Ecology
Further examples of Secchi reading
Water Clarity
Secchi Disk
What is it?
A secchi disk contains alternating black and white quadrants and is attached to a line. This line is used to lower the disk into a body of water with the purpose of measuring the clarity of the water. The depth at which the disk can no longer be seen is called the secchi depth and is the measurement recorded
Why do we measure it?
Secchi depth is important to measure because the clarity of water impacts the amount of light penetration and in turn can affect photosynthesis and the distribution of organisms. While people often focus on the negative aspect of losing clarity, completely clear water is usually not desirable either because that means the water is devoid of needed food like plankton.
Secchi disk readings are useful in comparing bodies of water or looking for changes to a specific body of water over time. Changes in clarity of water can be an indicator of a human threat to an ecosystem.
What affects it?
Clarity will decrease as color, abundance of algae or suspended sediments increase. The color of water is sometimes caused by staining, due to decay of plant material. Excess algae growth can occur where there is additional input of nutrients like phosphorus and nitrogen from agriculture and/or sewage treatment or septic system waste. An increase in suspended sediments can be the result of urban, agricultural or storm runoff.
Current Round Lake Measurements
3 meters (based on last 3 readings)
Zebra Mussels:
Wash Your Boat Before Entering Round Lake
There is a real concern about Zebra Mussels in our region. We are lucky so far not to have any reported on our lake. Nearby lakes, such as Lake Clear and Lake Dore are reported to be, not so lucky.
Zebra Mussels are filter feeders that attach themselves to solid surfaces. They breed very quickly, as females can release up to one million eggs each breeding season. After the eggs are fertilized, larvae (called veligers) emerge and are free-swimming for up to a month. The combination of these factors mean that Zebra Mussels can colonize in densities over 700,000 individuals per m2 on surfaces such as: boats, docks, rocks, plants, and native mussels.
Zebra Mussels can have significant negative impacts on freshwater habitats by out-competing native species for food. This means they can change the ecosystem by:
removing native species’ food sources, such as plankton
affecting fish spawning areas by changing important substrates, which impacts the survival of fish eggs
creating clearer water and allowing sunlight to penetrate deeper, which in turn increases the growth of submerged aquatic vegetation, leading to toxic algal blooms, and increasing pathogenic bacteria, avian botulism, and localized anoxia
Zebra Mussels are especially harmful for native mussels, many of which are species at risk. They outcompete these species for food and will attach themselves to native mussels, suffocating them. Zebra Mussels cause millions of dollars in damage every year by clogging intake structures in power stations and water treatment plants as well as damaging watercrafts. They also make a lake dangerous and unpleasant to swim in, due to the sharpness of the mussels.
What Can You Do?
Be aware of what Zebra Mussels look like and Always Wash your boat or watercraft thoroughly before bringing it into Round Lake. Spread the word on this important issue, and please report any sightings to: rlpoa.killaloe@gmail.com
Ticks
Encountering a tick is as easy as brushing against bushes or long grass in a tick-infested area. Ticks are members of the arachnid family and are unable to jump or fly. They survive by attaching themselves to mammals and birds and feeding on their blood. Ticks thrive in wooded, brushy areas with undergrowth and significant leaf litter that keep the ground damp. Most ticks are about three to five millimetres in length, but can expand significantly in size after feeding.
There are a number of different tick species in Ontario, but Ixodes scapularis, the blacklegged tick (also known as the deer tick), is of particular concern from a public health perspective. Blacklegged ticks can carry the bacterium Borrelia burgdorferi which, if transmitted to humans via a tick bite, may cause Lyme disease.