As the earth warms up, the temperature and other climate conditions will change. How much of a temperature change can sea urchins take?

The larger a volume of water the longer it will take to change temperature. By suspending a test tube with our eggs and sperm in it over a beaker with the temperature at our design conditions we can watch for effects of temperature. Ideally you should have a separate thermometer for each condition. Red alcohol thermometers can be had from scientific supply houses fairly inexpensively [down to $5 ea in lots of a dozen]

Suggested temperatures:


°C How to achieve:
1 4 Test tube of seawater sitting in crushed ice
2 15 Test tube of seawater sitting in water with a small amount of ice
3 25 Test tube of seawater sitting at room temperature
4 37 Test tube of seawater sitting in hot water from tap
  1. Add one drop of concentrated eggs to each.
  2. Swirl and let sit for five minutes so the eggs adjust to the new temperature.
  3. Add one drop of diluted sperm suspension and swirl briefly.
  4. Wait 5 minutes.
  5. Score eggs for fertilization. If time permits can also score for later development [Next period see if divided]
  6. Harder to do extended periods, without constantly watching temperature. Could score for a "temporary" temperature effect at fertilization, keeping the cultures at room temperature for later development.