Identifying imprints of externally derived dust and halogens in the sedimentary record of an Iberian alpine lake for the past ∼13,500 years - Lake Peixão, Serra da Estrela (Central Portugal)

J Moreno; A M Ramos; P M Raposeiro; R N Santos; T Rodrigues; F Naughton; F Moreno; R M Trigo; J Ibañez-Insa; P Ludwig; X Shi; A Hernández

doi:10.1016/j.scitotenv.2023.166179

Identifying imprints of externally derived dust and halogens in the sedimentary record of an Iberian alpine lake for the past ∼13,500 years - Lake Peixão, Serra da Estrela (Central Portugal)

Sci Total Environ. 2023 Dec 10:903:166179. doi: 10.1016/j.scitotenv.2023.166179. Epub 2023 Aug 11.

Authors

J Moreno¹, A M Ramos², P M Raposeiro³, R N Santos⁴, T Rodrigues⁵, F Naughton⁵, F Moreno⁶, R M Trigo⁷, J Ibañez-Insa⁸, P Ludwig⁹, X Shi¹⁰, A Hernández¹¹

Affiliations

¹ Universidade de Lisboa, Faculdade de Ciências, Instituto Dom Luiz, 1749-016 Lisboa, Portugal. Electronic address: jcmoreno@fc.ul.pt.
² Universidade de Lisboa, Faculdade de Ciências, Instituto Dom Luiz, 1749-016 Lisboa, Portugal; Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Karlsruhe, Germany.
³ CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Pólo dos Açores, Rua da Mãe de Deus, 9500-321 Ponta Delgada, Portugal; Faculdade de Ciências e Tecnologia, Universidade dos Açores, Rua da Mãe de Deus, 9500-321 Ponta Delgada, Portugal.
⁴ Instituto Português do Mar e da Atmosfera (IPMA), Rua C do Aeroporto, 1749-077 Lisboa, Portugal.
⁵ Instituto Português do Mar e da Atmosfera (IPMA), Rua C do Aeroporto, 1749-077 Lisboa, Portugal; Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Estrada da Penha, 8005-139 Faro, Portugal.
⁶ Independent Researcher, Caminho da Portela, n. ° 97, Cascalha, 4940-061 Bico PCR, Portugal.
⁷ Universidade de Lisboa, Faculdade de Ciências, Instituto Dom Luiz, 1749-016 Lisboa, Portugal; Departamento de Meteorologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-919, Brazil.
⁸ Geosciences Barcelona (GEO3BCN-CSIC), Lluís Solé i Sabarís s/n, E-08028 Barcelona, Spain.
⁹ Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Karlsruhe, Germany.
¹⁰ Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), China.
¹¹ Universidade da Coruña, GRICA Group, Centro Interdisciplinar de Química e Bioloxía (CICA), Rúa As Carballeiras, 15071 A Coruña, Spain.

PMID: 37572895
DOI: 10.1016/j.scitotenv.2023.166179

Abstract

Iberian lacustrine sediments are a valuable archive to document environmental changes since the last glacial termination, seen as key for anticipating future climate/environmental changes and their far-reaching implications for generations to come. Herein, multi-proxy-based indicators of a mountain lake record from Serra da Estrela were used to reconstruct atmospheric (in)fluxes and associated climatic/environmental changes over the last ∼13.5 ka. Depositions of long-range transported dust (likely from the Sahara) and halogens (primarily derived from seawater) were higher for the pre-Holocene, particularly in the late Bølling-Allerød-Younger Dryas period, compared to the Holocene. This synchronous increase could be related to a recognized dust-laden atmosphere, along with the combined effect of (i) an earlier proposed effective transport of Sahara dust for higher latitudes during cold periods and (ii) the progressive Polar Front expansion southwards, with the amplification of halogen activation reactions in lower latitudes due to greater closeness to snow/sea ice (halide-laden) surfaces. Additionally, the orographic blocking of Serra da Estrela may have played a critical role in increasing precipitation of Atlantic origin at higher altitudes, with the presence of snow prompting physical and chemical processes involving halogen species. In the Late Holocene, the dust proxy records highlighted two periods of enhanced input to Lake Peixão, the first (∼3.5-2.7 ka BP) after the end of the last African Humid Period and the second, from the 19th century onwards, agreeing with the advent of commercial agriculture, and human contribution to land degradation and dust emission in the Sahara/Sahel region. The oceanic imprints throughout the Holocene matched well with North Atlantic rapid climatic changes that, in turn, coincided with ice-rafted debris or Bond events and other records of increased storminess for the European coasts. Positive parallel peaks in halogens were found in recent times, probably connected to fire extinction by halogenated alkanes and roadway de-icing.

Keywords: (Hydro)climatic changes; Geochemical proxies; Lacustrine sediments; Lateglacial/Holocene transition; Northern African dust; Westerly Atlantic airflow.