Coral Reef Systems

Coral reefs are one of the world’s great ecological resources.  Each is filled with an extraordinarily diverse community of flora and fauna.  Reefs and their myriad of life serve as important marine habitats, as well as important economic assets for the people that live nearby.  Sadly, human cultural activities often damage reef livelihood.  As a result, thousands of kilometers of reef habitat are being lost globally, thereby upsetting marine ecology and, ultimately, threatening the stability of marine populations (1).  Conservation and protection of these systems, therefore, is vital.


Coral Reef Formation

Coral reefs occur in shallow warm waters of the tropics, on continental shelves and volcanic seamounts.  Individual coral animals have rigid calcium carbonate skeletons that cluster into coral communities.  As individual animals die, new generations build their skeletal homes on top of the older carbonate matrix, and a coral assemblage accumulates.  Significant reef structures develop over timescales of thousands of years (2).  An important characteristic of reef development is that growth often occurs in pulses followed by quiescent periods, rather than continuous accumulation (3).


Reefs as Ecological Resource

In addition to corals, reef structures are attractive to large numbers of species, including fish, seabirds, sea turtles, crustaceans, mollusks, sponges, jellyfish, worms, echinoderms, and many types of plankton, algae and seagrass.  Corals themselves are quite diverse, and many different species are typically present in a reef system.  The breadth of variety of organisms in a reef ecosystem — that is, its biodiversity — helps it tolerate changes to the environment.  Thus, reef biodiversity provides resilience against natural and, more importantly, anthropogenic activities that would otherwise upset the balance of local and/ or global ecosystems.  In addition, reefs protect land by dissipating wave energy, and preventing beach erosion, thus helping to preserve onshore habitats.


Reefs as Economic Resource

Coral reefs provide food to a significant fraction of the world’s population, and are especially important as a source of protein in tropical coastal areas(4).  With their extensive biodiversity, reefs are also inherently beautiful.  Because they are found in shallow waters relatively close to shore, reefs are thus attractive destinations for snorkeling, diving, boating, and nearly any water-based form of recreation.

The following types of reefs are found in the Dominican Republic (DR) (5):

  • Fringing Reefs developed through upward coral growth near the coastline;
  • Barrier Reefs formed on a deeper foundation further from shore, which are separated from shore by a lagoon; and
  • Patch Reefs, smaller structures often lying within the lagoon of a barrier reef (see figure).


Figure: Types of Coral Reefs (after Spalding et al., 2001)

Figure: Types of Coral Reefs (after Spalding et al., 2001)


Reef Degradation

Although magnificent and alluring, an astonishing 70% of the DR’s reefs are damaged or threatened(6).  S everal root causes are responsible, including:

  • sedimentation from upland deforestation, wetland removal, soil erosion, and coastal development (7);
  • direct damage and disease (8) (9);
  • pollution from domestic sewage, and fertilizer and pesticide runoff (10) (11); and
  • indirect factors like overfishing and warming ocean temperature(12).


Conservation measures — including educating residents and tourists — will help reverse the degradation trend and, in turn, protect the DR’s critical marine habitats.

(1) Mumby, P.J. and Steneck, S.S. (2008).  Coral reef management and conservation in light of rapidly evolving ecological paradigms.  Trends in Ecology and Evolution, 23(10): 555-563.

(2) Spalding M.D., Ravilious C., and Green E.P. (2001).  World Atlas of Coral Reefs.  UNEP World Conservation Monitoring Centre.  University of California Press:  Berkeley.


(4) Sorokin, Y (1995).  Coral Reef Ecology.  Ecological Studies, 102 (461 pp).  Springer:  Berlin.

(5) Spalding et al., Op. cit.

(6) Burke, L. and Maidens, J. (2004).  Reefs at Risk in the Caribbean.  81 pp.  World Resources Institute:  Washington DC.


(8) Burke and Maidens, Op. cit.

(9) Wielgus, J., Cooper E., Torres R., and Burke L. (2010).  Coastal Capital:  Dominican Republic.  Case studies on the economic value of coastal ecosystems in the Dominican Republic.  Working Paper.  World Resources Institute:  Washington, DC.

(10) Spalding et al., Op. cit.

(11) Wielgus et al., Op. cit.


Tom Pacioni

Tom Pacioni

Sustainability and environmental professional with a love of the beach. Tom studied coastal and nearshore depositional processes (MS Geology), and worked in Incident Command during the Deepwater Horizon spill and recovery. Spent a couple decades solving environmental and hydrogeology issues along the Gulf Coast as a Professional Geologist. Currently wrapping up a Sustainability Management MS at Columbia University.

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