Scientists know from studying diatoms around the world today that different types of diatoms prefer different climate conditions. Your task is to make predictions about what the climate was like 7000 years ago at five different locations, based on diatom cores which have been extracted from the lakebed sediment at each site.
Analysis of the cores has determined that they represent many thousands of years worth of deposition. Sections of each core which correspond to an approximate age of 7000 years old have been isolated, and a specimen of the dominant group of diatoms present in those layers has been mounted on a microscope slide.
Open the Flash file “What Diatom am I?” and click on each of the diatoms on the microscope slides. Using the tips provided in the sidebar, identify each diatom and record its name.
Using the information accompanying the images of diatoms magnified by a scanning electron microscope (below), note the respective climate preferences of the diatoms you have identified.
Discussion
Why is this method of studying climates which existed thousands of years a Read More
Scientists know from studying diatoms around the world today that different types of diatoms prefer different climate conditions. Your task is to make predictions about what the climate was like 7000 years ago at five different locations, based on diatom cores which have been extracted from the lakebed sediment at each site.
Analysis of the cores has determined that they represent many thousands of years worth of deposition. Sections of each core which correspond to an approximate age of 7000 years old have been isolated, and a specimen of the dominant group of diatoms present in those layers has been mounted on a microscope slide.
Open the Flash file “What Diatom am I?” and click on each of the diatoms on the microscope slides. Using the tips provided in the sidebar, identify each diatom and record its name.
Using the information accompanying the images of diatoms magnified by a scanning electron microscope (below), note the respective climate preferences of the diatoms you have identified.
Discussion
Why is this method of studying climates which existed thousands of years ago important?
What other methods do scientists use to learn about ancient climates?
Why is the study of ancient climates important?
Extensions
To learn more about climate change and the Arctic today and in the future, go to http://www.nature.ca/sila/edu/albedo_e.ppt
© 2007, Canadian Museum of Nature. All Rights Reserved.
Diatom Identification Activity
Alex Tirabasso
Canadian Museum of Nature
© 2007, Canadian Museum of Nature. All Rights Reserved.
Selected species of Aulacoseira live under the ice and bloom in late winter/early spring.
Paul Hamilton
© 2007, Canadian Museum of Nature. All Rights Reserved.
Cyclotella live suspended in the lake water and are good indicators of shorter ice covers and longer growing seasons.
Paul Hamilton
© 2007, Canadian Museum of Nature. All Rights Reserved.
Specific species of Cymbella prefer benthic, colder water conditions and a less productive or nutrient-poor environment. Species from this genus live in a variety of habitats from benthic mud/sediments to mucus tubes.
Paul Hamilton
© 2007, Canadian Museum of Nature. All Rights Reserved.
Specific species of Nitzschia are associated with more nutrient-rich environments which are typically warmer.
Paul Hamilton
© 2007, Canadian Museum of Nature. All Rights Reserved.
Specific species of Staurosira thrive in cold, nutrient-poor conditions.
Paul Hamilton
© 2007, Canadian Museum of Nature. All Rights Reserved.
Learning Objectives
- Appreciate the role and contribution of science and technology in our understanding of the world.
- Describe interactions between biotic and abiotic factors in an ecosystem.
- Value the role and contribution of science and technology in our understanding of phenomena that are directly observable and those that are not
