Effects of abiotic factors on biotic factors in the Pond Ecosystem, by Maham and Priya

Nosehill Park is one of the largest natural parks in all of Canada. It is home to a vast number of organisms in the three different ecosystems located in the park. These ecosystems include the pond, the forest, and the grasslands. An ecosystem is the set of relationships between the living resources, habitats and residents of an area. This includes water, soil, people, micro-organisms, plants, trees, fish, birds, and animals. Our trip to Nosehill Park focused mainly on the pond ecosystem of the area. The exact location of the area observed is shown in figure 1 and the dimension of the area measured is also given (8 by 18 ft). The pond we observed is a storm water pond, which means it is a manmade pond designed to collect rainwater from the roads during and after storms and the pond treats and filters the storm water. The outflow of the storm water pond is the drainage at the bottom of the pond which takes out excess water in the pond.

Figure 1. Area where we found organisms and observed water samples from Nosehill.

Figure 2. The submerged, emergent, and floating vegetation in the area we looked.

 Figure 3. The general outline of the Nosehill pond and showing the inflow and outflow of water which is an underwater drainage. The dark lines represent the roads and the striped area represents the hill area. The red box represents the area we observed.

                       

          All living factors are known as biotic factors. Our pond ecosystem has biotic factors such as humans, insects (micro-organisms), plants and algae. Abiotic factors are non-living factors that may affect the ecosystem being looked at. Some of these abiotic factors consist of air, water, and soil. Human interference such as adding a large amount of nutrients in the ecosystems affects the energy flows and climate through global warming. The three abiotic factors that affect the pond ecosystem and as well as it’s organisms are the water, as this component includes the temperature, pH , chemicals contained in the pond water, and seasonal changes. The second abiotic factor is light which is useful for plants in the pond during the process of photosynthesis and lastly soil which is essential for plants and for their roots.

In general, the trophic levels found in the pond ecosystem are the first trophic level which includes organisms such as phytoplankton, algae, and small micro-organisms. The second trophic level includes herbivores. For example, these herbivores can be mayflies, nymphs, and particular types of water beetles that fees on trophic level one. The third trophic level usually includes the pond fishes that feed on plants and animals from the first and second trophic levels.

While at Nosehill Park we found various kinds of organisms outside and inside the pond. The organisms that we found outside the pond include dragonflies specifically the spotted spreadwing and another dragonfly that was red in colour that we were not able to identify. We also captured a bee which we concluded to be a bumble bee specifically the bombus pratorum. Some of the plants that were found outside the pond include cattails, hardy grosses and reeds, grass sedge, grass umbrella, and some green moss. When we collected organisms from the inside of the pond we found algae, leeches, Order Arhynchobdellida, and horse hair worms along with some water fleas and freshwater shrimps.

Figure 4. Picture of the spotted spreadwing caught by Priya Rajbhandary and Maham Memon

So how do these abiotic factors (Water, light, soil) affect the biotic factors (such as the insects plant and algae). For these organisms, temperature (abiotic) can play a big role in the lifestyle of pond organisms. If there is a drastic change in the pond ecosystem most organisms living inside the pond such as the one listed above will most likely not be able to survive properly. However, there are still other organisms who have adapted to the temperature changes that may occur. Fishes and snails who are not usually able to adapt as much in the pond due to change in temperature will eventually move away from the shore and more towards the deeper end of the water and most insects move to the bottom of the pond to hibernate.

Oxygen is also a part of the abiotic factors which can affect the organisms living in the pond.  The next abiotic factor is light; light can also affect the pond organisms simply because light makes the process of photosynthesis in the plants which eventually releases oxygen to the other species of plants. Algae covers ponds so the light that is being given off will not be able to reach the plants and decrease available oxygen and food in water and see a decrease in animal life in the pond. The usual nitrate levels in Nosehill pond is usually 50 -60 ppm (Norm Meck 1996).  However, the nitrate level we recorded gave us 0ppm. This is due to large quantity of algae in the pond which decrease oxygen levels, which affects the decomposers as they are decreasing. When decomposers decompose biomass they give off nitrate back into the water. In this case, there is a decrease in decomposers so lower levels of nitrate is given off.

The normal phosphate level is 0.25-0.50m. When we measured the phosphate level of the sample pond water we got 0.25mg/L which we concluded was normal.  The pH is another abiotic factor that may affect the pond and its organisms. The normal pH level is usually between 6.5 and 8.5. From the water sample we collected from Nosehill had a pH of 7. This indicates that the pH of the pond is normal. The pH represents the level of carbon dioxide in the water. There are large number of organisms in the water, and the respiration systems of these organisms increase carbon dioxide which will lower the pH levels. More organisms mean that there is more carbon dioxide which means lower levels of pH. However, because of the location of Nosehill Park, there are residential areas and roads close to the park which results in pollution also affecting the pH.

            Overall, abiotic factors have a large impact on the biotic factors and the ecosystem they are a part of. Differences in the abiotic factors may bring change to the organisms living in it and as well as the pond itself.

References:

Maverick. (2007). Do you have any biotic and abiotic factors in a pond ecosystem. Retrieved October 25 2011 from http://in.answers.yahoo.com/question/index?qid=20080501182530AAEEksr

Lewis, Joe. "Pond Ecology." Yale-New Haven Teachers Institute, 1992. Web. 30 Oct 2011. <http://yale.edu/ynhti/curriculum/units/1992/5/92.05.07.x.html>.

Bio 20/30 IB Nose Hill (2008). Extension Questions etc from website. Retrieved October 25 2011 from http://bio20nosehill.webs.com/extensionquestions.htm