Look Deep Into The Lake EarthCache

All the good lakes are similar all the problematic lakes are unique in their own way (a twist on the famous Anna Karenina quote). This earthcache will try to teach you a bit about lake stratification, mixing issues and the uniqueness of Pink lake (unique, not problematic).

Water and Temperature a fun relationship.

Water is very unique since it is denser as a liquid than solid, remember ice traps air inside so it actually takes more volume and floats on water. That’s why we have a layer of ice on TOP of lakes and it does not sink. Water is actually the densest at 4 degrees Celsius so if it warms (or cools) it will get less dense. Now the denser the water the heavier so we can expect the water to be the denser on the bottom (around 4 degrees right)

That was interesting what about the changing of the seasons?

Now you are talking, well in Canada we have hot summers and cold winters right? Let's see what happens:

In the summer the sun heats the top layer (called epilmnion) which becomes less dense (right we talked about it) and therefore “floats” on the layer beneath it (hypolimnion) which doesn’t receive sunlight and remains cold. These 2 layers do not mix and since plants (and algae) need sunlight they grow mostly at the epimnion. I said mostly because the sunlight can penetrate in certain areas and reach other layers. When the algae (and zooplankton) dies they sink and are eaten by fish and other creature while causing oxygen consumption but since the bottom layer do not mix with the hotter top layer it actually has less oxygen and when it is consumed we can reach anoxic conditions which will actually affect the creatures living there.

Fall comes (and winter is coming soon) and we have less sunlight and colder nights. This actually increases the mixing of the layers since it cools down the top layer (epilmnion remember) and changes its density again. Wind also helps to cool down but also mix the water layers since the density differences shrink. This mixing will allow oxygen and other nutrients penetrate and reach the lower levels of the lake and inject life to those who need them.

Winter (we are in Canada), ice is formed on top of the lake and under it the water can not mix since the ice blocks the wind (and sunlight). Under the ice most water is around 4 degree but more importantly, no oxygen reaches bottom layers and all fish and living organisms who need ice die. In the bottom of the lake where we have anoxic conditions we also have release nutrients from the sediments like phosphorous (some organisms can use nitrogen or phosphorus instead of oxygen)

Spring, that one week in Canada, the ice melts and the wind help to mix the layers mixing the nutrients that were released, pumping oxygen and life blooms again and we see fish and algae.

This is a happy lake, that has a mixing cycle and is called DIMICITIC lake. This is not Pink lake, our lake is more unique (as I already told you) and to find out exactly how special it is you will have to follow this earthcache.

How to log this cache ?

Well the loop around the lake is around 2.5 Km but you don’t have to do all of it, but it is highly recommended (and you can also grab another earthcache GC2EFHM). Along the trail there are several informational signs combined with the text above you can find all the answers you need.

Important, you do not have to leave the trails, and in some area, you are not allowed to leave the trails. Also, beware of passion ivy in certain parts of the trail.

WP1 (Starting location)

1. What type of lake is Pink Lake (how do scientist call it)

2. What prevents it from mixing?

WP2.

1. What is the chemical that is released and washed into the lake?

2. What is the color the lake can turn into during July and August and why (based on the text above)

WP3

1. You will learn that Pink Lake contains more than one lake inside, how many lakes do we actually have? And what is the difference between them?

2. How dense is the layer of the sulfur bacteria?

3. What is the temperature at the bottom of the lake? Why is that?