It is important to determine their tolerance to changes in the environment, because without Daphnia, the food web might be thrown out of balance. Because Daphnia are also keystone species in the ecosystem, they could be used as indicators for pollution levels if further ecotoxicology studies like these are conducted. This experiment was interesting and informative, and the results gives us insight on how other organisms would respond to similar conditions.
The heart is the translucent fluttering sac located behind their tube gut. What a stressed out water flea actually looks like. What I imagine the water fleas’ hearts doing during the experiment. It seems like eutrophication has different consequences on heart rate depending on the turbidity of the water, and it would be interesting to do further research on this. While I prefer the Italian frames, its fun to mix it up with bikes from other countries. However, the combination of eutrophic and turbid water did not really have an effect, and there is likely an interaction between those factors that influence heart rate in some way. Since I no longer race bicycles, my greatest pleasure comes from finding and restoring them. My results showed that eutrophic water and turbid water did result in a higher average heart rate compared to the control. I predicted that the elevated concentrations of nutrients and sediment particles in the water would stress the water fleas and increase their heart rate. The heart (and other body contents) of a water flea is easily visible thanks to their transparent shell. I counted the number of heartbeats within the span of a minute, and compare average heart rates between treatments. After that, I placed each individual on a Petri dish under a microscope. pulex individuals into each beaker and let them acclimatize for 24 hours. For the turbid treatments, I scooped up some mud from a storm ditch and added a few squirts to the water.ĭifferent water treatments for my D. For the eutrophic treatments, I added known concentrations of nitrate and phosphate to the water. I had 4 treatments with different water conditions: control, eutrophic, turbid, and eutrophic and turbid combination. It is a microscopic zooplankton that feeds mainly on phytoplankton, and it is an important food source for many other trophic levels, especially fish.Ī cute lil water flea! Image obtained from I did this with Daphnia pulex, a common species of water flea ubiquitous to freshwater habitats. Both of these occurences are highly problematic for the ecosystem, you can learn more about that here and here.įor my independent project, I decided to test how organisms would respond to increased nutrient concentration and turbidity in the water.
Changing land use is also causing increased sedimentation as surface runoff erodes soil, carrying sediment with it and depositing it in freshwater systems. Deforestation, urban development, wastewater discharge, the list of activities that degrade water quality goes on and on.Įutrophication, which is caused by excess nutrients in the water, still happens often in lakes and rivers across the world, despite a reduction in nutrient loading since the 60s/70s. Unfortunately, these are common phenomenons nowadays due to various human activities. We have the choice of not jumping in for a swim, but the same can’t be said for the organisms that call these habitats their home.
Neither of these freshwater bodies look very inviting, right? If we wouldn’t want to even dip a toe in it, I can’t imagine the animals living in there are enjoying their afternoon swim either. Or how about this waterfall? Image obtained from When the flats become large enough to cause distortion the tip my not be doing any meaningful damage.Does this lake speak to you? Image obtained from
a new tip to compare against will be of help here. This takes skill and experience to have any meaningful optical determination. The square area (per Shure) may not apply with advanced tip shapes. an ML or MR will show much the same reflections until the ridges are worn down enough to contact the shoulder cuts or bottom out in the groove at the tip. all needles would shred your records if this was not the case with any minor wear.Ī true elliptical should last longer than a bi-radial or conical in this respect. The wear is predominately flat but there is a radius adjacent to the flats. Move the light source around to determine the flats from the radius. a point source lighting source (fibre optic) will be of immense aid here. If you flood the lighting with a diffuse source the curved areas will light up and skew your readings. I still have trouble determining stylus wear with this setup. This will get me to 280x optical with a 2x Barlow lens and 20x eyepieces. I've had a nice stereo microscope for about ten years, a Bausch and Lomb Stereozoom seven.
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