The samples were taken with a 30 cm diameter plankton net with 335 um mesh plankton netting. In almost all cases replicate vertical tows were taken with the length varying on the depth of the lake. The samples were preserved in an alcohol/formalin solution and stored in 250 mL Nalgene bottles. the samples were counted by taking a subsample of 1 or 2 mL from the bottle and emumerating all zooplankton by species using a M-5 steromicroscope. All samples were counted and enumerated by Amy Slaymaker. Notes: S-1, S-2, S-5, and camp pond density calculations were as follows: Density = (# counted)(bottle vol.)/(vol. counted)(tow vol.)(1000) tow volume = 0.146899 = p(net radius)2 ´ 2p(2), Net radius = 0.061 Reference Citations: None relevant to this particular data. Sampling Description. 15 lakes or locations within lakes were sampled in 1993 all coded with standard Arctic LTER site codes. 100 is Toolik lake mainstation situated in about 20 m of water in the southern part of the lake where 15m vertical tows were taken. 102 is Limno Bay of Toolik lake, the small steep-sided bay to the north of the lake. It was sampled approximately in the middle with a 5 m vertical tow. 103 is lake N-1 the large lake due north of Toolik, it was sampled in the north, deep basin with a 10 m vertical tow. 104 is lake N-2 a smalller lake due west of N-1. It is divided and the western basin fertilized. Two stations were sampled one in the treated and one in the reference both near the curtain. 108 is lake NE-12, a small lake northeast of Toolik. It was sampled in the middle with a 12 m vertical tow. 146 is is lake E-1, a small lake east of Toolik camp directly across from the road into camp. It was sampled in the middle with 11 m vertical tows. 116 is lake I-6, a small lake south of Toolik in the inlet series of lakes to Toolik Lake. It was sampled in the middle with 8 m vertical tows. 118 is lake I-8, another lake in the inlet series. It was sampled in the middle with 8 m vertical tows. 107 is lake S-6 a small lake south of Toolik. It was sampled with 6 m vertical tows. 156 is lake S-11 a small but deep lake south of Toolik. It was sampled with 10 m vertical tows. 149 is lake S-2 a small very shallow lake on the south shore of Toolik Lake. It was sampled with 180 degree 2m deep plankton net sweeps. 106 is lake S-5 a small shallow lake south of Toolik. It was sampled with 180 degee 2 m deep plankton net sweeps. 148 is lake S-1, another small, shallow lake south of Toolik. It was also sample with 180 degree net sweeps. 141 is Camp pond near the old campsite pad on the northeast shore of Toolik. It was sampled with 180 degree 2 m deep plankton net sweeps.