Light & Temperature Requirements

You will need to provide them with an appropriate amount of light on a regular basis because the only way they can grow is by producing their own food using a process called photosynthesis, just like plants do. So, make sure you grow them in a container that is clear so they can get light. They can grow in sunlight or artificial light as long as it's fairly bright but not too hot. As far as temperature, they need to be kept in an area that doesn't get too hot or too cold, so sometimes a window is not ideal. Also, don't keep them in your pocket or hold them too long because your body temperature will heat them up too much and they will die. Shipping is obviously a problem for these temperature reasons, sometimes the dinos don't survive shipping.

Light Cycles

These dinoflagellates have a circadian rhythm which controls their bioluminescence and photosynthesis on a 24-hour basis, i.e. they only photosynthesize when they “think” it's day and they only produce bioluminescence or flash when they “think” it's night. So, you need to grow them on a strict light schedule, otherwise their natural rhythms can't synchronize with the light cycle and they won't know when to flash and when not to flash.

Ideally, they should get 12 hours of light and 12 hours of darkness every 24 hours and at the same time every day. If you can do this, the dinos will be brightly luminescent whenever they are in their "night phase" and they will be pretty much non-luminescent when they are in their "day phase". If you have access to a grow light or an aquarium/terriarium light this is ideal, because then you can really control when they get their photosynthetic light. For example, you could grow them in a place that doesn't get any natural sunlight and instead give them artificial light at night so that in the daytime (when the sun is really out) the dinos will think it is nighttime and will be flashing brightly.

If you are doing experiments with these organisms remember that these rhythms will determine when you should perform the experiments. You should test their bioluminescence at the same time everynight so you know that the organism is at the same point in its natural rhythm each time.

Experimenting with the bioluminescence

There are many different simple experiments you can do with your bioluminescent dinos.

In a similar fashion to the way we perceive being touched, this is the type of stimulation that causes a dinoflagellate to produce a flash of light. Dinos are highly sensitive to anything that pushes on their cell wall, even the seawater they live in can cause them to flash if it becomes very rough and stirred up. That is what is happening whenever you shake the container that your dinos live in, the water is becoming very turbulent and pushing on their cell walls causing them to flash.

• What other types of stimulation cause them to flash?

• How much stimulation can the dinos withstand before their bioluminescence is exhausted? How long does it take for them to recover?

Changing their light cycles is an interesting study, but remember that it takes the dinos about a week to get used to the new light cycle (just like humans who travel to places that are in extremely different time zones, it takes a few days to get used to that time zone, because your circadian rhythms are confused).

• What immediate effects do you see if you put dinos in their nightphase into the light?

If you have a microscope to view the cells with, here are some observations you can make:

• What differences do you notice between a cell in the middle of its dayphase and one in the middle of its nightphase? Hint: the chloroplasts are the golden-brown bodies within the cell. How might you explain this?

• Examine the different stages in the life cycle of these asexually reproducing cells. (The enitre life cycle takes 5-7 days)

Currently, scientists are using the bioluminescence a dinoflagellate produces as an assay for detrimental effects caused by pollution in various marine environments. The bioluminescence that a dinoflagellate can produce reflects how healthy it is.

• What types of chemicals might be found in a polluted harbor that might affect organisms that live there?

How to measure the light...
When we test our dinos for light output we put them in small (15 ml) glass vials and stir them with a magnetic stirrer. The method that CISE recommends for measuring light output is to use a scale from 1-10, with 1 representing a relatively small amount of light and 10 representing a relatively large amount of light. You should always establish a group of cells that serve as "controls" which have been grown in normal conditions. To determine if your experimental cells have been affected by the treatment, compare their light output with the light output of the control cells. It is best to assume that your controls are producing light at level 5, so then if the experimental cells produce more light than the controls you give them a number higher than 5, and if they produce less light than the controls you give them a number lower than 5. Also, you have to be very careful not to "stimulate" the dinos before you actually measure their light output because the first time they flash they produce a lot more light than each successive flash. The other thing you have to consider is that whenever you add substances to the seawater that the dinos are in, that will cause them to flash. Even if you are just adding seawater, the seawater that they live in will be physically disturbed by any liquid being added to it, so the dinos will be stimulated by this physical disturbance of their surrounding water.

There are lots of things you could examine besides these listed here. Try to come up with an entire new idea that you could test using the bioluminescence of dinoflagellates.

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