The total amount of living material expressed as
either grams of carbon or kilocalories (1,000 calories) for a given
area of space (e.g., per square meter). Kilocalories are calculated
by placing together all of the living matter collected for a defined
area of riverbed and drying it. After recording the total weight, it
is then placed it in a bomb calorimeter. The calorimeter is filled with
pure oxygen and a spark ignites the contents. The amount of heat given
off is recorded in calories per gram of dried material.