Wednesday, April 25, 2007

Quarterly Macroinvertebrate Inventory

It is time again to test the water quality, both quantitatively and qualitatively, in Four Holes Swamp at the Audubon Center at the Francis Beidler Forest. Once a quarter, water samples are taken at various locations within the swamp along with macroinvertebrate samples from the bottom. The water samples are tested chemically (quantitative results) for dissolved oxygen, phosphates, nitrates, pH, and hardness. The macroinvertebrates are inventoried and the water quality is determined (qualitative results) based on the percentage of pollution-intolerant species versus the percentage of pollution-tolerant species.

It is ALWAYS enjoyable to get out of the office and into the swamp, even if only to collect water and macroinvertebrate samples. However, once back in the office, the act of picking the organisms from the sample tray can literally be a pain in the neck. In order to obtain accurate data, it is necessary to remove as many organisms as possible from the sample. This takes hours of peering into the sample tray, which causes pain in the neck and shoulders. Eyes get tired of staring at the sample that has long ago been picked clean of the larger organisms...or so one might think. An inch-long dragonfly nymph appearing after a sample has been picked over for two hours demonstrates nature's wonderful ability to camouflage and can crush the confidence in one's observation capabilities.

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