Figure 2.

Diatom Characteristics and Morphological Diversity.

(A) Scanning electron micrograph of the model centric species T. pseudonana with its characteristic cell wall of silica, viewed from the top.

(B) to (I) Light microscopy of the pennate model species P. tricornutum (B). This diatom exists in three interconvertible morphotypes: the fusiform, oval, and triradiate morphotypes, as shown in the figure. Scanning electron micrograph images of (C) Skeletonema tropicum, (D) a valve of a raphid pennate diatom, (E) Shionodiscus oestrupii var venrickiae, and (F) F. cylindrus. Light microscopy of (G) Chaetoceros sp, (H) Fragilariopsis kerguelensis, and (I) Pseudo-nitzschia sp from a natural phytoplankton sample collected at the Long Term Station MareChiara in the Gulf of Naples, Italy.

(J) Flipped ice floe in the Southern Ocean with dense population of sea-ice diatoms (e.g., F. cylindrus) at the ice-water interface. Images were kindly provided by Diana Sarno and Marina Montresor (Stazione Zoologica Anton Dohrn, Napoli, Italy) and James A. Raymond (Univeristy of Nevada, United States).