Below are sentences containing some vocabulary that you will need to understand the texts in this unit. Examine the words in bold and try to determine their meaning from the context in which they are used. These ten bold words will be assessed in the final exam and end of unit quizzes. When you are ready, take the practice quiz below and check your answers.
The problem with nitrogen is that it is an inert gas, which means that it is unavailable to living organisms in its gaseous form.
The nitrogen cycle is a biogeochemical cycle that describes how nitrogen and nitrogen- containing compounds are changed in nature.
Here they form a mutualistic relationship with the plant. The bacteria get carbohydrates (food) from the plant and, in exchange, produce ammonia which can be converted into nitrogen compounds that are essential for the survival of the plant.
Once the nitrates have been assimilated by the plants, they become part of the plants’ proteins.
Eutrophication is the addition of artificial or natural substances, such as nitrates and phosphates, through fertilizers or sewage, to an aquatic system.
Untreated sewage effluent and agricultural run-off carrying fertilizers are examples of human-caused eutrophication.
Many ecological effects can arise from eutrophication, but there are three particularly troubling ecological impacts: decreased biodiversity, changes in species composition and dominance, and toxicity effects.
Sometimes this can cause certain plant species to be favored over the others and one species may ’take over’ the ecosystem, resulting in a decrease in plant diversity.
Eutrophication generally promotes excessive plant growth and decay, favoring simple algae and plankton over other more complicated plants, and causes a severe reduction in water quality.