WEEK 8 LG 3.2.4- SULFUR CYCLE PDF

Subject Code: IS 1 Integrated Science 1 Module Code: 3.0 Investigating the Biosphere II Lesson Code: 3.2.4 Sulfur Cycle Time Frame: 30 minutes...

Subject Code: IS 1 Integrated Science 1 Module Code: 3.0 Investigating the Biosphere II Lesson Code: 3.2.4 Sulfur Cycle Time Frame: 30 minutes Components Tasks TA1 ATA2 (min) (min) Target After completing this module, you are expected to: 1 1. trace the sulfur cycle and describe how it affects the organisms; 2. identify the role of organisms in the sulfur cycle; and 3. identify the chemical reactions involved in the sulfur cycle. Hook You have learned in the previous learning guides the different 3 biogeochemical cycles – Carbon-Oxygen cycle, Nitrogen cycle, and Phosphorous cycle. In this module, you will be learning about one of the major elemental cycles, the Sulfur Cycle. By now, you should have an understanding of the concept of biogeochemical cycles. What are biogeochemical cycles and why are they important? Write your answer on the space provided below. _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ Ignite Before delving deeper into the discussion, let us first familiarize 15 ourselves with the substance, sulfur. Have you gone on a trip to the hot springs on the foot of a mountain and noticed a foul smell like rotten eggs? If you did, you might have encountered one form of sulfur. Sulfur is a common element found in rocks and minerals and comprises nearly 3% of Earth’s composition. It is an essential component in producing proteins and vitamins in the tissues of living organisms. 1 Time allocation suggested by the teacher. 2 Actual time allocation spent by the student (for information purposes only). Page 1 of 5  Figure 1. Sulfur crystals from the Kilauea Volcano in Hawaii. Image copyright: by Friedman, H. (n.d.) Minerals.net. Retrieved from https://www.minerals.net/mineral/sulfur.aspx The sulfur cycle is one of the essential processes that support many life forms and ecosystems. It describes how sulfur is transferred in the atmosphere, geosphere, and biosphere through different processes. Sulfur is important to living organisms because it is used to make methionine and cysteine, which are two of the essential amino acids needed to make proteins. It is also needed in some co- enzymes essential for various biological processes. Sulfur can come from natural sources in land and in the ocean. It can also be produced through human activities such as mining and burning of fossil fuels. In a terrestrial setting, sulfur mainly comes from volcanic activities and breakdown of rocks and minerals exposed in the Earth’s surface. Volcanic eruptions, although at sporadic occurrences, contribute sulfur gases to the atmosphere in the form of hydrogen sulfide. Sulfur is also deposited as sulfur crystals (see Figure 2) in volcanic vents and hot springs. Large sulfur deposits can be mined commercially because of its industrial use. Figure 2. A miner collects sulfur at Kawah Ijen, an active volcano in Indonesia. (Image copyright: Nunes, R.M. (2016, April 13). iStockphotos. Retrieved from https://www.istockphoto.com/photo/sulfur-miner-at-kawah-ijen- volcano-east-java-indonesia-gm520616928-91032967) Page 2 of 5 Volcanic sulfur gases emitted react with the oxygen in the air forming sulfur dioxide which is the component of the atmospheric sulfur. When sulfur dioxide is dissolved in the water droplets in the clouds, it becomes sulfuric acid. Sulfur goes back to the Earth’s surface as dust or particulate matter or as precipitation. Sulfur- bearing rocks and minerals also release sulfur when broken down into much smaller pieces and are incorporated into the soil as sulfates. Living organisms, such as plants and bacteria, take in sulfates and convert it to simpler, organic forms. This will then be passed on along the food chain and released back to the atmosphere as hydrogen sulfide or will be incorporated back into the soil as sulfates when organisms decompose. In a marine setting, sulfur is mainly deposited as sulfides underwater from hydrothermal vents or more commonly known as “black smokers”. Organisms known as extremophiles utilize this sulfur as sulfates and convert it into energy to be able to thrive in the absence of sunlight and oxygen. These organisms absorb the chemicals released in the hydrothermal vents and convert it into organic forms. Extremophiles were named as such because they flourish in very extreme environments. Deep marine ecosystems greatly depend on these extremophiles as the primary producers. Sulfur-rich deposits or sulfides may get washed up to land releasing sulfur into the soil. Sulfur may also enter the oceans through direct precipitation, as dust or particulate matter, or sulfur-bearing runoff from continental settings. Figure 3. Black smokers found on the ocean floor emit dark, sulfur-rich smoke. Image copyright: Ocean Exploration Trust. (2018, February 12). Deep sea fish use hydrothermal vents to incubate eggs. Phys.org. Retrieved from https://phys.org/news/2018-02-deep-sea-fish-hydrothermal-vents- incubate.html. Anthropogenic or human-induced activities greatly affect the natural processes of sulfur cycle. Activities such as mining and extraction of minerals, burning of fossil fuels, and processing of petroleum contribute large volumes of sulfur in the form of the harmful sulfur dioxide into the atmosphere. As a result, higher concentration of sulfuric acid is incorporated into rain clouds Page 3 of 5  causing a much more harmful acid rain. Acidification of aquatic habitats such as lakes and rivers can be harmful to the organisms such as fishes and plankton. Sulfur dioxide is also an air pollutant which can cause adverse effects to the respiratory health when inhaled. Figure 4. Simplified diagram of the sulfur cycle and its primary components and processes. Image from Miller, T. and Spoolman, S. (2015). Ecosystems: What Are They and How Do They Work? [Powerpoint Presentation] from Cengage Learning 2015. Navigate Based on your understanding in the previous section, answer the 6 following questions on the space provided below. 1. Why is sulfur cycle important? ________________________________________________ ________________________________________________ ________________________________________________ ________________________________________________ 2. What would happen if one of the processes involved in the sulfur cycle is interrupted or the rate of the processes is changed? ________________________________________________ ________________________________________________ ________________________________________________ ________________________________________________ ________________________________________________ ________________________________________________ ________________________________________________ ________________________________________________ Page 4 of 5  Knot SUMMARY: 5 The sulfur cycle is a collection of processes which describes the transfer of sulfur in the different spheres of the Earth. Sulfur mainly comes from volcanic activities on land and deep marine deposits near hydrothermal vents. Extremophiles utilize sulfur to harness energy for respiration. Human activities such as mining and burning of fossil fuels contribute large volumes of sulfur dioxide into the atmosphere. This results to adverse effects in the environment such as acid rain and air pollution. GRADED SUMMATIVE ASSESSMENT Encircle the letter of the correct answer. 1. What form of sulfur reacts with oxygen forming sulfuric acid and can cause acid rain? A. sulfate C. sulfur dioxide B. sulfide D. hydrogen sulfide 2. How do organisms incorporate sulfur back to the soil? A. Sulfur is absorbed by the soil during acid rain. B. Sulfur is released as a by-product of photosynthesis. C. Sulfur goes back to the soil when organisms decompose. D. Sulfur is emitted by plants living near hot springs and volcanoes. 3. Why are extremophiles important to deep sea ecosystems? A. They minimize water pollution. B. They act as the primary producers of deep-sea food chains. C. They provide oxygen for the organisms living in the ocean floor. D. They eat large predators that are dangerous to relatively smaller marine organisms. 4. Which of the following manmade activities helps minimize the amount of sulfur released to the atmosphere? A. Burning of coal and fossil fuels. B. Extraction and mining of minerals. C. Using petroleum with high sulfur content for vehicles. D. Utilizing renewable energy resources such as solar and wind energy. References: 1. Miller, T. & Spoolman, S. (2015). Living in the Environment. (18th Edition). Cengage Learning. 2. OpenStax. (2013, June 21). Biogeochemical Cycles. OpenStax, Cnx Biology. Prepared by Reviewed by Approved by MYRE ADRIENNE JADE F. GESULGA SUZETTE A. PALICTE ALICE C. MANUEL Special Science Teacher I Special Science Teacher IV Special Science Teacher IV PSHS-SRC PSHS-SMC PSHS - CVC Page 5 of 5