US Long-Term Ecological Research Network

Water Chemistry and Biology

The regional lakes survey in 2015 followed the standard LTER protocol for standard water chemistry and biology. Samples were taken as close to solar noon as possible. Seven lakes had replicates performed, which were chosen at random between the four lake classes.

Gas Sampling

Equipment list:

  • 1 liter jug
  • Two 30 cc syringes
  • One 20 cc syringe
  • Mylar bag rinsed with nitrogen
  • Glass vials
  • Syringe needles
  • Pump
  • Stopper with tubing and stopcocks

Before going to field:

Gas vials were first rinsed with nitrogen to purge all other air. 30 cc of air was then removed using a syringe to create a vacuum within the vial. Mylar bags were refilled with nitrogen when needed.

In field:

A one-liter jug was filled up with lake water at a half-meter depth using a standard pump.

The jug was left to overfill for approximately 30 seconds to flush it out. After it had overflowed, the tubing was carefully removed to make sure there was no headspace left within the jug. The stopper with tubing was placed on top and all stopcocks were closed.  Make sure there is NO headspace!  30 cc of nitrogen was extracted from the mylar bag using a 30 cc syringe. This 30 cc syringe was screwed onto one of the pieces of tubing. A second empty 30 cc syringe was screwed onto the other piece of tubing. The 30 cc of nitrogen was injected into the bottle while water was also extracted. Once the full amount of was injected all stopcocks were closed and the syringes were removed. The bottle was then shaken for 100 seconds. After this amount of time, the 30 cc syringe containing water was screwed back on and a 20 cc was also placed onto the tubing. 15 cc of the headspace was extracted while water was also being injected. All stopcocks were then closed and the 20 cc syringe was removed. 3 cc of air was rinsed from the syringe while the last 12 were injected into the appropriate vial. For gas blanks vial 12 cc of the pure nitrogen was injected into the vial. Two replicates were performed within field.

Protocol Format
Process
Protocol Type
field