Opinion on Climate Change and Coral Reefs - Different Effects in Two High-latitude Areas by Riegl - Book Report/Review Example

Journal article review 1. Author(s) of journal article being reviewed Riegl, B. 2. Title of journal article being reviewed Climate change and coral reefs: different effects in two high-latitude areas (Arabian Gulf, South Africa) 3. Year of article (2003). 4. Journal name Coral Reefs 5. Volume/Page Numbers Volume 22 and Number 4 6. What is the research question the author(s) are trying to address? This paper explores a published article that reports on results from various research findings about the effect of climate change on the coral reefs in the Arabian Gulf and South Africa. The article “Climate change and coral reefs: different effects in two high-latitude areas (Arabian Gulf, South Africa)” was received in 2002 and published online in 2003. The paper examines Bernhard Riegl’s research as he investigates two high-latitude areas that are both in the Indian Ocean; South Africa and southeastern Arabian Gulf. He tries to answer the research question why the coral reefs in Arabian Gulf are more stressed than those in South Africa do. /15 7. Describe what methodology the author(s) used to collect data. Riegl (2003) poses that climate change has resulted in changes in aragonite saturation rate and temperature anomalies that result in constant bleaching that suppresses sustained reef building. High-frequency temperatures, mass mortalities, and adaptation are some of the factors considered in answering the research question. The author uses various published studies and evidence to support his claim. The methodology involves the use of global climate models and statistics, repeated quantitative samples, diver grid-surveys, reports on analyses using computer software, municipality records, and articles on climate change and geographical mapping from other researchers (Riegl, 2003). /20 8. Describe the results the author(s) presented in your own format. Recent reports from developed global climate models have confirmed significant global warming trends that are associated with increased greenhouse gas emissions (Bauman et al., 2011). A large-scale disturbance in reef systems has coincidently occurred during this period. For example, reports from the 1997/1998 El Nino Southern Oscillation showed a record coral mortality and bleaching event with the effect felt across the globe (Arrieta, 2010). During this event, tropical reefs suffered more than high-latitude reefs. This observation is significant in proving that climate change is contributing to coral reef bleaching. However, it does not help in answering the question why the coral reefs in the Arabian Gulf have suffered more than in South Africa, being that they are both high-latitude reefs (Riegl, 2003). The author also reviews reports on marine biotic crises that have affected reef systems. Through observation of reefs, biologists have noted gradual disappearance and extinctions of certain genotypes of corals. There have also been reports on other species taking their place (Riegl, 2003). Graham et al. (2006) adds that these adaptive and evolutionary events have caused repeated and increased bleaching of corals. A study of high-latitude corals found that they persisted even in stressful environments than their counterparts in the tropical regions (Mumby et al., 2011). Graham et al. (2011) provides Arabian Gulf Corals an example citing that they survive the highest annual temperature variability encountered by other reef corals. These reefs are already showing the high stress levels. The South African reefs have shown the least documented rates of disturbances during the last decade (Riegl et al., 2011). The research involved the investigation of the Arabian Gulf southern continental coastline with the most closely studied area situated in Dubai Emirate. The studies had been conducted annually in the period 1995 to 2002. The research was carried out using transect studies, observations, repeated quantitative samples, measurements of water depth, and grid-surveys (Riegl, 2003). Documentation on the corals was made based on their species and structural composition (Hughes et al., 2003). South Africa was also a study area. Studies focused on sites in Sodwana Bay in KwaZulu/Natal Province. Beachrock and submerged Pleistocene dunes sequences were analyzed and their depths noted. Classification and ordination of corals used a square matrix of the coral cover. Data processing involved using matrices such as non-metric multidimensional scaling, Bray-Curtis similarity index, and Spearman rank-correlation. Sea-surface temperatures were obtained in both studies from municipality records and websites (Riegl, 2003). Knowlton et al. (2001) points out that Arabian Gulf observed both extreme negative and positive temperature excursions. The cold winter presents negative anomalies because it causes extreme cooling of the water surface, low tides, and generates a storm surge that result in repeated coral mortality (Baker et al., 2008). A case in point is the massive coral destruction during the severe winter of 1976. It is possible that positive temperatures coincided with the El Niño Southern Oscillation (ENSO) in 1998 that could have affected the Indian monsoon thus affecting the climate in Arabian Gulf (Bauman et al., 2011). During this period, unprecedented bleaching and coral death occurred in most of the shallow water coral in the Arabian Gulf. The Acropora species of coral had experienced the highest reoccurring mortality and regeneration events (Riegl, 2006). The study of the South African reef noted that they were situated in the headwaters of the Agulhas current and were not influenced by direct land runoff (Kiessling et al., 2006). The reason for this was that local rivers drained in to floodplains and swamps that had relatively small outlets or no outlets at all (Hughes et al., 2010). This prevents damaging of corals, as flooding that could kill nearby corals does not reach the shallow sea. This coral reef is protected from excess sedimentation and problems associated with water density changes (Smith et al., 2008). /10 9. What were the limitations of the study? The main limitation of the study is that it focused on bleaching caused by climate change and biotic factors to determine the stress on coral reefs. It did not touch on other coral reef stressors, such as human activities, blast fishing, ocean acidification, and the crown-of-thorns starfish that has devastating outbreaks in the Indian Ocean (McClanahan et al., 2011). Inclusion of these issues would provide a well-rounded explanation on the bleaching of corals. The study also mentions reef protection only in a few instances. A discussion of how the reefs in the Arabian Gulf and South Africa are protected would give readers more insight on the effects of human activities on reefs (Graham et al., 2011). /10 10. What were the overall conclusions the author(s) came to? Riegl (2003) came to a conclusion that the reef mortality patters in the Arabian Gulf are partly the result of oceanographic conditions. The Arabian Gulf reef was exposed to wind, waves, and a range of both positive and negative temperature excursions (Jackson, 2008). The reefs in South Africa are protected from extreme temperatures by a series of active water dynamics caused by the Agulhas current (Ostrander et al., 2000). There is also a swell generated in show counter flow that regulates the water temperatures, thus protecting the corals from extreme heating (Botsford et al., 2009). Even during summer, ‘cool events’ are observed mostly attributed to the up swell. In 1997-98 during the El Niño Southern Oscillation (ENSO) event, temperatures rose to the highest recorded levels in 15 years. However, no bleaching was observed in the South African reefs. Van Oppen et al. (2015) observes that the steep South African shelf also contributes in cooling the waters as it deflects warm currents away from the coast. The result of the Agulhas current and the steep shelf deflecting bottom layers of warm currents is that the upper surface waters where the corals are situated remain cool. This mechanism prevented bleaching in 1998 and 2002 ENSO events (Van Oppen et al., 2015). /10 11. How has the current study added to the knowledge of the subject? The findings in this paper allow readers to gain knowledge on evaluating the human consequences of climate change and global warming. The situation in the Arabian Gulf reef provides us with a glimpse in to the future. With its high temperature disturbance events and disappearing reef, it is a good lesson demands a turning point on the effects of human activities on climate change (Riegl, 2003). The South African study provides readers with a glimpse of the past and present. With its undisturbed coral system, it should provide us with the motivation to protect the beautiful natural resources we have left (Manzello et al., 2008). /10 12. References Arrieta, J. M., Arnaud-Haond, S., & Duarte, C. M. (2010). What lies underneath: conserving the oceans’ genetic resources. Proceedings of the National Academy of Sciences, 107(43), 18318-18324. http://www.pnas.org/content/107/43/18318.short Baker, A. C., Glynn, P. W., & Riegl, B. (2008). Climate change and coral reef bleaching: An ecological assessment of long-term impacts, recovery trends and future outlook. Estuarine, Coastal and Shelf Science, 80(4), 435-471. http://www.sciencedirect.com/science/article/pii/S0272771408003405 Botsford, L. W., White, J. W., Coffroth, M. A., Paris, C. B., Planes, S., Shearer, T. L., & Jones, G. P. (2009). Connectivity and resilience of coral reef metapopulations in marine protected areas: matching empirical efforts to predictive needs. Coral Reefs, 28(2), 327-337. http://link.springer.com/article/10.1007/s00338-009-0466-z De’ath, G., Fabricius, K. E., Sweatman, H., & Puotinen, M. (2012). The 27–year decline of coral cover on the Great Barrier Reef and its causes. Proceedings of the National Academy of Sciences, 109(44), 17995-17999. http://www.pnas.org/content/109/44/17995.short Graham, N. A. J., Nash, K. L., & Kool, J. T. (2011). Coral reef recovery dynamics in a changing world. Coral Reefs, 30(2), 283-294. http://link.springer.com/article/10.1007/s00338-010-0717-z Graham, N. A., Wilson, S. K., Jennings, S., Polunin, N. V., Bijoux, J. P., & Robinson, J. (2006). Dynamic fragility of oceanic coral reef ecosystems. Proceedings of the National Academy of Sciences, 103(22), 8425-8429. http://www.pnas.org/content/103/22/8425.short Jackson, J. B. (2008). Ecological extinction and evolution in the brave new ocean. Proceedings of the National Academy of Sciences, 105(Supplement 1), 11458-11465. http://www.pnas.org/content/105/Supplement_1/11458.short Kiessling, W., Simpson, C., Beck, B., Mewis, H., & Pandolfi, J. M. (2012). Equatorial decline of reef corals during the last Pleistocene interglacial. Proceedings of the National Academy of Sciences, 109(52), 21378-21383. http://www.pnas.org/content/109/52/21378.short Knowlton, N. (2001). The future of coral reefs. Proceedings of the National Academy of Sciences, 98(10), 5419-5425. http://www.pnas.org/content/98/10/5419.short Manzello, D. P., Kleypas, J. A., Budd, D. A., Eakin, C. M., Glynn, P. W., & Langdon, C. (2008). Poorly cemented coral reefs of the eastern tropical Pacific: Possible insights into reef development in a high-CO2 world. Proceedings of the National Academy of Sciences, 105(30), 10450-10455. http://www.pnas.org/content/105/30/10450.short McClanahan, T. R., Graham, N. A., MacNeil, M. A., Muthiga, N. A., Cinner, J. E., Bruggemann, J. H., & Wilson, S. K. (2011). Critical thresholds and tangible targets for ecosystem-based management of coral reef fisheries. Proceedings of the National Academy of Sciences, 108(41), 17230-17233. http://www.pnas.org/content/108/41/17230.short Mumby, P. J., Vitolo, R., & Stephenson, D. B. (2011). Temporal clustering of tropical cyclones and its ecosystem impacts. Proceedings of the National Academy of Sciences, 108(43), 17626-17630. http://www.pnas.org/content/108/43/17626.short Ostrander, G. K., Armstrong, K. M., Knobbe, E. T., Gerace, D., & Scully, E. P. (2000). Rapid transition in the structure of a coral reef community: the effects of coral bleaching and physical disturbance. Proceedings of the National Academy of Sciences, 97(10), 5297-5302. http://www.pnas.org/content/97/10/5297.short Riegl, B. (2003). Climate change and coral reefs: different effects in two high-latitude areas (Arabian Gulf, South Africa). Coral Reefs, 22(4), 433-446. Riegl, B. M., Purkis, S. J., Al-Cibahy, A. S., Abdel-Moati, M. A., & Hoegh-Guldberg, O. (2011). Present limits to heat-adaptability in corals and population-level responses to climate extremes. PloS One, 6(9), e24802. http://dx.plos.org/10.1371/journal.pone.0024802.g005 Van Oppen, M. J., Oliver, J. K., Putnam, H. M., & Gates, R. D. (2015). Building coral reef resilience through assisted evolution. Proceedings of the National Academy of Sciences, 112(8), 2307-2313. http://www.pnas.org/content/112/8/local/masthead.pdf /10 Read More