Due to the fact that algae live primarily near the surface of a lake, chlorophyll a samples are typically collected just below the surface. Collecting a sample at one station near the midpoint of the lake is often adequate for a simple characterization of seasonal changes or possible trends in chlorophyll. If the monitoring objective is to compare portions of the lake, then chlorophyll samples should be collected accordingly. Because algae can be blown by the wind, samples collected near shore or at the downwind end of the lake may not be representative of average lake conditions.