Ecological Evaluation Technical Guidance - State of New Jersey

density may vary with depth; therefore, sampling should be done at several depthsdetermined by the depth of the thermocline; the euphotic zone, if applicable; and overalldepth at the station. In shallow areas (one to two meters) subsurface samples (to a depthof one meter) are usually sufficient. In lentic environments, sample at one-meter intervalsfrom the surface to the lake bottom because these organisms are not confined to theeuphotic zone.Zooplankton analysis requires at least six liters in moderately and highly productivewaters. Sample size, preservation and storage are dependent upon certain variables. Referto the NJDEP Field Sampling Manual for details. Generally, freshwater samples forspecies composition analysis should be preserved with a solution of neutralized formalin(5 ml neutralized buffer with formalin/100 ml of sample). All preserved samples shouldbe stored in the dark immediately.When collecting live samples, leave at least a four-cm air space in the bottle and chill to4º C (e.g. in a cooler with ice) during transit storage. For delicate flagellated species, donot refrigerate sample bottles. Maintain in situ temperature by storing them out of directsunlight, in an ice chest, with some of the ambient water. Surface samples in streams,rivers, shallow estuaries and coastal water can be collected simply by inverting thesample bottle, immersing it up to one meter below the water surface and slowly filling itas it is removed from the water. A Kemmerer sampler may also be used by holding it in ahorizontal position and closing it manually. Samples collected for chlorophyll analysisshould not be fixed or preserved. Chlorophyll samples should be preserved by chilling to4°C. If species composition analysis is necessary, then samples should be collected in aseparate sample bottle, or fixed or preserved by laboratory staff after the aliquot forchlorophyll analysis is removed from the sample container.When deeper samples are needed, use of a Kemmerer, water bottle, Van Dorn or Judaysamplers is standard. All of these sampling devices basically consist of a metal or plastichollow cylinder with remotely activated stoppers at both ends. The sampler is lowered toa desired depth with a graduated line. Once at the desired depth, a heavy brass slug or“messenger” attached to the line is released. It slides down the line, and strikes therelease mechanism on the sampler which pulls the stoppers tight against the open ends ofthe cylinder, trapping the sample of water inside. The sampler is then withdrawn and thewater emptied into the sample container via a small spigot or tube in one of the stoppers.Use only nonmetallic samplers when metal analysis, algal assays, or primary productivitymeasurements will be performed on the sample. Sample bottle labels should identify thebody of water sampled and list the date of collection, collectors name, preservative ifpresent, and the type of biological analysis desired (determination of dominant or bloomspecies, total cell count, etc.). It is important that labels clearly identify live planktonsamples as being unpreserved.Ecological Evaluation Technical Guidance Document 105Version 1.2 8/29/12