A Late-Quaternary Pollen Record from Ka‘au Crater, O‘ahu, Hawai‘i

Hotchkiss, Sara C.; Juvik, James O.

doi:10.1006/qres.1999.2052

Cited by 57 publications

(56 citation statements)

References 34 publications

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“…Both the scenarios may be related to the limited patchy distribution of Hawaiian bogs and their brief geological lifespan (Mueller-Dombois 2006). Studies of pollen and radiocarbon in bog sediments reveal that modern Hawaiian bogs date primarily to the Holocene, and that the relative abundance of Metrosideros within and surrounding the bogs shows peaks and valleys that may correlate with wetter and drier climate phases during the latest Pleistocene through Holocene (Selling 1948;Burney et al 1995;Hotchkiss & Juvik 1999;Burney 2002). Most bogs apparently did not exist at their current locations at the Last Glacial Maximum, but other bogs may have existed at sites where environmental conditions were suitable at the time.…”

Section: Results (A) Phylogenetic and Comparative Analysesmentioning

confidence: 99%

Progressive island colonization and ancient origin of Hawaiian Metrosideros (Myrtaceae)

et al. 2008

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Knowledge of the evolutionary history of plants that are ecologically dominant in modern ecosystems is critical to understanding the historical development of those ecosystems. Metrosideros is a plant genus found in many ecological and altitudinal zones throughout the Pacific. In the Hawaiian Islands, Metrosideros polymorpha is an ecologically dominant species and is also highly polymorphic in both growth form and ecology. Using 10 non-coding chloroplast regions, we investigated haplotype diversity in the five currently recognized Hawaiian Metrosideros species and an established out-group, Metrosideros collina, from French Polynesia. Multiple haplotype groups were found, but these did not match morphological delimitations. Alternative morphologies sharing the same haplotype, as well as similar morphologies occurring within several distinct island clades, could be the result of developmental plasticity, parallel evolution or chloroplast capture. The geographical structure of the data is consistent with a pattern of age progressive island colonizations and suggests de novo intra-island diversification. If single colonization events resulted in a similar array of morphologies on each island, this would represent parallel radiations within a single, highly polymorphic species. However, we were unable to resolve whether the pattern is instead explained by ancient introgression and incomplete lineage sorting resulting in repeated chloroplast capture. Using several calibration methods, we estimate the colonization of the Hawaiian Islands to be potentially as old as 3.9 (K6.3) Myr with an ancestral position for Kaua'i in the colonization and evolution of Metrosideros in the Hawaiian Islands. This would represent a more ancient arrival of Metrosideros to this region than previous studies have suggested.

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Section: Results (A) Phylogenetic and Comparative Analysesmentioning

confidence: 99%

Progressive island colonization and ancient origin of Hawaiian Metrosideros (Myrtaceae)

et al. 2008

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“…data]), although subsurface drainage is possible. Today, peat soil has accumulated in the crater to a depth exceeding 3.6 m (Hotchkiss and Juvik 1999). Ka'au Crater experiences a subtropical climate with a weak seasonality and receives high annual precipitation (@415 cm) that is predominantly orographically controlled.…”

Section: Study Sitementioning

confidence: 99%

Methane Emission from a Tropical Wetland in Ka'au Crater, O'ahu, Hawai'i

Grand

Gaidos

2010

Pacific Science

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Natural tropical wetlands constitute an important but still poorly studied source of atmospheric methane, a powerful greenhouse gas. We measured net methane emission, soil profiles of methane generation and oxidation, and related environmental parameters in a tropical wetland occupying the Ka'au extinct volcanic crater on the Hawaiian island of O'ahu. The wetland has a fluctuating water table with dynamics that can be reproduced using precipitation data and a simple model. Median net methane flux was 117 mg m À2 day À1 and is consistent with measurements at other tropical sites. Net methane flux in the Commelina diffusa-dominated vegetation pattern (honohono) was significantly higher than that of the invasive Psidium cattleianum-dominated pattern (strawberry guava). Net methane emission in the honohono vegetation pattern was also significantly higher during the ''wet'' season compared with the ''dry'' season, although we did not find a clear correlation between net methane emission, water table level, or precipitation. We show that the measured fluxes are consistent with the integrated potential methane generation over the uppermost 30 cm of soil and consumption of @50% of that methane in the soil. Absence of a correlation between net methane emission and water table level may be due to suppression of the activity of strictly anaerobic methanogens by dynamic redox conditions in the upper layers of soil and varying rates of methane oxidation by facultive methanotrophs.

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“…First, we used cosmogenic 36 Cl surface-exposure dating to develop a new chronology for moraines and other landforms associated with the last two glacial expansions on Mauna Kea. Then, we developed high-elevation temperature and precipitation estimates for the Makanaka glaciations that are based on a glacier mass balance model for Mauna Kea, our glacial chronology, a pollen-based record of air temperatures from the nearby island of O'ahu (Hotchkiss and Juvik, 1999), an alkenone-derived record of sea-surface temperatures (SSTs) from the subtropical North Pacific (Lee and Slowey, 1999;Lee et al, 2001) and temperature lapse rates that include a new correction for atmospheric moisture. Finally, we analysed spatial patterns of precipitation during glacial times and speculate on the origin of moisture that caused precipitation sufficient to grow and maintain ice caps on Mauna Kea.…”

Section: Introductionmentioning

confidence: 99%

Ages and inferred causes of Late Pleistocene glaciations on Mauna Kea, Hawai'i

Pigati

Zréda

Zweck

et al. 2008

J Quaternary Science

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Glacial landforms on Mauna Kea, Hawai'i, show that the summit area of the volcano was covered intermittently by ice caps during the Late Pleistocene. Cosmogenic 36 Cl dating of terminal moraines and other glacial landforms indicates that the last two ice caps, called Older Makanaka and Younger Makanaka, retreated from their maximum positions approximately 23 ka and 13 ka, respectively. The margins and equilibrium line altitudes of these ice caps on the remote, tropical Pacific island were nearly identical, which would seem to imply the same mechanism for ice growth. But modelling of glacier mass balance, combined with palaeotemperature proxy data from the subtropical North Pacific, suggests that the causes of the two glacial expansions may have been different. Older Makanaka air atop Mauna Kea was likely wetter than today and cold, whereas Younger Makanaka times were slightly warmer but significantly wetter than the previous glaciation. The modelled increase in precipitation rates atop Mauna Kea during the Late Pleistocene is consistent with that near sea level inferred from pollen data, which suggests that the additional precipitation was due to more frequent and/or intense tropical storms associated with eastward-moving cold fronts. These conditions were similar to modern La Niñ a (weak ENSO) conditions, but persisted for millennia rather than years. Increased precipitation rates and the resulting steeper temperature lapse rates created glacial conditions atop Mauna Kea in the absence of sufficient cooling at sea level, suggesting that if similar correlations existed elsewhere in the tropics, the precipitation-dependent lapse rates could reconcile the apparent difference between glacial-time cooling of the tropics at low and high altitudes.

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A Late-Quaternary Pollen Record from Ka‘au Crater, O‘ahu, Hawai‘i

Cited by 57 publications

References 34 publications

Progressive island colonization and ancient origin of Hawaiian Metrosideros (Myrtaceae)

Progressive island colonization and ancient origin of Hawaiian Metrosideros (Myrtaceae)

Methane Emission from a Tropical Wetland in Ka'au Crater, O'ahu, Hawai'i

Ages and inferred causes of Late Pleistocene glaciations on Mauna Kea, Hawai'i

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