ORGANISMS IN THE WATER
A diverse marine biota occupies the shallow water
carbonate platform surrounding San Salvador Island in the eastern Bahamas.
Many organisms have a patchy distribution around San Salvador, which is the
result of specific habitat preferences. Seafloor environments here
include aragonite sand seafloors, sparse to thick seagrass beds, hardgrounds,
patch reefs, fringing reefs, and barrier reefs. Many of the inland lakes
and ponds on San Salvador have normal marine salinities and some normal marine
biotas. Other San Salvador lakes and ponds have hyposaline or brackish or
hypersaline waters.
The photos below show some common marine algae seen in
the waters around San Salvador Island.
Organisms in the water 2 (invertebrates)
Organisms in the water 3 (vertebrates)
Seagrass bed in southeastern Graham’s Harbour, northeastern San Salvador
Island. Seagrasses are fully marine angiosperms (flowering plants -
Plantae, Angiospermophyta). The seagrass beds here are dominated by
turtle grass (Thalassia testudinum) & manatee grass (Syringodium
filiforme). (Mark Peter photo, 2009)
Thalassia testudinum König, 1805 - turtle grass (Plantae,
Angiospermophyta, Najadales, Hydrocharitaceae) in South Pigeon Creek estuary,
southeastern San Salvador Island. (James St. John photo, 2011)
See
video of turtle grass bed in South Pigeon Creek estuary (same island).
Thalassia-Syringodium seagrass beds on shallow aragonite sand seafloor in
eastern Graham’s Harbour, northeastern San Salvador Island. The thin
seagrass stalks are manatee grass - Syringodium filiforme (Kützing,
1860) (Plantae, Angiospermophyta, Najadales, Cymodoceaceae). The wider
blades are turtle grass - Thalassia testudinum König, 1805. (James St.
John photo, 2010)
Penicillus dumetosus (Lamouroux, 1816) - shaving brush algae (calcareous
green algae - Plantae, Chlorophyta, Caulerpales, Udoteaceae) on aragonite sand
seafloor in eastern/southeastern Graham’s Harbour. Tiny particles of
aragonite (CaCO3) are present in these green algae. After
death and decay, the calcium carbonate grains become part of the seafloor
sediments. (left: Mark Peter photo, 2009; right: James St. John
photo, 2010)
Rhipocephalus phoenix (Ellis & Solander, 1786) - pinecone algae
(calcareous green algae - Plantae, Chlorophyta, Bryopsidales, Udoteaceae) on
aragonite sand seafloor in eastern Graham’s Harbour. This is another
green alga that contains tiny aragonite particles. (James St. John photos,
2010)
Udotea flabellum (Ellis & Solander, 1786) - mermaid’s fan alga
(calcareous green alga - Plantae, Chlorophyta, Caulerpales, Halimedaceae) in
Pigeon Creek estuary, southeastern San Salvador Island. As in Penicillus
and Rhipocephalus, Udotea is a calcareous green alga - it
contains small grains of aragonite (CaCO3), which eventually become
part of the seafloor sediments. (Mark Peter photo, 2009)
Padina jamaicensis (Collins, 1901) - white scroll algae (brown algae -
Plantae, Phaeophyta, Dictyotales, Dictyotaceae) in eastern Graham’s Harbour,
northeastern San Salvador Island. The chalky whitish appearance of this
brown alga is the result of the presence of tiny particles of calcium carbonate
(aragonite, CaCO3) on the surface of the folded blades (James St.
John photo, 2010)
Padina boergesenii Allender & Kraft, 1983 - leafy rolled-blade algae
(brown algae - Plantae, Phaeophyta, Dictyotales, Dictyotaceae) on patch reefs
in western French Bay, southwestern San Salvador Island. This gorgeous
brown alga is variable in coloration and color pattern, but slightly iridescent
bluish-greenish forms are somewhat common at French Bay patch reefs. (James St.
John photos, 2011)
Turbinaria turbinata (Linnaeus, 1753) - blistered saucer leaf algae (brown
algae - Plantae, Phaeophyta, Fucales, Sargassaceae) on patch reef in western
French Bay, southwestern San Salvador Island. (James St. John photo, 2011)
Microdictyon marinum (above & below) - network algae (green algae -
Plantae, Chlorophyta, Cladophorales, Anadyomenaceae) near Rocky Point/Sand
Dollar Beach, northwestern corner of San Salvador Island. (James St. John photos,
2011)
Acetabularia crenulata Lamouroux, 1816 - white mermaid's wine glass alga
(green alga - Plantae, Chlorophyta, Dasycladales, Polyphysaceae) & other
algae (some appear (?) to be Batophora) on aragonitic sandy substrate in
South Pigeon Creek estuary, southeastern San Salvador Island. Acetabularia
is the whitish-green plant near center-bottom with a slender stalk and small,
cup-like top. (James St. John photo, 2009)
Galaxaura calcareous red algae (Plantae, Rhodophyta, Nemaliales, Galaxauraceae)
in & from very shallow subtidal setting landward of Snapshot Reef,
Fernandez Bay, western margin of San Salvador Island. Galaxaura
red algae make calcareous skeletons of dichotomously branching tubes. (James
St. John photos, 2009)
Porolithon pachydermum (Foslie, 1904) (above & below) - “reef cement”, a
hard substrate-encrusting, calcareous red alga (Plantae, Rhodophyta,
Corallinales, Corallinaceae) on a patch reef in western French Bay,
southwestern San Salvador Island. Porolithon is a pinkish to
pale-pinkish, calcareous crust that occupies reef crest and near-reef crest
facies, where high-energy waves, intense sunlight, and occasional desiccating
conditions (from low tides) occur. It has been recognized as a very
important reef-building organism. Porolithon crusts frequently
have many subcircular openings, resulting in a “swiss cheese”-like
appearance. These are borings produced by the chiton Choneplax lata (Mollusca,
Polyplacophora). (James St. John photos, 2011)
Sargassum natans (Plantae, Phaeophyta, Fucales, Sargassaceae) in
seawater just west of North Point Peninsula, northeastern San Salvador Island.
Sargassum natans is a megaplanktonic brown alga that stays suspended in the
water column using small, subspherical, gas-filled floats. Some other
species of Sargassum are benthic (rooted or attached to the seafloor).
(James St. John photo, 2008)
More
photos (invertebrates)