Lab 2 EVR 4114 Climate Change Summer 2018 Palynology Assignment Palynology is th
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Lab 2 EVR 4114 Climate Change Summer 2018 Palynology Assignment Palynology is the study of using the changing assemblages of pollen from certain species which have specific climatic tolerances to reconstruct past climates for certain regions. Researchers measure the amount of pollen that comes from a certain species and the climate parameters in which they prefer to grow. They then assume that if high abundances of that species are present sometime in the past that the climate of that region was similar to that where the species currently grows. This is called the transfer function. The central North Island of New Zealand has experienced a large climate shift over the last 15,000 years. To reconstruct the change in climate over that period for this region, the palynologists extracted cores from bogs across the region, dated their stratigraphy and collected pollen from those cores. They were interested in the difference between the climates of two span shots in time reconstructed by the natural vegetation: 800 years BP and 15,000 years BP. The 800 years ago portions of the cores were used as a time period of "modem" natural vegetation. Four species of plants were used because of their known climate tolerances: 1. Rimu-maximum growth at average temperatures of 15 precipitation of 1300 mm C and average annual 2. Beech -maximum growth at average temperaturesf 7 °C and average annual precipitation of 750 mm 3. Tree Ferns - maximum growth at average temperatures of i15 C and average annual precipitation of 1350 mm 4. Herbs- maximum growth at average temperatures o6 oC and average annual precipitation of 800 mm This region of NZ is very close to the Central North Island Volcanic Plateau which has volcanoes that have erupted intermittently over the last 20,000 years. The tephra ejected from these eruptions has spread over hundreds of miles and contributed to the rich soils of this region. Assignment As the palynologist, you take one core and reconstruct the climate of the two time intervals. The first step is to date the core to know where the sections are that fit your two time periods. I. Write a paragraph on how you would go about finding this information? Think of the steps and techniques you can use to undertake this task. 2. Why do you think the palynologists would use the section of the core from 800 yr BP and not e very top of the core to reconstruct the natural vegetation of"modern" times?Explanation / Answer
2. First based on the visual appearance of the core sample we can devide it in to several parts. Each 2-5cm common looking core areas or common tephra non tephra layers can be subjected to composition comparison and radiocarbon dating. Once this data is obtained we can divide the core in to different geological time scales. Let us assume we have identified 800BP core at 80cm and 15000BP 1500cm. Now isolate fossil pollen from 800BP, 1500BP and compare with the current upper surface pollen, IF they are different or same we can conclude the changes in the climate also can be compared and contrasted with respect geological time scales. If we find herbs and beechs pollen at 1500cm core we can conclude that at 15000BP climate was near to glaciation or just then ice age is ending, if we find rimu and tree ferns pollen at 800cm or beyond core we can conclude that current climate shift has happened 800BPor beyond or little long after the end of glaciation or ice age.
3. Palynologists used 800BP core because they might have found that the native natural vegetation of present times exactly matching with 800BP core sample (This could have been minimum criteria). Also to make sure that manmade or man introduced plant species in to Newzealand pollen should not interfere with the results.
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