14 research outputs found
Late Holocene linkages between decade–century scale climate variability and productivity at Lake Tanganyika, Africa
Microlaminated sediment cores from the Kalya slope region of Lake Tanganyika provide a near-annually resolved paleoclimate record between ~~2,840 and 1,420 cal. yr B.P. demonstrating strong linkages between climate variability and lacustrine productivity. Laminae couplets comprise dark, terrigenous-dominated half couplets, interpreted as low density underflows deposited from riverine sources during the rainy season, alternating with light, planktonic diatomaceous ooze, with little terrigenous component, interpreted as windy/dry season deposits. Laminated portions of the studied cores consist of conspicuous dark and light colored bundles of laminae couplets. Light and dark bundles alternate at decadal time scales. Within dark bundles, both light and dark half couplets are significantly thinner than within light bundles, implying slower sediment accumulation rates during both seasons over those intervals. Time series analyses of laminae thickness patterns demonstrate significant periodicities at interannual¿centennial time scales. Longer time scale periodicities (multidecadal to centennial scale) of light and dark half couplet thicknesses are coherent and in some cases are similar to solar cycle periods on these time scales. Although laminae thickness cycles do not strongly covary with the actual ¿14C record for this same time period, two large ¿14C anomalies are associated with substantial decreases in both light and dark laminae thickness. In contrast to the multidecadal¿ centennial time scale, significant annual to decadal periodicities, which are broadly consistent with ENSO/PDO forcing and their impact on East African climate, are not coherent between light and dark half couplets. The coherency of light¿dark couplets at decadal¿centennial time scales, but not at shorter time scales, is consistent with a model of a long-term relationship between precipitation (recorded in wet season dark laminae thickness) and productivity (light laminae thickness), which is not manifest at shorter time scales. We hypothesize that this coupling results from long-term recharging of internal nutrient loading during wet periods (higher erosion of soil P) and reduced loading during drought intervals. The relationship is not expressed on short time scales during which the dominant control on productivity is wind-driven, dry season upwelling, which is uncorrelated with wet-season precipitation. Our record greatly extends the temporal record of this quasi-periodic behavior throughout the late Holocene and provides the first evidence linking decade- to century-scale episodes of enhanced productivity to enhanced precipitation levels and nutrient recharge in a productive tropical lake
Integrative genomic analysis implicates limited peripheral adipose storage capacity in the pathogenesis of human insulin resistance.
Insulin resistance is a key mediator of obesity-related cardiometabolic disease, yet the mechanisms underlying this link remain obscure. Using an integrative genomic approach, we identify 53 genomic regions associated with insulin resistance phenotypes (higher fasting insulin levels adjusted for BMI, lower HDL cholesterol levels and higher triglyceride levels) and provide evidence that their link with higher cardiometabolic risk is underpinned by an association with lower adipose mass in peripheral compartments. Using these 53 loci, we show a polygenic contribution to familial partial lipodystrophy type 1, a severe form of insulin resistance, and highlight shared molecular mechanisms in common/mild and rare/severe insulin resistance. Population-level genetic analyses combined with experiments in cellular models implicate CCDC92, DNAH10 and L3MBTL3 as previously unrecognized molecules influencing adipocyte differentiation. Our findings support the notion that limited storage capacity of peripheral adipose tissue is an important etiological component in insulin-resistant cardiometabolic disease and highlight genes and mechanisms underpinning this link.This study was funded by the UK Medical Research Council through grants MC_UU_12015/1, MC_PC_13046, MC_PC_13048 and MR/L00002/1. This work was supported by the MRC Metabolic Diseases Unit (MC_UU_12012/5) and the Cambridge NIHR Biomedical Research Centre and EU/EFPIA Innovative Medicines Initiative Joint Undertaking (EMIF grant 115372). Funding for the InterAct project was provided by the EU FP6 program (grant LSHM_CT_2006_037197). This work was funded, in part, through an EFSD Rising Star award to R.A.S. supported by Novo Nordisk. D.B.S. is supported by Wellcome Trust grant 107064. M.I.M. is a Wellcome Trust Senior Investigator and is supported by the following grants from the Wellcome Trust: 090532 and 098381. M.v.d.B. is supported by a Novo Nordisk postdoctoral fellowship run in partnership with the University of Oxford. I.B. is supported by Wellcome Trust grant WT098051. S.O'R. acknowledges funding from the Wellcome Trust (Wellcome Trust Senior Investigator Award 095515/Z/11/Z and Wellcome Trust Strategic Award 100574/Z/12/Z)
Landbouwpraktijk en waterkwaliteit in Nederland in de periode 1992-2002. Achtergrondinformatie voor de derde landenrapportage EU-Nitraatrichtlijn
Dit rapport levert de informatie die nodig is voor de derde landenrapportage die Nederland medio 2004 in het kader van de EU-Nitraatrichtlijn aan de Europese Commissie dient toe te zenden. Het rapport geeft een overzicht van de huidige landbouwpraktijk en kwaliteit van grond- en oppervlaktewater in Nederland, en laat tevens de ontwikkeling hiervan zien in met name de periode 1992-2002. Dit betreft een overzicht van de implementatie van de maatregelen uit de eerdere Actieprogramma's en gevolgen hiervan op de waterkwaliteitsontwikkeling tot nu toe. Verder geeft het een verwachting van de termijn waarop effecten van het derde Actieprogramma op de waterkwaliteit zichtbaar worden. Nederland is er in 1987 in geslaagd de stijgende tendens van nutrientenoverschotten in de landbouw om te buigen in een dalende tendens. Na de invoering van MINAS in 1998 vertoont het stikstofoverschot opnieuw een dalende tendens, na deze voor een periode van ongeveer zeven jaar stabiel waren geweest. In de rapportageperiode (1992-2002) is de waterkwaliteit verbeterd, zowel met betrekking tot de nitraatconcentraties als eutrofiering. Dit is het gevolg van de maatregelen die genomen zijn sinds 1987. Nitraatconcentraties in het diepe grondwater (> 30 m beneden maaiveld) nemen nog steeds toe als gevolg van de toename in het stikstofoverschot in de periode voor 1987. De verwachting is dat de waterkwaliteit zal in de volgende periode (2003-2006) verder zal verbeteren als gevolg van de maatregelen genomen in het tweede Actie Programma (1999-2003). Wat betreft de nitraatconcentraties in het diepe grondwater wordt verwacht dat de omkering van de stijgende tendens nog enig decennia kan duren.This overview provides the background information for the Netherlands Member State report, 'Nitrate Directive, status and trends of aquatic environment and agricultural practice' to be submitted to the European Commission mid-2004. It documents current agricultural practice, and groundwater and surface-water quality, in the Netherlands, outlines the trends in these waters (especially the 1992-2002 period) and assesses the time scale for change in water quality as a consequence of changes in farm practice. The report deals with the evaluation of the implementation and impact of the measures in the Action Programmes on water body quality. The Netherlands has, since 1987, reversed the increase of nitrogen and phosphorus surpluses in Dutch agriculture to a decrease. After the implementation of a mineral accounting system (MINAS) in 1998, the nitrogen surplus, which had been stable for about seven years, decreased again. In the reporting period (1992-2002) water quality, both with respect to nitrate concentration and eutrophication, improved due to measures taken since 1987. Nitrate concentrations in deep groundwater (> 30 m depth) still increase as a consequence of increasing nitrogen loads in the period before 1987. Water quality is expected to continue to improve in the next reporting period (2003-2006) as a result of measures taken during the second Action Programme (1999-2003). With respect to nitrate concentration in deep groundwater, reversal of the increasing trend is estimated to take several decades.VROMLNVV&
Landbouwpraktijk en waterkwaliteit in Nederland in de periode 1992-2002. Achtergrondinformatie voor de derde landenrapportage EU-Nitraatrichtlijn
This overview provides the background information for the Netherlands Member State report, 'Nitrate Directive, status and trends of aquatic environment and agricultural practice' to be submitted to the European Commission mid-2004. It documents current agricultural practice, and groundwater and surface-water quality, in the Netherlands, outlines the trends in these waters (especially the 1992-2002 period) and assesses the time scale for change in water quality as a consequence of changes in farm practice. The report deals with the evaluation of the implementation and impact of the measures in the Action Programmes on water body quality. The Netherlands has, since 1987, reversed the increase of nitrogen and phosphorus surpluses in Dutch agriculture to a decrease. After the implementation of a mineral accounting system (MINAS) in 1998, the nitrogen surplus, which had been stable for about seven years, decreased again. In the reporting period (1992-2002) water quality, both with respect to nitrate concentration and eutrophication, improved due to measures taken since 1987. Nitrate concentrations in deep groundwater (> 30 m depth) still increase as a consequence of increasing nitrogen loads in the period before 1987. Water quality is expected to continue to improve in the next reporting period (2003-2006) as a result of measures taken during the second Action Programme (1999-2003). With respect to nitrate concentration in deep groundwater, reversal of the increasing trend is estimated to take several decades.Dit rapport levert de informatie die nodig is voor de derde landenrapportage die Nederland medio 2004 in het kader van de EU-Nitraatrichtlijn aan de Europese Commissie dient toe te zenden. Het rapport geeft een overzicht van de huidige landbouwpraktijk en kwaliteit van grond- en oppervlaktewater in Nederland, en laat tevens de ontwikkeling hiervan zien in met name de periode 1992-2002. Dit betreft een overzicht van de implementatie van de maatregelen uit de eerdere Actieprogramma's en gevolgen hiervan op de waterkwaliteitsontwikkeling tot nu toe. Verder geeft het een verwachting van de termijn waarop effecten van het derde Actieprogramma op de waterkwaliteit zichtbaar worden. Nederland is er in 1987 in geslaagd de stijgende tendens van nutrientenoverschotten in de landbouw om te buigen in een dalende tendens. Na de invoering van MINAS in 1998 vertoont het stikstofoverschot opnieuw een dalende tendens, na deze voor een periode van ongeveer zeven jaar stabiel waren geweest. In de rapportageperiode (1992-2002) is de waterkwaliteit verbeterd, zowel met betrekking tot de nitraatconcentraties als eutrofiering. Dit is het gevolg van de maatregelen die genomen zijn sinds 1987. Nitraatconcentraties in het diepe grondwater (> 30 m beneden maaiveld) nemen nog steeds toe als gevolg van de toename in het stikstofoverschot in de periode voor 1987. De verwachting is dat de waterkwaliteit zal in de volgende periode (2003-2006) verder zal verbeteren als gevolg van de maatregelen genomen in het tweede Actie Programma (1999-2003). Wat betreft de nitraatconcentraties in het diepe grondwater wordt verwacht dat de omkering van de stijgende tendens nog enig decennia kan duren
Inventory of data, monitoring and model requirements for reporting for the EU Nitrates Directive in 2008
Het RIVM heeft een handleiding opgesteld voor de rapportage over de hoeveelheid nitraat in oppervlaktewater en de bovenste grondwaterlaag. Nederland moet daarover, net als alle andere EU-lidstaten, elke vier jaar verslag uitbrengen, conform de Europese Nitraatrichtlijn. De volgende rapportage vindt in 2008 plaats. In de handleiding staan de taken en acties beschreven die betrokken partijen moeten uitvoeren om de beschikbare informatie tijdig aan te leveren, af te stemmen en tot een geheel te smeden. Het doel is een snel en efficient rapportagetraject mogelijk te maken.RIVM has drawn up a manual in order to report the amount of nitrate in surface water and shallow groundwater. The Netherlands have to report this, like all other EU-countries, every four years, in accordance with the European Nitrate Directive. The next report is due in 2008. The manual contains a survey of the tasks and actions that must be followed up to round up all available information from the different parties in time and as a whole. Goal of this report is to facilitate a fast and efficient reporting process
Inventarisatie van de gegevens-, monitor- en modelbehoefte voor de EU-Nitraatrichtlijnrapportage 2008
Het RIVM heeft een handleiding opgesteld voor de rapportage over de hoeveelheid nitraat in oppervlaktewater en de bovenste grondwaterlaag. Nederland moet daarover, net als alle andere EU-lidstaten, elke vier jaar verslag uitbrengen, conform de Europese Nitraatrichtlijn. De volgende rapportage vindt in 2008 plaats. In de handleiding staan de taken en acties beschreven die betrokken partijen moeten uitvoeren om de beschikbare informatie tijdig aan te leveren, af te stemmen en tot een geheel te smeden. Het doel is een snel en efficient rapportagetraject mogelijk te maken
Nutrient cycling in Lake Kivu
This chapter summarizes the knowledge on mixing and transport processes in Lake Kivu. Seasonal mixing, which varies in intensity from year to year, influences the top ∼65 m. Below, the lake is permanently stratified, with density increasing stepwise from ∼998 kg m−3 at the surface to ∼1,002 kg m−3 at the maximum depth of 485 m. The permanently stratified deep water is divided into two distinctly different zones by a main gradient layer. This gradient is maintained by a strong inflow of relatively fresh and cool water entering at ∼250 m depth which is the most important of several subaquatic springs affecting the density stratification. The springs drive a slow upwelling of the whole water column with a depth-dependent rate of 0.15–0.9 m year−1. This upwelling is the main driver of internal nutrient recycling and upward transport of dissolved gases. Diffusive transport in the deep water is dominated by double-diffusive convection, which manifests in a spectacular staircase of more than 300 steps and mixed layers. Double diffusion allows heat to be removed from the deep zone faster than dissolved substances, supporting the stable stratification and the accumulation of nutrients and gases over hundreds of years. The stratification in the lake seems to be near steady-state conditions, except for a warming trend of ∼0.01°C year−1.