Eastern Pacific Coral Reef Ecosystem
297
19.6 Functional Interfaces with Adjacent Biotopes
Since sea grass communities are non-existent in the eastern Pacific and
coral reefs are usually distant from mangrove shores, there is likely little
nutrient and organic matter exchange between reefs and benthic, plantdominated ecosystems. Coral reefs and mangrove communities are often
in close proximity or even juxtaposed in the Caribbean. Possibly the predominant coarse-grained calcareous sediments in the Caribbean, compared with mostly fine-grained siliciclastic sediments in the eastern Pacific, provide for more efficient circulation and oxygen exchange, thus
allowing for the frequent commingling of mangrove and reef-associated
taxa. Perhaps the most important inter-community interactions involve
mangroves serving as: ( 1) sediment and nutrient sinks, improving the quality of water from terrestrial sources, (2) nursery habitats for invertebrates
and fishes that migrate to reefs as they mature, and (3) coral reefs providing protective barriers, diminishing the impact of wave assault and substrate erosion (Ogden 1997). The extent of such co-dependencies in the
eastern Pacific has not been investigated.
Planktonic productivity is often high in the eastern Pacific, and abundant suspension-feeding populations (e.g. oysters, endolithic sponges and
bivalves, sedentary polychaetes, and barnacles) and fish planktivores associated with reefs attest to this rich food source.
Coral-dominated communities are usually surrounded by rubble/sand
biotopes, and these commonly grade into sand/mud biotopes in deeper
waters. Rhodolith communities are sometimes present adjacent to reefs,
usually in deeper water (10-100m) on sandy substrates with strong circulation. These communities consist dominantly of free-living calcareous red
algae, but also support a high diversity of invertebrate and fish species.
Several reef-associated fishes forage on animals living among and beneath
the rhodoliths. Most of the associated corals are unattached and have colonized the rhodolith communities from nearby coral communities either as
larvae or as partial or whole adult colonies transported down-slope by
physical disturbances (e.g. storm-generated turbulence) or bioturbation
(organism-induced movements).
19.7 Natural and Anthropogenic Impacts
For the past few decades, western American coral reefs have sustained significant damage from both anthropogenic and natural disturbances. The
297
19.6 Functional Interfaces with Adjacent Biotopes
Since sea grass communities are non-existent in the eastern Pacific and
coral reefs are usually distant from mangrove shores, there is likely little
nutrient and organic matter exchange between reefs and benthic, plantdominated ecosystems. Coral reefs and mangrove communities are often
in close proximity or even juxtaposed in the Caribbean. Possibly the predominant coarse-grained calcareous sediments in the Caribbean, compared with mostly fine-grained siliciclastic sediments in the eastern Pacific, provide for more efficient circulation and oxygen exchange, thus
allowing for the frequent commingling of mangrove and reef-associated
taxa. Perhaps the most important inter-community interactions involve
mangroves serving as: ( 1) sediment and nutrient sinks, improving the quality of water from terrestrial sources, (2) nursery habitats for invertebrates
and fishes that migrate to reefs as they mature, and (3) coral reefs providing protective barriers, diminishing the impact of wave assault and substrate erosion (Ogden 1997). The extent of such co-dependencies in the
eastern Pacific has not been investigated.
Planktonic productivity is often high in the eastern Pacific, and abundant suspension-feeding populations (e.g. oysters, endolithic sponges and
bivalves, sedentary polychaetes, and barnacles) and fish planktivores associated with reefs attest to this rich food source.
Coral-dominated communities are usually surrounded by rubble/sand
biotopes, and these commonly grade into sand/mud biotopes in deeper
waters. Rhodolith communities are sometimes present adjacent to reefs,
usually in deeper water (10-100m) on sandy substrates with strong circulation. These communities consist dominantly of free-living calcareous red
algae, but also support a high diversity of invertebrate and fish species.
Several reef-associated fishes forage on animals living among and beneath
the rhodoliths. Most of the associated corals are unattached and have colonized the rhodolith communities from nearby coral communities either as
larvae or as partial or whole adult colonies transported down-slope by
physical disturbances (e.g. storm-generated turbulence) or bioturbation
(organism-induced movements).
19.7 Natural and Anthropogenic Impacts
For the past few decades, western American coral reefs have sustained significant damage from both anthropogenic and natural disturbances. The