Nutrition
 
  Nutrition
 
 
Primary productivity hot buttons for primary producers part of BCCR hot button for cyanobacteria productivity part of BCCR hot button for phytoplankton 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. However, a number of sessile/sedentary invertebrates, such as corals, gorgonians, sea anemones, jellyfishes, sponges, and tunicates, and even some motile forms, such as certain nudibranchs and clams, also host photosynthesising symbionts. This section deals with primary productivity in invertebrates other than corals. Other primary-productivity topics can be accessed via the icons below.

NOTE information on photosynthesis in corals can be found in another section: CORALS: A CASE STUDY

 

Primary productivity: invertebrates

  Sponges, gorgonians, sea anemones/jellyfishes, and tunicates are considered in this section, while SNAILS & CLAMS are presented in their own section.
 
 
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of tunnel through coral reef taken from a video

"Hmmm! Nice bunch of grunts and porkfishes. Even a dark area like this one will have some photosynthesising organisms...plants, and perhaps some invertebrates but not, of course, in the abundance to be found outside in the open sunlight." - Cuba 2004

NOTE Anisotremus virginicus

 
 

Primary productivity: invertebrates: sponges

 
 
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of a barrel sponge taken from a video

"Many sponges, including this barrel sponge, contain photosynthesising bacteria. This is interesting, because sponges actually feed on bacteria, but ones quite different from their symbionts" - Turneffe Island, Belize 2000. Video courtesy Andy Stockbridge, Belize

NOTE Xestospongia muta

 
 

photograph of tube sponge
An estimated three-quarters of all sponge species contain cyanobacterial symbionts. Photosynthetic activity of the symbionts provides nutrient and energy materials, such as amino acids, glycerol, and sugars, to the sponge host.

 

 

 

 

 

 

 

Brown tube-sponge
Ageles conifera 0.1X







 
 

Primary productivity: invertebrates: gorgonians

 
 
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of a fan gorgonian taken from a video

"Gorgonians are carnivorous and obtain most of their nutrients from zooplankton captured by the polyps. However, many gorgonians also contain photosynthesising symbiotic zooxanthellae of the type found in corals, and you can see that they like to grow in well-lighted conditions."- Turneffe Island, Belize 2000. Video courtesy Andy Stockbridge, Belize

NOTE featured here: sea fan Gorgonia sp.

 
 

photo collage of photosynthesising gorgonians
Tissues of many gorgonians are brownish-coloured owing to their content of zooxanthellae symbionts.

NOTE these special symbiotic plant cells are considered in detail in CORALS: A CASE STUDY: PHOTOSYNTHESIS and in CORAL BLEACHING

 
 

Primary productivity: invertebrates: sea anemones/jellyfishes

 
 
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of a sea anemone taken from a video

"It seems odd that sea anemones have photosynthesising symbiontic plant cells in their gut tissues, similar to those found in corals, but maybe it explains why their tentacles are always hanging out in the sunlight." -Texas State Aquarium, Corpus Christi 2005

NOTE possible a giant anemone Condylactis gigantea

 
 

If certain anemone species are starved, they communicate their nutritional status to their symbionts photograph of sea anemone Condylactis giganteavia a chemical signal termed "host-release factor". The symbionts, thought to be the same or similar to those found in corals, respond by releasing photograph of sea anemone Aiptasiaproportionately larger amounts of phytosynthates (mostly glycerol) to their hosts. Fitt 1985 Proc 5th Int Coral Reef Symp 6: 131; Davy & Cook 2001 Comp Biochem Physiol A 129: 487; Cook & Davy 2001 Hydrobiol 461: 71.


Tentacles of a giant anemone Condylactis
gigantea
extend from a rock crevice. Does this
aid in catching prey? In photosynthisis? Or in both?



Studies on the Indo-Pacific sea anemone
Aiptasia
suggest that the host-release factor
may be a type of amino acid 0.5X

 
photograph showing a variety of different photosynthesising invertebratesAll of the organisms in this photograph with a red check-mark are capable to some extent of photosynthesis. The one that is not, a SCUBA-diver, is marked with a red X.
  photographs of upside-down jellyfishes Cassiopea xamachanaUpside-down jellyfishes Cassiopea spp. contain photosynthesising algal symbionts similar to those found in sea anemones and corals. The jellyfishes favour shallow-water habitats where they commonly lie with mouth and tentacles uppermost, perhaps the better to illuminate their photosynthesising symbionts which, as in other cnidarians, are found in the gut tissues.
 
 

Primary productivity: invertebrates: tunicates

 
 
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of a colonial tunicate on a sponge taken from a video

"You wouldn't know it by the colour, but the colonial tunicates growing on this sponge are likely to have symbiotic plant cells in their tissue." -St. Thomas 2007

NOTE Trididemnum solidum

 
 

photograph of colonial tunicate overgrowing a brain coral
Many colonial tunicates contain symbionts in their tissues whose photosynthetic activity augments their host's normal bacterial and micro-planktonic diet.

 

 

 

 

Mat tunicate Trididenmum solidum
overgrowing a brain coral 1.5X

 
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