Background: Water stratification is when water masses with different properties - salinity (halocline), oxygenation (chemocline), density (pycnocline), temperature (thermocline) - form layers that act as barriers to water mixing which could lead to anoxia or euxinia.[1] These layers are normally arranged according to density, with the least dense water masses sitting above the more dense layers.

Water stratification also creates barriers to nutrient mixing between layers. This can affect the primary production in an area by limiting photosynthetic processes. When nutrients from the benthos cannot travel up into the photic zone, phytoplankton may be limited by nutrient availability. Lower primary production also leads to lower net productivity in waters.[2]

Situation: Scientists studied water stratification in two saltwater lakes. they were trying to find out why the fish population decreased in Long lake, and was very healthy and abundant in Shoal lake. They found out the phenomenon occurred more often in Long lake, leading to very many unpleasant chain effects.

Question: Which lake had more denser layers of water?
Answer: Long lake

Situation: Scientists studied water stratification in two saltwater lakes. they were trying to find out why the fish population decreased in Long lake, and was very healthy and abundant in Shoal lake. They found out the phenomenon occurred more often in Long lake, leading to very many unpleasant chain effects.

Question: Which lake had less denser layers of water?
Answer: Shoal lake

Situation: Scientists studied water stratification in two saltwater lakes. they were trying to find out why the fish population decreased in Long lake, and was very healthy and abundant in Shoal lake. They found out the phenomenon occurred more often in Long lake, leading to very many unpleasant chain effects.

Question: Which lake had a smaller fish population?
Answer: Long lake

Situation: Scientists studied water stratification in two saltwater lakes. they were trying to find out why the fish population decreased in Long lake, and was very healthy and abundant in Shoal lake. They found out the phenomenon occurred more often in Long lake, leading to very many unpleasant chain effects.

Question: Which lake had a larger fish population?
Answer: Shoal lake

Situation: Scientists studied water stratification in two saltwater lakes. they were trying to find out why the fish population decreased in Long lake, and was very healthy and abundant in Shoal lake. They found out the phenomenon occurred more often in Long lake, leading to very many unpleasant chain effects.

Question: Which lake had less  phytoplankton?
Answer: Long lake

Situation: Scientists studied water stratification in two saltwater lakes. they were trying to find out why the fish population decreased in Long lake, and was very healthy and abundant in Shoal lake. They found out the phenomenon occurred more often in Long lake, leading to very many unpleasant chain effects.

Question: Which lake had more phytoplankton?
Answer: Shoal lake

Situation: Scientists studied water stratification in two saltwater lakes. they were trying to find out why the fish population decreased in Long lake, and was very healthy and abundant in Shoal lake. They found out the phenomenon occurred more often in Long lake, leading to very many unpleasant chain effects.

Question: Which lake had a lower net productivity?
Answer: Long lake

Situation: Scientists studied water stratification in two saltwater lakes. they were trying to find out why the fish population decreased in Long lake, and was very healthy and abundant in Shoal lake. They found out the phenomenon occurred more often in Long lake, leading to very many unpleasant chain effects.

Question: Which lake had a higher net productivity?
Answer: Shoal lake

Situation: Scientists studied water stratification in two saltwater lakes. they were trying to find out why the fish population decreased in Long lake, and was very healthy and abundant in Shoal lake. They found out the phenomenon occurred more often in Long lake, leading to very many unpleasant chain effects.

Question: Which lake had more dissolved nutrients?
Answer: Shoal lake

Situation: Scientists studied water stratification in two saltwater lakes. they were trying to find out why the fish population decreased in Long lake, and was very healthy and abundant in Shoal lake. They found out the phenomenon occurred more often in Long lake, leading to very many unpleasant chain effects.

Question: Which lake had fewer dissolved nutrients?
Answer: Long lake

Situation: High lake had a lot of fresh and salt water mixing, therefore presented layers of stratified water.The water was poor in nutrients.Low lake had no such problems and it was a very abundant and prolific fishing spot.

Question: Which lake had fewer dissolved nutrients?
Answer: High lake

Situation: High lake had a lot of fresh and salt water mixing, therefore presented layers of stratified water.The water was poor in nutrients.Low lake had no such problems and it was a very abundant and prolific fishing spot.

Question: Which lake had more dissolved nutrients?
Answer: Low lake

Situation: High lake had a lot of fresh and salt water mixing, therefore presented layers of stratified water.The water was poor in nutrients.Low lake had no such problems and it was a very abundant and prolific fishing spot.

Question: Which lake had more dense layers of water?
Answer: High lake

Situation: High lake had a lot of fresh and salt water mixing, therefore presented layers of stratified water.The water was poor in nutrients.Low lake had no such problems and it was a very abundant and prolific fishing spot.

Question: Which lake had less dense layers of water?
Answer: Low lake

Situation: High lake had a lot of fresh and salt water mixing, therefore presented layers of stratified water.The water was poor in nutrients.Low lake had no such problems and it was a very abundant and prolific fishing spot.

Question: Which lake had less benthos?
Answer: High lake

Situation: High lake had a lot of fresh and salt water mixing, therefore presented layers of stratified water.The water was poor in nutrients.Low lake had no such problems and it was a very abundant and prolific fishing spot.

Question: Which lake had more benthos?
Answer: Low lake

Situation: High lake had a lot of fresh and salt water mixing, therefore presented layers of stratified water.The water was poor in nutrients.Low lake had no such problems and it was a very abundant and prolific fishing spot.

Question: Which lake had more phytoplankton?
Answer: Low lake

Situation: High lake had a lot of fresh and salt water mixing, therefore presented layers of stratified water.The water was poor in nutrients.Low lake had no such problems and it was a very abundant and prolific fishing spot.

Question: Which lake had less phytoplankton?
Answer: High

Situation: High lake had a lot of fresh and salt water mixing, therefore presented layers of stratified water.The water was poor in nutrients.Low lake had no such problems and it was a very abundant and prolific fishing spot.

Question: Which lake had less anoxia?
Answer: Low lake

Situation: High lake had a lot of fresh and salt water mixing, therefore presented layers of stratified water.The water was poor in nutrients.Low lake had no such problems and it was a very abundant and prolific fishing spot.

Question: Which lake had more anoxia?
Answer: High lake

Situation: The marine biologists studied two areas of the Black Sea. Area A, situated at the mouth of the Danube River, which presented high levels of water stratification, because of the fresh water discharged by the river; and area B, situated 35 miles south, where the water was less stratified and more oxygenated.

Question: Which of the two areas had more phytoplankton?
Answer: area B

Situation: The marine biologists studied two areas of the Black Sea. Area A, situated at the mouth of the Danube River, which presented high levels of water stratification, because of the fresh water discharged by the river; and area B, situated 35 miles south, where the water was less stratified and more oxygenated.

Question: Which of the two areas had less phytoplankton?
Answer: area B

Situation: The marine biologists studied two areas of the Black Sea. Area A, situated at the mouth of the Danube River, which presented high levels of water stratification, because of the fresh water discharged by the river; and area B, situated 35 miles south, where the water was less stratified and more oxygenated.

Question: Which of the two areas had less salinity?
Answer: Area A

Situation: The marine biologists studied two areas of the Black Sea. Area A, situated at the mouth of the Danube River, which presented high levels of water stratification, because of the fresh water discharged by the river; and area B, situated 35 miles south, where the water was less stratified and more oxygenated.

Question: Which of the two areas had more salinity?
Answer: area B

Situation: The marine biologists studied two areas of the Black Sea. Area A, situated at the mouth of the Danube River, which presented high levels of water stratification, because of the fresh water discharged by the river; and area B, situated 35 miles south, where the water was less stratified and more oxygenated.

Question: Which of the two areas had more dense water?
Answer: area B

Situation: The marine biologists studied two areas of the Black Sea. Area A, situated at the mouth of the Danube River, which presented high levels of water stratification, because of the fresh water discharged by the river; and area B, situated 35 miles south, where the water was less stratified and more oxygenated.

Question: Which of the two areas had less dense water?
Answer: Area A

Situation: The marine biologists studied two areas of the Black Sea. Area A, situated at the mouth of the Danube River, which presented high levels of water stratification, because of the fresh water discharged by the river; and area B, situated 35 miles south, where the water was less stratified and more oxygenated.

Question: Which of the two areas was less oxygenated?
Answer: Area A

Situation: The marine biologists studied two areas of the Black Sea. Area A, situated at the mouth of the Danube River, which presented high levels of water stratification, because of the fresh water discharged by the river; and area B, situated 35 miles south, where the water was less stratified and more oxygenated.

Question: Which of the two areas was more oxygenated?
Answer: area B

Situation: The marine biologists studied two areas of the Black Sea. Area A, situated at the mouth of the Danube River, which presented high levels of water stratification, because of the fresh water discharged by the river; and area B, situated 35 miles south, where the water was less stratified and more oxygenated.

Question: Which of the two areas has lower net productivity?
Answer: Area A

Situation: The marine biologists studied two areas of the Black Sea. Area A, situated at the mouth of the Danube River, which presented high levels of water stratification, because of the fresh water discharged by the river; and area B, situated 35 miles south, where the water was less stratified and more oxygenated.

Question: Which of the two areas has higher net productivity?
Answer: area B