John Edward O, Tanchuco Section: TFEG1
Ana Larissa H. Guerrero
John Aldwin U. Co
Candace Beatrice P. Tan
Rowell S. Hernandez

Experiment # 1
THE ECOSYSTEM AND ITS CLIMATIC FACTORS

Abstract

Climatic factors are a specific type of abiotic components that determine the long-term weather pattern in a particular area. In this experiment, the researchers investigated key climatic factors, namely: temperature, light intensity, relative humidity, wind speed, wind direction, atmospheric pressure, precipitation and rate of evaporation. The study sites of the investigators are located at the College of Medicine, Pedro Gil St., University of the Philippines Manila and were collected last November 19, 2010. The ecological significance and possible relationships between the two climatic factors was also investigated so as to accurately describe the climatic factors. Shared data from other groups, who investigated other sites around the UP Manila campus, was also compared with the values of the investigators as a point of comparison. The thorough investigation of these climatic, abiotic factors is essential to our full understanding of the interactions in a given ecosystem under study (the study site, in particular).

Keywords: climatic factors, temperature, light, precipitation, humidity, evaporation

Introduction:

The interactions between biotic components in an ecosystem are determined by the abiotic factors in the immediate, physical environment. The abiotic factors in their habitat are primary indicators in the abundance and distribution of organisms.

The basic unit of ecology (an ecosystem) is composed of biotic or living factors, and abiotic or non-living factors. These two components are inseparable and are continually interacting in a given ecosystem. The abiotic factors can be further classified into climatic, edaphic and topographic factors.

The researchers focused on the climatic factors for investigation in this experiment. Weather refers to the temporary conditions resulting from changes in the atmosphere. Climate is a long term pattern of weather. Climate is a complex, multi-factorial combination resulting from the interaction of temperature, humidity, precipitation wind, and cloudiness at a specific place and time. It can be concluded that both weather and climate influence the abundance and distribution of organisms. Climate and weather also determine the availability of heat and water and amount of solar energy that can be utilized by producers.

At the end of this experiment the researchers achieved the following objectives: (1) familiarity with the different climatic factors (2) observation of the possible relationships existing among these factors and (3) performance of field measurements for these climatic factors.

Materials and Methods:

On Nov. 19, 2010 at 1:30PM, groups were assigned particular areas around the UP Manila campus for climatological observation. For every particular area, two study sites were chosen with five random points in each site. The climatic factors measured in the experiment included temperature, light intensity, relative humidity, wind speed, wind direction, atmospheric pressure, and the rates of precipitation and evaporation.

Firstly, aerial temperature was measured using a laboratory thermometer. The thermometer was suspended for three minutes before any readings were made. The units used for the values recorded were in degrees Celsius. Another factor measured was light intensity. It was measured using a light meter while holding it at arm’s length with the light sensing plate directed towards the direction of the sun. The recorded values were in units of foot-candela. As for the measurements of relative humidity, the slingshot psychrometer was used. The cloth wrapped in the wet bulb thermometer of the instrument was moistened with distilled water. After which, the device was rotated in the air for two minutes. The readings in the wet and dry bulb thermometer were then recorded and the transformation table was referred to estimate the % relative humidity values. The next climatic factor measured in this experiment was wind speed and direction. Ideally, a wind meter should be used by positioning it at eye level with the wind scale facing the user. A compass should be used to indicate the direction of the wind stream. As for atmospheric pressure, a barometer should be used and recorded in hPa. Precipitation should be measured with the use of a rain gauge. Lastly, the rate of evaporation should be measured by allowing a known volume of water in an Aluminum pan to evaporate over a period of 24 hours. However, due to lack of equipment, location and time constraints, the values for the last few factors were referred from data of the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA).

Results:

General Conditions | Cloudy, overcast | Slight to moderate wind presence | Humid | No precipitation | Date: November 19, 2010 (Friday) |
Table 1: General conditions of climactic factors (1:41 -2:05 pm) at the Lady Medicine Garden, UP-Manila

Climactic Factors | Mean Data | Temperature (°C) | 30.56 | Light Intensity (ft-candela) | 130.6 | Relative Humidity (%) | 76.6 | Wind Velocity (m/s) | 2.0 m/s | Atmospheric Pressure (hPa) | 1009 | Precipitation Rate (mL/day) | No precipitation | Evaporation Rate (mL/m2·hour) | - |
Table 2: Measurements of climactic factors (1:41 -2:45 pm) at the Lady Medicine Garden, UP-Manila
The designated study site was a vast garden with an abundance of grasses, trees, some flowers and living organisms. The weather on that day was cloudy with overcast skies. Slight winds are blowing over the area, but not strong enough for the investigators to exactly pinpoint its origin and direction. A moderately tall statue dominated the middle of the garden while the remainder of the ground surrounding the grass-covered garden was a mixture of towering trees, grasses and flower beds.

Table 1 presents the general climactic data as observed macroscopically at 1:41 pm onwards. The data was acquired at five random points with the mean value recorded at the table. As indicated, the average temperature reading was 30.56°C; average light intensity was at 130.6 foot-candela; relative humidity was averaged at 76.6%; wind velocity at 2.0 m/s. No amount of rainfall was noted for the particular time frame of data collection. The evaporation rate was not collected due to lack of instrument and safe location to leave the pans in the study site. The atmospheric pressure of 1009 hPa was recorded and taken from the archives of Weather Underground, Inc.

Climactic Factors | Mean Data | Temperature (°C) | 31.50 | Light Intensity (ft-candela) | 136.6 | Relative Humidity (%) | 72.7 | Wind Velocity (m/s) | 2.0 m/s | Atmospheric Pressure (hPa) | 1009 | Precipitation Rate (mL/day) | No precipitation | Evaporation Rate (mL/m2·hour) | - |
Table 3: Measurements of climactic factors (2:05 -2:45 pm) at the College of Medicine Parking Lot, UP-Manila

The next study site was a large parking lot with a few patches of grass, a few towering trees and minimal life forms on the ground. The weather was also cloudy with overcast skies. Slight winds are blowing in the area. The parking lot was filled with cars and while the immediate surroundings were lined with few grass patches and a number of trees. Table 3 presents the general climactic data as observed macroscopically at 2:05 pm onwards. Data was acquired at five random points with the mean value recorded in the above table. As indicated, the average temperature reading was 31.5°C; average light intensity was at 136.6 foot-candela, relatively slightly higher than the Lady Medicine Garden since this area contained fewer trees; relative humidity was averaged at 72.7%; wind velocity is still at 2.0 m/s. No amount of rainfall was noted for the time frame of data collection, and the evaporation rate was not collected due to lack of instrument and safe location to leave the pans. The atmospheric pressure of 1009 hPa was recorded and taken from the archives of Weather Underground, Inc.

Discussion:

The Climatic Factors’ Ecological Significance

Even at the microcosmic level at which the environmental climatic factors were examined, it was readily observable that conditions were the result of the collective effects of these respective factors. Notes on the studied conditions can be found in Table 1. The factors that were established to be of relevance were those of light intensity, temperature, humidity, wind velocity, atmospheric pressure, among others. Measurements acquired of these parameters can be found in Table 2. Their particular contributions to the overall environmental condition and their inter-relationships with each other have been discussed herein.

Light Intensity

Light intensity as a character in the ecological climatic profile mainly comes from the sun. Since data collection was done at a time when no other light sources such as street lights and car headlights were yet present or significant. Sunlight that came through from the sun was affected by the atmosphere, most significantly cloud cover. An approximated reading of unhindered sunlight should have measured at 10,000 foot-candela, a reading proportional to the amount of clouds that prevent the light from reaching the ground.

The obtained averages of 130.6 and 136.6 foot-candela did not match up to this expected value even factoring in the overcast nature of the sites. This anomaly may be explained by a malfunctioning of the photometer.

In urban areas such are those that were studied, light intensity is not just influenced by cloud density, but may also be attributed to cover provided by surrounding buildings that also block light and reflect it away from the area, as also discussed in temperature below.

Temperature

Temperature is not merely a benchmark of total heat in a particular locality, rather in ecology it is a sum of several factors – including humidity, variety of heat sources at hand, and reflected solar energy. It’s main significance to the biotic elements of the system lies in organisms’ need for thermoequilibrium, meaning that achievement of their full functionality is dependent upon a certain temperature range. Proteins essential to life as well as lipids in membrane structures denature if temperature drop below or climb above the range limits. Environmental temperature is then an important consideration especially for organisms which are either completely or partially dependent on these values not having adapted mechanisms to regulate their own internal temperature.

In the locales assessed, average temperature was gauged at 30.56°C and 31.5°C. These values roughly matched estimates provided by the weather services of PAGASA on this day.
As an urban zone, the Pedro Gil sites were characterized by dense infrastructure. These surrounding buildings were known to have an effect on temperature distribution and those accounted for in the observations of the group. The tall buildings along the street cast some large shadows over certain areas in the first site. Over the day, it can be assumed these shadows were shifting in position along with the movement of the sun. Given this, light and thus solar energy would not hit any particular point all throughout the day. Another consideration with these tall structures was that they also reflect the light and energy away from the site as some had significant glass and metal composition.

Another additional factor of the city site was that it provided alternate heat sources. Significant among these were the emissions of automobiles. Sites were located alongside a moderately busy street. The fuel in the cars that passed by combusted in the engine and released heat into the atmosphere, but they also released gases. These gases were capable of heat trapping.

Trees in the garden, as a biotic factor, had a similar effect as these buildings, though perhaps not on the same scale. Trees also provided shade and obstacles for the sun’s light.

Another factor affecting temperature was the wind. Wind has a given tendency to distribute heat in an area evenly given no obstacles.

There was however about a degree of difference in the two sites in Pedro Gil. This can accounted for in that urban areas tend not to have even distribution of temperature despite the wind’s factored effect. The areas were several meters apart, and had different coverage in terms of clouds in the sky as well as cover from surrounding buildings. It can also be remarked that these areas were at different distances from the road.

Humidity

Humidity is a measurement of the saturation of the air with water vapor, expressed in a percentage (Smith & Smith, 2009). An area’s humidity is dependent upon two things: temperature and availability of water for evaporation. A greater temperature tends to drive up the humidity in an area due to a higher evaporation rate.

The afternoon the study was conducted was a warm with 76.6% and 72.7% recorded humidity in the two sites, levels which seem notably high. These values however are considerably typical of tropical areas, such as the Philippines, especially in an urbanized area where there is no shortage of supply for possible water evaporation. Humid air is cooler and thus follows the natural tendency to move towards areas of higher heat, such urban heat islands. Urban heat islands in effect draw upon themselves increased precipitation. The site of data gathering, being within this urban heat island, had these amounts of humidity.

Wind Speed

Wind speed, referenced earlier, is a measurement of the movement of atmospheric gases due to a pressure gradient. Temperature has a hand in these movements as a spike in temperature heats up the air causing it to rise. This, in turn, reduces pressure at the surface which then allows low-lying cool air to move in from areas of greater surface pressure (Smith & Smith, 2009). The particular region of study, being inland of a coastal area exhibits wind movement between land breezes and sea breezes due to these temperature differences.

Data gathered showed wind velocity to be at 2 m/s in both sites. Wind bouncing off the nearby buildings could have influenced the collected data.

Atmospheric Pressure

Surface pressure was mentioned in the above section and is a notable factor affecting climatic conditions. Air, though less dense than other matter, accounts for trillions of tons of weight in the atmosphere. This weight is what acts as a downward force on the surface of the Earth. This force over a given area is then what is called atmospheric pressure.

One correlated factor to atmospheric pressure is amount of water vapor in the air, or humidity. Increased humidity causes an increase in atmospheric pressure. This effect is what is termed vapor pressure.

Measurements taken on the day indicated that Manila’s atmospheric pressure was 1009 hPa.

Precipitation

Precipitation is a major stage of the hydrological or water cycle. It is any product of condensation or vapor that is deposited back to the Earth’s surface, typically in freshwater bodies. Precipitation as a measurable quantity is then the amount of this deposition at a given rate. Precipitation comes in the forms of rain, snow, hail, sleet, graupel, among other. More than half a million cubic kilometers worth of water precipitates each year.

Because there was no rainfall in the day measurements were recorded, precipitation was indicated as not being present for the areas, in line with the prediction of weather services that there was only a low percentage chance of rain.

Evaporation Rate
Evaporation has been mentioned several times already and is also a stage in the hydrological cycle. Many factors control, effect, and interact with evaporation and its rate. Included among these are temperature, humidity, wind, and surface area (Meng & Meng, 1997).

Increased temperature leads to increased evaporation due to the fact that heat is proportional to temperature. The energy of heat is required to break the intermolecular forces of attraction between the water molecules in solutions not yet evaporated.

Vapor pressure, which was discussed above, is a component of both humidity and atmospheric pressure. Evaporation only occurs when two interacting vapor pressure forces in the system have a certain relationship. The first of the two interacting vapor pressures is the vapor pressure of the solution, which is essentially the vapor pressure in a solution that will be the source of evaporation, VPs. The second vapor pressure, then, is the atmospheric vapor pressure, VPa. Evaporation only occurs when VPs > VPa.

Humidity as we mentioned is proportional to vapor pressure. Thus we can say when there are higher levels of humidity, there are also a greater rates of evaporation.
When there is evaporation, VPa increases with the continuous inundation of evaporated water molecules. If air then is still, the evaporation rate will eventually peter since the pressure difference between VPs and VPa will shift and no longer favor evaporation. Thus wind speed plays a factor in evaporation, as wind blowing the humid air away and replacing it with less humid air prevents this condition of decreased vapor pressure difference (Hill & Wyse, 1987).

Lastly, surface area’s relationship with evaporation is directly proportional. The more area of a solution that can be evaporated is in contact with these above factors, the more evaporation is likely to occur.

No rate of evaporation could be recorded the day the study was conducted.

Conclusion

The climatic condition of any given locale is the result of the complex inter-relationships formed between the varying factors – temperature, wind, precipitation, pressure, etc.

The main energy source in the environment is that of the sun’s light. This solar radiation reacts with the air, heating it. This reaction along with Earth’s movements cause wind movement. Wind movement then is also affected by atmospheric pressure, with pressure gradients dictating the direction of wind movement. The sun’s heat also gives thrust to the hydrological cycle, which causes evaporation, which is linked to humidity. At 100% humidity, precipitation will occur. These all contribute to the temperature of an area.

None of these relationships are unidirectional. They are all interdependent, and it is this interplay which gives a certain area their unique climatic profile.

In the study conducted, the urban setting caused alterations to typical expected values, however all of these were reasonable given the effects of the city to the environment and relationships between values still reflected the expectations.

Bibliography:

[1] Hallare, AV. (2010). Student Handbook in Biology 160: General Ecology. University of the Philippines Manila, Ermita, Manila.

[2] Hallare, AV. (2006). General Ecology: Concepts and Selected Laboratory Exercises. University of the Philippines Manila, Ermita, Manila.

[3] Cruz, F.T. & Villarin, J.T. 2005. Urban modification of the climate of Metro Manila, Philippines. Manila Observatory.

[4] Cruz, F.T. and Villarin J.T. 2003. Changes in the surface temperature and winds due to the growth of the Metro Manila urban area. Manila Observatory.

[5] Smith, R. and Smith, T. 2009. Climate. Elements of Ecology. Seventh Edition. New York: Pearson Benjamin Cummings.

[6] Hill, R. W., & Wyse, G. H. 1987. Organism, environment, and adaptation. In Animal Physiology (137-138). New York: Harper Collins

Appendix:
The Research Group’s Data:

I. Study Site I: Lady Medicine Garden, College of Medicine, UP Manila Test Site No. | Temperature (oC) | Light Intensity (candela) | Relative Humidity | | | | Dry bulb (oC) | Wet Bulb (oC) | % | 1 | 30.5 | 138 | 31.5 | 28.5 | 80 | 2 | 31 | 135 | 31 | 27.5 | 76.5 | 3 | 30.5 | 126 | 30.5 | 27 | 76.5 | 4 | 30.3 | 122 | 30.5 | 27 | 76.5 | 5 | 30.5 | 132 | 31 | 27 | 73.5 |
Table 4. Raw data for climatic factors in Study Site I, Lady Medicine Garden, UP Manila

Wind Speed (m/s) | Atm. Pressure (hPa) | Precipitation (ml/ day) | Rate of Evaporation-on(ml/ day) | 2 | 1009 | No prec. | - | 2 | 1009 | No prec. | - | 2 | 1009 | No prec. | - | 2 | 1009 | No prec. | - | 2 | 1009 | No prec. | - |
Table 5. Table 4 continued

II. Study Site II: College of Medicine Parking Lot Test Site No. | Temperature (oC) | Light Intensity (candela) | Relative Humidity | | | | Dry bulb (oC) | Wet Bulb (oC) | % | 1 | 31 | 132 | 31 | 27.5 | 76.5 | 2 | 30.5 | 134 | 32 | 28 | 74 | 3 | 32.5 | 137 | 32 | 27.5 | 71 | 4 | 32 | 140 | 32 | 27 | 68 | 5 | 31.5 | 140 | 32 | 28 | 74 |
Table 6. Raw data for climatic factors in Study Site II, College of Medicine Parking Lot, UP Manila Wind Speed (m/s) | Atmospheric Pressure (hPa) | Precipitation (ml/ day) | Rate of Evaporation (ml/ day) | 2 | 1009 | No prec. | - | 2 | 1009 | No prec. | - | 2 | 1009 | No prec. | - | 2 | 1009 | No prec. | - | 2 | 1009 | No prec. | - |

Table 7. Table 6 continued
\
Data from other Research Groups: * Location: Philippine General Hospital – UP Manila, Pedro Gil St. corner Taft Avenue, Manila Study Site | Temp | Relative Humidity | Diff | Humidity | | (ºC) | Wet | Dry | | (%) | A | 30 | 25 | 31 | 6 | 61-62 | | 30 | 28 | 33 | 5 | 68-69 | | 30 | 28 | 32 | 4 | 74 | | 30 | 28 | 32 | 4 | 74 | | 30 | 25 | 32 | 7 | 57 | | | | | | | B | 30 | 27 | 32 | 5 | 68 | | 30 | 27 | 32 | 5 | 68 | | 30 | 28 | 32 | 4 | 74 | | 30 | 28 | 32 | 4 | 74 | | 30 | 27 | 32 | 5 | 68 | | | | | | | C | 30 | 28 | 32 | 4 | 74 | | 31 | 28 | 32 | 4 | 74 | | 30 | 28 | 32 | 4 | 74 | | 30 | 28 | 32 | 4 | 74 | | 31 | 28 | 32 | 4 | 74 | | | | | | | D | 30.5 | 28 | 32 | 4 | 74 | | 32 | 29 | 32 | 3 | 80 | | 31 | 29 | 32 | 3 | 80 | | 31 | 29 | 33 | 4 | 74-75 | | 32 | 29 | 33 | 4 | 74-75 | | | | | | | E | 31 | 27 | 32 | 5 | 68 | | 31 | 27 | 33 | 6 | 62-63 | | 30 | 28 | 33 | 5 | 68-69 | | 30 | 28 | 33 | 5 | 68-69 | | 31 | 28 | 33 | 5 | 68-69 |
Table 8. Data on Temperature and Relative Humidity in Five Study Sites – PGH Chapel

Study Site | Temp | Relative Humidity | Diff | Humidi-ty | | (ºC) | Wet | Dry | | (%) | A | Mean | 30 | 26.8 | 32 | 5.2 | 67 | Median | 30 | 28 | 32 | 5 | 68.5 | Mode | 30 | 28 | 32 | 4 | 74 | | | | | | | B | Mean | 30 | 27.4 | 32 | 4.6 | 70.4 | Median | 30 | 27 | 32 | 5 | 68 | Mode | 30 | 27 | 32 | 5 | 68 | | | | | | | C | Mean | 30.4 | 28 | 32 | 4 | 74 | Median | 30 | 28 | 32 | 4 | 74 | Mode | 30 | 28 | 32 | 4 | 74 | | | | | | | D | Mean | 31.3 | 28.8 | 32.4 | 3.6 | 76.6 | Median | 31 | 29 | 32 | 4 | 74.5 | Mode | 31.5 | 29 | 32 | 4 | 77.25 | | | | | | | E | Mean | 30.6 | 27.6 | 32.8 | 5.2 | 67.2 | Median | 31 | 28 | 33 | 5 | 68.1 | Mode | 31 | 28 | 33 | 5 | 68.1 |
Table 9. Statistical Data on Temperature and Relative Humidity in Five Study Sites - PGH Chapel

* Location: CAS Oblation Garden, UP Manila, Padre Faura, Ermita Manila

| | | | |

Study Site | Temp(°C) | Light Intensity (ft-candle) | Relative HumidityDRY WET | Wind Speed (m/s) | A | 31 | 32 73.5 | 31.5 27.5 | 0.3-1.5 | | 30 | 28. 73.5 | 31 27 | 0.3-1.5 | | 31 | 27 67.5 | 31.5 27 | 0.3-1.5 | | 32 | 2 67.5 | 32 27.5 | 0.3-1.5 | | 30 | 9 67.5 | 31 26.5 | 0.3-1.5 | | Ave: 30.8 | Ave: 19.6 | Ave: 69.9 | Ave: 0.3-1.5 |
Table 10. Data on Temperature, Light Intensity, Wind Speed and Relative Humidity in Five Random Points – Oblation Ga