Question 1

Why is the concentration of carbon dioxide in Earth's atmosphere rapidly increasing?

Accepted Answer

Human activities such as burning fossil fuels, deforestation, and industrial processes release significant amounts of carbon dioxide into the atmosphere, leading to its rapid increase.

Question 2

Forests along rivers in the Pacific Northwest that have lost their salmon populations are less productive because the

Accepted Answer

Salmon bring essential nutrients like nitrogen from the ocean to river ecosystems, which support forest productivity.

Question 3

Micronutrients

Accepted Answer

Micronutrients are essential nutrients required by living organisms in smaller quantities than macronutrients. Examples include vitamins, minerals, and trace elements.

Question 4

In an area with nitrogen- poor soil, legumes often dominate over other plants because they

Accepted Answer

Legumes have a symbiotic relationship with nitrogen-fixing bacteria (rhizobia) in their root nodules, allowing them to access atmospheric nitrogen and thrive in nitrogen-poor soils.

Question 5

The greenhouse effect, which has become a major ecological concern, is caused by

Accepted Answer

The greenhouse effect is primarily caused by the increase in atmospheric concentrations of greenhouse gases like CO2, CH4, and N2O, which trap heat in the atmosphere.

Question 6

What are the sources of sulfur in the atmosphere?

Accepted Answer

Sulfur in the atmosphere primarily comes from human activities like burning coal, which accounts for about 75%, and natural sources like volcanoes and hot springs.

Question 7

When nitrogen oxides and sulfur dioxide combine with water vapor in the air, they are converted to nitric acid and sulfuric acid, respectively. This precipitation that then falls to the Earth is known as

Accepted Answer

Acid deposition is the precipitation that then falls to the Earth when nitrogen oxides and sulfur dioxide combine with water vapor in the air and are converted to nitric acid and sulfuric acid, respectively.

Question 8

When you observe a lake that has been affected by acid deposition, you might expect to find

Accepted Answer

Acid deposition can cause the leaching of metals like aluminum into the water, leading to clear water with high metal levels and a decline in fish populations.

Question 9

Farmers often include legumes as part of their normal crop rotation. This practice increases the overall production of their crops by

Accepted Answer

Legumes have a symbiotic relationship with nitrogen-fixing bacteria, which convert atmospheric nitrogen into a form that plants can use, thus enriching the soil with nitrogen and enhancing crop production.

Question 10

The greenhouse effect is the ability of

Accepted Answer

The greenhouse effect is the ability of certain gases to retain heat in the atmosphere instead of allowing it to be reflected back into space.

Question 11

Carbon dioxide and other greenhouse gases cause Earth's temperature to increase by

Accepted Answer

Greenhouse gases like carbon dioxide absorb heat energy and trap it in the atmosphere, preventing it from escaping back into space, which leads to an increase in Earth's temperature.

Question 12

Phosphate fertilizers have increased the amount of phosphate in lakes and other bodies of water. What effect does this increase have on the phytoplankton in the water?

Accepted Answer

Phosphate is a nutrient that phytoplankton need for growth. When phosphate levels in the water increase, phytoplankton populations can grow rapidly.

Question 13

Once used by an organism, carbon- and nitrogen- based nutrients are unavailable for other organisms.

Accepted Answer

Once used by an organism, carbon- and nitrogen-based nutrients can be recycled and become available for other organisms through processes such as decomposition and nutrient cycling.

Question 14

Each summer, a large "dead zone" devoid of fish and other animals develops where the Mississippi River flows into the Gulf of Mexico. What causes this?

Accepted Answer

The dead zone is primarily caused by nutrient pollution from fertilizers, which leads to excessive algae growth. When the algae die and decompose, oxygen levels in the water decrease, creating hypoxic conditions that cannot support marine life.

Question 15

Burning coal and oil to release energy also releases , which are overloading Earth's nutrient cycles.

Accepted Answer

Burning coal and oil releases sulfur, carbon, and nitrogen compounds, which contribute to environmental issues like acid rain and greenhouse gas emissions, affecting Earth's nutrient cycles.

Question 16

Human- caused disturbances of the cycle may be contributing to global warming.

Accepted Answer

The carbon cycle is heavily impacted by human activities, such as burning fossil fuels and deforestation, which increase atmospheric CO2 levels and contribute to global warming.

Question 17

The present range of the sugar maple in North America extends from the Atlantic Ocean west to the Mississippi River and from southern Ontario, Quebec, and New Brunswick south to Tennessee and Virginia. If the global temperature rises 10°C in the future, where will the range of sugar maples be found?

Accepted Answer

As global temperatures rise, the suitable habitat for sugar maples will likely shift northward, as these trees prefer cooler climates.

Question 18

Nitrogen is the most abundant element in the atmosphere, and a crucial component of proteins, vitamins, and nucleic acids. However, plants and other producers cannot use nitrogen in its natural form (N2). Nitrogen has to undergo a process called nitrogen fixation. What does this process involve?

Accepted Answer

Nitrogen fixation is the process by which certain bacteria convert nitrogen gas (N2) from the atmosphere into ammonia (NH3), which can then be used by plants.

Question 19

The hydrologic cycle is different from other nutrient cycles in that

Accepted Answer

The hydrologic cycle is primarily a physical process involving the movement of water through the atmosphere, oceans, and land, with minimal direct involvement of living organisms compared to other nutrient cycles.

Question 20

Acid deposition is the result of interference with the cycles.

Accepted Answer

Acid deposition is primarily caused by the release of sulfur dioxide (SO2) and nitrogen oxides (NOx) into the atmosphere, which then react with water vapor to form sulfuric and nitric acids.

Quiz 29: Energy Flow and Nutrient Cycling in Ecosystems