A relic coral fauna threatened by global changes and human activities, Eastern Brazil

• Published in: Marine pollution bulletin Vol. 51; no. 5; pp. 599 - 611
• Main Authors: Leão, Zelinda M.A.N., Kikuchi, Ruy K.P.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 01-01-2005; Elsevier
• Subjects: Abrolhos reefs; Animal, plant and microbial ecology; Animals; Anthozoa - physiology; Applied ecology; Biological and medical sciences; Brazil; Brazilian coral fauna; Cnidaria. Ctenaria; Conservation of Natural Resources; Demography; Ecosystem; Ecotoxicology, biological effects of pollution; Endemic species; Environment; Fossils; Fundamental and applied biological sciences. Psychology; Geography; Geologic Sediments - analysis; Holocene sea level; Invertebrates; Marine and brackish environment; Mussismilia braziliensis; Mussismilia harttii; Population Dynamics; Species Specificity; South America; Brazil; America; Brazil, Bahia; ASW, Brazil; Brazilian coral fauna; Mussismilia braziliensis; Endemic species; Abrolhos reefs; Holocene sea level; Fauna; Sea level; Abrolhos reels: Holocene sea level; Marine environment; Aquatic environment; Coelenterata; Human activity; Coral; Global change; Cnidaria; Water pollution; Invertebrata; Holocene; Climate modification; Anthropogenic factor
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2005.04.024

Coral species composition of drilled cores from emergent bank reefs, and coral cover of the surface of old and living reefs located along the coast of the state of Bahia, Eastern Brazil, revealed that there is a marked change in the occurrence of the major building coral species in different time intervals of the reef structure, as well as in the living surface of reefs located in two different geographical sites. Holocene core sections from two reef areas (12° 40′S–38° 00′W and 18° 00′S–39° 00′W) have as major reef builders, on its topmost core interval (3 to 4 ky old), the endemic coral
Mussismilia braziliensis Verrill, 1868, which also dominate on the 2.5–3.5
ky old surfaces of truncated reef tops. At the base of the cores (the 2
m lower interval, older than 4
ky BP), another endemic coral
Mussismilia harttii Verrill, 1868 is the dominant reef component. The relative abundance of
M. braziliensis on the living surfaces of shallow reefs from both areas, shows that in the southern area, it is up to 98% on reefs located 60
km off the coast, in depths between 3 and 4
m, but do not exceed 1.3% on the surface of the northern reefs located 1–2
km off the coast in depths 4–5
m. The Holocene falling sea level that occurred along the coast of Brazil since 5.1
ky BP, causes an increasing runoff into the area of coastal reefs. This phenomenon may have affected the nearshore reef building fauna, replacing a more susceptive coral fauna with one better adapted to low light levels and higher sediment influx. The high turbidity associated with early Holocene shelf flooding, should also be responsible for the absence of
M. braziliensis during the initial stages of reef buildup in Brazil. At the present time, the rapidly increasing human pressure, due to changes in land uses of the coastal zone (increasing sedimentation rate, nutrification of coastal waters, industrial pollution) and underwater practices, such as overfishing and an intense tourism, is aggravating the recovery capacity of this already naturally threatened coral community. If this situation coupled with increasing sea surface temperature persists, modern coral reef growth, in Brazil cannot be maintained and the major reef building coral species of the reefs in Bahia, a remnant endemic coral fauna will very soon appear in the list of endangered species.