Earth Exploration Toolkit chapter – June 2009
ROSCOE – Research at Ocean Spreading Centers: Outreach to Education
Working Title:
Life in Extreme Environments: Exploring underwater volcanoes at oceanic spreading centers
Big idea:
No one expected to find abundant life in the deep ocean bottom thriving in hot fluids along plate boundaries, but the surprise discovery in 1979 of a rich biologic ecosystem in an environment of high pressure, toxic chemicals, frequent eruptions, and complete darkness completely changed our understanding of how life can exist. Research in the 30 years since the first discovery has helped us better understand how heat from the earth's interior is released through underwater hydrothermal vents, and how the complex interaction of geology and chemistry create an environment where life can be supported through chemosynthesis.
Outline of case study: (Shona)
First exploration of divergent margin towing underwater cameras and sensors in 1977 revealed hydrothermal vents and the first evidence of these ecosystems (large dead clam shells on the seafloor)
Expected to find volcanic features like lava flows and underwater hot springs
Subsequent research in 1979 when Alvin visited the Galapagos revealed an undersea world brimming with life (Rose Garden Vent Field)
Focus on surprise and wonder of the discovery
How can life exist in such an apparently hostile environment?
No light, high pressure, constant earthquakes and eruptions, extreme temperatures
Reference to pdf article in Oceanus by Robert Ballard
Reference to audio file of Jack Corliss' first observation of the Clambake site
Dive and Discovery pages at WHOI provide excellent background information on these sites and the tools used in their exploration
Conclude with statement that hydrothermal vents at oceanic spreading centers have changed our views of where life can exist and flourish, both on earth and in the universe.
Objectives of this activity:
Guide students through a similar process of discovery, using tools and data from the Ridge 2000 Data Portal ( other sources.
Provide students with instructions on using GeoMapApp to explore the topography, biology, and chemistry of the underwater volcanoes along oceanic spreading centers.
Outline of major parts of the activity:
Part 1: Explore the Galapagos spreading center using GeoMapApp – introduce basic functions of the tool using the location of the first discovery and underwater images from the site.
Part 2: Create a topographic profile across the East Pacific Rise – explore relationships between locations of hydrothermal vents and the topography of a spreading center using high-resolution data from Ridge 2000 research at EPR.
Part 3: Investigate the life forms that populate the East Pacific Rise – view images taken at the site, make observations, and explore relationships between location, species concentration and diversity, vent structures, and water temperature.
Part 4: Dig deeper into the chemistry that supports life on the East Pacific Rise – use chemistry data from rock samples to identify elements that are used by bacteria for chemosynthesis.
Part 1 procedure outline:
1. Open GeoMapApp
2. Open data set of global distribution of vent regions (Interridge)
Questions for students (recognizing and interpreting patterns)
- Do you see a pattern in how these vent regions are distributed?
- What big topographic feature is commonly associated with these regions?
3. Use table to identify Galapagos vent region and zoom in
4. Open image layer to explore archived photos from the discovery site (Breea and Vicki developing this)
Part 2 procedure outline:
1. Open hydrothermal vent location data from EPR
2. Zoom into location of vent field using zoom tool
Questions for students (reading tabular data)
- When were these locations mapped?
- How deep below sea level are these locations?
3. Draw a profile across ridge axis to create 2-D vertical cross-section of topography and draw the cursor over the graph
Questions for students (interpreting graphs)
- What do the x and y axes on the graph represent?
- What do the colors on the map represent?
4. Use the view menu to show the color scale (vertical axis) and map scale (horizontal axis)
Questions for students (interpreting graphs and drawing inferences)
- What kind of feature does the shape of this profile remind you of?
- Does the location of the hydrothermal vents on the profile tell you anything about what kind of feature this might be?
- Is it surprising to find this kind of feature on the bottom of the ocean?
5. Load high-resolution topography data (ABE) from EPR and zoom in on vent sites that are located where high-res data is available (northern end of zone)
6. Draw several profiles across ridge axis so that they intersect vents
Questions for students (interpreting graphs and drawing inferences)
- What new feature do you see on each of these graphs using the high-resolution data?
- Where are the vents located on these graphs?
7. Explanation section on Divergent Plate Margins and OceanicSpreadingCenters (Vicki, Karin)
· Description of circulation patterns in aesthenosphere (driven by heat release from core?)
· Simulation of plate motions at spreading centers
· Creation of new oceanic seafloor through volcanic activity
· Inflation and deflation
· Seafloor spreading, collapse, permeable seafloor
· Black smokers - hydrothermal vent chimneys with black smoke
· What happens when hot magma comes in contact with cold seawater?
Part 3 procedure outline:
1. Explanation section on Creatures that live near a Hydrothermal Vent (Breea?)
· Description of types of creatures that can be found
· Sample picture with organisms identified (Breea/Vicki)
2. Retain high-resolution topography and vent location data from Part 2.
3. Load image subset from EPR (Breea and Vicki developing this)
4. Explore vent field images and record observations in editable data table:
- Life present or not present
- Estimate number of animals in each image
- Smoking chimney structures present or not present
- Evidence of rock collapse present or not present
- Water cloudy or not cloudy
- Temperature data (Vicki developing this)
5. Use color by value to explore spatial patterns in observations and relate to vent locations
Questions for students: (interpreting patterns and making inferences)
- Need some questions!
- Draw profile of temperature vs vent location parallel to axis
Remaining tasks to make this complete (and to finalize the story):
· temperature data
· images (Vicki and Breea will write captions for MediaBank)
· presentation of images
· spreadsheet with empty columns that can be used for students to add their observations.
Part 4 procedure outline:
1. Explanation section on role of bacteria in a hydrothermal vent ecosystem (Karin, Breea, Shona)
· Question – how can tube worms live in such an extreme environment?
· What are the raw materials living things need in order to grow and thrive? Living things adapt to their environment in order to survive. They consume what is available. The rocks at the EPR are called basalt, also the most common rock on earth. What is in basalt that provides important nutrients to living things? (Karin's notes)
· Split open a tube worm to find bacteria
· Chemosynthesis – bacteria reduce sulfur to create energy for converting inorganic carbon into food for the tube worm
· Schematics of organisms explaining chemosynthesis (Breea)
· Compare with photosynthesis
· Role of bacteria in our own bodies
· Role of bacteria in other extreme environments
2. Load chemistry data from EPR (Karin developing this)
· Identify a few rock samples for which we have chem data
· Identify an image of acquisition for students to understand where nutrients come from
Questions for students (extend understanding to other contexts)
- How does the chemistry data support the hypothesis that bacteria are the key organism in this ecosystem?
- What are some other extreme environments that might use similar methods for supporting life?
Notes: this section is still somewhat vague on what we will have students actually do as part of the activity – still needs to be worked out more thoroughly once we know what the data can provide students to work with