HI~ I hope this helps
(these answers were hand-written meaning I did not copy and paste so, feel free to use the answers freely)
1.
When ecosystems change rapidly the fundamental environmental cycles such as the circulation of water, carbon and nutrients can change as ecosystems depend on them. The usage of factors such as freshwater, carbon dioxide emissions and fertilizer provides a large benefit to humas therefore meaning, that large and rapid changes to an ecosystem could also effect the things we as humans rely on.
2.
Complex organic matter is broken down by decomposers into carbon dioxide, water etc. The ecosystem is affected based upon the fact that the decomposition of organic matter that is produced by plants, animals and soil organisms is an important process which affects the different important ecosystem processes like nutrient cycling and carbon sequestration.
3. (could have two answers- I recommend the second)
Adaptation- due to the mutation process which results in changes in the structure and function of organisms, these ecosystems would be different as well as unique. The organisms which possesses the traits needed to adapt could then survive as its unique characteristics due to mutation would provide a strong ability
Rise in temperature- If the temperature located on earth was to rise, organisms would have a higher living rate as bacterial life flourishes in warmer temperatures and dies out in colder ones.
4.
~The rapid change of increased food production provides better life sustainability to those living in the ecosystem.
~The rapid change in a large increasing number of organisms could be helpful as they often live of off one another.
5.
~Rapid growth of things such as phytoplankton which cause dead zones are harmful to the ecosystem. Dead zones create zones where too much oxygen is consumed resulting in areas where plants and sea life can no longer survive.
~Whereas the rapid increase of organisms could also be harmful to an ecosystem as the possibility of the organism outnumbering the food sources could become prominent.