Incoherency in Central American hydroclimate proxy records spanning the last millennium

Obrist‐Farner, Jonathan; Steinman, Byron A.; Stansell, Nathan D.; Maurer, J.

doi:10.1002/essoar.10510848.1

Cited by 5 publications

(14 citation statements)

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Section: Discussionsupporting

confidence: 89%

“…The diversification of abiotic factors may be a reason for the heterogeneous response of ecosystems to global climate changes related to the LIA. Similar conclusions were drawn in a recently published paper by Obrist-Farner et al (2022). They suggest that any single climatic factor (e.g., ITCZ, NAO, ENSO) cannot explain the full regional patterns of hydroclimatic changes in Central America and, therefore, the disparate signals derived from paleorecords are a result of a combination of several driving factors.…”

Section: The Little Ice Age In Central Americaa Regional Perspectivesupporting

confidence: 86%

“…However, Obrist-Farner et al (2022), further suggest that system diversity (including lakes), may not be the main source of discrepancy as they found disparities even when comparing similar systems or speleothem records from the same cave.…”

Section: The Little Ice Age In Central Americaa Regional Perspectivementioning

confidence: 88%

“…Blue Hole (Gischler et al, 2008); 17. Lake Izabal (Obrist-Farner et al, 2022); 18. Lake Amatitlán (Velez et al, 2011); 19.…”

Section: Discussionunclassified

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Imprints of the Little Ice Age and the severe earthquake of AD 2001 on the aquatic ecosystem of a tropical maar lake in El Salvador

et al. 2022

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Using a 530-year sediment record from the maar Lake Apastepeque, El Salvador, and based on diverse geochemical and biological (cladocerans, chironomids, diatoms, ostracods, testate amoebae) indicators, we estimated climatic and environmental alterations during the Little Ice Age (LIA) and reconstructed the recent history of the lake. Results demonstrate relatively humid conditions in the mid-elevations (500 m a.s.l.) of El Salvador during most parts of the LIA, resulting in high lake levels. Contrarily, the first part of the LIA was characterized by drier climates comparable to studies from Mexico and Belize, which correlated this phase with the Spörer minimum. Regional comparison with palaeorecords from the northern Neotropics reveals a high heterogeneity in local expressions of the LIA in Central America, likely connected to the high topographic heterogeneity of the region. Since the beginning of the 20th century, Lake Apastepeque has experienced enhanced human impact expressed as increased nutrient supply. The most recent period was characterized by significant environmental disturbance, which we relate to an upper-crustal earthquake, one of the strongest over the last 500 years, that affected the region on 13th February 2001 (Mw = 6.6, epicentre at 10 km depth, 30 km from the lake). The release of toxic bottom components such as hydrogen sulphide and high turbidity and turbulence of water caused major species turnover in the lake ecosystem, resulting in a massive fish kill and colonization by large cladocerans. Modern sediments still show slightly altered biota communities compared to pre-earthquake assemblages, indicating that the ecosystem has still not fully recovered.

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Section: Discussionsupporting

confidence: 89%

Section: The Little Ice Age In Central Americaa Regional Perspectivesupporting

confidence: 86%

Section: The Little Ice Age In Central Americaa Regional Perspectivementioning

confidence: 88%

“…Blue Hole (Gischler et al, 2008); 17. Lake Izabal (Obrist-Farner et al, 2022); 18. Lake Amatitlán (Velez et al, 2011); 19.…”

Section: Discussionunclassified

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Imprints of the Little Ice Age and the severe earthquake of AD 2001 on the aquatic ecosystem of a tropical maar lake in El Salvador

et al. 2022

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“…Data for replicating the results of this study are available at the National Oceanic and Atmospheric Administration National Centers for Environmental Information paleoclimate data repository (Obrist‐Farner & Steinman, 2022).…”

Section: Data Availability Statementmentioning

confidence: 99%

Incoherency in Central American Hydroclimate Proxy Records Spanning the Last Millennium

Obrist‐Farner

Steinman

Stansell

et al. 2023

Paleoceanog and Paleoclimatol

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Continued global warming is expected to result in reduced precipitation and a drier climate in Central America. Projections of future changes are highly uncertain, however, due to the spatial resolution limitations of models and insufficient observational data coverage across space and time. Paleoclimate proxy data are therefore critical for understanding regional climate responses during times of global climate reorganization. Here we present two lake‐sediment based records of precipitation variability in Guatemala along with a synthesis of Central American hydroclimate records spanning the last millennium (800–2000 CE). The synthesis reveals that regional climate changes have been strikingly heterogeneous, even over relatively short distances. Our analysis further suggests that shifts in the mean position of the Intertropical Convergence Zone, which have been invoked by numerous studies to explain variability in Central American and circum‐Caribbean proxy records, cannot alone explain the observed pattern of hydroclimate variability. Instead, interactions between several ocean‐atmosphere processes and their disparate influences across variable topography appear to have resulted in complex precipitation responses. These complexities highlight the difficulty of reconstructing past precipitation changes across Central America and point to the need for additional paleo‐record development and analysis before the relationships between external forcing and hydroclimate change can be robustly determined. Such efforts should help anchor model‐based predictions of future responses to continued global warming.

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Distinct Modes of Aged Soil Carbon Export in a Large Tropical Lake Basin Identified Using Bulk and Compound‐Specific Radiocarbon Analyses of Fluvial and Lacustrine Sediment

Parker¹,

Ahad

Obrist‐Farner

et al. 2023

JGR Biogeosciences

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The 14C content of sedimentary organic matter and specific organic molecules provide valuable information on the source and age of organic matter stored in sediments, but these data are limited for tropical fluvial and lake sediments. We analyzed 14C in bulk organic matter, palmitic acid (C16), and long‐chain n‐alkanoic acids (C24, C26, C28), within fluvial and lake sediments in the catchment of Lake Izabal, a large tectonic lake basin in Guatemala. We combined these measurements with bulk and compound‐specific δ13C measurements, as well as sediment OC:N ratios, to understand the source and age of sedimentary organic matter in different regions of the lake catchment. Most fatty acid and bulk OM samples were characterized by pre‐modern carbon, indicating important input of aged carbon with residence times of hundreds to thousands of years into sediments. We identified two mechanisms leading to aged carbon export to sediments. In the high‐relief and deforested Polochic catchment, older OM and fatty acids are associated with low %TOC and low OC:N, indicating aged organic matter associated with eroded mineral soil. In the smaller, low‐relief, and largely forested Oscuro catchment, old OM and fatty acids are associated with high %TOC and high OC:N ratios, indicating export of undegraded aged plant biomass from swamp peat. The age of bulk OM and fatty acids in Lake Izabal sediments is similar to the ages observed in fluvial sediments, implying that fluvial input of aged soil carbon makes an important contribution to lake sediment carbon reservoirs in this large tropical lake.

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Incoherency in Central American hydroclimate proxy records spanning the last millennium

Cited by 5 publications

References 0 publications

Imprints of the Little Ice Age and the severe earthquake of AD 2001 on the aquatic ecosystem of a tropical maar lake in El Salvador

Imprints of the Little Ice Age and the severe earthquake of AD 2001 on the aquatic ecosystem of a tropical maar lake in El Salvador

Incoherency in Central American Hydroclimate Proxy Records Spanning the Last Millennium

Distinct Modes of Aged Soil Carbon Export in a Large Tropical Lake Basin Identified Using Bulk and Compound‐Specific Radiocarbon Analyses of Fluvial and Lacustrine Sediment

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