Environmental control of the oxygen isotope composition of Porites coral microatolls

McGregor, Helen; Fischer, Matt J.; Gagan, Michael K.; Fink, David; Woodroffe, Colin D.

doi:10.1016/j.gca.2011.04.017

Cited by 42 publications

(44 citation statements)

References 71 publications

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“…Selected corals were slabbed with a gasoline-operated saw, and cross-sectional slices were X-radiographed to determine growth history, further verifi ed by oxygen-isotope analysis (Woodroffe et al, 2003;McGregor et al, 2011aMcGregor et al, , 2011b.…”

Section: Methodsmentioning

confidence: 99%

“…Many larger living microatolls occur at Cecile Peninsula at a slightly higher elevation, 1.2 ± 0.09 m (1σ, n = 13). One has been sliced and its annual growth history examined, indicating lateral extension rates of 15-23 mm/yr (McGregor et al, 2011a). At Benson Point, microatolls occur at a similar elevation to those at Northeast Point, 0.78 ± 0.08 m (1σ, n = 2), but they occur considerably lower, 0.14 ± 0.01 m (1σ, n = 6), at Southeast Point.…”

Section: Living Microatollsmentioning

confidence: 97%

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Mid-Pacific microatolls record sea-level stability over the past 5000 yr

Woodroffe

McGregor

Lambeck

et al. 2012

Geology

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There has been geographical variation in sea level since rapid postglacial melting of polar ice ceased ~6 k.y. ago, refl ecting isostatic adjustments of Earth and ocean surfaces to past (and ongoing) redistribution of ice and water loads. A new data set of over 100 fossil microatolls from Christmas (Kiritimati) Island provides a Holocene sea-level record of unparalleled continuity. Living reef-fl at corals grow up to a low-tide level. Adjacent fossil microatolls, long-lived Porites corals up to several meters in diameter, occur at similar elevations (±0.1 m), and extensive fossil microatolls in the island interior are at consistent elevations within each population. Collectively, they comprise an almost continuous sequence spanning the past 5 k.y., indicating that, locally, sea level has been within 0.25 m of its present position, and precluding global sea-level oscillations of one or more meters inferred from less stable locations, or using other sea-level indicators. This mid-Pacifi c atoll is tectonically stable and far from former ice sheets. The precisely surveyed and radiometrically dated microatolls indicate that sea level has not experienced signifi cant oscillations, in accordance with geophysical modeling, which implies that the eustatic contribution from past ice melt and the isostatic adjustment of the ocean fl oor to loading largely cancel each other at this site.

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Section: Methodsmentioning

confidence: 99%

Section: Living Microatollsmentioning

confidence: 97%

Mid-Pacific microatolls record sea-level stability over the past 5000 yr

Woodroffe

McGregor

Lambeck

et al. 2012

Geology

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“…This difference may act as a significant source of variability in climate reconstructions depending on the diel period over which calcification occurs (Chalker, 1977;Barnes and Crossland, 1978), as lateafternoon peaks in reef flat temperature are unlikely to be representative of the ambient oceanic conditions. This biasing of temperatures in shallow waters has severe implications for attempts at reconstructing absolute temperature based on coral colonies that occur on ponded reef flats, e.g., microatolls (Woodroffe and Gagan, 2000;McGregor et al, 2011a;Wu et al, 2013). To some extent, similar issues may affect data from corals collected from shallow lagoons.…”

Section: Environmental Setting Of the Coral Colonymentioning

confidence: 99%

Geochemistry-based coral palaeoclimate studies and the potential of ‘non-traditional’ (non-massive Porites) corals: Recent developments and future progression

Sadler

Webb

Nothdurft

et al. 2014

Earth-Science Reviews

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“…We compare these data to an ensemble of nine state-of-the-art global climate models (GCMs) from the Paleoclimate Modeling Intercomparison Project (PMIP3 28 ), which include simulations of pre-industrial (piControl) as well as industrial era (historical) and MH (midHolocene) climate (Table S2). The datasets represent the most comprehensive collection of oxygen isotope measurements on Holocene corals 16,17,24,25,[29][30][31][32][33][34][35] and mollusks 26,[36][37][38] to date from the tropical Pa- Table S1 and Fig. S1).…”

mentioning

confidence: 99%

Links between tropical Pacific seasonal, interannual and orbital variability during the Holocene

et al. 2015

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The El Niño-Southern Oscillation (ENSO) influences climate and weather over much of the globe, so uncertainties in its response to external forcing 1 hinder long-range climate predictability. Modeling studies have argued that such forcings may affect ENSO either via the seasonal cycle [2][3][4][5][6] or extratropical influences [7][8][9] , but this link is poorly constrained by the short instrumental record. Here we synthesize a pan-Pacific network of high-resolution marine biocarbonates spanning discrete snapshots of the Holocene (past ∼ 10,000 years), which we use to constrain a set of global climate model (GCM) simulations via a forward model 10 and a consistent treatment of uncertainty. Observations suggest important reductions in ENSO variability throughout the interval, most consistently during 3-5 kyBP, when ∼2/3 reductions are inferred. The magnitude and timing of these ENSO variance reductions bear little resemblance to those simulated by GCMs, or to equatorial insolation. The central Pacific witnessed a notable mid-Holocene increase in seasonality, at odds with the reductions 11 simulated by GCMs. Finally, while GCM aggregate behavior is consistent with an inverse relationship between seasonal amplitude and ENSO-band variance in sea-surface temperature 3,6,12, 13 , this relationship is not borne out by these observations. The synthesis suggests that tropical Pacific climate is highly variable, but exhibited millennia-long periods of reduced ENSO variability whose origins, whether forced or unforced, are a crucial issue for model development and long-term climate prediction.2 ENSO, the non-linear interaction between the tropical Pacific atmosphere and ocean, is the leading pattern of global interannual variability, with important physical, ecological, and human impacts. Yet, predicting its long-term behavior in the face of continued greenhouse forcing has proven elusive 1 . While the predictive skill of climate models at interannual timescales can be tested using instrumental observations, such records are too short to evaluate the fidelity of modelsimulated tropical Pacific variability on decadal-to centennial-timescales, i.e. those relevant for future climate projections. This motivates the use of paleoclimate observations, which cover a much longer time span and predate the observations used to develop and tune climate models, hence providing an out-of-sample test of their predictive ability 14 .The mid-Holocene (MH, ca 6,000 yrs before present; 6 kyBP) represents a key target for evaluating the simulated response of ENSO to changes in external forcing. While ice volume and greenhouse gas concentrations were essentially similar to today, the latitudinal and seasonal distribution of incoming solar radiation (insolation) was markedly different as a result of precession 15 : seasonal contrast was amplified in the northern hemisphere and reduced in the southern hemisphere. Thus, the mid-Holocene provides an opportunity to explore the link between changes in the seasonal cycle, meridional asymmetry in th...

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Environmental control of the oxygen isotope composition of Porites coral microatolls

Cited by 42 publications

References 71 publications

Mid-Pacific microatolls record sea-level stability over the past 5000 yr

Mid-Pacific microatolls record sea-level stability over the past 5000 yr

Geochemistry-based coral palaeoclimate studies and the potential of ‘non-traditional’ (non-massive Porites) corals: Recent developments and future progression

Links between tropical Pacific seasonal, interannual and orbital variability during the Holocene

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