Primary productivity: phytoplankton hot buttons for primary producers part of BCCR hot button for cyanobacteria productivity part of BCCR hot button for phytoplanktonp productivity part of BCCR hot button for invertebrates primary productivity part of BCCR hot button for seaweeds/seagrasses productivity part of BCCR  

There are several routes of entry for the sun's energy into the coral-reef ecosystem. These include cyanobacteria, phytoplankton, seaweeds, and seagrasses. A number of sessile/sedentary invertebrates, such as corals, gorgonians, sea anemones, and sponges, and even some motile forms, such as certain nudibranchs and clams, host photosynthesising symbionts. This section deals with phytoplankton; other topics can be accessed via the icons.

NOTE information on photosynthesis in corals can be found elsewhere in the ODYSSEY: CORALS: A CASE STUDY

seahorse dive leader for Biology of Caribbean Coral Reefs photograph of reef showing fishes eating phytoplankton "See all this crud in the water? Photographers hate it, but the fishes sure like it! You can see them chomping away. It could be zooplankton, or perhaps aggregates of detritus and phytoplankton. It's ironic that good 'viz' generally indicates an absence of phytoplankton, but it is phytoplankton that ultimately governs the health of the reef." - Little Cayman 2003

photograph of phytoplankton courtesy Brian Leander, University of British ColumbiaPhytoplankton is made up of microscopic sengle-celled plants and represents the basis of the reef's economy. Many zooplankters, such as copepods and invertebrate larvae, subsist solely on phytoplankton. The major larger-sized constituents of phytoplankton are diatoms, coccolithophores, and dinoflagellates. Photograph courtesy Brian Leander, University of British Columbia.

NOTE lit. "plant wanderer", referring to the fact that the single-cell components of phytoplankton float passively in the sea

NOTE trumpet-shaped single-cell organisms characterised by cell walls constructed of calcium carbonate (chalk). The White Cliffs of Dover are residues of past coccolithophore blooms







Live phytoplankton, mostly diatoms in chain-
form. Diatoms live in protective cases known
as frustules, made of silica (glass) 300X


photograph of red tideWhen conditions are ideal for growth and, depending upon the species, localised blooms of phytoplankton may turn the water red, infect shellfish with a toxin known as paralytic shellfish poisoning (PSP), cause the water to luminesce, and kill fishes by clogging their delicate gill tissues.

NOTE like all plants, phytoplankton have chlorophyll pigments, but these are masked by accessory photosynthetic pigments that absorb light strongly in the green part of the spectrum. The red wavelengths are mostly reflected, thus causing the phytoplankton to appear red in colour







A bloom of dinoflagellates,
known as "red tide"