Directions: Use the information provided and your knowledge of Life Science to answer the following questions. Show all work where necessary.
Directions: Use the information provided and your knowledge of Life Science to answer the following questions. Show all work where necessary.
Along rocky coastlines, tide pools form in shallow depressions that fill with seawater during high tide and partially dry during low tide. These pools experience dramatic daily changes in temperature, oxygen, and especially salinity as water evaporates or rainwater dilutes the salt concentration.
Different organisms vary widely in how well they tolerate these fluctuations:
Mussels and barnacles can tightly close their shells to prevent water loss and tolerate short periods of exposure.
Hermit crabs and small snails can survive moderate salinity changes but must retreat to deeper pools during extreme conditions.
Sea stars and sea cucumbers require stable, fully marine conditions and often die if trapped in upper pools that dry out or become too fresh after rain.
Field data from the Monterey Bay Aquarium Research Institute (MBARI) and University of Oregon intertidal surveys show that survival rates depend strongly on how much the salinity changes. In upper tide pools where salinity can swing from
These patterns illustrate that within one small habitat, some organisms survive well (mussels, barnacles), some less well (crabs, snails), and some cannot survive at all (sea stars, sea cucumbers) when environmental stress exceeds their tolerance limits.
Salinity (ppt) | Mussel Survival (%) | Hermit Crab Survival (%) | Sea Star Survival (%) |
|---|---|---|---|
15 | 65 | 40 | 0 |
25 | 80 | 70 | 20 |
35 | 90 | 85 | 85 |
45 | 75 | 55 | 15 |
50 | 60 | 30 | 0 |
Make a claim, provide the evidence, and explain your reasoning for the statement:
“In tide pools, some organisms survive well under changing salinity, some survive less well, and some cannot survive at all.”
Respond with a clear claim, supporting evidence from the passage or data, and reasoning that links your evidence to the claim.
Refer to Table 1 in the Tide Pool Organisms and Salinity Fluctuations resource.
Describe how changing salinity levels affect the survival of mussels, hermit crabs, and sea stars.
Which tide pool organism can survive the widest range of salinity changes?
Why can mussels survive better in upper tide pools than sea stars?
If heat waves or pollution increase stress in tide pools, what are two actions people could take to help protect these coastal organisms?