Outbreaks

Outbreaks

Example: Crown-of-thorns starfish on the Great Barrier Reef

Introduction to/Summary of the Problem

Coral reef ecosystems around the world are being degraded. In the past 30 years, the Great Barrier Reef has lost approximately half of its coral population from adverse weather conditions, coral predator and disease outbreaks, and coral bleaching (source: PNAS and Science Daily). The environmental impact of both natural disasters and human interferences on the corals has led to devastating consequences. The effect of natural disasters on coral reefs can be difficult to predict and control. However, by studying the influence that human behavior has on predator and disease outbreaks and other contributing factors of coral reef degradation, we can identify characteristics that enable coral reefs to adapt to an array of environmental pressures and provide potential solutions to prevent further coral decline.

Coral Predator Outbreaks

Crown-of-thorns Starfish (COTS) on the Great Barrier Reef

This predatory seastar feeds on corals, destroying them with digestive enzymes and their unrestricted, carnivorous diet. While these outbreaks have been characterized as “slow and methodical,” the starfish posed a major threat to an area known as the Coral Triangle in 2012, one of the richest regions in terms of biodiversity.

    A. Causes of Outbreak

                1. Increased pollution and rise in nitrogen levels as a result of
                2. Surge in phytoplankton population due to runoff
                3. Shifts in weather patterns and climate such as El Niño, noted in the extreme El Nino of 1997-1998 

    B. Possible Solutions

                1. Reduce run-off pollution promoting phytoplankton as a source of food for COTS
                2. Survey and control population of COTS
                     a. Ethical Concerns: Is this safe for the surrounding environment?
                3. Regulate and restrict industrial and agricultural development along the reef
                     a. Invest in programs like Project Catalyst to promote responsible and sustainable agricultural efforts

Infectious Disease Outbreaks

Black-band, Yellow-band, Red-band, White-band, White Plague, and White Pox diseases

In the last decade, infectious disease outbreaks have spread rapidly and led to an increase in mortality among coral reefs (source: National Oceanic and Atmospheric Conditions). These diseases are characterized by spots, bands, and/or lesions on the surface of the coral. Eventually, untreated corals are reduced to a white skeleton.

Disease and location

    A. Causes of Outbreak

                 1. Increase in temperatures
                 2. Decline in water quality due to pollutants
                 3. Rise in CO2 levels and decreases in pH levels (ocean acidification)

    B. Possible Solutions

                  1. Apply antibiotic treatment
                  2. Regulate and restrict industrial and agricultural development along the reef
                  3. Reduce run-off pollution to decrease chemical impact on water quality

Resources: http://www.sciencedaily.com/releases/2008/01/080114112308.htm (Science Journal)

           http://www.pnas.org/content/109/44/17995.full.pdf+html (Science Journal) 
           http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0047363 (Science Journal) 
           http://coralreef.noaa.gov/threats/climate/ 
            

http://www.reefresilience.org/coral-reefs/stressors/predator-outbreaks/crown-of-thorns-starfish/