Ello. My name is Steve Irwin and today, I am going to present to you my journey into an unknown freshwater lake.
This lake, however, could have actually been called a pond. There are no scientific differences between lakes and ponds, lakes are simply known as being "bigger." Anyways, the first thing I noticed as I waded through the lake was the soil underneath my feet. The soil type was silt. Silt is a granular type of soil with a loose sediment feel to it. Silt is rocky material that has been eroded down into mud. It could have come from Rocky Mountains or white, sandy beaches.
(LakeMat 2011).
However, not all lakes have silt as their primary soil type. There are also: "littoral soil, silty clays, calcareous soil, finely grained silts and clays, and bay mud" (Lake Biome Project 2011).
Lakes contain many dissolved minerals, the most common being salt and gravel. For more on the minerals in freshwater lakes, see http://www.waterencyclopedia.com/Mi-Oc/Mineral-Resources-from-Fresh-Water.html.
I picked up a handful of silt and it ran through my fingers and back onto the lake floor. I then continued into the water with my oxygen tank and scuba gear.
Credits to: Shutterstock http://footage.shutterstock.com/clip-5042456-stock-footage-holding-a-stone-while-submerged-in-the-lake-the-hand-holding-a-stone-found-in-the-underwater-lake.html
There are different layers of a lake. From top to bottom: littoral, epilimnion, thermocline, hypolimnion, and finally benthos (RMB 2013).
As I began to swim down to the hypolimnion zone, the surface began to ripple as rain drops graced the water. Lake biomes get up to 38 inches of rain a year (Lake Biome Project 2011), which is a decent amount and are why lakes are often associated with wetlands and marshes.
Credits to: Goose lake Weather Blog http://gooselakeweather.com/wp/
The average rainfall per year for Goose Lake is about 35 inches.
I noticed that the temperature was moderate, being that it is Spring. The temperature of lakes ranges from 4 C to 22 C bottom to top (The Wild Classroom 2003). During the winter, lakes can freeze over and then the temperature ranges from 4 C to 0 C bottom to top (2003). Thank goodness it's not winter!
Credits to: Judith Ramsey http://www.minnesota-visitor.com/scuba-diving-lake-superior.html
As I went underwater, I noticed thousands of organisms swimming all around me. I couldn't believe how many life forms could live in one single body of water. There couldn't possibly be that much oxygen in here to sustain so many beings, right? Wrong. There is enough oxygen to support most of the organisms living in freshwater lakes. The rest are life forms such as anaerobes (i.e. types of bacteria) that live anaerobically (living without air) in the mud, and others simply can go short periods without oxygen like different larvae. For those that live aerobically, the lower the temperature the more the oxygen. Thus, when temperatures rise, there's a problem. "At 5 degrees C (and at normal air pressure) one liter of water contains only 8.9 cc oxygen and at 20 degrees C it contains 6.4 cc." The higher the temperatures, the more air taken in by animals and thus, the less oxygen that is left in the water.
(Life in Freshwater 2013).
I swam for a few minutes before I saw a ray of light shine through the murky waters. The primary source of energy for more lakes is sunlight. However, that all depends on five things: "1. the time of day and the season 2. the depth 3. the turbidity of the water (how clear the water is) 4. amount of cloud cover 5. altitude of the lake." The most intense sunlight will occur at: a more acute angle, shallow waters, clear waters, few clouds, and a higher altitude.
(2013).
Credits to: Matthew V. Veazey http://www.downstreamtoday.com/news/article.aspx?a_id=37698&AspxAutoDetectCookieSupport=1
Next to the light was a snail, crawling its way along the bottom of the lake. It then occurred to me that the snail would be an easy target without any shelter. The best shot prey have at finding shelter is in the roots of rooted or aquatic plants, underneath lily pads, and amongst floating algae. However, a snail in clear waters will have a much tougher time finding shelter from predators than a snail in muddy waters, much like the lake I am swimming in now.
After focusing on the abiotic features of the lake I was snorkeling in, I then began to focus on the biotic aspects.
I continued my swim through the waters of Lake No Name and then all of the sudden, out of the corner of my eye, I spotted some algae! Blimey! I struck out with my hand and grabbed a large piece of the plant and sniffed it. After tussling with it a bit, I took out my handy dandy microscope and noticed that it was indeed phytoplankton! Croukie! Phytoplankton and periphyton are the primary photosynthesizers in lakes (Wikipedia 2013). Other producers in lakes are known as aquatic plants (2013).
Credits to: Wikimedia http://commons.wikimedia.org/wiki/File:Phytoplankton_Lake_Chuzenji.jpg
Aquatic plants are also referred to as macrophytes or hydrophytes, and are simply plants that have adapted to living in water. They are either rooted in the substrate and have their leaves and flowers floating, or rooted in the substrate with the flowers and leaves showing but not floating, or completely submersed. Types of aquatic plants in lakes include water lilies, cattails, fresh water algae and sea lettuce. Aquatic plants are sources of food, oxygen, and habitats in the benthic zone.
(2013).
My adventure continued when I saw a zooplankton floating around. Jimminy! That thing was massive (not really). The zooplankton is the primary consumer in lakes, which is why it resisted so heavily (not really). They feed on algae, bacteria, and detritus (partially decayed organic material). Secondary consumers are planktivorous fish or predaceous invertebrates, which prey on zooplankton.
(Lake Access 2014).
They include Crustaceans (crab, lobsters, shrimp, etc...), molluscs (e.g. clams and snails), numerous types of insects, and Benthic organisms. (Wikipedia 2013).
The best known consumers in lakes are fish. Large fish eat medium fish which eat small fish which eat plankton (Lake Access 2014).
The decomposers of the lake are bacteria, fungi, and other microorganisms. "They feed on the remains of all aquatic organisms and in so doing break down or decay organic matter, returning it to an inorganic state. Some of the decayed material is subsequently recycled as nutrients, such as phosphorus (in the form of phosphate, PO4-3) and nitrogen (in the form of ammonium, NH4+) which are readily available for new plant growth. Carbon is released largely as carbon dioxide that acts to lower the pH of bottom waters. In some zones carbon can be released as methane gas (CH4). Methane gas causes the bubbles in lake ice." Decomposers are found in all zones of the lake, although they are most effective in the hypolimnion zone, where there is the most dead organic matter.
(2014).
Credits to: Underwater Times http://www.underwatertimes.com/news.php?article_id=10629137840
Here is a detailed picture of the Lake Food Webb (get it?):
Credits to: WSU http://lakewhatcom.wsu.edu/UserFiles/Image/AboutWatershed/food_web.jpg
As I swim around, I see microorganisms everywhere and wonder how they've been able to survive all these years. Well, the answer is that they've adapted. Algae would normally sink to the bottom of the lake because many have a higher density than water. However, they have an adaptation that has "developed density changing mechanisms, by forming vacuoles and gas vesicles or by changing their shapes to induce drag, slowing their descent." This way, they are able to stick close to the surface and get the sunlight they need for photosynthesis.
(Wikipedia 2013).
The plants I see around me also have evolutionary adaptations. Aquatic plants have an adaptation that makes them both flexible and tough to withstand the winds and waves of the lake.
(2013).
The animals of the lake also have adaptations. For example, the water strider has an adaptation that allows it to burrow into the mud at the bottom of the lake and become dormant when its habitat dries up (2013).
Credits to: Wikipedia http://en.wikipedia.org/wiki/Water_strider
There are three types of symbiotic relationships in lakes: mutualism, commensalism, and parasitism. Mutualism: when algae and fungi work together to form communities that produce oxygen and food for the other. Commensalism: pond weed gives food and shelter to a fish and the pond weed isn't affected. Parasitism: the sea lamprey attaches to a trout and sucks its blood until it dies.
(Lakes and Ponds 2014).
Credits to: The Water Line http://www.lmvp.org/Waterline/volume14num1/plants.html
Blimey, it looks as if my adventure is coming to its end. Good news though, mate, I'm going to be traveling to all the different lake biomes of the world! You can check me out on this here map:
Credits to http://www.endoh7735.com/lakes/english/world_lakes.gif
As I go to all of these wonderful places, it is truly a disappointment to see the human influence on lakes. However, the overall opinion is mixed. While we humans have been placing beaches and thus populating lakes for centuries, the lake has become contaminated with the toxins of our pollution. Water levels have lowered as a result of us. However, we are taking steps to removing sewage and so hopefully in the future, we can help clean the dirty water we produced.
(Britannica 2014).
It'll sure be interesting to see if humans can turn their influence around in the future!
Thanks for taking part in my lake adventure, hope to see you next time mate!
Sources:
http://lakebiomeproject.blogspot.com/2011/01/precipitation-and-temperature.html
http://www.lakemat.com/education/lake-weed-blog/2011/01/types-soils-your-lake-bottom
http://www.thewildclassroom.com/biomes/lake.html
http://www.lifeinfreshwater.org.uk/Web%20pages/ponds/Abiota%20Ponds/Light.htm
http://rmbel.info/right-now-lakes-are-like-layer-cakes/
http://en.wikipedia.org/wiki/Lake_ecosystem
http://www.lakeaccess.org/ecology/lakeecologyprim14.html
http://lakesandponds2012p2.edublogs.org/sample-page/
http://www.britannica.com/EBchecked/topic/243396/Great-Lakes/39981/Human-impact-on-the-lakes
I noticed that the temperature was moderate, being that it is Spring. The temperature of lakes ranges from 4 C to 22 C bottom to top (The Wild Classroom 2003). During the winter, lakes can freeze over and then the temperature ranges from 4 C to 0 C bottom to top (2003). Thank goodness it's not winter!
As I went underwater, I noticed thousands of organisms swimming all around me. I couldn't believe how many life forms could live in one single body of water. There couldn't possibly be that much oxygen in here to sustain so many beings, right? Wrong. There is enough oxygen to support most of the organisms living in freshwater lakes. The rest are life forms such as anaerobes (i.e. types of bacteria) that live anaerobically (living without air) in the mud, and others simply can go short periods without oxygen like different larvae. For those that live aerobically, the lower the temperature the more the oxygen. Thus, when temperatures rise, there's a problem. "At 5 degrees C (and at normal air pressure) one liter of water contains only 8.9 cc oxygen and at 20 degrees C it contains 6.4 cc." The higher the temperatures, the more air taken in by animals and thus, the less oxygen that is left in the water.
(Life in Freshwater 2013).
I swam for a few minutes before I saw a ray of light shine through the murky waters. The primary source of energy for more lakes is sunlight. However, that all depends on five things: "1. the time of day and the season 2. the depth 3. the turbidity of the water (how clear the water is) 4. amount of cloud cover 5. altitude of the lake." The most intense sunlight will occur at: a more acute angle, shallow waters, clear waters, few clouds, and a higher altitude.
(2013).
Credits to: Matthew V. Veazey http://www.downstreamtoday.com/news/article.aspx?a_id=37698&AspxAutoDetectCookieSupport=1
Next to the light was a snail, crawling its way along the bottom of the lake. It then occurred to me that the snail would be an easy target without any shelter. The best shot prey have at finding shelter is in the roots of rooted or aquatic plants, underneath lily pads, and amongst floating algae. However, a snail in clear waters will have a much tougher time finding shelter from predators than a snail in muddy waters, much like the lake I am swimming in now.
After focusing on the abiotic features of the lake I was snorkeling in, I then began to focus on the biotic aspects.
I continued my swim through the waters of Lake No Name and then all of the sudden, out of the corner of my eye, I spotted some algae! Blimey! I struck out with my hand and grabbed a large piece of the plant and sniffed it. After tussling with it a bit, I took out my handy dandy microscope and noticed that it was indeed phytoplankton! Croukie! Phytoplankton and periphyton are the primary photosynthesizers in lakes (Wikipedia 2013). Other producers in lakes are known as aquatic plants (2013).
Aquatic plants are also referred to as macrophytes or hydrophytes, and are simply plants that have adapted to living in water. They are either rooted in the substrate and have their leaves and flowers floating, or rooted in the substrate with the flowers and leaves showing but not floating, or completely submersed. Types of aquatic plants in lakes include water lilies, cattails, fresh water algae and sea lettuce. Aquatic plants are sources of food, oxygen, and habitats in the benthic zone.
(2013).
My adventure continued when I saw a zooplankton floating around. Jimminy! That thing was massive (not really). The zooplankton is the primary consumer in lakes, which is why it resisted so heavily (not really). They feed on algae, bacteria, and detritus (partially decayed organic material). Secondary consumers are planktivorous fish or predaceous invertebrates, which prey on zooplankton.
(Lake Access 2014).
They include Crustaceans (crab, lobsters, shrimp, etc...), molluscs (e.g. clams and snails), numerous types of insects, and Benthic organisms. (Wikipedia 2013).
The best known consumers in lakes are fish. Large fish eat medium fish which eat small fish which eat plankton (Lake Access 2014).
The decomposers of the lake are bacteria, fungi, and other microorganisms. "They feed on the remains of all aquatic organisms and in so doing break down or decay organic matter, returning it to an inorganic state. Some of the decayed material is subsequently recycled as nutrients, such as phosphorus (in the form of phosphate, PO4-3) and nitrogen (in the form of ammonium, NH4+) which are readily available for new plant growth. Carbon is released largely as carbon dioxide that acts to lower the pH of bottom waters. In some zones carbon can be released as methane gas (CH4). Methane gas causes the bubbles in lake ice." Decomposers are found in all zones of the lake, although they are most effective in the hypolimnion zone, where there is the most dead organic matter.
(2014).
Credits to: Underwater Times http://www.underwatertimes.com/news.php?article_id=10629137840
Here is a detailed picture of the Lake Food Webb (get it?):
Credits to: WSU http://lakewhatcom.wsu.edu/UserFiles/Image/AboutWatershed/food_web.jpg
As I swim around, I see microorganisms everywhere and wonder how they've been able to survive all these years. Well, the answer is that they've adapted. Algae would normally sink to the bottom of the lake because many have a higher density than water. However, they have an adaptation that has "developed density changing mechanisms, by forming vacuoles and gas vesicles or by changing their shapes to induce drag, slowing their descent." This way, they are able to stick close to the surface and get the sunlight they need for photosynthesis.
(Wikipedia 2013).
The plants I see around me also have evolutionary adaptations. Aquatic plants have an adaptation that makes them both flexible and tough to withstand the winds and waves of the lake.
(2013).
The animals of the lake also have adaptations. For example, the water strider has an adaptation that allows it to burrow into the mud at the bottom of the lake and become dormant when its habitat dries up (2013).
Credits to: Wikipedia http://en.wikipedia.org/wiki/Water_strider
There are three types of symbiotic relationships in lakes: mutualism, commensalism, and parasitism. Mutualism: when algae and fungi work together to form communities that produce oxygen and food for the other. Commensalism: pond weed gives food and shelter to a fish and the pond weed isn't affected. Parasitism: the sea lamprey attaches to a trout and sucks its blood until it dies.
(Lakes and Ponds 2014).
Credits to: The Water Line http://www.lmvp.org/Waterline/volume14num1/plants.html
Blimey, it looks as if my adventure is coming to its end. Good news though, mate, I'm going to be traveling to all the different lake biomes of the world! You can check me out on this here map:
Credits to http://www.endoh7735.com/lakes/english/world_lakes.gif
As I go to all of these wonderful places, it is truly a disappointment to see the human influence on lakes. However, the overall opinion is mixed. While we humans have been placing beaches and thus populating lakes for centuries, the lake has become contaminated with the toxins of our pollution. Water levels have lowered as a result of us. However, we are taking steps to removing sewage and so hopefully in the future, we can help clean the dirty water we produced.
(Britannica 2014).
It'll sure be interesting to see if humans can turn their influence around in the future!
Thanks for taking part in my lake adventure, hope to see you next time mate!
Sources:
http://lakebiomeproject.blogspot.com/2011/01/precipitation-and-temperature.html
http://www.lakemat.com/education/lake-weed-blog/2011/01/types-soils-your-lake-bottom
http://www.thewildclassroom.com/biomes/lake.html
http://www.lifeinfreshwater.org.uk/Web%20pages/ponds/Abiota%20Ponds/Light.htm
http://rmbel.info/right-now-lakes-are-like-layer-cakes/
http://en.wikipedia.org/wiki/Lake_ecosystem
http://www.lakeaccess.org/ecology/lakeecologyprim14.html
http://lakesandponds2012p2.edublogs.org/sample-page/
http://www.britannica.com/EBchecked/topic/243396/Great-Lakes/39981/Human-impact-on-the-lakes
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