Oceanic Dead Zones Reading Answers

Sep 12, 2024

Oceanic Dead ZonesReading Answers is an academic reading answers topic. Oceanic Dead Zones Reading Answers has a total of 13 IELTS questions in total, from 28-30 you have to label the picture with correct words, and from 31-40 fill in the blanks with correct words.

Candidates should read the IELTS Reading passage thoroughly to recognize synonyms, identify keywords, and answer the questions below. IELTS Reading practice papers, which feature topics such as The Oceanic Dead Zones Reading Answers. Candidates can use IELTS reading practice questions and answers to enhance their performance in the reading section.

READING PASSAGE - 3

OCEANIC DEAD ZONES

Dead zones are areas of water bodies where aquatic life cannot survive because of low oxygen levels. They begin to form when excess nutrients, primarily nitrogen and phosphorus, enter coastal waters and help fertilise blooms of algae. The major nutrient sources are fertilisers, sewage, and the burning of fossil fuels. When these algae die and sink to the bottom of the sea, they provide a rich food source for bacteria, which in the act of decomposition consume dissolved oxygen from the surrounding waters. This decomposition also breaks them down to nutrients again, continuing the cycle. If stratification of the water column prevents the mixing or dissolution of atmospheric oxygen into these waters, the deleted areas will remain oxygen poor. Shallow waters are much less likely to stratify compared to deep waters, and are thus less liable to develop hypoxia. First, shallow waters tend to be well-mixed by winds and tides, and second, waters that are shallow and clear enough to allow light to reach the bottom can support primary oxygen producers such as phytoplankton, algae, and seagrasses that release oxygen during photosynthesis. The darkness of deeper water prevents phytoplankton from producing the required oxygen. As the situation worsens, more and more oxygen is used up until all organisms die, and a dead zone is formed.

Dead zones are primarily a problem for bays, lakes and coastal waters, since they receive excess nutrients from upstream sources. About half of the hypoxic zones around the world are seasonal, as oxygen depletion occurs in spring and summer following the increase in phytoplankton that results from nutrient enrichment. These hypoxic zones usually last from a few weeks to several months; however, in some locations, about 8 per cent of worldwide hypoxic conditions occur continuously throughout the year. The size of these hypoxic zones can vary significantly from year to year.

As human populations increase and the land suffers further degradation, requiring more and more fertiliser, dead zones will become more commonplace. For example, every year now, near where the Mississippi River goes into the sea, large dead zones form of 22,000 square kilometres. These areas are totally devoid of fish and other life except for anoxic bacteria. Farming using excessive nitrogen fertilisers in the river's catchment area is blamed for this and a plan has been formulated to reduce dead zones by 30 per cent over the next 3 years. When some types of algae blooms are large and produce chemicals, or toxins, the event is called a harmful algal bloom. Harmful algal blooms can occur in lakes, reservoirs, rivers, ponds, bays and coastal waters, and the toxins they produce can be harmful to human health and aquatic life. Harmful algal blooms are mainly the result of a type of algae called cyanobacteria, also known as blue-green algae. These harmful algal blooms release toxins that contaminate drinking water, causing illnesses for animals and humans. After being consumed by small fish and shellfish, these toxins move up the food chain and can hurt bigger animals like sea lions, turtles, dolphins, birds, manatees, and fish. Even if algal blooms are not toxic, they can hurt aquatic life by obstructing the sunlight and clogging fish gills.

Algal blooms and dead zones also have less obvious effects. Economists have examined the effects of nutrient overenrichment on both market goods, primarily commercial fisheries, and nonmarket industries, primarily recreational. Although many aquatic ecosystems have yet to be properly studied in this regard, there is plenty of research that shows how much impact dead zones have had on these two economic spheres. For example, it's been recently shown that there would be considerable benefits in terms of the economy to reducing nitrogen loading and hypoxic conditions in the Baltic Sea, which is an area that has long suffered dead zones caused by these problems. It has been suggested that reducing dead zone areas in the Baltic could be valued at about 10 billion dollars.

A more fundamental effect of hypoxia is the loss of energy from the ocean. By precluding or stunting the growth of bottom-dwellers such as governments spend billions of dollars per year to combat nutrient pollution or prevent its effects. In order to improve the situation, a variety clams and worms, hypoxia robs their predators of an important source of nutrition. For example, scientists estimate that Chesapeake Bay in the United States loses about 10,000 metric tons of energy to hypoxia each year, 5 percent of the Bay's total production of food energy. The Baltic Sea has lost 30 percent of its food energy - a condition that has contributed to the significant decline in its fisheries' yields. Dead zones are a key stressor of marine ecosystems and rank with overfishing, habitat loss, and harmful algal blooms as global environmental problems. They take a toll on the economy, hurting industries and sectors that depend on clean water. In addition, federal, state and local of action is required, including regulatory programs, the education of the various areas of society that are in any way involved and the takes place effectively and successfully.

Questions 28-30

Label the diagram below.

Write NO MORE THAN ONE WORD for each answer.

THE CREATION OF DEAD ZONES

Nutrient runoff from agriculture, (28)........... and fossil fuels.

Answer: sewage

Supporting statement: The major nutrient sources are fertilizers, sewage, and the burning of fossil fuels.

Keywords: fertilizer, sewage

Keyword Location: 1st paragraph, 3rd line

Explanation: The major nutrient sources are fertilizers, sewage, and the burning of fossil fuels. Thus the correct word is sewage.

Dead algae here sustain (29)............., which in turn, use up the oxygen, leading to the death of all aquatic life.

Answer: Bacteria

Supporting statement: When these algae die and sink to the bottom of the sea, they provide a rich food source for bacteria, which in the act of decomposition consume dissolved oxygen from the surrounding waters.

Keywords: algae, bacteria, oxygen

Keyword Location: 1st paragraph,4th line

Explanation: When these algae die and sink to the bottom of the sea, they provide a rich food source for bacteria, which in the act of decomposition consume dissolved oxygen from the surrounding waters. Thus the correct word is bacteria.

This area is less likely to suffer from (30)............., as water is mixed easily and light can reach it.

Answer: hypoxia

Supporting statement: Shallow waters are much less likely to stratify compared to deep waters, and are thus less liable to develop hypoxia.

Keywords: hypoxia, shallow waters

Keyword Location: 1st paragraph,7th line

Explanation: If stratification of the water column prevents the mixing or dissolution of atmospheric oxygen into these waters, the deleted areas will remain oxygen-poor. Shallow waters are much less likely to stratify compared to deep waters, and are thus less liable to develop hypoxia. Thus the correct word is hypoxia.

Questions 31-33

Write NO MORE THAN TWO WORDS for each answer.

OCEANIC DEAD ZONES

- Many oceanic areas suffer from dead zones; they can be permanent or (31)....... The size varies.

Answer: Seasonal

Supporting statement: About half of the hypoxic zones around the world are seasonal, as oxygen depletion occurs in spring and summer following the increase in phytoplankton that results from nutrient enrichment

Keywords: hypoxic, seasonal, summer

Keyword Location: 2nd paragraph,2nd line

Explanation: About half of the hypoxic zones around the world are seasonal, as oxygen depletion occurs in spring and summer following the increase in phytoplankton that results from nutrient enrichment

- With more (32)......... of agricultural land, there will be more dead zones like the ones at the mouth of the Mississippi River.

Answer: degradation

Supporting statement: As human populations increase and the land suffers further degradation, requiring more and more fertilizer, dead zones will become more commonplace. For example, every year now, near where the Mississippi River goes into the sea, large dead zones form of 22,000 square kilometers.

Keywords: degradation, Mississippi, dead zones

Keyword Location: 3rd paragraph, 1st line

Explanation: As human populations increase and the land suffers further degradation, requiring more and more fertilizer, dead zones will become more commonplace. For example, every year now, near where the Mississippi River goes into the sea, large dead zones form 22,000 square kilometers. Thus the correct answer is degradation.

Nitrogen pollution from the (33)..................... Of the river has created very large dead zones.

Answer: catchment area

Supporting statement: Farming using excessive nitrogen fertilisers in the river's catchment area is blamed for this and a plan has been formulated to reduce dead zones by 30 percent over the next 3 years.

Keywords: nitrogen fertilizer, catchment area, dead zones

Keyword location: 3rd paragraph,3rd line

Explanation: Farming using excessive nitrogen fertilizers in the river's catchment area is blamed for this and a plan has been formulated to reduce dead zones by 30 percent over the next 3 years. Thus the correct answer is catchment area.

Questions 34-40

Write NO MORE THAN TWO WORDS for each answer.

OCEANIC DEAD ZONES

- Harmful algal blooms can pollute drinking water and can make animals sick. As the toxins are absorbed into this water and the (34) ..., larger animal and humans can be affected.

Answer: food chain

Supporting statement:After being consumed by small fish and shellfish, these toxins move up the food chain and can hurt bigger animals like sea lions, turtles, dolphins, birds, manatees, and fish.

Keywords: fish, toxin,food chain

Keyword Location: 3rd paragraph,8th line

Explanation: After being consumed by small fish and shellfish, these toxins move up the food chain and can hurt bigger animals like sea lions, turtles, dolphins, birds, manatees, and fish. Thus the correct answer is a food chain.

In the sea, the blooms can block both the sun and (35)........

Answer: fish gills

Supporting statement: Even if algal blooms are not toxic, they can hurt aquatic life by obstructing the sunlight and clogging fish gills.

Keyword: algal blooms, obstructing, clogging fish gills

Keyword Location: 3rd paragraph,last line

Explanation: Even if algal blooms are not toxic, they can hurt aquatic life by obstructing the sunlight and clogging fish gills. Though the algal blooms are not toxic they cause clogging of fish gills harming their life. Thus the correct answer is fish gills.

- Dead zones also affect market and nonmarket goods, in the business and (36)........ sectors.

Answer: recreational

Supporting statement: Economists have examined the effects of nutrient over-enrichment on both market goods, primarily commercial fisheries, and nonmarket industries, primarily recreational.

Keywords: economists, nonmarket industries, recreational

Keyword Location: 4th paragraph, 2nd line

Explanation: Economists have examined the effects of nutrient over-enrichment on both market goods, primarily commercial fisheries, and nonmarket industries, primarily recreational. Thus the correct word is recreational.

(37)................ - already illustrates the effects and the (38)................ of improving the economic situation in various areas.

Answer: research

Supporting statement: Although many aquatic ecosystems have yet to be properly studied in this regard, there is plenty of research that shows how much impact dead zones have had on these two economic spheres. Keyword: aquatic ecosystems, research, economic sphere

Keyword Location: 4th paragraph, 3rd line

Explanation: there is plenty of research that shows how much impact dead zones have had on these two economic spheres. Thus the correct answer is research.

Answer: benefits

Supporting statement: For example, it's been recently shown that there would be considerable benefits in terms of the economy to reducing nitrogen loading and hypoxic conditions in the Baltic Sea, which is an area that has long suffered dead zones caused by these problems.

Keywords: benefits, economy

Keyword location:4th paragraph, 4th line

Explanation: For example, it's been recently shown that there would be considerable benefits in terms of the economy to reducing nitrogen loading and hypoxic conditions in the Baltic Sea, which is an area that has long suffered dead zones caused by these problems. Thus the correct answer is benefit.

- (39)................ is also taken from the oceans by dead zones by removing food. The Chesapeake Bay and Baltic Sea have been studied in this regard.

Answer: Energy

Supporting statement:A more fundamental effect of hypoxia is the loss of energy from the ocean

Keywords: hypoxia, energy

Keyword location:5th paragraph, 1st line

Explanation: A more fundamental effect of hypoxia is the loss of energy from the ocean. Thus the correct answer is energy.

Dead zones have various negative effects and a lot of money is spent on controlling them.

- New laws, (40)................ of important stakeholders and resources are required to make a positive difference.

Answer: Education

Supporting statement:In addition, federal, state and local of action is required, including regulatory programs, the education of the various areas of society that are in any way involved and takes place effectively and successfully.

Keywords: action, education, society

Keyword Location: 5th paragraph, last line

Explanation: In addition, federal, state, and local action is required, including regulatory programs, the education of the various areas of society that are in any way involved and the takes place effectively and successfully. Thus the correct word is education.

Read More IELTS Reading Related Samples