withDerek andStephanie

Ecology is the scientific study of

how living things interact with

each other and their

environment.

Today:

Begin an experiment examining how acidicwater, which is a result of ocean acidification, affects the shells of marine organisms such as mussels and clams.

How are living things affected by the changingenvironment?

OCEAN ACIDIFICATION

• More acid in the water makes it difficult for organisms such as corals, mussels, sea urchins, and clams, to build shells.

OCEAN ACIDIFICATION

Carbon dioxide in the atmosphere (the air) mixes with the ocean water and makes it more acidic.

More acid in the water makes it difficult for organisms such as

corals, mussels, sea urchins, and clams, to build shells, which

are made of mostly calcium. This is for two reasons:

1. It’s harder for them to grow new shell because there is less calcium in the water.

2. The acid also directly dissolves the calcium in the already existing shell.

How do we measure acidity in the water?

pH in the ocean is dropping!

Everything in the environment is connected, so if marine organisms with shells are affected,

many others are affected as well.

1. You will come up and get 2 cups of shells. Then you will weigh each cup on the scale.

WHAT IS THE WEIGHT, IN GRAMS, OF EACH CUP?

Write this down in your notebook and on the sticky paper and stick it on the cup and.

2. Next, you will get a cup of vinegar, a cup of

water, and two pH strips.

Gently swirl the pH strips in each cup.

WHAT IS THE pH OF EACH CUP?

Pour the vinegar over one cup of shells and

the water over the other cup of shells.

Write down the pH of each on the stickypaper on the cup and in your notebook.

3. We will leave the shells in the vinegar and

water for 1 week. After 1 week we willweigh each cup and see if there is a

changein the weight of the shells.

Based on what you learned about oceanacidification, if the shells in the vinegardecreased in weight, whereas the shells in

thewater did not, what does this suggest?

WRITE THESE DOWN IN YOUR NOTEBOOK:

IS THE WATER OR THE VINEGAR MOREACIDIC?

DO YOU HYPOTHESIZE THAT THE SHELLSIN THE VINEGAR OR WATER WILL CHANGEWEIGHT?

WILL THE WEIGHT GO UP OR DOWN?

WHY DO YOU THINK SO?

HOW SCIENCE WORKS:

The Scientific MethodHypothesis,Prediction

Experiment,Measurements

Analyzedata

DrawConclusions

Note: You will need to use the same type of shells to put inthe water and vinegar for comparison. We gave the studentsthe option of using mussels or sea urchin shells (or ‘tests’). The urchin tests were almost gone after a week in vinegar andour scale was not sensitive enough to detect the remainingweight.

Although this still showed that the acidic solution wasdamaging the calcium carbonate shell, it would have been betterto have a more sensitive scale or to have left the shells in vinegar for a shorter period of time.

At the end of the experiment we had the students graph the % weight change of the shells in vinegar and the shells in water.