The Study of Biodiversity

The Study of Biodiversity
Biodiversity is an important theme in biology and is crucial to the prosperity and survival of humans. The benefits that ecosystems and individual species provide to humans are countless: clean air and water, detoxification and decomposition of wastes, preservation of fertile soils, control of agricultural pests, aesthetic beauty, (Campbell & Reece, 2002) and many more. Moreover, biodiversity is commonly studied to view community structure and the health of a particular region. Species richness and abundance values can help biologists address certain environmental concerns and possible solutions to issues they may find. Bio Science 1 students at Solano Community College often conduct studies of freshwater macroinvertebrates in Suisun Creek to view biodiversity and to determine water quality. The upstream and downstream sites rests on private property identified to the students only as Â?FrankÂ?s PlaceÂ?. The settings of the Suisun Creek sites were both overwhelmed with vegetation and overhead canopies. Timing of sampling is directly related to the resulting collected species. Species diversity indices, such as Family-level biotic Index, are used to provide important information on the community structure of freshwater macroinvertebrates and can often tell us the overall health of the region we are studying also fbi provides a rapid, but less critical, evaluation of streams in the field by biologists who can recognize arthropod families by sight.2 The non-living, abiotic components that the class attempted to research at all three stream locations included taking readings of the water?s: temperature (oC), dissolved oxygen [% saturation and (mg/l)], conductivity (Â?S), specific conductance (Â?S), salinity (ppt), and pH. Dissolved oxygen is a measured value of the oxygen content that is present in the water. Low amounts of oxygen present in the water can be fatal to the insects, plants, and animals that live near or within the stream. A low dissolved oxygen content is often an indicator of organic pollution. Oxygen in aquatic environments is highly variable and generally low, and may be affected by many factors, such as temperature, salinity, respiration, and photosynthesis of aquatic plants.3 The more Dissolved oxygen is in creeks the better and healthier the water is for organisms to survive. Conductivity is a measure of how well the water can conduct an electrical impulse. It is also dependent on the water temperature and the dissolved solutes. Conductivity is affected by the presence of inorganic wastes in the water. The pollution or wastes are ions that carry out a negative charge. Conductivity is a measure of the flow of electrical current, made possible in water by ions in solution. Conductivity is sometimes used as an index of pollution. 4The measure of specific conductance is very similar to the measuring conductivity; however, the temperature was fixed at 25 degrees Celsius. Basically, all one is measuring then for specific conductance are the salts present. Salinity is a measure of how much salt exists in the water. The biotic or living components that the class observed included the bio diversity of aquatic insects. After catching as many insects at the streams as possible, the class combined their invertebrate findings and brought them back to the lab to take a better look under the microscope. The water appearance was clear muddy since its rainy season and the streambed coating was orange- reddish and brown-greenish color. The class goal was to identify as many species of insects and to count the abundance of each species from each stream. A group of volunteers from the Sierra foothills found that Tracking the abundance and diversity of invertebrates within the streams and lakes was one of the best ways to monitor the health of the water (Levy, Sharon, 1998). After reading up on their report, I found out that they found more conductivity in one body of water than the other due to one of the locations having easy access to minerals or materials that pollute the water. Therefore, my hypothesis is to compare and contrast the biodiversity of macroinvertebrates in two different site locations of Suisun Creek and to provide possible explanations for their differences and similarities. Materials and Methods: [image] Suisun Creek is located in Solano County, California and is branch of Napa River, which flows to Suisun Marsh. Two sampling sites were considered for this study. Site B as downstream and located on the Franks place or also known as FrankÂ?s main place. A faculty member of Solano Community College privately owns Franks place. FrankÂ?s Place is available from Freeway 80 off Suisun Valley Road. FrankÂ?s place is approximately 5 miles down Suisun Valley Road on the right at 8431. Both had the most noticeable characteristics of a stream such as rapid runs, pools, and riffles. Suisun Creek is approximately 100 meters away from the bottom of the driveway of the residence. FrankÂ?s Place of Suisun Creek was investigated on November 3, 2004 from approximately 10:30 am through 1:00 pm. Site A was upstream from this region and located approximately 20 m away. In order for the class to complete this experiment at the stream, the equipment needed included: waders, a tape measure, meter ruler, probe model # (ysi-85), pH detector (Piccolo Plus), catching nets 500-micron mesh Â?D netÂ?, plastic bottles with ethanol alcohol, buckets, and a paper and a pen for recording the results. For this experiment each group in the class-needed waders so that its members were are able to get into the water without getting wet. The tape measure was used at each site in order to measure out a distance of width and meter ruler to measure the depth. The probes ysi-85 that the class used to collect the abiotic data were able to calculate readings such as salinity, dissolved O2, and conductivity, etc. In order for the readings to be correct, each probe had to be calibrated properly and set to the right mode. The probe was a very delicate instrument and it had to be used correctly. In order to insure accurate measurements, the user of the probe had to gently bob the detector up and down in the water. Then user had to wait until the number stabilized out on the screen of the probe; the number was then recorded. It was important that each research team try not to submerge the probes tip in the mud to reduce damage to the instrument. The pH meter (Piccolo Plus) was used in the same fashion as the probe, bobbing up and down until the temperature was stabilized. The stream velocities were measured using a Swoffer model 2100 flow meter and measured at sixty percent. The biotic data was measured and caught by Â?D netsÂ?. In addition to the nets, the insects collected in this experiment were also found in abundance under decaying logs, leaves, and under large rocks near the shoreline of the streams. Yet the class found that the best way to obtain the most macroinvertebrates was to drag the catching nets on the bottom of the stream, the insects would then get caught up in the mesh. From there the insects found were put then into plastic bottles, and buckets. The bottles and buckets were then brought back to the laboratory for examination. The insects were preserved in ethanol alcohol. Back in the lab, the biology class used a key to aquatic insect orders, also known as a dichotomous key. The key helped each group identify step by step what each organism was down to the family and order. Hilsenhoff fbi numbers to find the tolerance in insects and also find the water quality. Results: Table 1 lists the abiotic factors measured in the stream for the two sampling sites, along with their averages. Both sites had similar readings. Site A (upstream) and Site B (downstream) both had air temperature 18Â?C, a temperature of about 13.3Â?C, and a salinity of 0.2 ppt. The only moderate differences between the two sites were conductance, specific conductance, Dissolved O2 (% Saturation), Dissolved O2. A pH result for Site B wasnÂ?t provided. For Site A, the conductance was 329ms, the specific conductance was 426ms, Dissolved O2 was 146% and Dissolved O2 was 15.2 mg/L. The readings at Site B were slightly higher with a 342ms conductance, 441ms specific conductance, but slightly lower Dissolved O2 was 95.8% and Dissolved O2 was 9.57 mg/L. Table 1 Water Quality Average Upstream Average Downstream Temperature (oC) 13.3 13.3 Dissolved O2 (% Saturation) 146 95.8 Dissolved O2 (mg/L) 15.2 9.57 Conductivity (Â?S) 329 342 Specific Conductivity (Â?S @ 25 oC) 426 441 Salinity (ppt) 0.20 0.2 pH 6.59
Data wasnÂ?t provided
[image] Graph ~1. Shows the temperature for both sites are the same 13.3oC. [image] Graph~ 2. Shows the Dissolved oxygen % for Site A 146 and Site B 95 which shows that Site A is higher. [image] Graph ~3 shows water is more soluble when temperature decreases. (Physics T � V) [image] Graph ~ 4 The conductivity level remains fairly constant between both sites A and B of Suisun Creek. [image] Graph~ 5 The specific conductivity level remains fairly constant between both sites A and B of Suisun Creek. [image] Graph~6 The salinity for both site is exactly the same for both sites. [image] Graph ~6. The pH results for site B wasn�t provided. Table 2 lists the different organism observed at the two sampling sites along with their abundance. 10 different species were identified at Site A (upstream) with of 370 individuals. The most abundant species was Order Diptera with 161 individuals followed closely by Order Ephemeroptera with 82 individuals. The least abundant species identified at Site A was Class Bivalvia, and Order Megaloptera with only 1 individual. The Family-level biotic diversity index for Site A was calculated to be 5.33. 11 different species were identified at Site B (downstream) with one unknown individuals for a total of 316 individuals. The most abundant species collected at Site B was Order Diptera with 176 individuals followed by Order Ephemeroptera with 83 individuals. The least abundant species were Order Odonata Cordulegastride, Lyphalini and Order unknown-head attached each with only 1 individual. The Family-level biotic diversity index for Site B was calculated to be 5.35. Table 2 Organism Location / Numbers Family (Order) Upstream (Site A) Downstream (Site B) simulidae (Diptera) 161 170 Chironomidae (Diptera) N/A 6 Baetudae (Ephemeroptera) 82 83 Hydropsychidae (Trichoptera) 41 14 Polycentropodidae (Trichoptera) N/A 11 Sericostomatidae (Trichoptera) 69 N/A Coenagrionidae (Odonata) 3 N/A Cordulegastride (Odonata) N/A 1 Sialidae (Megaloptera) 1 N/A Class Bivalvia 1 N/A Class Gastropoda 2 N/A Oligochaeta 7 20 Planaria 3 4 Tick N/A 2 Lymphalini N/A 1 Unknown-head attached N/A 1 [image] Family Biotic indices (fbi) were calculated for each of the two samples taken at two different sites. The results are shown in table 3. fbi in upstream and downstream is fair which means there is reasonably large pollution, which affects the organisms. Table 3 Locations Family Biotic Index (F.B.I ) Upstream (Site A) 5.33 Downstream (Site B) 5.35 Discussion: Analyzing the sample in fall could affect our results because the location received a lot of rainfall causing runoff of fertilizer or polluted materials into the stream (Lebanon High School Students 1997). No matter what type of pollution is present in a stream, it will have a negative effect on water quality and its ability to sustain life.5 Suisun Creek Site B has a run. This means that the water was moving along at a constant velocity. At site B, the water appeared to be muddy and it had a orange to reddish tint to it. The water was not clear. Our research group could not detect any streambed coating or any odor. However, the bottom composition of the stream was made out of, 50% cobble and 50% boulder. The bank and shoreline of the stream had roots. The bank was also vegetated. The stream was under an umbrella of trees in several of the regions were readings were recorded. The stream?s width 30 ft 5 in. and ranged in depth of 5 to about 10 inches, so the meter stick really came in handy. The stream appeared to be rich in bio-diversity. Like site B, Suisun Creek Site A was also covered for the most part by tall trees and a lot of vegetation, overhead canopies, logs and roots. However, the bottom composition of the stream was made out of 30% course Gravel and 70% Cobble. Suisun Creek Site A has a riffle. This means that the water was moving along the cobble with a faster flow. There was also a lot of decay, leaves and big branches within the stream. This stream width 19ft and ranged in depth from 0 inches to about 6inches. This stream appeared clear and there was no odor. The stream was the cleanest out of the both sites and it didn?t appear to be disturbed by a lot of human actions. Site A contained pools, riffles and runs. Pools are small areas of standing water. Riffles are rapid portions of streams and a run is where the water is moving at constant velocity. Average velocity for Site B was 0.34 ft/sec whereas Site A was 2.90 ft/sec. The flow of water could affect the life cycle of organisms. Even in relatively pristine watersheds not yet affected directly by modern urban development, stream diversions can result in reduced flow velocity and water depth, thereby changing habitat conditions and potentially reducing habitat availability. Dewatering of stream reaches can also inhibit downstream dispersal of larvae and upstream migration of post larvae, which are critical to the life cycles of many native species. 6 By conducting this study, we were able to see several trends in the biodiversity of Suisun Creek. The abiotic factors measured at the upstream and downstream sites shows clear lines of similarity. These values tell us that the two sites are relatively comparable and that Suisun Creek does not differ much throughout. Family Biotic index for Site B (downstream) is slightly higher than the upstream site, but only differs by about 0.02. This tells us that the evenness of species distribution at the two sites was almost identical. This is an expected result since the abiotic factors at the two sites were almost identical as well. Factors such as the amount of dissolved oxygen in the stream and conductivity play a role in the abundance and type of species that will be found in the region. To get enough oxygen, some species must live in fast-flowing, turbulent water. These insects have developed the equivalent of grappling hooks, Velcro, and anchoring nets to hold onto rocks and resist the current. Others have found ways to carry air bubbles about with them. Some denizens of oxygen-poor lake bottoms use hemoglobin to store oxygen and release it when needed.7 Species richness was higher at Site B than at Site A. Many factors can play a role in species richness, pollution for example. One of the advantages of more organisms found because the �Franks Place� is away from many human disturbances. Pollution from cars such as exhaust fumes and oil buildup on the roads has slighter chance of reaching both sites. In fall since it, rains a lot the soil erosion could hurt the organism�s habitats. These types of natural disturbances have some effect at Site A and may be a possible explanation for a lower species richness value. Another reason may be that Site A has fewer resources than Site B. Abundant resources are required to maintain a diverse community. If two similar species compete for the same limited resource, one population will tend to use the resources more efficiently and eventually eliminate the other population (Campbell & Reece, 2002). This would drive species richness at Site B down. Yet another reason for the difference in species richness between the two sites may have to do with predation. Site B may have dominant competitors that do not allow other species to colonize the area. Site A on the other hand may have a keystone predator that helps maintain species richness by reducing the amount of the best competitors so that less competitive species are maintained (Campbell & Reece, 2002). Another trend discovered in this study involves the high abundance of Order Diptera at both the upstream and downstream site. This discovery may have to do with the process of natural selection. Order Diptera may have over time accumulated heritable traits that made it better suited to its environment at both regions of the creek. This would explain its high abundance in Suisun Creek. Overall, this study has helped us learn key aspects about Suisun Creek�s biodiversity. We have learned that the evenness of species distribution throughout the creek is relatively similar. However, species richness does differ at different regions of the creek and we have provided possible explanations for the dissimilarities

The Study of Biodiversity 9.1 of 10 on the basis of 3716 Review.