BIBLIOS

Document type
Journal articles

Document subtype
Full paper

Title
Foraminiferal evidence of major environmental changes driven by the sun-climate coupling in the western Portuguese coast (14th century to present)

Participants in the publication
J. Moreno (Author)
IDL
F. Fatela (Author)
Dep. Geologia
IDL
E. Leorri (Author)
F. Moreno (Author)
M.A. Gonçalves (Author)
Dep. Geologia
IDL
J.J. Gómez-Navarro (Author)
M.F. Araújo (Author)
M.C. Freitas (Author)
Dep. Geologia
CEGUL
IDL
R.M. Trigo (Author)
Dep. Engenharia Geográfica, Geofísica e Energia
IDL
W.H. Blake (Author)

Summary
New paleoclimatic data from the Casa Branca salt marsh, in the southwest coast of Portugal, are compared with\\nrecords previously published on the northwest coast (Caminha salt marsh) to offer a more comprehensive\\noverview of the environmental evolution of the west Iberian margin over the last six centuries. These reconstructions\\nare based on the foraminiferal records of two dated sediment cores retrieved from the high marsh\\nsettings and supported by geochemical-sedimentological data.\\nBoth marshes were originally formed in the AD 1300s, between the Medieval Climatic Anomaly (MCA) and\\nthe Little Ice Age (LIA), highlighting a major episode of increased sediment supply in lower estuaries linked to\\nclimate-driven changes in continental runoff. Afterwards, the two marshes evolved under different climatic\\nregimes as reflected by their foraminiferal assemblages. The environmental conditions are characterized by\\nhigher salinity in Casa Branca (southwest), with Jadammina macrescens and Trochammina inflata as dominant\\nspecies, than in Caminha (northwest), where Haplophragmoides spp. dominates. We suggest that a long-term\\ntrend of a net gain in evapotranspiration at Casa Branca inducing a higher marsh salinity baseline may explain\\nthis microfaunal contrast. Trochammina inflata seems to be a good indicator of drier periods in the studied area,\\nconnected to key events of aeolian large-dust input to the southwest coast of Portugal. The influence of the most\\nimportant climate drivers was assessed, namely external (solar) and internal (North Atlantic Oscillation – NAO)\\nforcings.\\nSpectral and wavelet transform coherence analyses were used to detect solar footprints on foraminiferal and\\nclimate-related time series. A main significant quasi-periodicity was identified within the range of the secular\\nGleissberg cycle of solar activity modulating the annual NAO and regional spring-summer (simulated) temperatures\\nafter AD 1700. This stronger solar-climate coupling may be related to the known upward secular trend\\nin the total solar irradiance after the Maunder Minimum.


Institution
FACULDADE DE CIÊNCIAS DA UNIVERSIDADE DE LISBOA

Where published
Estuarine, Coastal and Shelf Science

Publication Identifiers
ISSN - 0272-7714

Publisher
Elsevier BV



Document Identifiers
DOI - https://doi.org/10.1016/j.ecss.2018.11.030
URL - http://dx.doi.org/10.1016/j.ecss.2018.11.030

Rankings
SCIMAGO Q1 (2018) - 1.052 - Oceanography
SCOPUS Q1 (2017) - 1.059 - Oceanography
Web Of Science Q1 (2018) - 2.611 - OCEANOGRAPHY - SCIE