Patch
reefs are located behind the reef flat or barrier reef and
are typically located in shallow waters of 10-20 feet in
depth. They are small and isolated coral skeleton islands that form a
circular or oval shape. The outer edge of each patch reef is
completely surrounded by sand that extends to meet deeper sea grass
meadows. This sandy area is formed by the distance that
herbivorous fish feel is within safe foraging range from the
patch reef. Patch reefs are highly variable in both size and
development and contain species that are adapted to living
on the open reef. These include: hard corals, gorgonians,
boring sponges, and sporadic colonies of macro algae as well
as adjacent sea grass beds. Because of the lack of nutrients
in this habitat, macro algae are much more limited in
diversity and colony size.
Depending on the location of the
reef, many open water macro algae thrive in this
environment, including calcerous algae such as Halimeda,
Gracilaria, Halymenia, Haliptilon, Liagora
and other calcified encrusting red algae. The brown algae
Dictoya also makes its appearance on the patch reef, but its growth is smaller and more compact due to the strong
current and lack of available nutrients.
Patch
reefs certainly fall into the category of most mixed reef
aquariums today. They are typically formed by stacking live
rock high in the tank to create a wall on the back of the
aquarium. Then the rockwork is filled with a combination of
photosynthetic organisms including hard and soft corals,
single specimens of macro algae and other invertebrates to
form a miniature reef biotope. While this can be done
attractively, a true patch reef would have a single
collection of rocks arranged to appear as one structure
located in the center of the aquarium. Just like a lagoon
style biotope, this type of aquascape is more suited to
wide, shallow tanks so that a substantial area of sand can
be arranged around the reef.
The
unique aquascape (pictured) of aquarist Jaide
Swarthout mimics a miniature patch reef surrounded by
sand and a surrounding sea grass bed. Notice the use of
driftwood, which is normally seen in freshwater
planted aquariums. This minimalist approach is very
appealing and allows for easier maintenance |