Ricardo De Pol-Holz

• Ph.D. Oceanography
• Scientific Director at Crono Austral

The Southern Ocean plays a prominent role in the Earth's climate and carbon cycle. Changes in the Southern Ocean circulation may have regulated the release of CO2 to the atmosphere from a deep-ocean reservoir during the last deglaciation. However, the path and exact timing of this deglacial CO2 release are still under debate. Here we present measur...

At the end of the Last Glacial Maximum (19,000 to 11,000 years ago), atmospheric carbon dioxide concentrations rose while the Delta(14)C of atmospheric carbon dioxide declined(1,2). These changes have been attributed to an injection of carbon dioxide with low radiocarbon activity from an oceanic abyssal reservoir that was isolated from the atmosphe...

During the last deglaciation, the opposing patterns of atmospheric CO2 and radiocarbon activities (δ14C) suggest the release of 14C-depleted CO2 from old carbon reservoirs. Although evidences point to the deep Pacific as a major reservoir of this 14C-depleted carbon, its extent and evolution still need to be constrained. Here we use sediment cores...

1] We report the last glacial-interglacial transition of marine denitrification off northern Chile based on sedimentary nitrogen isotopes. Our results show a relatively early, large and abrupt transition from low to high denitrification regimes consistent with recently-reported data from off Peru. The deglaciation is characterized by millennial-sca...

The response of the tropical climate in the Indian Ocean realm to abrupt climate change events in the North Atlantic Ocean is contentious. Repositioning of the intertropical convergence zone is thought to have been responsible for changes in tropical hydroclimate during North Atlantic cold spells1–5, but the dearth of high-resolution records outsid...

Reconstructing rainfall variability and moisture sources is a critical aspect to understand past and future hydroclimate dynamics. Here, we use changes in the deuterium content of land-plant leaf waxes from two marine sediment cores located off Chile to reconstruct changes in rainfall amount and variation in moisture sources over the last ~50 ka. T...

In order to expand our in-house capabilities for tree-ring ¹⁴C measurements in support of atmospheric ¹⁴C reconstruction research, we designed a very versatile and inclusive procedure to produce high-quality α-cellulose homogenized extracts. The procedure can be easily scaled up or down (≤10 to 40 samples) and/or modified on demand (chemical steps...

Atmospheric radiocarbon (¹⁴C) recorded in tree rings has been widely used for atmospheric ¹⁴C calibration purposes and climate studies. But atmospheric ¹⁴C records have been limited along tropical latitudes. Here we report a sequence from 1937 to 2007 of precisely measured ¹⁴C dates in tree rings of the parenchyma-rich Hymenolobium petraeum tree sp...

Our understanding of glacial isostatic rebound across Patagonia is highly limited, despite its importance to constrain past ice volume estimates and better comprehend relative sea-level variations. With this in mind, our research objective is to reconstruct the magnitude and rate of Late Glacial and Holocene glacial isostatic adjustment near the ce...

In this study, we used stable isotopes of oxygen (δ¹⁸O), deuterium (δD), and dissolved inorganic carbon (δ¹³CDIC) in combination with temperature, salinity, oxygen, and nutrient concentrations to characterize the coastal (71°–78°W) and an oceanic (82°–98°W) water masses (SAAW—Subantarctic Surface Water; STW—Subtropical Water; ESSW—Equatorial Subsur...

This paper presents a compilation of atmospheric radiocarbon for the period 1950–2019, derived from atmospheric CO 2 sampling and tree rings from clean-air sites. Following the approach taken by Hua et al. (2013), our revised and extended compilation consists of zonal, hemispheric and global radiocarbon ( ¹⁴ C) data sets, with monthly data sets for...

Radiocarbon data used in ''Radiocarbon bomb-peak signal in tree-rings from the tropical Andes register low latitude atmospheric dynamics in the Southern Hemisphere''

Geochemical and stable isotope measurements in the anoxic marine zone (AMZ) off northern Chile during periods of contrasting oceanographic conditions indicate that microbial processes mediating sulfur and nitrogen cycling exert a significant control on the carbonate chemistry (pH, A T , DIC and p CO 2 ) of this region. Here we show that in 2015, a...

South American tropical climate is strongly related to the tropical low-pressure belt associated with the South American monsoon system. Despite its central societal role as a modulating agent of rainfall in tropical South America, its long-term dynamical variability is still poorly understood. Here we combine a new (and world’s highest) tree-ring...

Mining is a major industry in the Atacama Desert, one of the world's leading regions for copper and other minerals. Intense industrialization of copper mining in the mid-twentieth century has likely led to significant environmental pollution through the deposition of heavy metals in the hyperarid Atacama, but how heavy metal pollution has changed o...

Southern Hemisphere Holocene glacier chronologies are important for unraveling past climate change, mid-to-high latitude teleconnections, and regional to global climate forcing. At present, a significant number of glacier chronologies for Patagonia are based on ¹⁴C dating, which may afford only maximum- or minimum-limiting dates. Here, we combine g...

As with most living organisms, human populations respond to climatic, environmental, and population pressures by transforming their range and subsistence strategies over space and time. An understanding of human ecology can be gained when the archaeological record is placed within the context of dynamic landscape changes and alterations in natural...

Turbulent bottom currents significantly influence the formation of cold-water coral mounds and sedimentation processes on continental slopes. Combining records from coral mounds and adjacent slope sediments therefore provide an unprecedented palaeo-archive to understand past variations of intermediate water-mass dynamics. Here, we present coral age...

Free access link before May 19, 2020: https://authors.elsevier.com/a/1apgY-JmAmJeR Organic-rich sediments of the southernmost Chilean Pacific coast and its fjord system constitute an important component of the global marine carbon budget. Sediment records from Trampa and Caribe bays and Churruca fjord in the western Magellan fjord system have been...

A Late glacial – Holocene palaeoecological record, constrained by a robust chronology, from a peat bog near Punta Burslem (54°54’S, 67°57’W) on Isla Navarino, southernmost Patagonia documents the shifts in intensity and focus of the Southern Westerly Winds (SWWs) at these high latitudes. Such long-term records are required to reconstruct and better...

Coeval changes in atmospheric CO2 and ¹⁴C contents during the last deglaciation are often attributed to ocean circulation changes that released carbon stored in the deep ocean during the Last Glacial Maximum (LGM). Work is being done to generate records that allow for the identification of the exact mechanisms leading to the accumulation and releas...

Palaeoenvironmental data for the Late Glacial and Holocene periods are provided from Caleta Eugenia, in the eastern sector of Canal Beagle, southernmost Patagonia. The record commences at c. 16 200 cal a bp following glacier retreat in response to climatic warming. However, cooler conditions persisted during the Late Glacial period. The onset of mo...

Coastal seas, and in particular estuarine systems, were significantly affected by Quaternary sea level changes. Furthermore, the dynamics of shelf and coastal evolution have had a strong impact on coastal landscapes inhabited by humans. The postglacial evolution of the vast North Sea shelf with its huge drainage systems, e.g. the Elbe Paleovalley a...

Coastal seas, and in particular estuarine systems, were significantly affected by Quaternary sea level changes. Furthermore, the dynamics of shelf and coastal evolution have had a strong impact on coastal landscapes inhabited by humans. The postglacial evolution of the vast North Sea shelf with its huge drainage systems, e.g. the Elbe Paleovalley a...

The Magallanes-Tierra del Fuego region, Southern Patagonia (53-56°S) features a plethora of fjords and remote and isolated islands, and hosts several thousand glaciers. The number of investigated glaciers with respect to the multiple Neoglacial advances is based on a few individual studies and is still fragmentary, which complicates the interpretat...

The present study describes the discovery of a singular sedimentary structure corresponding to an ichnite that was excavated at the paleo-archaeological site Pilauco (Osorno, Chile). The trace fossil is associated with megafauna bones, plant material and unifacial lithic tools. Here we present a detailed analysis of the Pilauco ichnite and associat...

Supporting information on the associated materia (lithics and fossils), taxonomic comparisons and additional experimental data. (DOCX)

Artifact. 14AA-P33-180213 made on aphanitic basalt. Flake with active distal and lateral links. (TIF)

Unconformity between coarse gravel (PB6) and sandy peat (base of PB7), grid AC10, the red arrow indicates the north. The stratigraphic context is the same in the grid AD14. (TIFF)

Artifact 14AD-P173B-220111 made on aphanitic basalt. Primary flake with a distal point. (TIF)

Artifact 15AD-P126-2501 made on aphanitic basalt by tertiary reduction, with distal and lateral retouching. Probably a scraper. (TIF)

Artifact 17AA-P056-050213, made on dacitic glass. Primary flake with active distal and right lateral. Scraper. (TIF)

Artifact 17AA-P81-120115, made on aphanitic basalt by tertiary reduction, with retouching. Scraper. (TIF)

Image analysis of the anterior haft of the fossil ichnite. Keys were placed to facilitate the identification of features and their respective locations. A) X-Ray image showing the absence of clast (C) imbedded into the sediment lump (SL). Clasts are observed elsewhere under the ichnite (depth is not known), as well as 4 screws (s) used to build the...

Flake 15AC-P185-27111 made on dacitic glass, bifacial knapping. (TIF)

Spatial distribution of the human footprint (ichnite), lithic material and gomphotere bones in grids 14AD, 14AC, 15AD and 15AC, in the northwestern side of Pilauco site. Numbers refers to the lithics presented in S1 Table. (TIF)

Schematic view of the experimental setting. Trackmakers walked on the rehidrated fossilbed sediment. (TIF)

Schematic representation of the sediment textural composition. Notice that trackbed samples have a slightly higher mud and gravel content than the rest. Infilling sediment has a lower gravel content. (TIF)

Petrographic and spatial position of artifacts, flakes and debitage in grids 14AC, 14AD, 15AD and 15AC in the northwestern side of Pilauco site. Numbers referred at S2 Fig. (DOCX)

Detailed temperature reconstructions over the past 2,000 years are important for contextualizing modern climate change. The midlatitude SE Pacific is a key region in this regard in terms of understanding the climatic linkages between the tropics and southern high latitudes. Multicentennial timescale temperature variability remains, however, poorly...

A previously undocumented type of wetland is described from the Atacama Desert in northern Chile (3000 m above sea level), sustained exclusively by direct precipitation and perched above the regional water table. Geomorphological mapping, pedostratigraphy, geochemistry, and analysis of contemporary vegetation is used to understand wetland formation...

Reconstructions of past Saharan dust deposition in marine sediments provide foundational records of North African climate over time scales of 10 ³ to 10 ⁶ years. Previous dust records show primarily glacial-interglacial variability in the Pleistocene, in contrast to other monsoon records showing strong precessional variability. Here, we present the...

Megaturbidites have been the focus of many paleoseismic and paleoenvironmental studies because they can provide evidence for catastrophic and/or hazardous events with potentially major environmental implications. During a recent research cruise in Baker Fjord, Chile (47°54'S-74°30'W), a megaturbidite was described between the Northern and Southern...

We present 37 new radiocarbon ( ¹⁴ C) measurements from mollusk shells fragments sampled along the Chilean continental margin and stored in museum collections with known calendar age. These measurements were used to estimate the modern pre-bomb regional marine ¹⁴ C age deviations from the global ocean reservoir (∆R). Together with previously publis...

The Southern Westerly Winds (SWW) are the surface expression of geostrophic winds that encircle the southern mid-latitudes. In conjunction with the Southern Ocean, they establish a coupled system that not only controls climate in the southern third of the world, but is also closely connected to the position of the Intertropical Convergence Zone and...

The Chilean Patagonia constitutes one of the most important and extensive fjord systems worldwide, therefore can be used as a natural laboratory to elucidate the pathway of both organic and inorganic matter in the receiving environment. In this study we use data collected during an intensive oceanographic cruise along the Magellan Strait into the A...

The abundance of the southern Pacific mollusk loco (Concholepas concholepas), among other conspicuous marine supplies, are often cited as critical resources behind the long-term cultural and demographic fluctuations of prehistoric hunter-gatherers in the coastal Atacama Desert. These societies inhabited one of the world's most productive marine env...

In the past two decades, much has been learned about the late Quaternary climate history of the Atacama Desert with some details still unclear about the seasonality, timing and extent of wet and dry phases. Modern climate studies reveal that, far from exhibiting a unique pattern, seasonal precipitation originates from many sources and mechanisms. F...

We describe the stratigraphy, age and correlation of a prominent tephra marker, named Lepué Tephra, extensively distributed in north-western Patagonia. Lepué Tephra is well dated at c. 11 000 cal a BP from numerous lake and soil cover-bed sequences and its recognition is useful for assessing the rate and timing of deglaciation as well as associated...

Current scientific evidence shows that humans colonized South America at least 15,000 years ago, but there are still many unknown aspects of this process, including the major and minor migratory routes involved, and the pattern of successive occupation of a diverse continental mosaic of ecosystems. In this context, the role of the Andean highlands...

Archaeological and palaeoecological studies throughout the Americas have documented widespread landscape and environmental transformation during the pre-Columbian era. The highly dynamic Formative (or Neolithic) period in northern Chile (ca. 3700–1550 yr BP) brought about the local establishment of agriculture, introduction of new crops (maize, qui...

Archaeological sites reviewed for this research. (XLSX)

Paleo rodent-middens and leaf litter samples reviewed in this research (RM: rodent middens; LL: leaf litter). (XLSX)

Chronology and geographical settings for Prosopis records retrieved from palaeoecological and archeological archives. n/a indicates no available information. (XLSX)

Provenience of the samples. (DOCX)

Archaeological sites from which Algarrobo has been assumed to exist pre-3700 yr BP dates. Dates are referential to the sites. (XLSX)

Few studies have examined in detail the sequence of events during the last glacial termination (T1) in the core sector of the Patagonian Ice Sheet (PIS), the largest ice mass in the Southern Hemisphere outside of Antarctica. Here we report results from Lago Edita (47∘8′ S, 72∘25′ W, 570 m a.s.l.), a small closed-basin lake located in a valley overr...

The 2008 eruption of Volcán Chaitén (VCha) in northwestern Patagonia was the first explosive rhyolitic eruption to have occurred within a century and provided an unprecedented scientific opportunity to examine all facets of the eruption ranging from magma rheology/ascent rates to ash-fall effects on biota and infrastructure. Up to very recently it...

We present a new coccolithophore productivity reconstruction spanning the last 300 ka in core GeoB12613-1 retrieved from the western tropical Indian Ocean (IO), an area that mainly derives its warm and oligotrophic surface waters from the eastern IO. Application of a calibrated assemblage-based productivity index indicates a reduction in estimated...

The high Andes of western South America feature extreme ecological conditions that impose important physiological constraints on humans including high-elevation hypoxia and cold stress. This leads to questions regarding how these environments were colonized by the first waves of humans that reached them during the late Pleistocene. Based on previou...

We examine the response of Nothofagus forests to climate change and disturbance regimes over the last 3200 years near Coyhaique (45°S), central–east Chilean Patagonia, using fine-resolution pollen and charcoal records from lake sediment cores. Closed-canopy deciduous Nothofagus forests have dominated the region with little variation until the arriv...

Shell middens, large heaps of refuse materials that are often interspersed with burials, hearths and other cultural features, provide important data regarding the lifestyles of past coastal and maritime dwellers. Despite the abundance of organic materials, radiocarbon ages from shell middens can be a challenge to interpret because marine shells are...

Sediment depositional patterns along the upper continental slope of the northern South China Sea (SCS) have been studied using two sediment cores (GeoB16601-6, 20°09.07′N, 116°14.38′E, 1012 m water depth and GeoB16602-4, 18°57.12′N, 113°42.64′E, 951 m water depth) recovered during RV SONNE Cruise SO-221 “INVERS”. Sediment cores were analyzed for bu...

Few studies have examined in detail the sequence of events during the last glacial termination (T1) in the core sector of the Patagonian Ice Sheet (PIS), the largest ice mass in the southern hemisphere outside Antarctica. Here we report results from Lago Edita (47°8' S, 72°25' W, 570 m.a.s.l.), a small closed-basin lake located in a valley overridd...

The age of organic material discharged by rivers provides information about its sources and carbon cycling processes within watersheds. Although elevated ages in fluvially transported organic matter are usually explained by erosion of soils and sedimentary deposits, it is commonly assumed that mainly young organic material is discharged from flat t...

Nature Communications 7: Article number: 11487 10.1038/ncomms11487 (2016); Published: May092016; Updated: June032016 The affiliation details for R. De Pol-Holz are incorrect in this Article. The correct affiliation details for this author are given below: GAIA-Antartica, Universidad de Magallanes, Punta Arenas 01855, Chile.

This chapter presents the use of radiocarbon (14C) as a powerful dating tool for placing paleoclimate records on a common timescale. The basics of past climate change are presented, as is the use of 14C in foraminifera as a tracer of past ocean mixing. The quest for unveiling the mechanisms behind the “mystery interval” is introduced. The recent I...

Supplementary Figures 1-10, Supplementary Tables 1-4 and Supplementary References.

Two Holocene tephras encountered in outcrops, cores and trenches in bogs, and lake cores in the area around Cochrane, southern Chile, are identified (based on their age, tephra glass color and morphology, mineralogy, and both bulk and glass chemistry) as H1 derived from Hudson volcano, and MEN1 derived from Mentolat volcano. New AMS radiocarbon age...

During the last deglaciation, the opposing patterns of atmospheric CO2 and radiocarbon activities (D14C) suggest the release of 14C-depleted CO2 from old carbon reservoirs. Although evidences point to the deep Pacific as a major reservoir of this 14C-depleted carbon, its extent and evolution still need to be constrained. Here we use sediment cores...

The age of organic material discharged by rivers provides information about its sources and carbon cycling processes within watersheds. While elevated ages in fluvially-transported organic matter are usually explained by erosion of soils and sediments, it is commonly assumed that mainly young organic material is discharged from flat tropical waters...

Mineral dust aerosols play a major role in present and past climates. To date, we rely on climate models for estimates of dust fluxes to calculate the impact of airborne micronutrients on biogeochemical cycles. Here we provide a new global dust flux data set for Holocene and Last Glacial Maximum (LGM) conditions based on observational data. A compa...

Archaeological sites composed only of surficial lithics are widespread in arid environments. Numerical dating of such sites is challenging, however, and even establishing a relative chronology can be daunting. One potentially helpful method for assigning relative chronologies is to use lithic weathering, on the assumption that the most weathered ar...

Cold-water coral ecosystems present common carbonate factories along the Atlantic continental margins, where they can form large reef structures. There is increasing knowledge on their ecology, molecular genetics, environmental controls and threats available. However, information on their carbonate production and accumulation is still very limited,...

This study presents newly obtained coral ages of the cold-water corals Lophelia pertusa and Madrepora oculata collected in the Alboran Sea and the Strait of Sicily (Urania Bank). These data were combined with all available Mediterranean Lophelia and Madrepora ages compiled from literature to conduct a basin-wide assessment of the spatial and tempor...

Mineral dust aerosols play a major role in present and past climates. To date, we rely on climate models for estimates of dust fluxes to calculate the impact of airborne micronutrients on biogeochemical cycles. Here we provide a new global dust flux data set for Holocene and Last Glacial Maximum (LGM) conditions based on observational data. A compa...

Volcán Chaitén (southern Chile, ∼43°S) initiated an historically unprecedented eruption in A.D. 2008, surprising the local inhabitants, Chilean and Argentine authorities, and the geologic community. Available data at the time indicated an absence of explosive eruptions from this rhyolitic volcano since a large-magnitude eruptive event dated at ca....

Here we provide three new Holocene (11–0 cal ka BP) alkenone-derived sea surface temperature (SST) records from the southernmost Chilean fjord region (50–53°S). SST estimates may be biased towards summer temperature in this region, as revealed by a large set of surface sediments. The Holocene records show consistently warmer than present-day SSTs e...

Throughout the transition from the last Glacial to the current Interglacial, rising atmospheric CO 2 levels were accompanied by declining atmospheric Δ 14 C values. A likely mechanism, influencing both components is the deglacial release of CO 2 , stored for millennia in the deep Ocean, to the atmosphere. Due to its long residence time within the o...

Aim In deserts, past climate change (and particularly past rainfall variability) plays a large role in explaining current plant species distributions. We ask which species were most and which were least affected by changes in rainfall during the late Quaternary in northernmost Chile.LocationQuebrada La Higuera (QLH; 18° S), a shallow canyon that cu...