“Air Drill” for Submerged Massive Coral Drilling

Adachi, Hiroshi; Abe, Osamu

doi:10.4031/002533203787537311

Cited by 13 publications

(5 citation statements)

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“…Sampling method and X-radiographs. In March 2009, five coral cores were obtained using an air drill 30 from three living colonies of Porites lutea at two sampling sites, namely, Fongafale Island (TV09 fg01-03; 8°31′7.3″S, 179°11′43.9″E, Fig. 1c,d) and Funafala Island (TV09fh-11 and TV09fh-12; 8°37′48.4″S, 179°04′44″E, Figs.…”

Section: Methodsmentioning

confidence: 99%

Anthropogenic Anoxic History of the Tuvalu Atoll Recorded as Annual Black Bands in Coral

Nakamura

Takahashi

Sunamura

et al. 2020

Sci Rep

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Atoll islands are small, low-lying and highly vulnerable to sea level rise (SLR). Because these islands are fully composed of the skeletons from coral reef creatures, the healthy coral ecosystem plays a pivotal role in island resilience against SLR. The environmental deterioration of reefs caused by increases in the human population has been recently reported, but the timing and process are unknown. We investigated the annual black bands in a coral boring core from Fongafale Island, the capital of Tuvalu, which is a symbolic atoll country that is being submerged due to SLR. The iron redox state and microbial gene segments in the coral skeleton might be new environmental indicators that reveal the linkage between anthropogenic activity and coral reef ecosystems. Our findings provide the first demonstration that iron sulfide has formed concentrated black layers since 1991 under the seasonal anoxic conditions inside coral annual bands. Since the 1990s, increasing human activity and domestic waste-induced eutrophication has promoted sludge and/or turf algae proliferation with the subsequent seasonal destruction, resulting in sulfate reduction by anaerobic bacteria. With the recent climate variability, these anthropogenic effects have induced the mass mortality of branching corals, deteriorated the coral reef ecosystem and deprived the resilience of the island against SLR.

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Section: Methodsmentioning

confidence: 99%

Anthropogenic Anoxic History of the Tuvalu Atoll Recorded as Annual Black Bands in Coral

Nakamura

Takahashi

Sunamura

et al. 2020

Sci Rep

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“…The five Porites coral colonies (C1–C5) were 50–80 cm in diameter and living at a depth of less than 1 m from near the river mouth to the reef crest. The coral drilling was performed using an air‐drill [ Adachi and Abe , 2003]. In this study, we created a 1 in (2.5 cm) diameter core tube, and we drilled 30 cm cores from the tops of the coral colonies.…”

Section: Methodsmentioning

confidence: 99%

Nitrogen isotopes of organic nitrogen in reef coral skeletons as a proxy of tropical nutrient dynamics

Yamazaki

Watanabe

Tsunogai

2011

Geophys. Res. Lett.

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Understanding tropical nutrient dynamics is essential for quantifying marine productivity. In tropical and subtropical oceans, however, the spatial and continuous observation of nutrients has been scarce because of low nutrient concentration. The nitrogen isotopes of organic nitrogen in coral skeletons (δ15N_[coral]) could be used to record nitrogenous nutrient origins at oceanic surfaces. Here, we show the intra- and inter-reef variations of δ15N_[coral] in the western Pacific. The zonal distribution of δ15N_[coral] was found inside a coral reef corresponding with δ15N of seawater nitrate (δ15N_[nitrate]). The extended analysis of δ15N_[coral] among various coral reefs also shows a latitudinal gradient from tropical to temperate in the western Pacific. The δ15N_[coral] records high-resolution dynamics of nitrogenous nutrients through the geologic time scale

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“…[6] We sampled a coral core obtained using an air drill [Adachi and Abe, 2003] Figure 2). Precipitation is concentrated during two seasons in East Africa, with long rain period in April and short rain period from October to November ( Figure 2).…”

Section: Methodsmentioning

confidence: 99%

Indian Ocean Dipole index recorded in Kenyan coral annual density bands

Iijima

Nakamura

McClanahan³

et al. 2006

Geophysical Research Letters

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The Indian Ocean Dipole (IOD), which governs climate variability not only over the Indian Ocean but also globally, produces precipitation anomalies in the East African short rain period from October to November. These precipitation anomalies were recorded in annual bands from a coral core obtained in the Malindi Marine Park, Kenya. A signature of the IOD in precipitation was detected in the coral core by luminescence intensity under UV light and by oxygen isotope values dated to January, a few months after the short rain period. Anomalies of the oxygen isotope values correlated well with high and low precipitation, which were related to positive and negative IOD indices, respectively. This study suggests that the coral annual band record is effective for reconstructing IOD events and should be able to reconstruct the IOD record prior to instrumental observations.

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“Air Drill” for Submerged Massive Coral Drilling

Cited by 13 publications

References 0 publications

Anthropogenic Anoxic History of the Tuvalu Atoll Recorded as Annual Black Bands in Coral

Anthropogenic Anoxic History of the Tuvalu Atoll Recorded as Annual Black Bands in Coral

Nitrogen isotopes of organic nitrogen in reef coral skeletons as a proxy of tropical nutrient dynamics

Indian Ocean Dipole index recorded in Kenyan coral annual density bands

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