The Tundra Ecosystem

What are the two bacteria species involved in the process of nitrification?

Nitrosomonas and Nitrobacter

Why is the conversion of nitrites into nitrates important?

Ammonia gas is toxic for plants

What is the process called when primary producers take in nitrogen compounds from the soil?

Assimilation

What are the different forms in which nitrogen compounds are available in the soil?

Ammonia, nitrite ions, nitrate ions, and ammonium ions Signup and view all the answers

How does nitrogen enter the food web?

When primary consumers eat the plants Signup and view all the answers

What is the process called when nitrogen is released back into the soil from organic matter?

Ammonification Signup and view all the answers

What is the final stage of the nitrogen cycle?

Denitrification Signup and view all the answers

What is the byproduct of denitrification?

Free nitrogen gas Signup and view all the answers

What is the role of the nitrogen cycle in plants?

Helps plants to synthesize chlorophyll and provides usable nitrogen compounds Signup and view all the answers

How do human activities contribute to the nitrogen cycle?

Combustion of fuels and use of nitrogen fertilizers Signup and view all the answers

What are some characteristics of the tundra biome?

Some characteristics of the tundra biome include an extremely cold climate, low biotic diversity, simple vegetation structure, limitation of drainage, short season of growth and reproduction, energy and nutrients in the form of dead organic material, and large population oscillations. Signup and view all the answers

What are some indicator species of the tundra biome?

Some indicator species of the tundra biome include willows, sedges, and grasses. Signup and view all the answers

What is a keystone species in the tundra biome and why is it important?

The Arctic fox is a keystone species in the tundra biome. It is important because it serves as food for polar bears, wolves, kittiwakes, and snowy owls. Signup and view all the answers

How can you identify a tundra biome?

A tundra biome can be identified by its long, dark, and cold winters with mean temperatures below 0°C for six to 10 months of the year. It also has a layer of permanently frozen ground called permafrost. Signup and view all the answers

What are the steps involved in the nitrogen cycle?

The steps involved in the nitrogen cycle are nitrogen fixation, nitrification, assimilation, ammonification, and denitrification. Signup and view all the answers

What is nitrogen fixation and how does it occur?

Nitrogen fixation is the process of converting inert atmospheric nitrogen into the usable form of ammonia. It occurs through symbiotic bacteria like Azotobacter and Rhizobium, which have nitrogenase enzymes that combine gaseous nitrogen with hydrogen to form ammonia. Signup and view all the answers

What is the role of Azotobacter and Rhizobium in nitrogen fixation?

Azotobacter and Rhizobium are bacteria that play a major role in nitrogen fixation. They have nitrogenase enzymes that can combine gaseous nitrogen with hydrogen to form ammonia. Signup and view all the answers

How can nitrogen fixation occur besides atmospheric fixation?

Nitrogen fixation can also occur through industrial fixation, which involves manufacturing ammonia under high temperature and pressure conditions. Signup and view all the answers

What is nitrification and what does it involve?

Nitrification is the process of converting ammonia into nitrate. It involves the presence of bacteria in the soil. Signup and view all the answers

What is the main form of atmospheric nitrogen and how is it converted into ammonia?

The main form of atmospheric nitrogen is inert. It is converted into ammonia through the process of nitrogen fixation, where symbiotic bacteria deposit the inert nitrogen gas into soils from the atmosphere and surface waters. Signup and view all the answers