Antarctic Ice Shelf Drilling Expedition

• January 2020: Geologists began drilling into Weddell Sea ice shelf (California-sized)
• Location: 160 miles from ice shelf edge, 1 mile thick ice surface
• Harsh conditions: no shelter from polar storms, 24-hour summer sun
• Goal: explore ocean floor beneath ice shelf, collect seabed samples
• Previous belief: conditions below crushing ice shelf cannot support life

Drilling Process and Unexpected Discovery

• 20 painstaking hours to bore through half-mile of ice
• Total explored area under ice shelf: approximately tennis court size
• Sample collection method: lowering kit on rope through ice hole to ocean floor
• Unexpected obstacle: camera hit boulder (only large rock within 20ft radius)
• Accidental discovery when camera swung around boulder at 4600ft depth

Life Forms Discovered

• Tiny tentacle-like organisms resembling enoki mushrooms
• Sponge-type organisms on boulder's other side
• Thin bacterial layer (microbial mat) covering rock parts
• Identified as marine sponges - immobile filter feeders
• Previously thought to be first organisms to disappear under ice shelves

Feeding Mechanism Mystery

• Filter feeders require phytoplankton and creatures eating phytoplankton
• Phytoplankton need light for energy (microscopic plants)
• Boulder location: 160 miles from any light source
• Phytoplankton cannot survive in this environment
• Question: what sustains these creatures?

Ecosystem Comparison

• Ice shelf edge: shallow water with sea spiders, sea stars, urchins
  • Sunlight penetrates, feeds plants/algae ecosystem
  • Supports larger wildlife: fish, penguins, whales, seals
• Deeper under ice shelf: less light = less life
• Mariana Trench comparison: 26,000ft below sea level
  • No light, crushing pressure
  • Mariana Snailfish survive on marine snow

Marine Snow Food Source

• Dead marine creatures sink to bottom
• Bodies broken into smaller pieces during descent
• Becomes food for deep-sea creatures
• Mariana Trench snailfish: eat marine snow fallen up to 7 miles
• Problem: sponges are immobile, food must find them
• No marine snow creators observed under ice shelf

Breakthrough Discovery: Horizontal Food Transport

• Collaboration with British Antarctic Survey
• Hypothesis: marine snow drifting horizontally, not vertically
• Ocean currents in Ross Sea carry marine snow under ice shelf
• Some currents located 930 miles away
• Single plankton piece: years to travel the distance
• Sponges/bacteria nourished by materials traveling up to 1000 miles
• Distance: hundreds of times further than typical marine snow travel

Ocean Current Mechanism

• Faraway currents bring warmer seawater under ice shelf
• Water cools and sinks, displacing existing seawater
• Creates suction effect generating slow current
• Drags nutrients hundreds of miles to sustain life