven modes of transport. The food web is reliant on the lower trophic level to
sustain the next higher level for growth and reproduction. Although phytoplankton have
received attention as the primary producers of aquatic environments, considerably less
attention has focussed on the essential link between the primary producers and the primary
recyclers within the global food web. Heterotrophic bacteria are the means by which used
nutrients (waste products, sloppy feeding, etc) are recycled into a usable form which can then
be re–introduced into the ecosystem for use by both phytoplankton and other biota instead of
being lost from the system. The need to rapidly and accurately count and size bacteria within
an aquatic ecosystem is key to understanding the direct links between the primary recyclers
and producers as well as other biota within the food web and ecosystem carbon linkages.
Bacterial numbers, biomass and productivity illustrates; the general health of the ecosystem;
nutrient status, predator prey interactions and carbon input of the system. Traditional
enumeration of bacteria is tedious and time consuming. We present here the use of image
analysis macros to count and measure the length and width of each bacterial cell. This
method resulted in a time saving of 7 – 11 months. The macros will be described and its
applications discussed.
Keywords: microbial loop, bacteria, counting, food web, ecosystem