Lab 8 – Solve the mystery of the dying crabs

In 2017, crab fishing off the coast of Oregon was hurt when crab traps, which would normally be full of lively and tasty crabs, instead yielded dead and dying crabs. The Oregon Department of Fish and Wildlife put a remote camera on a crab trap near the OOI Oregon Inshore Mooring. Using data from the OOI and other sources, scientists worked together to try to determine the cause of the dying crabs. In this exercise we will look at OOI data for May and June of 2017 to recreate their findings. What was killing the crabs? What OOI oceanographic data can help solve this mystery?

In this exercise we will look at three data sets, all of which were collected over the same time period in 2017. First we will look at dissolved oxygen (DO) in ocean water at this site, which is measured in milligrams per liter (mg/L). Next we will examine seawater temperatures (T), and finally we will examine northward wind speed, which will help us determine if the wind was blowing more north or south, and how strongly.

Activities in this Lab

Learning Outcomes

  • LO1. Describe patterns in individual data sets and correlations between the different data types presented.
  • LO2. Interpret the provided dissolved oxygen, temperature and wind speed data.
  • LO3. Explain the relationship between wind direction and anoxic events on the Oregon Coast using evidence and relevant scientific concepts to support your conclusions.

Background Information

  • Key terms: dissolved oxygen, hypoxia, anoxia
  • Data collection: We will use data collected by the Ocean Observatories Initiative, an initiative that has stationed equipment for collecting data in different locations around the world. Our data comes from the Coastal Endurance Array off the coast of Oregon (see map below).

The Coastal Endurance Array includes multiple oceanographic instruments attached along cables running from the surface down to the seafloor. The drawing below shows where the different data instruments are located in the ocean. Wind data in the activity were collected at the Shelf Surface mooring (2) and the dissolved oxygen and temperature data were collected at the Inner Shelf mooring (1) on the seafloor.