YSI ADV6600 - Manual (Page 190)

Appendix E. Chlorophyll Measurements
ADV6600
Y S I Environmental
Page 180
Are there precautions that I should take when acquiring samples for laboratory analysis?
Yes. The key is to obtain a sample which is representative of the water being measured by
the YSI 6025 in vivo. The mistake most often made is to simply immerse an open bottle in
the environmental water. Under these conditions, any macroscopic surface plant or algal
matter (which also contains chlorophyll) will also be introduced into the sample even
though it is not present in the subsurface zone where the probe is measuring fluorescence.
If this happens, your laboratory analysis will always be erroneously high relative to the in
vivo chlorophyll data from the YSI 6025.
For surface sampling you can minimize this effect greatly by placing the sealed bottle a
foot or more below the water surface and only then removing the cap and allowing the
container to fill. The cap should then be reinstalled before removing the bottle from the
water. A better technique is to acquire commercially available water sampling devices that
are designed specifically to acquire a representative sample at a particular depth.
You should also take precautions to stabilize your samples for transport back to the
laboratory. The samples should be kept cool and in the dark (e.g., in an ice chest) until the