The distribution of trace metals and relative abundance of macronutrients are reflected in the plankton community structure. For example, the selection of phytoplankton with a high surface area to volume ratio results in HNLC regions being dominated by nano- and picoplankton. This ratio allows for optimal utilization of available dissolved nutrients. Larger phytoplankton, such as diatoms, cannot energetically sustain themselves in these regions. Common picoplankton within these regions include genera such as prochlorococcus (not generally found in the North Pacific), synechococcus, and various eukaryotes. Grazing protists likely control the abundance and distribution of these small phytoplankton.