Plankton communities are generally diverse, but when a particular species makes up 80% or more of the population, it is called a "bloom." The Spring boom in Sandy Hook Bay occurs as the days get longer, often as early as February and sometimes when there is still ice on much of the bay and rivers.

Left: Chaetoceros (Diatom)

The dominant creatures in the Spring bloom are Phytoplankton and the golden-brown color on a secchi disc in the water (Forel-Ule Scale XVI-XVII) is a clue that diatoms are present in great numbers.

Left: Odontella and Asterionella (lower right corner) Diatoms

A close-up of a single Coscinodiscus diatom reveals chloroplasts and the disk-shape of centric diatoms that make up much of the drifting species. Pennate (Pen-shaped) diatoms predominate in the sediments where there is light, and sometimes discolor tidepools to a golden-brown color too.

Left: Coscinodiscus

Plankton is collected with a plankton net to determine the species present in the water. Much of the phytoplankton is tiny Nannoplankton (0.005-0.060) in size.

Left: Skeletonema, Asterionella and Chaetoceros (Diatoms)

To determine the abundance of particular species, a measured amount of water can be taken and preserved temporarily with a few drops of Iodine for qualitative analysis by counting individual specimens.

Zooplankton are always present too, and these copepods are grazing on the diatoms. They are considered Macroplankton, up to 1.0 mm in size and visible to the naked eye.

The smaller nauplius larva of barnacles are Microplankton (Between 0.060-1.0 mm) and visible with a magnifying lens.

Left: Calanus (Copepods) and Balanus (Barnacles)

Images courtesy of OIPL (Ocean Institute Plankton Lab)