Patterns of alluvial deposition in Andean lake consistent with ENSO trigger

Hagemans, Kimberley; Nooren, Kees; Haas, Tjalling de; Córdova, Mario; Hennekam, Rick; Stekelenburg, Martin C.A.; Rodbell, Donald T.; Middelkoop, H.; Donders, Timme H.

doi:10.1016/j.quascirev.2021.106900

Cited by 8 publications

(18 citation statements)

References 32 publications

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“…1,500-year intervals starting at 7.0 kyr BP, followed by an increase in ENSO activity between ca. 4.2 kyr BP and ∼1.2 kyr BP, and a subsequent reduction toward the present (Moy et al, 2002;Toth et al, 2012;Hagemans et al, 2021). This coincides with fire events at higher frequencies from 7.0 kyr BP, their surge at 4.1 kyr BP, and two notable peaks at 3.8 and 2.6 kyr BP in the Monquentiva record and suggest a climate control on fire activity through the Holocene.…”

Section: Did Climate Induce Fires In Monquentiva?supporting

confidence: 65%

Holocene Fires and Ecological Novelty in the High Colombian Cordillera Oriental

Espinoza

Franco-Gaviria

Castañeda³

et al. 2022

Front. Ecol. Evol.

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Rapid climate changes and the increasing presence of humans define the Holocene Epoch (11.6 calibrated kiloyears before present – hereafter kyr BP), when biological systems have faced the most recent and abrupt environmental changes. Understanding how biodiversity responds to extrinsic factors requires determining the effects of varying climatic conditions, changes in disturbance regimes, and increasing anthropogenic impacts. Despite being one center for biodiversity, the potential synergies of long-term anthropogenic and climate changes in shaping areas of high Andean biodiversity have yet to be explored fully. Here we present new pollen and charcoal records from the Pantano de Monquentiva (hereafter Monquentiva) on the highlands of the eastern flank of the Colombian Cordillera Oriental (CCO) to document relationships between climate, vegetation, and fire through the Holocene. We found compositional transitions at 8.7, 6.1, and 4.1 kyr BP at Monquentiva resulting from the interaction of climate, fire, and human occupation. Reduced moisture and temperature caused a compositional shift in Páramo vegetation from ca. 8.7 kyr BP. Fire activity was recorded throughout the Holocene and increased slightly during the Mid-Holocene when regional and local fire decoupling suggested human activities as the source of ignition. Mid-Holocene fires had a large effect on the vegetation composition at Monquentiva which recorded a rapid shift at ca. 6.8 kyr BP. Fire activity increased sharply from 4.1 kyr BP, promoting the reorganization of plant communities at 3.8 kyr BP. This shift in fire activity was likely related to more severe ENSO events and subsequently intensified by human activities after 3.8 kyr BP. Although high climatic sensitivity explains most Holocene vegetation changes in the eastern flank of the CCO, our study highlights the relevance of fire activity, uneven distribution of climatic variables, and human intervention to the composition of the vegetation we see today.

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Section: Did Climate Induce Fires In Monquentiva?supporting

confidence: 65%

Holocene Fires and Ecological Novelty in the High Colombian Cordillera Oriental

Espinoza

Franco-Gaviria

Castañeda³

et al. 2022

Front. Ecol. Evol.

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“…Recent debate on the interpretation of the sedimentological proxy for ENSO reconstructions (Schneider et al, 2018) has led to renewed study of the exact sediment cascade and meteorological conditions that lead to the layered organic–clastic pattern in the lake sediment record. The resulting new chronological data from both subbasins of Laguna Pallcacocha and the alluvial fans and improved high-resolution meteorological data show a tight link between high-intensity rainfall anomalies, debris flow activity, and clastic sedimentation patterns in the lake record and confirm it as a valid ENSO proxy (Hagemans et al, 2021).…”

Section: Introductionmentioning

confidence: 77%

“…The age-depth model of Laguna El Ocho was established on the basis of the 210 Pb dating and was interpolated with the cubic-b spline method in Tilia v. 1.7.16 (Grimm, 1991). Negative values in the observed 210 Pb profile of Laguna El Ocho (Fig.…”

Section: Chronologymentioning

confidence: 99%

“…If these algal communities are indeed strongly temperature driven, they could present a sensitive proxy for reconstructing rapid temperature shifts further back in time in the Tropical Andes, a region where local climate variability on interannual timescales is primarily driven by the El Niño Southern Oscillation (ENSO) (Kiefer and Karamperidou, 2019). For example, the lithostratigraphy of sediments from Laguna Pallcacocha, a small lake situated in the páramo of the CNP, is a key record for reconstructions of past ENSO dynamics (Moy et al, 2002; Hagemans et al, 2021; Mark et al, 2022). Current palaeoclimatological interpretations from the lake archive are based on depositional patterns and elemental composition of clastic layers in the lake record (Moy et al, 2002; Mark et al, 2022), as well as pollen assemblages registering concurrent landscape disturbance (Hagemans et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

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Anthropogenic activities in the páramo trigger ecological shifts in Tropical Andean lakes

et al. 2023

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A robust understanding of the impact of anthropogenic activities on high-altitude tropical aquatic ecosystems is key for the conservation and protection of the Tropical Andean biodiversity hot spot. We present the results of a multiproxy study of lake sediments from the high Andean páramo of El Cajas National Park, a UNESCO biosphere reserve in Ecuador. The main site, Laguna Pallcacocha, is well known for recording El Niño–driven clastic flood layers that are triggered by high-intensity rainfall anomalies from the eastern Pacific. The second site, Laguna El Ocho, does not contain clastic laminations, providing a control. The records show abrupt shifts in diatom assemblages ca. AD 1991 in both high-elevation Andean lakes accompanied by local changes in páramo composition that suggest a sudden nutrient enrichment of the environment. The diatom assemblages from Laguna Pallcacocha, in relation to the clastic input events, are remarkably stable and do not show evident El Niño signals at the analysed resolution. Based on comparison with the nonlaminated El Ocho record, we deduce the main source of this nutrient enrichment to be the construction of a heavily transited road that runs through the park, while climate warming played secondary role by amplifying its effects.

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“…In this study, we used a suite of time-slice earth system model simulations of multiple intervals since 12 ka BP to show that combined changes in the frequency of Eastern Pacific, Central Pacific, and coastal El Niño events, as well as a change in the strength of the hydroclimate impact of these flavors, reconcile central Pacific proxies that show highly variable ENSO in the Holocene with eastern Pacific proxies indicating large decreases in ENSO-related hydroclimatic variability in the early Holocene. In addition, a seeming contrast between a central or western Pacific proxy record indicating enhanced La Niña conditions and an eastern Pacific proxy indicating enhanced El Niño conditions over the same past period can be reconciled as partially resulting from increased frequency of Coastal events instead of a change in basin-scale ENSO, due to the fact that Coastal El Niño events have supersized precipitation impacts in the far eastern Pacific 13 , 22 , 23 during otherwise basin-scale neutral or La Niña conditions. Our focus on the impacts of changes in the frequency and impacts of all ENSO flavors can thus help frame and better interpret past or future response of ENSO to other external forcings, including greenhouse gas emissions and volcanic eruptions, and its global and tropical hydroclimatic impacts, as clearly shown by the strong correlation between ENSO diversity and SST and precipitation variability in both the central and eastern Pacific.…”

Section: Resultsmentioning

confidence: 99%

Holocene hydroclimatic variability in the tropical Pacific explained by changing ENSO diversity

Karamperidou

DiNezio

2022

Nat Commun

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Understanding El Niño-Southern Oscillation (ENSO) response to past climate forcings is hindered by conflicting paleoclimate evidence. Records from the eastern Pacific show an intensification of ENSO variability from early to late Holocene, while records from the central Pacific show highly variable ENSO throughout the Holocene without an obvious relation to insolation forcing, which is the main climate driver during this interval. Here, we show via climate model simulations that conflicting Holocene records can be reconciled by considering changes in the relative frequency of the three preferred spatial patterns in which El Niño events occur (Eastern Pacific, Central Pacific, and Coastal) and in the strength of their hydroclimatic impacts. The relationship between ENSO diversity and variance is not only crucial for interpreting paleo-ENSO records and understanding ENSO response to external forcings but can also be used across climate model simulations to help evaluate the realism of ENSO projections in a changing climate.

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Patterns of alluvial deposition in Andean lake consistent with ENSO trigger

Cited by 8 publications

References 32 publications

Holocene Fires and Ecological Novelty in the High Colombian Cordillera Oriental

Holocene Fires and Ecological Novelty in the High Colombian Cordillera Oriental

Anthropogenic activities in the páramo trigger ecological shifts in Tropical Andean lakes

Holocene hydroclimatic variability in the tropical Pacific explained by changing ENSO diversity

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