Skip to main content
Pearson+ LogoPearson+ Logo
Ch. 40 - Water and Electrolyte Balance in Animals
Freeman - Biological Science 8th Edition
Freeman8th EditionBiological ScienceISBN: 9780138276263Not the one you use?Change textbook
All textbooksFreeman 8th EditionCh. 40 - Water and Electrolyte Balance in AnimalsProblem 12b
Chapter 40, Problem 12b

Fish and other aquatic organisms are exposed to many types of water pollutants, including metals such as aluminum. Although a low level of aluminum is found in unpolluted water, many lakes and streams have an increased level because of mining, sewage treatment, and accidental spills of toxic materials. Aluminum pollution can result in mass fish die-offs. In a laboratory, scientists exposed freshwater bony fish (Prochilodus lineatus) to water with a high level of aluminum and compared their blood osmolarity to that of fish exposed to water with a normal aluminum level (control). The results of the experiment are shown here (asterisks indicate P<0.05 between control and treated groups at a given time).
Do the data support the hypothesis that aluminum interferes with osmoregulation in freshwater fishes? Explain.

Verified step by step guidance
1
Begin by understanding the concept of osmoregulation, which is the process by which organisms maintain the balance of water and salts in their bodies to ensure proper cellular function.
Examine the experimental setup: scientists exposed freshwater bony fish to high levels of aluminum and compared their blood osmolarity to fish in normal aluminum conditions. Blood osmolarity is a measure of the concentration of solutes in the blood, which is crucial for osmoregulation.
Analyze the data provided in the experiment. Look for changes in blood osmolarity between the control group and the aluminum-exposed group. Pay attention to any significant differences indicated by asterisks, which denote statistical significance (P<0.05).
Consider the implications of the data: if the aluminum-exposed fish show a significant change in blood osmolarity compared to the control group, it suggests that aluminum may interfere with the fish's ability to regulate osmolarity, supporting the hypothesis.
Conclude by synthesizing the information: if the data show consistent and significant differences in blood osmolarity between the two groups, it supports the hypothesis that aluminum interferes with osmoregulation in freshwater fishes. Discuss how this interference could lead to physiological stress or harm to the fish.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
1m
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Osmoregulation

Osmoregulation is the process by which organisms maintain the balance of water and electrolytes in their bodies to ensure proper cellular function. In freshwater fish, osmoregulation involves actively absorbing salts through their gills and excreting excess water to prevent dilution of body fluids. Disruption in this process can lead to physiological stress or death, making it crucial for survival in varying aquatic environments.
Recommended video:
Guided course
07:16
Osmoregulation and Nitrogenous Waste

Effects of Aluminum Pollution

Aluminum pollution in aquatic environments can have toxic effects on fish and other organisms. High levels of aluminum can interfere with gill function, impairing the ability of fish to regulate ion exchange and water balance, which is essential for osmoregulation. This can lead to increased blood osmolarity, physiological stress, and potentially mass die-offs, highlighting the importance of monitoring and controlling aluminum levels in water bodies.
Recommended video:
Guided course
03:36
Pollution and Climate Change

Experimental Design and Statistical Significance

In scientific experiments, comparing treated and control groups helps determine the effect of a variable, such as aluminum exposure. Statistical significance, indicated by P-values (e.g., P<0.05), shows whether observed differences are likely due to the treatment rather than random chance. In this study, significant differences in blood osmolarity between groups suggest aluminum's impact on osmoregulation, supporting the hypothesis that aluminum interferes with this vital process in freshwater fish.
Recommended video:
Guided course
02:50
Experimental Design Example 1
Related Practice
Textbook Question

Biologists have been able to produce mice that lack functioning genes for aquaporins. How would the urine of these mice compare to that of mice with normal aquaporins?

a. Lower volume and lower osmolarity

b. Lower volume and higher osmolarity

c. Higher volume and lower osmolarity

d. Higher volume and higher osmolarity

711
views
Textbook Question

To test the hypothesis that mussels are osmoconformers, researchers exposed mussels to water of varying osmolarities and then drew hemolymph samples from the mussels. Graph the data provided here. Put the independent variable on the x-axis and the dependent variable on the y-axis.

Is the researchers' hypothesis supported by the data? Explain.

667
views
Textbook Question

Fish and other aquatic organisms are exposed to many types of water pollutants, including metals such as aluminum. Although a low level of aluminum is found in unpolluted water, many lakes and streams have an increased level because of mining, sewage treatment, and accidental spills of toxic materials. Aluminum pollution can result in mass fish die-offs such as the one pictured here. How does this occur? Which of the following is an osmoregulatory challenge that freshwater fishes need to overcome?

a. Diffusion of sodium ions out of the body

b. Diffusion of water out of the body

c. Active transport of sodium ions out of the body

d. Active transport of water out of the body

787
views
Textbook Question

Fish and other aquatic organisms are exposed to many types of water pollutants, including metals such as aluminum. Although a low level of aluminum is found in unpolluted water, many lakes and streams have an increased level because of mining, sewage treatment, and accidental spills of toxic materials. Aluminum pollution can result in mass fish die-offs.

Why did the scientists do this experiment in a laboratory instead of simply collecting fish from a river with a high aluminum level and documenting their osmoregulatory ability?

457
views
Textbook Question

Fish and other aquatic organisms are exposed to many types of water pollutants, including metals such as aluminum. Although a low level of aluminum is found in unpolluted water, many lakes and streams have an increased level because of mining, sewage treatment, and accidental spills of toxic materials. Aluminum pollution can result in mass fish die-offs. The scientists also measured the activity of Na+/K+-ATPase in the gills of the fish exposed to aluminum and compared it to that of the control fish.

What do you suppose were their results? Explain.

513
views
Textbook Question

Fish and other aquatic organisms are exposed to many types of water pollutants, including metals such as aluminum. Although a low level of aluminum is found in unpolluted water, many lakes and streams have an increased level because of mining, sewage treatment, and accidental spills of toxic materials. Aluminum pollution can result in mass fish die-offs.

True or false: Water moves by osmosis across a fish's gills to an area with a higher sodium ion concentration because water molecules are attracted to the sodium ions.

515
views