(Table 1) U and Th isotopic composition and 230Th ages of samples from the A1 and C1 corals of Legare Anchorage

The 14C reservoir age of the surface ocean was determined for two Holocene periods (4908-4955 and 3008-3066 calendar (cal) B.P.) using U/Th-dated corals from Biscayne National Park, Florida, United States. We found that the average reservoir ages for these two time periods (294 ± 33 and 291 ± 27 years, respectively) were lower than the average value between A.D. 1600 and 1900 (390 ± 60 years) from corals. It appears that the surface ocean was closer to isotopic equilibrium with CO2 in the atmosphere during these two time periods than it was during recent times. Seasonal d18O measurements from the younger coral are similar to modern values, suggesting that mixing with open ocean waters was indeed occurring during this coral's lifetime. Likely explanations for the lower reservoir age include increased stratification of the surface ocean or increased D14C values of subsurface waters that mix into the surface. Our results imply that a more correct reservoir age correction for radiocarbon measurements of marine samples in this location from the time periods ~3040 and ~4930 cal years B.P. is ~292 ± 30 years, less than the canonical value of 404 ± 20 years.

Stable carbon isotopes of Planulina wuellerstorfi of sediment core MD01-2444

The observation that Greenland and Antarctic temperatures have followed a specific 'asymmetrical' pattern on millennial time-scales sets rigid constraints on any viable theory of abrupt climate change. The further observation that the very same asymmetry is also reflected in planktonic and benthic d18O measurements from the Northeast Atlantic has extended this constraint to include a specific response in the ocean. Here we present records of deep-water temperature, d18O and d13C variability from the Northeast Atlantic that help to shed light on the links between overturning circulation perturbations, sea-level variability and inter-hemispheric climate change on millennial time-scales. Results indicate that while deep-water temperatures in the Northeast Atlantic have tracked Greenland climate, the d18O signature of local deepwater (d18Odw) has varied in a manner more reminiscent of Antarctic temperature variability. The previously identified correspondence of Antarctic warm events with benthic d18O minima in the Northeast Atlantic is thus found to apply specifically to d18Odw minima, and to extend beyond Marine Isotope Stage 3 to the entirety of the last 50 ka. It is impossible to reconcile completely the Iberian Margin d18Odw record with existing reconstructions of millennial sea-level variability, leading to the conclusion that a significant portion of the d18Odw record must represent local hydrographic change. This is supported by benthic d13C measurements, which suggest the incursion during Greenland stadials of a colder, low-d18O and low-d13C water-mass, of presumed Antarctic origin. These observations confirm a one-to-one coupling of inter-hemispheric climate events with changes in the Atlantic overturning circulation, but fail to rule in or out a unique mechanism by which they were triggered.

Sedimentology and geochemistry of ODP Site 184-1144

We analyzed sediment from Ocean Drilling Program (ODP) Site 1144 in the northern South China Sea to examine the weathering response of SE Asia to the strengthening of the East Asian Monsoon (EAM) since 14 ka. Our high-resolution record highlights the decoupling between continental chemical weathering, physical erosion and summer monsoon intensity. Mass accumulation rates, Ti/Ca, K/Rb, hematite/goethite and 87Sr/86Sr show sharp excursions from 11 to 8 ka, peaking at 10 ka. Clay minerals show a shorter-lived response with a higher kaolinite/(illite + chlorite) ratio at 10.7-9.5 ka. However, not all proxies show a clear response to environmental changes. Magnetic susceptibility rises sharply between 12 and 11 ka. Grain-size becomes finer from 14 to 10 ka and then coarsens until ~7 ka, but is probably controlled by bottom current flow and sealevel. Sr and Nd isotopes show that material is dominantly eroded from Taiwan with a lesser flux from Luzon, while clay mineralogy suggests that the primary sources during the Early Holocene were reworked via the shelf in the Taiwan Strait, rather than directly from Taiwan. Erosion was enhanced during monsoon strengthening and caused reworking of chemically weathered Pleistocene sediment largely from the now flooded Taiwan Strait, which was transgressed by ~8 ka, cutting off supply to the deep-water slope. None of the proxies shows an erosional response lasting until ~6 ka, when speleothem oxygen isotope records indicate the start of monsoon weakening. Although more weathered sediments were deposited from 11 to 8 ka when the monsoon was strong these are reworked and represent more weathering during the last glacial maximum (LGM) when the summer monsoon was weaker but the shelves were exposed.

Stable oxygen isotope and Mg/Ca ratios of planktonic foraminifera from the Caribbean and North Atlantic

Variations in the strength of the North Atlantic Ocean thermohaline circulation have been linked to rapid climate changes during the last glacial cycle through oscillations in North Atlantic Deep Water formation and northward oceanic heat flux. The strength of the thermohaline circulation depends on the supply of warm, salty water to the North Atlantic, which, after losing heat to the atmosphere, produces the dense water masses that sink to great depths and circulate back south. Here we analyse two Caribbean Sea sediment cores, combining Mg/Ca palaeothermometry with measurements of oxygen isotopes in foraminiferal calcite in order to reconstruct tropical Atlantic surface salinity during the last glacial cycle. We find that Caribbean salinity oscillated between saltier conditions during the cold oxygen isotope stages 2, 4 and 6, and lower salinities during the warm stages 3 and 5, covarying with the strength of North Atlantic Deep Water formation. At the initiation of the Bølling/Allerød warm interval, Caribbean surface salinity decreased abruptly, suggesting that the advection of salty tropical waters into the North Atlantic amplified thermohaline circulation and contributed to high-latitude warming.

Radiocarbon data, oxygen isotopic composition in foraminifera, freshwater diatoms data, and salinity estimations from ODP Holes 167-1019C and 167-1019D

Massive discharges of freshwater from the glacial lake Missoula to the northeast Pacific Ocean are thought to have sculpted the Channeled Scablands of eastern Washington and debouched via the Columbia River near 46°N. The dynamics and timing of these events and their impact on northeast Pacific circulation remain uncertain. Here we date marine records of anomalous freshwater inputs to the ocean based on freshwater diatoms, oxygen isotopes in foraminifera, and radiocarbon data. Low-salinity plumes from the Columbia River reduced sea-surface salinities by as much as 6 psu (practical salinity units) more than 400 km away between 16 and 31 cal (calendar) ka B.P. Anomalously high abundances of freshwater diatoms in marine sediments from the region precede generally accepted dates for the existence of glacial Lake Missoula, implying that large flooding or freshwater routing events were common during the advance of the Cordilleran Ice Sheet and that such events require multiple sources.

High-resolution pollen record of ODP Hole 175-1078C

To address the connection between tropical African vegetation development and high-latitude climate change we present a high-resolution pollen record from ODP Site 1078 (off Angola) covering the period 50-10 ka BP. Although several tropical African vegetation and climate reconstructions indicate an impact of Heinrich Stadials (HSs) in Southern Hemisphere Africa, our vegetation record shows no response. Model simulations conducted with an Earth System Model of Intermediate Complexity including a dynamical vegetation component provide one possible explanation. Because both precipitation and evaporation increased during HSs and their effects nearly cancelled each other, there was a negligible change in moisture supply. Consequently, the resulting climatic response to HSs might have been too weak to noticeably affect the vegetation composition in the study area. Our results also show that the response to HSs in southern tropical Africa neither equals nor mirrors the response to abrupt climate change in northern Africa.

A high-resolution Lateglacial and Holocene palaeoceanographic record from the Greenland Sea

We present an unprecedented multicentennial sediment record from the foot of Vesterisbanken Seamount, central Greenland Sea, covering the past 22.3 thousand years (ka). Based on planktic foraminiferal total abundances, species assemblages, and stable oxygen and carbon isotopes, the palaeoenvironments in this region of modern deepwater renewal were reconstructed. Results show that during the Last Glacial Maximum the area was affected by harsh polar conditions with only episodic improvements during warm summer seasons. Since 18?ka extreme freshwater discharges from nearby sources occurred, influencing the surface water environment. The last major freshwater event took place during the Younger Dryas. The onset of the Holocene was characterized by an improvement of environmental conditions suggesting warming and increasing ventilation of the upper water layers. The early Holocene saw a stronger Atlantic waters advection to the area, which began around 10.5 and ended quite rapidly at 5.5?ka, followed by the onset of Neoglacial cooling. Surface water ventilation reached a maximum in the middle Holocene. Around 3?ka the surface water stratification increased leading to subsequent amplification of the warming induced the North Atlantic Oscillation at 2?ka.

(Table S1) Age determination of sediment cores of the Gulf of Alaska

Oxygen isotope data from planktonic and benthic foraminifera, on a high-resolution age model (44 14C dates spanning 17,400 years), document deglacial environmental change on the southeast Alaska margin (59°33.32'N, 144°9.21'W, 682 m water depth). Surface freshening (i.e., d18O reduction of 0.8 per mil) began at 16,650 ± 170 cal years B.P. during an interval of ice proximal sedimentation, likely due to freshwater input from melting glaciers. A sharp transition to laminated hemipelagic sediments constrains retreat of regional outlet glaciers onto land circa 14,790 ± 380 cal years B.P. Abrupt warming and/or freshening of the surface ocean (i.e., additional d18O reduction of 0.9 per mil) coincides with the Bølling Interstade of northern Europe and Greenland. Cooling and/or higher salinities returned during the Allerød interval, coincident with the Antarctic Cold Reversal, and continue until 11,740 ± 200 cal years B.P., when onset of warming coincides with the end of the Younger Dryas. An abrupt 1 per mil reduction in benthic d18O at 14,250 ± 290 cal years B.P. likely reflects a decrease in bottom water salinity driven by deep mixing of glacial meltwater, a regional megaflood event, or brine formation associated with sea ice. Two laminated opal-rich intervals record discrete episodes of high productivity during the last deglaciation. These events, precisely dated here at 14,790 ± 380 to 12,990 ± 190 cal years B.P. and 11,160 ± 130 to 10,750 ± 220 cal years B.P., likely correlate to similar features observed elsewhere on the margins of the North Pacific and are coeval with episodes of rapid sea level rise. Remobilization of iron from newly inundated continental shelves may have helped to fuel these episodes of elevated primary productivity and sedimentary anoxia.

Table 1. Radiocarbon dates from TPC522 and box core surface samples from BC521 and BC523

Recent intensification of wind-driven upwelling of warm upper circumpolar deep water (UCDW) has been linked to accelerated melting of West Antarctic ice shelves and glaciers. To better assess the long term relationship between UCDWupwelling and the stability of theWest Antarctic Ice Sheet, we present a multi-proxy reconstruction of surface and bottom water conditions in Marguerite Bay, West Antarctic Peninsula (WAP), through the Holocene. A combination of sedimentological, diatom and foraminiferal records are, for the first time, presented together to infer a decline in UCDW influence within Marguerite Bay through the early to mid Holocene and the dominance of cyclic forcing in the late Holocene. Extensive glacial melt, limited sea ice and enhanced primary productivity between 9.7 and 7.0 ka BP is considered to be most consistent with persistent incursions of UCDW through Marguerite Trough. From 7.0 ka BP sea ice seasons increased and productivity decreased, suggesting that UCDW influence within Marguerite Bay waned, coincident with the equatorward migration of the Southern Hemisphere Westerly Winds (SWW). UCDW influence continued through the mid Holocene, and by 4.2 ka BP lengthy sea ice seasons persisted within Marguerite Bay. Intermittent melting and reforming of this sea ice within the late Holocene may be indicative of episodic incursions of UCDW into Marguerite Bay during this period. The cyclical changes in the oceanography within Marguerite Bay during the late Holocene is consistent with enhanced sensitively to ENSO forcing as opposed to the SWW-forcing that appears to have dominated the early to mid Holocene. Current measurements of the oceanography of the WAP continental shelf suggest that the system has now returned to the early Holocene-like oceanographic configuration reported here, which in both cases has been associated with rapid deglaciation.

Layer description, carbon and nitrogen content and stable isotope record of bulk sedimentary organic matter from Laguna Potrok Aike

An investigation of stable isotope (d13C TOC and d15N TN) and elemental parameters (TOC, TN contents and TOC/TN ratios) of bulk organic matter (<200 µm) from sediment cores recovered from the Patagonian lake Laguna Potrok Aike (Argentina) in the framework of the ICDP deep drilling project PASADO provided insights into past changes in lake primary productivity and environmental conditions in South Patagonia throughout the last Glacial-Interglacial transition. Stratigraphically constrained cluster analyses of all proxy parameters suggest four main phases. From ca 26,100 to 17,300 cal. years BP, lacustrine phytoplankton was presumably the predominant organic matter source in an aquatic environment with low primary productivity rates. At around 17,300 cal. years BP, abrupt and distinct shifts of isotopic and elemental values indicate that the lacustrine system underwent a rapid reorganization. Lake primary productivity (phytoplankton and aquatic macrophytes) shows higher levels albeit with large variations during most of the deglaciation until 13,000 cal. years BP. The main causes for this development can be seen in improved growing conditions for primary producers because of deglacial warming in combination with expedient availability of nutrients and likely calm wind conditions. After 13,000 cal. years BP, decreased d13C TOC values, TOC, TN contents and TOC/TN ratios indicate that the lake approached a new state with reduced primary productivity probably induced by unfavourable growing conditions for primary producers like strengthened winds and reduced nutrient availability. The steady increase in d15N TN values presumably suggests limitation of nitrate supply for growth of primary producers resulting from a nutrient shortage after the preceding phase with high productivity. Nitrate limitation and consequent decreased lacustrine primary productivity continued into the early Holocene (10,970-8400 cal. years BP) as reflected by isotopic and elemental values.

Organic and inorganic geochemical measurements of sediment core GeoB7702-3

It has long been known that extreme changes in North African hydroclimate occurred during the late Pleistocene yet many discrepancies exist between sites regarding the timing, duration and abruptness of events such as Heinrich Stadial (HS) 1 and the African Humid Period (AHP). The hydroclimate history of the Nile River is of particular interest due to its lengthy human occupation history yet there are presently few continuous archives from the Nile River corridor, and pre-Holocene studies are rare. Here we present new organic and inorganic geochemical records of Nile Basin hydroclimate from an eastern Mediterranean (EM) Sea sediment core spanning the past 28 ka BP. Our multi-proxy records reflect the fluctuating inputs of Blue Nile versus White Nile material to the EM Sea in response to gradual changes in local insolation and also capture abrupt hydroclimate events driven by remote climate forcings, such as HS1. We find strong evidence for extreme aridity within the Nile Basin evolving in two distinct phases during HS1, from 17.5 to 16 ka BP and from 16 to 14.5 ka BP, whereas peak wet conditions during the AHP are observed from 9 to 7 ka BP. We find that zonal movements of the Congo Air Boundary (CAB), and associated shifts in the dominant moisture source (Atlantic versus Indian Ocean moisture) to the Nile Basin, likely contributed to abrupt hydroclimate variability in northern East Africa during HS1 and the AHP as well as to non-linear behavior of hydroclimate proxies. We note that different proxies show variable gradual and abrupt responses to individual hydroclimate events, and thus might have different inherent sensitivities, which may be a factor contributing to the controversy surrounding the abruptness of past events such as the AHP. During the Late Pleistocene the Nile Basin experienced extreme hydroclimate fluctuations, which presumably impacted Paleolithic cultures residing along the Nile corridor.

Speleothem master chronologies: combined Holocene O-18 and C-13 records from the North Island of New Zealand and their palaeoenvironmental interpretation

The stable isotope records of four stalagmites dated by 19 TIMS uranium series ages are combined to produce master chronologies for delta(18)O and delta(13)C The delta(18)O records display good overall coherence, but considerable variation in detail. Variability in the delta(13)C records is greater, but general trends can still be discerned. This implies that too fine an interpretation of the structure of individual isotopic records can be unreliable. Speleothem delta(18)O values are demonstrated to show a positive relationship with temperature by comparing trends with other proxy records, but also to respond negatively to rainfall amount. Speleothem delta(13)C is considered to be most influenced by rainfall. The postglacial thermal optimum occur-red around 10.8 ka BP, which is similar in timing to Antarctica but up to 2000 years earlier than most Northern Hemisphere sites. Increasingly negative delta(18)O values after 7.5 ka BP indicate that temperatures declined to a late mid-Holocene minimum centred around 3 ka BP, but more positive values followed to mark a warm peak about 750 years ago which coincided with the 'Mediaeval Warm Period' of Europe. Low 5110 values at 325 years BP suggest cooling coincident with the 'Little Ice Age'. A marked feature of the delta(13)C record is an asymmetric periodicity averaging c. 2250 years and amplitude of c. 1.9parts per thousand. It is concluded that this is mainly driven by waterbalance variations with negative swings representing particularly wet intervals. The 5110 record shows a higher-frequency cyclicity with a period of c. 500 years and an amplitude of c. 0.25 parts per thousand. This is most likely to be temperature-driven, but some swings may have been amplified by precipitation.

Laparoscopic greater curvature plication in morbidly obese women with type 2 diabetes:effects on glucose homeostasis, postprandial triglyceridemia and selected gut hormones

Background: Laparoscopic greater curvature plication (LGCP) is an emerging bariatric procedure that reduces the gastric volume without implantable devices or gastrectomy. The aim of this study was to explore changes in glucose homeostasis, postprandial triglyceridemia, and meal-stimulated secretion of selected gut hormones [glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1), ghrelin, and obestatin] in patients with type 2 diabetes mellitus (T2DM) at 1 and 6 months after the procedure. Methods: Thirteen morbidly obese T2DM women (mean age, 53.2 ± 8.76 years; body mass index, 40.1 ± 4.59 kg/m2) were prospectively investigated before the LGCP and at 1- and 6-month follow-up. At these time points, all study patients underwent a standardized liquid mixed-meal test, and blood was sampled for assessment of plasma levels of glucose, insulin, C-peptide, triglycerides, GIP, GLP-1, ghrelin, and obestatin. Results: All patients had significant weight loss both at 1 and 6 months after the LGCP (p≤0.002), with mean percent excess weight loss (%EWL) reaching 29.7 ;plusmn2.9 % at the 6-month follow-up. Fasting hyperglycemia and hyperinsulinemia improved significantly at 6 months after the LGCP (p<0.05), with parallel improvement in insulin sensitivity and HbA1c levels (p<0.0001). Meal-induced glucose plasma levels were significantly lower at 6 months after the LGCP (p<0.0001), and postprandial triglyceridemia was also ameliorated at the 6-month follow-up (p<0.001). Postprandial GIP plasma levels were significantly increased both at 1 and 6 months after the LGCP (p<0.0001), whereas the overall meal-induced GLP-1 response was not significantly changed after the procedure (p ;gt0.05). Postprandial ghrelin plasma levels decreased at 1 and 6 months after the LGCP (p<0.0001) with no significant changes in circulating obestatin levels. Conclusion: During the initial 6-month postoperative period, LGCP induces significant weight loss and improves the metabolic profile of morbidly obese T2DM patients, while it also decreases circulating postprandial ghrelin levels and increases the meal-induced GIP response. © 2013 Springer Science+Business Media New York.

Examining factors associated with excess mortality in older people (age ≥ 70 years) with diabetes - a 10-year cohort study of older people with and without diabetes

Aims: To compare all-cause mortality in older people with or without diabetes and consider the associated risk of comorbidity and polypharmacy. Methods: A 10-year cohort study using data from the Health Innovation Network database (2003-2013) comparing mortality in people aged ≥ 70 years with diabetes (DM cohort) (n = 35 717) and without diabetes (No DM cohort) (n = 307 918). Results: The mean age of the DM cohort was 78.1 ± 5.8 years vs. 79.0 ± 6.3 years in the No DM cohort. Mean diabetes duration was 8.2 ± 8.1 years, and 30% had diabetes for > 10 years. The DM cohort had a greater comorbidity load and people in this cohort were prescribed more therapies than the No DM cohort. The 5- and 10-year survival rates were lower in the DM cohort at 64% and 39%, respectively, compared with 72% and 50% in the No DM cohort. The excess mortality in the DM cohort was greatest in those aged <75 years with longer duration diabetes, the relative hazard for mortality was higher in females. Although comorbidity and polypharmacy were associated with increased mortality risk in the DM cohort, this risk was lower compared with the No DM cohort. The hazard ratios (95% confidence interval) for comorbidities > 4 and medicines ≥ 7 were 1.29 (1.19 to 1.41) and 1.34 (1.25 to 1.43) in the DM cohort and 1.63 (1.57 to 1.70) and 1.48 (1.40 to 1.56) in the No DM cohort, respectively. Conclusions: There is significant excess mortality in older people with diabetes, which is unexplained by comorbidity or polypharmacy. This excess is greatest in the younger old with longer disease duration, suggesting that it may be related to the effect of diabetes exposure.

Effects of Land Use on Sources and Ages of Inorganic and Organic Carbon in Temperate Headwater Streams

The amounts, sources and relative ages of inorganic and organic carbon pools were assessed in eight headwater streams draining watersheds dominated by either forest, pasture, cropland or urban development in the lower Chesapeake Bay region (Virginia, USA). Streams were sampled at baseflow conditions six different times over 1 year. The sources and ages of the carbon pools were characterized by isotopic (δ13C and ∆14C) analyses and excitation emission matrix fluorescence with parallel factor analysis (EEM–PARAFAC). The findings from this study showed that human land use may alter aquatic carbon cycling in three primary ways. First, human land use affects the sources and ages of DIC by controlling different rates of weathering and erosion. Relative to dissolved inorganic carbon (DIC) in forested streams which originated primarily from respiration of young, 14C-enriched organic matter (OM; δ13C = −22.2 ± 3 ‰; ∆14C = 69 ± 14 ‰), DIC in urbanized streams was influenced more by sedimentary carbonate weathering (δ13C = −12.4 ± 1 ‰; ∆14C = −270 ± 37 ‰) and one of pasture streams showed a greater influence from young soil carbonates (δ13C = −5.7 ± 2.5 ‰; ∆14C = 69 ‰). Second, human land use alters the proportions of terrestrial versus autochthonous/microbial sources of stream water OM. Fluorescence properties of dissolved OM (DOM) and the C:N of particulate OM (POM) suggested that streams draining human-altered watersheds contained greater relative contributions of DOM and POM from autochthonous/microbial sources than forested streams. Third, human land uses can mobilize geologically aged inorganic carbon and enable its participation in contemporary carbon cycling. Aged DOM (∆14C = −248 to −202 ‰, equivalent14C ages of 1,811–2,284 years BP) and POM (∆14C = −90 to −88 ‰, 14C ages of 669–887 years BP) were observed exclusively in urbanized streams, presumably a result of autotrophic fixation of aged DIC (−297 to −244 ‰, 14C age = 2,251–2,833 years BP) from sedimentary shell dissolution and perhaps also watershed export of fossil fuel carbon. This study demonstrates that human land use may have significant impacts on the amounts, sources, ages and cycling of carbon in headwater streams and their associated watersheds.