BI 170.1 Lab Report 1 (Abiotic Factors) PDF

Preview

Summary

Abiotic Factors of a Jungle...

Description

Exercise 1: Measurement of Abiotic Factors

Group 1: AJERO, Mary Grace COLOYAN, Peterni QUINTIN, Nicole REYES, Danielle SALVADOR, Marina

Bi 170.1 - C Mr. Paulo Joson, M.Sc. 13 June 2016

INTRODUCTION Ecology is the study of the relationships between organisms and their environment. Its basic unit called ecosystem is defined as a biological community of interacting living organisms and their physical environment. It has two main components which are the biotic factors or the living component and the abiotic factors or the non-living component. Abiotic component includes the physical and chemical factors such as water, light, wind, soil, humidity, minerals and gases which has a significant impact on the entire ecosystem. The experiment aims to measure the various abiotic factors namely light intensity, temperature, salinity and pH level using light meter, thermometer, hand-held refractometer and pH meter respectively. It also aims to determine and practice proper handling and usage of measuring devices. MATERIALS AND METHODOLOGY A site within the Ateneo de Manila University campus was selected by the researches given the following criteria: (1) safety; (2) accessibility; (3) lack of human disturbances and; (4) presence of a water source. The chosen 8 x 28 m site was roped off and divided into 1x1 m squares. The squares were labeled according to its position in relation to an origin corner. This was done by giving the squares a corresponding letter and number label according to its position. The letter corresponded to the number of meters away it was widthwise from the origin point (1-1.9m-A, 2-2.9m-B, 3-3.9m-C, 4-4.9m-D, 5-5.9m-E, 6-6.9m-F, 7-7.9m-G, 8-8.9m-H), while the number corresponded to how far away it was from the origin lengthwise. For example, if the square was within the first meter in the shorter side and on the 25th meter on the longer side, it would be called A25. Stratified Random sampling was then done to get four (4) sample plots with low, medium, and high-light intensities. An Apple iPhone application called “RANDOM.ORG” was used to get a random letter from 28 four times. Samples of the soil were obtained from the four sample plots, and then the temperature, salinity sunlight, and pH of the samples were obtained. The temperature was taken with a brand thermometer by placing the thermometer in a 3 inch hole in the soil that was made with a metal spatula. It was left for 2 minutes, then the reading was recorded, while the thermometer was still in the soil, alongside the time of measurement. The amount of sunlight was taken with the Extech Instruments EasyView Series Wide Range  Light Meter that was placed on the ground, as near as it could be to the soil. The most “stable” measurement (lux) (the measurement that did not change for at least five seconds) was recorded alongside the time of measurement. Soil was collected with the spatula and was placed in a 500 mL Pyrex B  eaker until the amount of soil reached the 100 mL mark on the 500 mL beaker. The four 500 mL Pyrex beakers were labelled according to the plot where the soil sample was taken from. The soil samples that were taken from the sample plots were taken back to the Bi 170.1 Ecology Laboratory (C) classroom to get the pH and salinity with the EUTECH INSTRUMENTS Waterproof Series p  H meter and the Lutron S  alt Meter. 100 mL distilled water was added to each of the soil samples and a Pyrex  stirring rod was used to stir the mixture. The salinity was taken with the Lutron S  alt Meter by placing the probe in the soil and water mixture. The measurement appeared on the monitor of the meter in percent (%) and was recorded, alongside the time of the measurement. Distilled water was used to

wash the salt meter in between the different measurements. The pH was also taken with  H meter. Before measuring with the the EUTECH INSTRUMENTS Waterproof Series p  H meter, the probe was washed with EUTECH INSTRUMENTS Waterproof Series p deionizing water to remove trace ions and was calibrated using the 7.0 pH solution. To measure the pH of the soil using the soil and water solutions, the probe was washed with deionizing water then placed in the solutions and the measurements appeared on the monitor of the meter. The pH measurements were recorded, including temperature and time of measurement, afterwards. Distilled water was used to wash the salt meter because it is considered as almost pure since through distillation, possible microorganisms, chemicals, and other contaminants are removed (Mittal 2012). It is necessary to use distilled water in calibrating and in washing the equipment because of its lack of foreign contaminants thus it is unlikely to alter the results of the experiment. Despite this, deionized water is used with the pH meter. This is to ensure the complete removal of ions which highly affects pH. All measurements were done on June 8, 2016 from 2:10 PM - 4:30 PM. Results The measurements found in the following table (Table 1) were obtained on June 8, 2016 at the Jesuit Residences. The amount of sunlight (lux) was obtained using the Extech Instruments EasyView Series Wide Range  Light Meter, the temperature (°C)  was obtained using brand t hermometer, the salinity (%) was obtained using a Lutron S  alt Meter, and the pH was obtained using the EUTECH INSTRUMENTS Waterproof Series p  H meter. Table 1. The location, amount of sunlight received (lux), temperature (°C), salinity (%), and  pH of the four soil samples (A-D) obtained from the site, Jesuit Residences, on 6/8/16 Soil Sample A

Soil Sample B

Soil Sample C

Soil Sample D

Mean Values

Quadrant

C15

E1

H10

G22

Light Intensity

0.51 lux (6/8/16, 2:28 PM)

1.61 lux (6/8/16, 2:43 PM)

1.33 lux (6/8/16, 2:54 PM)

3.65 lux (6/8/16, 3:01 PM)

1.775

Soil Temperature

29°C  (6/8/16, 2:34 PM)

29°C (6/8/16, 2:45 PM)

29°C  (6/8/16, 2:55 PM)

29°C  (6/8/16, 3:02 PM)

29°C 

Soil Salinity

0.00% (6/8/16, 3:27 PM)

0.00% (6/8/16, 3:29 PM)

0.00% (6/8/16, 3:32 PM)

0.00% (6/8/16, 3:34 PM)

0.00%

Soil pH

5.76 at 25° C (6/8/16, 3:44 PM)

5.64 at 25°C  (6/8/16, 3:45 PM)

5.10 at 25°C  (6/8/16, 3:46 PM)

5.46 at 25° C (6/8/16, 3:48 PM)

5.49°C 

Figure 1. Aerial view photo of the sample site as generated by Google Earth. The chosen sampling site is a few meters east of the Church of the Gesu in Ateneo de Manila University and a few meters west of the Jesuit Residences in the same university (Figure 1). The entire area was within the same GPS coordinate (14 38’26” N, 121 4’50” E). The area is not typically disturbed by human activity as indicated by the absence of a foot-constructed path, and the plants are not cut, mowed, watered or maintained as in most areas around the campus. There are no bodies of water found in the site, but two major depressions are present and are suspected to serve as artificial water source when precipitation in the form of rain occurs (the main source of water). Despite that, the area was moist enough to support the growth of various fungal species such as mushrooms and those in lichens. It was also noted that the ground is covered by dead organic material (mostly dried leaves) and that it is almost completely shaded by the tall woody plants, herbaceous plants and epiphytes that dominate the entire area, extending even outward the site. DISCUSSION Figure 1 shown above is an aerial map generated by the application Google Earth showing the location of the sampling site selected according the criteria stated in the methodology and the group’s preference. In determining the location of the site, Global Positioning System (GPS) was used in determining the coordinates. Originally developed for military purposes, it can be used by civilians. Most receivers nowadays possess portability (with smartphones even having this feature), self-calibration, and the abilities to provide bearings and store coordinates. These features are exceptionally handy in field studies of unexplored places. However, GPS requires unhindered signal reception from satellites for accurate and precise results. Various errors can arise from the satellite signal integrity and timing of signal reception , which are expressed as User Equivalent Range Errors

(Kleusberg and Langley, 1990). By inputting the coordinates of the area as retrieved by the iPhone 6 Compass application, Google Earth was able display the aerial map. Table 1 displays the parameters measured in order to assess the abiotic factors present in the sampling site chosen by the group. Since the depressions that can serve as an artificial water source did not contain water because no precipitation occurred during the sampling day, simple random sampling was done. There was no need to conduct stratified random sampling because no water source can create subgroups or strata, thus uniformity is assumed between all 1x1 plots. Convenience or haphazard sampling was not done, as a randomizing tool was used for the selection of the 1x1 plots. Light intensity and soil temperature measurements were done in site (in-situ) because the parameters cannot be measured precisely and accurately if samples were to be retrieved and have their parameters measured in laboratory conditions. One instance that could alter the data would be when soil is transferred to a beaker, the sample soil can gain or lose heat as it is separated from the ground of the sampling site and as it comes in contact with the beaker. Young and Freedman (2012) points out that conduction might happen as the soil sample is being transferred. Light intensity is also dependent on the site itself, as different trees in the site can block the sunlight to the sensor. Soil salinity and pH was measured by taking soil samples because the concentration of H+ and salts in the soil does not change substantially as the soil is being transferred from a source to a container. Light intensity As the sampling was done in an afternoon, the main source of light is the sun. The average sunlight intensity in the site measured as close as possible to the soil (~0 ft) is 1.775 lux, which has an SD of 1.3343. The relatively high differences of these values is attributed to the varying presence of tall plant species and epiphytes that are not found throughout the area. They can provide shades that will definitely lower down the light intensity received by a site. Also, the presence of clouds above the site can definitely alter the sunlight intensity received for each site, especially since the day was cloudy at the time of sampling. The soil samples were obtained from sites with varying light intensities because it affects the photosynthetic and phototropic processes and biomasses of plants and provides for the plant’s energy and survival (Combalicer et al. 2012). It is an essential factor in forest regeneration and growth and has a major effect on the flora and fauna of an ecosystem. Soil temperature During the sampling period, the soil temperature of the site is approximately 29.0 o C and similar across all samples as indicated by the SD of 0. The soil in the site belongs to a soil regime that encompasses almost all the land area of the Philippines. The soil is classified to be isohyperthermic, which have annual soil temperatures of more than 22°C. Bai, et al. (2013) states that soil temperature affects a lot of physical, chemical and biological processes in the environment. These include the growth of plants and fungi, respiration of the organisms that thrive in the soil, microbial activity, storage of organic matter, and the accumulation of minerals. While the light intensities of the sample plots were not close to each other, it can be inferred that these discrepancies did not affect the soil temperature. This may have something to do with the insulation of the soil by the dried leaves, which

may have absorbed the heat that came from the different intensities. Also, as the points where the temperature were gathered gets deeper from the surface, the temperature between different plots gets closer. Additionally, water temperature varies as much as soil temperature does. Since water has greater thermal stability than soil due to its specific heat capacity, the amount of heat required to change a unit of mass of a substance by one degree in temperature. The capacity of water to absorb heat energy without changing temperature is greater than that of soil. It takes approximately 1 calorie of energy to heat 1 cm3 of water 1°C. On the other hand, dry soil has 0.19 cal/ g ° C while wet soil has 0.35 cal/ g°C (Molles 2014). Soil pH The average pH of the soil was measured to be 5.49, meaning site can be classified as acidic. The acidity and basicity of soil is affected by a number of factors including fertilizer use, mineral content, climate, weathering, and decomposition activity. The pH on the other hand, affects the biological activity, chemical properties, and availability of nutrients. Certain plants thrive in acidic soils, while some cannot tolerate such and require alkaline ones. The nutrients in soils of different pH also vary: aluminum, boron, and iron are available for uptake in acidic soils since they are more soluble in acidic substances, while calcium, phosphorus, and magnesium are more available in alkaline conditions. The soil pH in the sample supports Ericaceous plants such as azaleas thrive in these soils. However, considering other confounding factors such as the other parameters mentioned here along with extraneous variables such as elevation (NRCS, 2011). Soil salinity Salinity of soil in the sampling site is low such that all sites had values of 0.00%. Salinity, or salt content, is determined by the amount of water-soluble inorganic mineral content present in the soil. Sodium chloride (NaCl), calcium chloride (CaCl2), and sodium bicarbonate (NaHCO3), sodium sulfate (Na2SO4), are some of the most common salts found in the soil. Accumulation of salts in the soil are caused by poor drainage, low leaching, and irrigation with salt-rich water, which are not applicable in the site since water generally flows downward due to the site’s high elevation. Only a number of plant species can thrive in soils with high salinity. Most plants would be unable to draw as much water from saline soils because there would be less diffusion of water from the soil to the roots (Provin and Pitt, 2012). However, certain plants known as accumulators and hyperaccumulators are known to accumulate high amounts of metal ions that are otherwise dangerous for some plants. There were no established correlation between the factors seen. Initially, soil salinity and pH, and light intensity and soil temperature were assumed to have correlations since some salts alter pH while light intensity can elevate the temperature of anything that receives sunlight. However, since soil temperature and salinity were seen to be constant, no patterns can be observed. This might be due to the different plant species in the area that can affect especially the edaphic (soil-related) factors in the site. However, the general soil temperature and light intensity might be indicative of the climate, and even elevation of the site. Soil pH and soil salinity are major determinants of soil quality that could support plant and microbial life (Muller and Spoolman, 2007). The four abiotic factors can give a general

idea on the ability of the environment within the site to support life, even if no correlation can be established between them. Since all of the parameters have values that permit them support the growth of plants and animals, it can be said that the environment within the site is can support a specific community of flora and fauna. Sling psychrometer The sling psychrometer is a hygrometer, an instrument used to measure relative humidity. This instrument is composed of a handle with two thermometers attached. One of these thermometers are referred to as the dry-bulb thermometer while the other one as the wet-bulb thermometer. The wet-bulb thermometer is called as such due to the cloth sock wrapped around its bulb. This cloth sock is meant to be soaked in water before using the sling psychrometer. To use the device, the handler has to swing the psychrometer around. The purpose behind this is to allow the thermometers to encounter a high amount of air. This helps the evaporation of the water in the cloth sock to occur rapidly. For water to change from liquid to gas, it has to absorb the heat of the surface it is on, which in this case is the cloth sock. The change in temperature would be reflected on the wet-bulb thermometer. The dry-bulb thermometer measures the temperature of the environment as a reference. The larger the difference between the temperatures acquired by the two thermometers is, the higher the capability of the surrounding air to hold water vapor. This means that the humidity is low. The smaller the difference between the temperatures is, the lower the capability of air to hold water vapor. In other words, the humidity is high. After taking the difference in temperature, a table is used to determine the relative humidity (Reisel 2015). CONCLUSION The correlation between the soil’s temperature, pH, salinity, and the intensity of light it received was inconclusive. This may be due to the other factors not taken into consideration during the experiment such a relative humidity and the occurrence of rain right before sampling was done. Despite the lack of correlation, it was evident that the site was more than able to support certain forms of life. Sources Bai Y Scott TA Min Q. 2014. Climate change implications of soil temperature in the Mojave Desert, USA. Frontiers of Earth Science 8(2):302-308. Combalicer EA Ho WM Lee DK Park YD Phonguodume C Sawathvong S. 2012. Effects of Light Intensities on Growth Performance, Biomass Allocation and Chlorophyll Content of Five Tropical Deciduous Seedlings in Lao PDR. Journal of Environmental Science and Management 7(1): 60-67. Kleusberg A Langley RB. 1990. The limitations of GPS. GPS World: Innovation 1(2): 50-52. Mittal KL. 1987. Treatise on clean surface technology. 1. New York (NY): Plenum Press Molles MC. 2014. Ecology: concepts and applications. Sixth Edition. Philippines: McGraw-Hill Education. 102-103 p. Muller GT Spoolman SE. 2009. Essentials of ecology. Belmont CA: Brooks/Cole CENGAGE Learning.

Provin T Pitt JL. 2012. Managing soil salinity. Texas A&M Agrilife Extension Service, Texas A&M University System, United States Department of Agriculture. Reisel JR. 2014. Principles of engineering thermodynamics. Boston (MA): Cengage Learning. Young HD Freedman RA Ford L. 2012. University physics with modern physics. 13. San Francisco(CA): Pearson Education, Inc....