Question

Please explain how the total NPP relates to the other two graphs or what all the graphs tell you.

Figure 543 NPP by Biome Type (a) NPP per unit area b)Area covered, by (c) Total NPP ecosystem type Algal beds and reefs Tropical wet forest Wetlands Tropical seasonal forest Temperate evergreen forest Estuary Temperate deciduous forest Savanna Boreal forest Woodland and shrubland Cultivated land Temperate grassland Upwelling zones Ocean neritic zone Lake and stream Tundra Open ocean Desert and semidesert scrub Rock, sand, ice Aquatic Terrestrial 0 500 1000 1500 2000 2500 012 3 4 5 6 65 05 10 15 20 25

Answer 1

We al know that NPP stands for Net Primary Productivity . This is the amount of carbon uptake after subtracting Plant Respiration from Gross Primary Productivity which is the total rate at which any ecosystem captures and stores carbon for a given period of time.

The world's ecosystems vary greatly in NPP. In terms of NPP per unit area, estuaries, tropical forests, marshes etc are the most productive. In fact, the more dynamic an ecosystem is, the more will be its total NPP.

In the above graphs, the relationship between the NPP and the area covered by an ecosystem is depicted.

Graph A tells us about the Net Primary Productivity of the ecosystem and graph B tells us about the total area covered by that particular ecosystem. Finally, graph C shows how Total NPP varies with the NPP and area covered by the ecosystem.

In graph [A] , one can see that the highest NPP is for aguatic algal beds and reefs but the area covered by them is very less. So. naturally the total NPP is affected.

For Tropical wet forests, the NPP is high and the area covered by this biome is on the higher side. So, the total NPP is the highest for land ecosystems.

Now, lets observe this relationship for Open oceans. In graph [A] , the NPP for oceans is a miniscule amount but the area covered by these water bodies is immense. In graph [C] , the total NPP shown is the highest for the open ocean bodies.

Likewise, the NPP for ocean neritic zone is quite less [graph A] , but the area covered by this is the second highest [graph B] . For this reason, the total NPP for this ecosystem is the third highest [ graph C].

On comparing more data, we observe a similar relationship between the graphs A,B and C.

The graphs show that the area covered by an ecosystem plays a very important role in its total NPP. This can be easily made out when you compare each ecosystem depicted in the three graphs.