LICHENS AND ATMOSPHERIC CYCLES Objectives for Exam 1 1 List and describe the basic processes within the water and carbon cycles 2 Discuss the structure classification and uses of lichens 3 Explain how aspects of the water and carbon cycles as well as pollutants can impact lichens Objective for Portfolio 1 Identify draw and label lichen organisms viewed with a microscope Clean up After making and viewing your lichen slide rinse the slide and cover slip and put them in the bins by the sink Leave the stations in good condition for the next class Safety Microscope slides can break easily Report any broken glass In today s activity we will be examining two nutrient cycles the carbon cycle and the water cycle as well as their impacts on lichens a community of organisms that can provide information about air quality Part I What is a Lichen 1 At first lichens may look like a single organism but they are actually a community of two or more species living together Different species living in close association over time is called symbiosis In the case of the lichen the structure we see is a fungus and living inside the fungus is one or more different species that can photosynthesize We will cover photosynthesis in more detail next week basically it is a chemical process that uses sunlight energy to convert carbon dioxide into sugars and other organic compounds Pigments particularly green pigments are involved in absorbing sunlight Which green organisms do we usually think of when we think of photosynthesis 2 Microscopic species of algae and cyanobacteria can also photosynthesize these are the organisms living inside of fungi making up the lichen community Study the lichen at your table The primary structure you can see is the also called the mycosymbiont meaning fungus partner the greenish color or blue green is from the smaller organisms living inside either or also called the photosymbionts meaning photosynthetic partners Now you will rotate through four stations to learn more about lichens and their relationships to nutrient cycles and pollution Part II Lichen Stations Station A Lichens Water and Air Pollution Water Cycle 1 Using the Water Cycle poster as a reference sketch and label the water cycle including precipitation condensation run off groundwater evaporation and transpiration evaporation from plants 11 2 There are three types of precipitation water does not only fall to the ground in liquid form as rain it also precipitates in frozen form as and precipitates in gaseous form as Acid Precipitation 3 Many compounds react with water molecules as the move from one part of the water cycle to another From the poster sulfur dioxide can react with water to produce and nitrous oxide can react with water to produce 4 Some species of lichens are extremely sensitive to acidic precipitation One lichen in particular Lobaria pulmonaria tree lungwort is extremely susceptible to acidic conditions it cannot even grow on acidic barks From the map provided Lobaria can be found From the Plants of the Pacific Northwest Coast book which includes lichens too what does Lobaria pulmonaria look like p 489 Easy to identify appearance and widespread distribution make Lobaria a commonly used biotic indicator of acid precipitation in the environment Biotic indicators are organisms used to detect particular aspects of environmental conditions like acidity pollution climate etc Other Air Pollutants and Lichens 5 Using the Air Pollution Chart also reproduced as a smaller green handout list major air pollutants in addition to nitrous oxide and sulfur dioxide 6 Lichens can be used a biotic indicator species for many air pollutants The first large scale air quality monitoring program using lichens was started in the Pacific Northwest following a protocol developed at OSU The data is accessible from the U S Forest Service National Lichens Air Quality Database and Clearinghouse website http gis nacse org lichenair Select Lichen Images from the left column and from the pull down menu click on Effects of Pollution How does the bark of red alder trees differ in areas with air pollution Station B Lichens and Carbon Carbon Cycle 1 Using the Carbon Cycle poster as a reference plants and other organisms like algae and cyanobacteria remove carbon dioxide from the atmosphere and use it for the process of Carbon dioxide can leave the atmosphere and enter oceanic waters through the process of Through sedimentation of the remains of organisms carbon can be stored in rocks limestone Over the long term partially decayed organisms were converted into the fossil fuels natural gas oil and coal Through drilling and mining these can be removed from the earth and the carbon dioxide from these fuels is released into the atmosphere through the process of 12 2 All organisms carry out the process of respiration Respiration is using sugars and oxygen for cellular activity releasing carbon dioxide a bit of water and heat energy Some organisms can also carry out photosynthesis which is almost the opposite reaction Photosynthesis requires carbon dioxide and in the presence of sunlight energy to produce sugars and oxygen 3 In drought conditions like summer in Corvallis the organisms in a lichen community can be relatively inactive From the data provided explain what happens to photosynthesis and respiration in a lichen at low water content approximately 20 and high water content approximately 75 Lichen Growth 4 Lichen communities are typically slow growing some types grow less than 1 0 mm length year Lichens grow in three dimensions but the primary growth for many species is in diameter A lichen was traced on a piece of acetate Looking at the acetate approximately how long ago was this tracing made Gently lay the acetate over the lichen lining up the X marks on the tree bark with the marks made on the acetate Using the provided ruler approximately how much has the lichen grown in that time period mm Has it grown more in one direction than another Why may a lichen community benefit from growing in a certain direction Lichen Substances 5 Lichens play an important role in many food webs From the display provided list some of the organisms that eat lichens 6 Thought Question Lichen communities produce almost 1000 chemical substances not produced by other organisms Some of these chemicals give lichens a unique color or make them toxic How can color and or a toxic chemical protect a lichen community 7 From the material provided describe a few human