Planktonic foraminifera and their proxies for the reconstruction of surface-ocean climate parameters

Els foraminífers planctònics són organismes que permeten avaluar el paper que té la superfície dels oceans en el procés de canvi climàtic, a causa del seu hàbitat superficial, l'estructura calcària de la seva closca i la seva preservació al registre sedimentari oceànic. De fet, l'existència abundant de sediments carbonatats rics en les closques calcítiques dels foraminífers fan d'aquests una eina útil per a una gran varietat d'estudis paleoceanogràfics a escales de temps que varien entre dècades i mil·lennis. En aquest article es revisen els mètodes proxy més importants emprats per a reconstruir variables climàtiques relacionades amb la superfície oceànica mitjançant foraminífers, que comprenen tant els mètodes geoquímics (isotòpics i elementals) com els basats en associacions. La temperatura gaudeix d'un èmfasi especial, perquè és el paràmetre climàtic més important de la superfície de l'oceà, tot i que també es tracten propietats relacionades de caràcter físic, químic i biològic —com són la salinitat, la productivitat, l'ús de nutrients, la meteorització, la circulació—, i propietats del sistema carbonat —com l'alcalinitat, el pH i el [CO3 2-] 2-. S'avalua cada proxy de manera sistemàtica i s'especifica, per a cada mètode, la seva base científica, alguns exemples breus i una projecció futura de la seva evolució.Planktonic foraminifera are useful organisms to assess the surface ocean’s role in climate change, due to their upper water column habitat, calcium carbonate mineral structure, and preservation in the deep-sea sedimentary record. Carbonate sediments rich in the calcitic shells of foraminifera are abundant in both space and time, which allows their use in an array of paleoceanographic studies over time scales ranging from decadal to glacial-interglacial, as well as beyond and between. Here we review the most important “proxy” methods to reconstruct surface-ocean climatic variables using planktonic foraminifera. These methods include assemblage-based and geochemical-based (both isotopic and elemental) approaches. The natural emphasis is on temperature, the most important climatic parameter of the surface ocean, although related physical, chemical, and biological properties are addressed as well, such as salinity, productivity, nutrient utilization, weathering, circulation, and oceanic C-system properties including alkalinity, pH, and [CO3 2-]. In our systematic evaluation of each foraminiferal proxy, we provide the basis for each method, brief examples, and a glimpse into the future, when current research needs will hopefully be met

Planktonic foraminifera and their proxies for the reconstruction of surface ocean climate parameters

Planktonic foraminifera are useful organisms to assess the surface ocean's role in climate change, due to their upper water column habitat, calcium carbonate mineral structure, and preservation in the deep-sea sedimentary record. Carbonate sediments rich in the calcitic shells of foraminifera are abundant in both space and time, which allows their use in an array of paleoceanographic studies over time scales ranging from decadal to glacial-interglacial, as well as beyond and between. Here we review the most important proxy methods to reconstruct surface-ocean climatic variables using planktonic foraminifera. These methods include assemblage-based and geochemical-based (both isotopic and elemental) approaches. The natural emphasis is on temperature, the most important climatic parameter of the surface ocean, although related physical, chemical, and biological properties are addressed as well, such as salinity, productivity, nutrient utilization, weathering, circulation, and oceanic C-system properties including alkalinity, pH, and [CO3 2-]. In our systematic evaluation of each foraminiferal proxy, we provide the basis for each method, brief examples, and a glimpse into the future, when current research needs will hopefully be met.Els foraminífers planctònics són organismes que permeten avaluar el paper que té la superfície dels oceans en el procés de canvi climàtic, a causa del seu hàbitat superficial, l'estructura calcària de la seva closca i la seva preservació al registre sedimentari oceànic. De fet, l'existència abundant de sediments carbonatats rics en les closques calcítiques dels foraminífers fan d'aquests una eina útil per a una gran varietat d'estudis paleoceanogràfics a escales de temps que varien entre dècades i mil·lennis. En aquest article es revisen els mètodes proxy més importants emprats per a reconstruir variables climàtiques relacionades amb la superfície oceànica mitjançant foraminífers, que comprenen tant els mètodes geoquímics (isotòpics i elementals) com els basats en associacions. La temperatura gaudeix d'un èmfasi especial, perquè és el paràmetre climàtic més important de la superfície de l'oceà, tot i que també es tracten propietats relacionades de caràcter físic, químic i biològic com són la salinitat, la productivitat, l'ús de nutrients, la meteorització, la circulació, i propietats del sistema carbonat com l'alcalinitat, el pH i el [CO3 2-]. S'avalua cada proxy de manera sistemàtica i s'especifica, per a cada mètode, la seva base científica, alguns exemples breus i una projecció futura de la seva evolució

The Free and Cued Selective Reminding Test in Parkinson's Disease Mild Cognitive Impairment : Discriminative Accuracy and Neural Correlates

Altres ajuts: This work was partially supported by grants from La Marató TV3 (20142910, 2014/U/477); FIS (PI14/02058, PI15/00962); CIBERNED.Introduction: Memory alterations are common in Parkinson's disease (PD) patients but the mechanisms involved in these deficits remain poorly understood. The study aims to explore the profile of episodic memory deficits in non-demented early PD patients. Methods: We obtained neurological, cognitive and behavioral data from 114 PD patients and 41 healthy controls (HC). PD participants were grouped as normal cognition (PD-NC) and mild cognitive impairment (PD-MCI) according to the Level II criteria of the Movement Disorders Society Task Force (MDS-TF). We evaluate the performance amongst groups on an episodic memory task using the Free and Cued Selective Reminding Test (FCSRT). Additionally, gray matter volume (GMV) voxel based morphometry, and mean diffusivity (MD) analyses were conducted in a subset of patients to explore the structural brain correlates of FCSRT performance. Results: Performance on all subscores of the FCSRT was significantly worse in PD-MCI than in PD-NC and HC. Delayed total recall (DTR) subscore was the best at differentiating PD-NC from PD-MCI. Using crosstabulation, DTR allowed identification of PD-MCI patients with an accuracy of 80%. Delayed free and cued recall was associated with decreased GMV and increased MD in multiple fronto-temporal and parietal areas. Conclusion: Encoding and retrieval deficits are a main characteristic of PD-MCI and are associated with structural damage in temporal, parietal and prefrontal areas

The Behavioral and Psychological Symptoms of Dementia in Down Syndrome (BPSD-DS) Scale:Comprehensive Assessment of Psychopathology in Down Syndrome

People with Down syndrome (DS) are prone to develop Alzheimer's disease (AD). Behavioral and psychological symptoms of dementia (BPSD) are core features, but have not been comprehensively evaluated in DS. In a European multidisciplinary study, the novel Behavioral and Psychological Symptoms of Dementia in Down Syndrome (BPSD-DS) scale was developed to identify frequency and severity of behavioral changes taking account of life-long characteristic behavior. 83 behavioral items in 12 clinically defined sections were evaluated. The central aim was to identify items that change in relation to the dementia status, and thus may differentiate between diagnostic groups. Structured interviews were conducted with informants of persons with DS without dementia (DS, n = 149), with questionable dementia (DS+Q, n = 65), and with diagnosed dementia (DS+AD, n = 67). First exploratory data suggest promising interrater, test-retest, and internal consistency reliability measures. Concerning item relevance, group comparisons revealed pronounced increases in frequency and severity in items of anxiety, sleep disturbances, agitation & stereotypical behavior, aggression, apathy, depressive symptoms, and eating/drinking behavior. The proportion of individuals presenting an increase was highest in DS+AD, intermediate in DS+Q, and lowest in DS. Interestingly, among DS+Q individuals, a substantial proportion already presented increased anxiety, sleep disturbances, apathy, and depressive symptoms, suggesting that these changes occur early in the course of AD. Future efforts should optimize the scale based on current results and clinical experiences, and further study applicability, reliability, and validity. Future application of the scale in daily care may aid caregivers to understand changes, and contribute to timely interventions and adaptation of caregiving

Boron isotopes in foraminifera : systematics, biomineralisation, and CO2 reconstruction

Funding: Fellowship from University of St Andrews, $100 (pending) from Richard Zeebe, UK NERC grants NE/N003861/1 and NE/N011716/1.The boron isotope composition of foraminifera provides a powerful tracer for CO2 change over geological time. This proxy is based on the equilibrium of boron and its isotopes in seawater, which is a function of pH. However while the chemical principles underlying this proxy are well understood, its reliability has previously been questioned, due to the difficulty of boron isotope (δ11B) analysis on foraminferal samples and questions regarding calibrations between δ11B and pH. This chapter reviews the current state of the δ11B-pH proxy in foraminfera, including the pioneering studies that established this proxy’s potential, and the recent work that has improved understanding of boron isotope systematics in foraminifera and applied this tracer to the geological record. The theoretical background of the δ11B-pH proxy is introduced, including an accurate formulation of the boron isotope mass balance equations. Sample preparation and analysis procedures are then reviewed, with discussion of sample cleaning, the potential influence of diagenesis, and the strengths and weaknesses of boron purification by column chromatography versus microsublimation, and analysis by NTIMS versus MC-ICPMS. The systematics of boron isotopes in foraminifera are discussed in detail, including results from benthic and planktic taxa, and models of boron incorporation, fractionation, and biomineralisation. Benthic taxa from the deep ocean have δ11B within error of borate ion at seawater pH. This is most easily explained by simple incorporation of borate ion at the pH of seawater. Planktic foraminifera have δ11B close to borate ion, but with minor offsets. These may be driven by physiological influences on the foraminiferal microenvironment; a novel explanation is also suggested for the reduced δ11B-pH sensitivities observed in culture, based on variable calcification rates. Biomineralisation influences on boron isotopes are then explored, addressing the apparently contradictory observations that foraminifera manipulate pH during chamber formation yet their δ11B appears to record the pH of ambient seawater. Potential solutions include the influences of magnesium-removal and carbon concentration, and the possibility that pH elevation is most pronounced during initial chamber formation under favourable environmental conditions. The steps required to reconstruct pH and pCO2 from δ11B are then reviewed, including the influence of seawater chemistry on boron equilibrium, the evolution of seawater δ11B, and the influence of second carbonate system parameters on δ11B-based reconstructions of pCO2. Applications of foraminiferal δ11B to the geological record are highlighted, including studies that trace CO2 storage and release during recent ice ages, and reconstructions of pCO2 over the Cenozoic. Relevant computer codes and data associated with this article are made available online.Publisher PDFPeer reviewe

Non-motor symptom burden in patients with Parkinson's disease with impulse control disorders and compulsive behaviours : results from the COPPADIS cohort

The study was aimed at analysing the frequency of impulse control disorders (ICDs) and compulsive behaviours (CBs) in patients with Parkinson's disease (PD) and in control subjects (CS) as well as the relationship between ICDs/CBs and motor, nonmotor features and dopaminergic treatment in PD patients. Data came from COPPADIS-2015, an observational, descriptive, nationwide (Spain) study. We used the validated Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease-Rating Scale (QUIP-RS) for ICD/CB screening. The association between demographic data and ICDs/CBs was analyzed in both groups. In PD, this relationship was evaluated using clinical features and treatment-related data. As result, 613 PD patients (mean age 62.47 ± 9.09 years, 59.87% men) and 179 CS (mean age 60.84 ± 8.33 years, 47.48% men) were included. ICDs and CBs were more frequent in PD (ICDs 12.7% vs. 1.6%, p < 0.001; CBs 7.18% vs. 1.67%, p = 0.01). PD patients had more frequent previous ICDs history, premorbid impulsive personality and antidepressant treatment (p < 0.05) compared with CS. In PD, patients with ICDs/CBs presented younger age at disease onset, more frequent history of previous ICDs and premorbid personality (p < 0.05), as well as higher comorbidity with nonmotor symptoms, including depression and poor quality of life. Treatment with dopamine agonists increased the risk of ICDs/CBs, being dose dependent (p < 0.05). As conclusions, ICDs and CBs were more frequent in patients with PD than in CS. More nonmotor symptoms were present in patients with PD who had ICDs/CBs compared with those without. Dopamine agonists have a prominent effect on ICDs/CBs, which could be influenced by dose

CO2 storage and release in the deep Southern Ocean on millennial to centennial timescales

This work was supported by NERC Standard Grant NE/N003861/1 to J.W.B.R. and L.F.R., a NOAA Climate and Global Change VSP Fellowship to J.W.B.R, NERC Standard Grant NE/M004619/1 to AB and JWBR, a NERC Strategic Environmental Science Capital Grant to A.B. and J.W.B.R., Marie Curie Career Integration Grant CIG14-631752 to AB, an ERC consolidator grant to L.F.R., NSF grant OCE-1503129 to J.F.A., and NERC studentships to B.T. and E.L.The cause of changes in atmospheric carbon dioxide (CO2) during the recent ice ages is yet to be fully explained. Most mechanisms for glacial–interglacial CO2 change have centred on carbon exchange with the deep ocean, owing to its large size and relatively rapid exchange with the atmosphere1. The Southern Ocean is thought to have a key role in this exchange, as much of the deep ocean is ventilated to the atmosphere in this region2. However, it is difficult to reconstruct changes in deep Southern Ocean carbon storage, so few direct tests of this hypothesis have been carried out. Here we present deep-sea coral boron isotope data that track the pH—and thus the CO2 chemistry—of the deep Southern Ocean over the past forty thousand years. At sites closest to the Antarctic continental margin, and most influenced by the deep southern waters that form the ocean’s lower overturning cell, we find a close relationship between ocean pH and atmospheric CO2: during intervals of low CO2, ocean pH is low, reflecting enhanced ocean carbon storage; and during intervals of rising CO2, ocean pH rises, reflecting loss of carbon from the ocean to the atmosphere. Correspondingly, at shallower sites we find rapid (millennial- to centennial-scale) decreases in pH during abrupt increases in CO2, reflecting the rapid transfer of carbon from the deep ocean to the upper ocean and atmosphere. Our findings confirm the importance of the deep Southern Ocean in ice-age CO2 change, and show that deep-ocean CO2 release can occur as a dynamic feedback to rapid climate change on centennial timescales.PostprintPeer reviewe

Beyond equilibrium climate sensitivity

ISSN:1752-0908ISSN:1752-089

Planktonic foraminifera and their proxies for the reconstruction of surface ocean climate parameters

Planktonic foraminifera are useful organisms to assess the surface ocean's role in climate change, due to their upper water column habitat, calcium carbonate mineral structure, and preservation in the deep-sea sedimentary record. Carbonate sediments rich in the calcitic shells of foraminifera are abundant in both space and time, which allows their use in an array of paleoceanographic studies over time scales ranging from decadal to glacial-interglacial, as well as beyond and between. Here we review the most important proxy methods to reconstruct surface-ocean climatic variables using planktonic foraminifera. These methods include assemblage-based and geochemical-based (both isotopic and elemental) approaches. The natural emphasis is on temperature, the most important climatic parameter of the surface ocean, although related physical, chemical, and biological properties are addressed as well, such as salinity, productivity, nutrient utilization, weathering, circulation, and oceanic C-system properties including alkalinity, pH, and [CO3 2-]. In our systematic evaluation of each foraminiferal proxy, we provide the basis for each method, brief examples, and a glimpse into the future, when current research needs will hopefully be met.Els foraminífers planctònics són organismes que permeten avaluar el paper que té la superfície dels oceans en el procés de canvi climàtic, a causa del seu hàbitat superficial, l'estructura calcària de la seva closca i la seva preservació al registre sedimentari oceànic. De fet, l'existència abundant de sediments carbonatats rics en les closques calcítiques dels foraminífers fan d'aquests una eina útil per a una gran varietat d'estudis paleoceanogràfics a escales de temps que varien entre dècades i mil·lennis. En aquest article es revisen els mètodes proxy més importants emprats per a reconstruir variables climàtiques relacionades amb la superfície oceànica mitjançant foraminífers, que comprenen tant els mètodes geoquímics (isotòpics i elementals) com els basats en associacions. La temperatura gaudeix d'un èmfasi especial, perquè és el paràmetre climàtic més important de la superfície de l'oceà, tot i que també es tracten propietats relacionades de caràcter físic, químic i biològic com són la salinitat, la productivitat, l'ús de nutrients, la meteorització, la circulació, i propietats del sistema carbonat com l'alcalinitat, el pH i el [CO3 2-]. S'avalua cada proxy de manera sistemàtica i s'especifica, per a cada mètode, la seva base científica, alguns exemples breus i una projecció futura de la seva evolució

Instrumental validation of Globigerinoides ruber Mg/Ca as a proxy for NE Pacific summer SST

Accurate reconstruction of sea surface temperature (SST) is a high research priority, given that it is such a crucial variable in the Earth's climate system. The Mg/Ca composition of Globigerinoides ruber (white) has been calibrated and applied for a number of tropical and extratropical paleo-SST reconstructions, though validation studies of the proxy against instrumental observations are relatively scarce. Here we present a validation of G. ruber Mg/Ca-derived SSTs against instrumental summer values, firstly from the modern seasonal water column perspective, and secondly from a 20th century observational time series. The study occurs in the San Lázaro Basin (SLB), one of the marginal basins in the NE Pacific known for very high sedimentation rates, excellent preservation, laminated sequences, and the ability to record upwelling processes on high-resolution timescales, from interannual climatic variability (El Niño / Southern Oscillation (ENSO)) to interdecadal (e.g., the Pacific Decadal Oscillation (PDO)). Results suggest that the proxy best reflects the summer season. The proxy-instrument time-series comparison for summer SSTs displays remarkable agreement, driven largely by ENSO cycles for the past century, with some events missing due to scarcity of foraminiferal specimens and/or lack of sufficient temporal resolution. This study validates the G. ruber Mg/Ca proxy for summer SSTs in this region, and suggests its high fidelity to reconstruct summer SST from SLB over longer timescales to record multi-decadal and multi-centennial variabilities