Roberto Bao

Roberto Bao
University of A Coruña | UDC · Centre for Advanced Scientific Research (CICA)

About

87
Publications
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Publications

Publications (87)
Article
Human land use and climate change threaten ecosystems and natural resources, particularly on remote islands such as the Azores Archipelago in the North Atlantic. Since the official Portuguese settlement of the archipelago in the 15th and 16th centuries humans have extensively modified the Azorean landscape, with invasive plants dominating the prese...
Article
Full-text available
A multiproxy approach was applied to a sediment core retrieved from the deep crater lake Funda, located in the middle of the North Atlantic Ocean on Flores Island, Azores archipelago (Portugal). The purpose of this study was to determine how this ecosystem responded to natural and anthropogenic forces over the last millennium. We distinguished thre...
Article
Significance We use a diverse set of lake and landscape proxy indicators to characterize initial human occupation and its impacts on the Azores Archipelago. The occupation of these islands began between 700 and 850 CE, 700 years earlier than suggested by documentary sources. These early occupations caused widespread ecological and landscape disturb...
Conference Paper
The discovery and settlement of the Azores archipelago is generally attributed to the Portuguese during the XVth century, but recent insights have raised questions about whether the islands were discovered earlier. Paleolimnological data from São Miguel suggest that the island was settled 150 years before the official Portuguese arrival date. To pi...
Conference Paper
The camoebians are ubiquitous microorganisms in aquatic ecosystems with a characteristic theca that is very resistant to physicochemical degradation; thus, they are incorporated into paleoecological records, providing valuable information. The Doniños freshwater lake (43° 29.50’’ N, 8° 18.70’’ W) (4 m a.s.l.) is a coastal back-barrier perched lake...
Article
The Atacama Desert in northern Chile is one of the driest deserts on Earth. Hyperaridity persists at least since the Miocene and was punctuated by pluvial phases. However, very little is known about the timing, regional spread and intensities of precipitation changes. Here, we present a new precipitation record from a sedimentary sequence recovered...
Chapter
Between ca.8400-7000 cal BP Late Mesolithic communities occupied the Sado valley embankments, upstream Alcácer do Sal, Portugal. The consumption of marine resources is attested by the shell waste abandoned in several sites (known as shell middens) and later confirmed by isotopic analyses on bone collagen from individuals buried in these locations....
Article
Full-text available
Modern precipitation anomalies in the Altiplano, South America, are closely linked to the strength of the South American summer monsoon (SASM), which is influenced by large-scale climate features sourced in the tropics such as the Intertropical Convergence Zone (ITCZ) and El Niño–Southern Oscillation (ENSO). However, the timing, direction, and spat...
Article
The impacts of natural- and human-induced processes on lake ecosystems in remote oceanic islands remain to be fully elucidated. These lakes are excellent candidates to analyze the importance of anthropogenic vs. natural forces driving lacustrine long-term ecological evolution from previous pristine pre-colonized conditions. Disentangling the effect...
Article
Full-text available
Paleoclimate records from the Atacama Desert are rare and mostly discontinuous, mainly recording runoff from the Precordillera to the east, rather than local precipitation. Until now, paleoclimate records have not been reported from the hyperarid core of the Atacama Desert (<2 mm/yr). Here we report the results from multi-disciplinary investigation...
Article
Full-text available
Modern precipitation anomalies in the Altiplano region of South America are closely linked to the strength of the South American Summer Monsoon (SASM) which is influenced by large-scales climate components sourced in the tropics such as latitudinal shifts of the Intertropical Convergence Zone (ITCZ) and El Niño-Southern Oscillation (ENSO). However,...
Article
Full-text available
Estuaries are sensitive to changes in global to regional sea level, to climate-driven variation in rainfall and to fluvial discharge. In this study, we use source and environmentally sensitive proxies together with radiocarbon dating to examine a 7-m-thick sedimentary record from the Sado estuary accumulated throughout the last 3.6 kyr. The lithofa...
Article
Full-text available
We examine the Holocene environmental changes in a wet dune slack of the Portuguese coast, Poço do Barbarroxa de Baixo. Lithology, organic matter, biological proxies and high-resolution chronology provide estimations of sediment accumulation rates and changes in environmental conditions in relation to sea-level change and climate variability during...
Conference Paper
Full-text available
Environmental reconstructions based on lacustrine sedimentary records are important tools to assess long-term changes in lake conditions and correlate these changes with environmental drivers, such as climatic fluctuations, volcanic activity and anthropogenic disturbances. Here we present the main impacts of these drivers on Lake Caveiro (Pico isla...
Conference Paper
Full-text available
During the second half of XX century, lake eutrophication has become a matter of concern all over the world. The increase in lake productivity has been mainly related to inputs of nutrients, particularly phosphorus (P) and nitrogen (N), originated by local human activities. However, evidence of lake eutrophication on remote areas with no significan...
Conference Paper
Full-text available
Cladocera occupy an intermediate trophic level in aquatic food webs, responding to bottom-up and top-down control of the food web. Furthermore, Cladocera shells are resistant to degradation and their remains often accumulate in lake sediments. Therefore, Cladocera fossil remains from lake sediments can be used to assess past environmental condition...
Poster
Full-text available
Cladocera occupy an intermediate trophic level in aquatic food webs, responding to bottom-up and top-down control of the food web. Furthermore, Cladocera shells are resistant to degradation and their remains often accumulate in lake sediments. Therefore, Cladocera fossil remains from lake sediments can be used to assess past environmental condition...
Article
Coastal back-barrier perched lakes are freshwater bodies that are elevated over sea-level and are not directly subjected to the inflow of seawater. This study provides a detailed reconstruction of the Doniños back-barrier perched lake that developed at the end of a small river valley in the rocky coast of the north-west Iberian Peninsula during the...
Poster
Full-text available
The Azores archipelago has provided significant clues to the ecological, biogeographic and evolutionary knowledge of oceanic islands. Palaeoecological records are comparatively scarce, but they can provide relevant information on these subjects. We report the palynological reconstruction of the vegetation and environmental dynamics of the São Migue...
Conference Paper
Full-text available
Although research focus mostly on high marshes the understanding of sedimentation rates and patterns along the whole intertidal environment is key to improve projection models in different scenarios of sea level rise (SLR). This study presents the results from the analysis of a sediment core collected in a low marsh on the North bank of Caldeira de...
Article
The Azores archipelago has provided significant clues to the ecological, biogeographic and evolutionary knowledge of oceanic islands. Palaeoecological records are comparatively scarce, but they can provide relevant information on these subjects. We report the palynological reconstruction of the vegetation and landscape dynamics of the São Miguel Is...
Article
Little is known about the effect of top predator introduction in historically fishless communities, especially on remote islands. This issue is important because it might strongly affect climate reconstructions derived from biota assemblages such as chironomids. Head capsule larval remains of chironomids have been studied in a 660 years lacustrine...
Article
The coupling of lake dynamics with catchment biogeochemistry is considered the key element controlling primary production in mountain lakes at time scales of a few decades to millennia, yet little is known on the impacts of the morphometry of lakes throughout their ontogeny. As Lake Chungará (Central Andean Altiplano, northern Chile) experienced lo...
Article
Full-text available
The rocky and indented coast of NW Iberia is characterized by the presence of highly valuable and vulnerable, small and shallow barrier–lagoon systems structurally controlled. The case study was selected to analyse barrier–lagoon evolution based on detailed sedimentary architecture, chronology, geochemical and biological proxies. The main objective...
Conference Paper
Full-text available
The North Atlantic Oscillation (NAO) is the main atmospheric circulation mode controlling climate variability in the Northern Hemisphere. Instrumental records of the NAO are relatively short, and therefore proxy approaches are essential to understand its evolution over longer time periods. Diatom oxygen isotope ratios are increasingly being used fo...
Article
Full-text available
Subfossil biotic assemblages in lakes’ surface sediments have been used to infer ecological conditions across environmental gradients. Local variables are usually the major drivers of assemblage composition, but in remote oceanic islands biogeo- graphic filters may play a significant role. To assess the contribution of local and regional filters in...
Article
Full-text available
The reigning paradigm holds that Easter Island suffered a socio-ecological collapse (ecocidal or not) sometime in the last millennium, prior to European contact (AD 1720). We discuss some novel paleoecological and archaeological evidence that challenges this assumption. We use this case study to propose a closer collaboration between archaeology an...
Article
a b s t r a c t Earlier palynological studies of lake sediments from Easter Island suggest that the island underwent a recent and abrupt replacement of palm-dominated forests by grasslands, interpreted as a deforestation by indigenous people. However, the available evidence is inconclusive due to the existence of extended hiatuses and ambiguous chr...
Article
a b s t r a c t Diatom-based carbon and oxygen isotope analyses (d 13 C diatom and d 18 O diatom) were performed on diatom-rich laminated sediments of Lake Chungará (Andean Altiplano, northern Chile) deposited during the Lateglacial and Early Holocene (12,400e8300 cal years BP) to reconstruct climate change and environ-mental response across this m...
Conference Paper
Full-text available
Azores archipelago lies in the southern area of the dipole that defines the North Atlantic Oscillation (NAO). During the negative phase of the NAO, the Azores high pressure is displaced southwards allowing the storms to cross the islands increasing the precipitation in this area and also in southern Europe. This fact makes them excellent key places...
Article
Full-text available
We analyzed the patterns of nucleotide sequence variation at three mitochondrial DNA loci, the noncoding mitochondrial control region and two genes (cytochrome b and cytochrome oxidase I) of Gavia immer in the largest collection of wintering individuals from Southern Europe to date. The sample consisted of 33 birds, oiled during the 2002/2003 Prest...
Data
Electropherograms from the three nucleotide variants (C, T and Y= C+T) found in the mitochondrial control region.
Poster
The North Atlantic Oscillation (NAO) climate mode controls, to a large extent, the winter climate of southwestern Europe. The dominant role played by the NAO on climatic and environmental variables has a direct impact on terrestrial ecosystems and in the distribution development and phenology of many species, which could be related to the variabili...
Article
Carbonate and organic matter sedimentation and isotopic signatures in Lake Chungará, Chilean altiplano, during the last 12.3 kyr, Palaeogeography (2011), doi: 10.1016/j.palaeo.2011.05.036 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manu...
Article
Biogeochemical cycles and sedimentary records in lakes are related to climate controls on hydrology and catchment processes. Changes in the isotopic composition of the diatom frustules (δ18Odiatom and δ13Cdiatom) in lacustrine sediments can be used to reconstruct palaeoclimatic and palaeoenvironmental changes. The Lago Chungará (Andean Altiplano, 1...
Article
Full-text available
The late glacial-Holocene transition from the Lago Chungará sedimentary record in northern Chilean Altiplano (18°S) is made up of laminated sediments composed of light-white and dark-green pluriannual couplets of diatomaceous ooze. Light-white sediment laminae accumulated during short-term extraordinary diatom blooms whereas dark-green sediment lam...
Article
Full-text available
Great Northern Divers collected during the impact assessment of the Prestige oil spill were studied and compared with similar casualties collected during three other major oil spills. Biometrics (notably wing length and bill length) were also compared with data collected in Canadian and European breeding areas in an attempt to find the possible (br...
Article
Easter Island (SE Pacific, 27°S) provides a unique opportunity to reconstruct past climate changes in the South Pacific region based on terrestrial archives. Although the general climate evolution of the south Pacific since the Last Glacial Maximum (LGM) is coherent with terrestrial records in southern South America and Polynesia, the details of th...
Article
Full-text available
Sedimentary architecture and paleoclimate for the last 34 000 cal years BP and human activity during the last 850 years have been reconstructed from the Raraku Lake sediments in Easter Island (SE Pacific, 27°S) using a high-resolution multiproxy study of 8 cores, 36 AMS radiocarbon dates and correlation with previous core studies. The Last Glacial...
Conference Paper
The Lateglacial-early Holocene transition from the Lago Chungará record (northern Chilean Altiplano) is made up of laminated sediments composed by light and dark pluriannual couplets of diatomaceous ooze. Light sediment laminae accumulated during short-term diatom blooms whereas dark sediment laminae represent the baseline limnological conditions d...
Conference Paper
High-resolution laminated lacustrine sediments are excellent archives of the past hydrological changes and they provide valuable insights about the climatic processes that trigger these changes. The paleoclimatic records located in the Southern Hemisphere are fundamental for understanding the evolution of the El Niño - Southern Oscillation (ENSO) s...
Article
Full-text available
A high resolution multiproxy study (magnetic susceptibility, X-ray diffraction, XRF scanner, gray-colour values, Total Organic Carbon, Total Inorganic Carbon, Total Carbon and Total Biogenic Silica) of the sedimentary infill of Lago Chungará (northern Chilean Altiplano) was undertaken to unravel the environmental forcings controlling its evolution...
Article
A multiproxy study of sediment cores from Zonar Lake (37{degrees}29'00''N, 4{degrees}41'22''W, 300 m a.s.l.) supported by 11 14C AMS dates provides the first high-resolution centennial-scale reconstruction of past humidity changes in southern Spain during the last 4000 years. Arid periods occurred prior to 2.9 cal. kyr BP and during 1.3--0.6 cal. k...
Article
Oxygen isotopes of diatom silica and petrographical characterisation of diatomaceous laminated sediments of Lago Chungará (northern Chilean Altiplano) have allowed us to establish its palaeohydrological evolution during the Lateglacial–early Holocene (ca. 12 000–9400 cal. yr BP). These laminated sediments are composed of light and dark pluriannual...
Article
Full-text available
2008. The palaeohydrological evolution of Lago Chungará (Andean Altiplano, northern Chile) during the Lateglacial and early Holocene using oxygen isotopes in diatom silica. ABSTRACT: Oxygen isotopes of diatom silica and petrographical characterisation of diatomaceous laminated sediments of Lago Chungará (northern Chilean Altiplano) have allowed us...
Article
Lake Chungará (18°15'S, 69°09'W, 4520 m above sea-level) is the largest (22.5 km2) and deepest (40 m) lacustrine ecosystem in the Chilean Altiplano and its location in an active volcanic setting, provides an opportunity to evaluate environmental (volcanic vs. climatic) controls on lacustrine sedimentation. The Late Quaternary depositional history o...
Article
This paper examines the interdependence among the different forcing factors in the evolution of the Traba coastal wetland (Galicia, NW Spain) based on lithofacies and diatom analyses of three cores reaching the basement. According to radiocarbon data, the wetland originated 5700 cal yr BP, a time when similar systems on the Atlantic coast of the Ib...
Article
High-resolution geochemical analyses obtained using an X-ray fluorescence (XRF) Core Scanner, as well as mineralogical data from the Lago Chungará sedimentary sequence in the northern Andean Chilean Altiplano (18°S), provided a detailed reconstruction of the lacustrine sedimentary evolution during the last 14,000cal.yrBP. The high-resolution analys...
Article
High-resolution geochemical analyses obtained using an X-ray fluorescence (XRF) Core Scanner, as well as mineralogical data from the Lago Chungaraedimentary sequence in the northern Andean Chilean Altiplano (18S), provided a detailed reconstruction of the lacustrine sedimentary evolution during the last 14,000 cal. yr BP. The high-resolution analys...
Technical Report
Technical online documentation of the approach in case of a wildlife response during major oil spills, Available online www.oiledwildlife.eu