Question

Question 18:

a. Describe what would happen to 100 g of wood chips that were spread on the ground in an area of temperate forest. Compare this outcome to the outcome you'd expect for 100 g of wood chips left in an arctic tundra ecosystem. What's different about the two ecosystems and how will it influence the outcome for the wood chips?  

b. Which of the following lakes would be most likely to develop an anoxic dead zone? Lake 1 is shallow, located in a warm region and is surrounded by farms. Lake 2 is deep and located in a mountainous region surrounded by forests. Discuss the elements of each that could contribute or work against the formation of a dead zone.

Answer 1

18.

.a.

The chips of wood left in the temperate ecosystem would get decomposed due to the microbes because temperature in the temperate ecosystem is higher than the temperature in the Arctic tundra. Where as the same mass of wood chips will remain undecomposed for longer period of time in the Arctic tundra because of the lower temperature at the Arctic tundra.Thus this difference in the rate of decomposition between the two ecosystems is mainly due to difference in the temperature.

b.

Lake 1 because it is shallow located in a warm region and surrounded by farms the reason is that when it is surrounded by the farms fertilizers will escape from these farmlands and will enter the lake. Due to this there will be rapid growth of the algae causing algal bloom. But with very high concentration of Nitrogen from the farm fertilizers these algae will start growth a will die. There death will attract their decomposition by the aerobic bacteria which will produce anoxic conditions in the Lake 1. Moreover, the region being warm and the lake being shallow, the temperature of the water will favour the growth of the decomposers and will lead to the formation of dead zone.

Where as Lake 2 is deep, surrounded by the forest means there is no nutrient addition to the lake and hence there will be no algal bloom and due to depth the temperature of water will be low, thus less favourable for microorganisms, and hence less chances for draining all the oxygen from the lake.