Indian Ocean Dipole index recorded in Kenyan coral annual density bands

Iijima, Hiroko; Nakamura, N.; McClanahan, Tim R.; Behera, Swadhin K.; Yamagata, Toshio

doi:10.1029/2006gl027168

Cited by 38 publications

(19 citation statements)

References 24 publications

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“…The southwest region is also characterized by large inter-and intra-annual variability that is persistent through winter and summer seasons and experiencing strong periodicities at different frequencies. The 50 to 60 yr cycle has been found in many temperature time series for the region and is probably a combination of the IOD and ENSO cycles (Saji et al 1999, Cole et al 2000, Kayanne et al 2006, Sakova et al 2006. The strong temperature rise in 1961 is most likely an IOD effect, whereas the 1983 event is a strong ENSO effect, and the 1998 peak reflects a combined ENSO and IOD interaction (Saji et al 1999).…”

Section: Discussionmentioning

confidence: 99%

Recent seawater temperature histories, status, and predictions for Madagascar’s coral reefs

McClanahan

Ateweberhan²,

Omukoto³

et al. 2009

Mar. Ecol. Prog. Ser.

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Recent temperature histories and benthic surveys of Madagascar's coral reefs are presented from 3 disparate regions in order to develop an understanding of the relationship between sea surface temperature (SST) and benthic cover, coral diversity, and community structure. Results indicate the presence of distinct temperature zones influenced by windward and seaward positions, latitude, intra-and inter-annual cycles, and local hydrodynamics. Southwest reefs had SSTs with the lowest mean, highest variation, fastest rise, strongest periodicities and highest cumulative degree heating weeks during recent warm events. These reefs were distinguished by a low number of coral taxa and a high cover of erect algae and had recently undergone a major decline in coral cover and change in community structure. Northwestern and eastern reefs had SSTs with moderate means and variation, lower temperature rises, and weaker periodicities. They also had higher coral cover and numbers of coral genera, and communities more typical of Indian Ocean coral communities undisturbed by temperature anomalies. Northwestern reefs had the lowest cumulative degree heating weeks and a high frequency of rare 'boutique' taxa that are usually found deeper or in lowdisturbance environments. Eastern reefs had a developed reef structure and may have the greatest potential for surviving climate change, while the northwest may be more amenable to protecting rare taxa. The more temperate reefs of the south showed large-scale degradation and no evidence for a refuge for coral communities, and require increased herbivory and associated fisheries management to reduce erect algal abundance.

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Section: Discussionmentioning

confidence: 99%

Recent seawater temperature histories, status, and predictions for Madagascar’s coral reefs

McClanahan

Ateweberhan²,

Omukoto³

et al. 2009

Mar. Ecol. Prog. Ser.

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“…Goddard and Graham 1999;Latif et al 1999). Recently, Kayanne et al (2006) found a strong relationship to East Africa rainfall in a 15-year-long monthly resolved coral d…”

Section: Discussionmentioning

confidence: 99%

Western Indian Ocean marine and terrestrial records of climate variability: a review and new concepts on land–ocean interactions since AD 1660

Zinke

Pfeiffer

Timm

et al. 2008

Int J Earth Sci (Geol Rundsch)

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We examine the relationship between three tropical and two subtropical western Indian Ocean coral oxygen isotope time series to surface air temperatures (SAT) and rainfall over India, tropical East Africa and southeast Africa. We review established relationships, provide new concepts with regard to distinct rainfall seasons, and mean annual temperatures. Tropical corals are coherent with SAT over western India and East Africa at interannual and multidecadal periodicities. The subtropical corals correlate with Southeast African SAT at periodicities of 16-30 years. The relationship between the coral records and land rainfall is more complex. Running correlations suggest varying strength of interannual teleconnections between the tropical coral oxygen isotope records and rainfall over equatorial East Africa. The relationship with rainfall over India changed in the 1970s. The subtropical oxygen isotope records are coherent with South African rainfall at interdecadal periodicities. Paleoclimatological reconstructions of land rainfall and SAT reveal that the inferred relationships generally hold during the last 350 years. Thus, the Indian Ocean corals prove invaluable for investigating land-ocean interactions during past centuries.

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“…1). This region is influenced by the El Nin˜o Southern Oscillation (ENSO; Cole et al 2000), and the Indian Ocean also contains its own endogenous cycle known as the Indian Ocean Dipole (IOD), which is a pressure gradient between Sumatra and the Arabian Peninsula and has greatest impacts in the eastern and western margins of the Indian Ocean (Saji et al 1999, Webster et al 1999, Kayanne et al 2006. The natural variability of the western Indian Ocean SST dipole and ENSO has been detected from coral skeleton isotope records of the past 300 years (Charles et al 1997, Cole et al 2000, Zinke et al 2004, 2005, Damassa et al 2006, Kayanne et al 2006.…”

Section: Study Area and Backgroundmentioning

confidence: 99%

Effects of Climate and Seawater Temperature Variation on Coral Bleaching and Mortality

McClanahan¹,

Ateweberhan²,

Muhando³

et al. 2007

Ecological Monographs

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256

203

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Abstract. Coral bleaching due to thermal and environmental stress threatens coral reefs and possibly people who rely on their resources. Here we explore patterns of coral bleaching and mortality in East Africa in 1998 and 2005 in a region where the equatorial current and the island effect of Madagascar interact to create different thermal and physicochemical environments. A variety of temperature statistics were calculated, and their relationships with the degree-heating months (DHM), a good predictor of coral bleaching, determined. Changes in coral cover were analyzed from 29 sites that span .1000 km of coastline from Kenya to the Comoros Islands. Temperature patterns are influenced by the island effect, and there are three main temperature environments based on the rise in temperature over 52 years, measures of temperature variation, and DHM. Offshore sites north of Madagascar that included the Comoros had low temperature rises, low DHM, high standard deviations (SD), and the lowest relative coral mortality. Coastal sites in Kenya had moderate temperature rises, the lowest temperature SD, high DHM, and the highest relative coral mortality. Coastal sites in the south had the highest temperature rises, moderate SD and DHM, and low relative coral mortality. Consequently, the rate of temperature rise was less important than background variation, as reflected by SD and kurtosis measures of sea surface water temperature (SST), in predicting coral survival across 1998. Coral bleaching responses to a warm-water anomaly in 2005 were also negatively related to temperature variation, but positively correlated with the speed of water flow. Separating these effects is difficult; however, both factors will be associated with current environments on the opposite sides of reefs and islands. Reefs in current shadows may represent refugia where corals acclimate and adapt to environmental variation, which better prepares them for rising temperature and anomalies, even though these sites are likely to experience the fastest rates of temperature rise. We suggest that these sites are a conservation priority and should be targeted for management and further ecological research in order to understand acclimation, adaptation, and resilience to climate change.

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Indian Ocean Dipole index recorded in Kenyan coral annual density bands

Cited by 38 publications

References 24 publications

Recent seawater temperature histories, status, and predictions for Madagascar’s coral reefs

Recent seawater temperature histories, status, and predictions for Madagascar’s coral reefs

Western Indian Ocean marine and terrestrial records of climate variability: a review and new concepts on land–ocean interactions since AD 1660

Effects of Climate and Seawater Temperature Variation on Coral Bleaching and Mortality

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