A microbial ecologist wants to study a bacterium that is adapted to growth in lake water containing very low nutrient concentrations. Assuming that a suitable growth medium is available for this organism, which type of culture would be best to use for growing this organism in the lab?
A) this organism cannot be grown in the lab.
B) a batch culture using a low-nutrient medium
C) on Petri plates containing a low-nutrient medium
D) a chemostat using a low-nutrient medium

D) a chemostat using a low-nutrient medium

Explanation:

A chemostat is a bioreactor in which a constant chemical environment is maintained. In the bioreactor the fresh medium is added, whereas the culture liquid, left out nutrients, microorganisms and metabolic end products are removed from the medium at the same rate to keep the volume of the culture constant.

The volume and concentration of the nutrient medium can be maintained in the chemostat bioreactor.

According to the given situation, the bacteria can be cultured in low-nutrient growth medium that is the lake water to observe its adaptation under the low-nutrient concentration.

it has to be understood that the sea water contains a huge amount of sodium and chlorine ions and if they enter the cell of the atlantic cod fish, the cell will shrivel and the fish will die. to avoid such a condition, the fish uses active transport for the purpose of removing the ions against the gradient.

explanation:

the atlantic cod is not a maritime osmoconformer. its native application of salts is less than that of the seawater it lives in. it is continually falling water from the gills to the ocean via osmosis.

countering that, the fish is going to be swallowing seawater. but since its internal collection of salts is lower than seawater, the fish will want to go free of excess salt, and since that's going upon a gradient, then active transport, requiring energy, must be used to pump out the salt. much marine fish use the organs to filter out the salt and these fish discharge very straight urine.