Long Island Sound Hypoxia Simulation

Investigate the factors leading to summer hypoxia and its effects on marine life.

Environmental Controls

Represents fertilizer from lawns and agriculture, and wastewater treatment plant discharge.

Summer heating warms the surface water, reducing its density.

What is this? Observe how it affects the water column layers and oxygen levels!

Annual Cycle Simulation January

Simulates dynamic changes over the course of a year.

Cross-Section View

Data Log

Understanding Hypoxia in Long Island Sound

Every summer, the western and central portions of Long Island Sound experience a severe environmental problem known as hypoxia, which literally means "low oxygen."

The Recipe for Disaster

  • Nutrient Runoff: Rain washes nitrogen from fertilizers, sewage, and urban runoff into the sound.
  • Algal Blooms: These excess nutrients act as food, causing microscopic phytoplankton (algae) to reproduce explosively in the sunlit surface waters.
  • Decomposition: When the algae die, they sink to the bottom. Bacteria consume them in a process of decomposition that uses up the dissolved oxygen in the bottom water.

Inquiry Challenge 1: The Summer Barrier

Try raising the Surface Temperature while keeping runoff high. Notice the dotted white line that appears? This is the pycnocline, a density barrier caused by warm, less-dense water floating on top of colder, denser bottom water. This stratification prevents oxygen from the surface from mixing down to the bottom, trapping the marine life below.

Inquiry Challenge 2: The Mystery Factor

What happens in the late summer or early fall that finally breaks the hypoxia cycle? Increase the Mystery Factor "X". What real-world weather events does this represent, and how does it affect the pycnocline and the bottom oxygen levels?