http://library.um.ac.id/free-contents/downloadpdf.php/buku/complexation-reactions-in-aquatic-systems-an-analytical-approach-j-buffle-translators-s-p-kounaves-a-kounaves-and-r-s-altman-12623.pdf

Complexation reactions in aquatic systems : an analytical approach / J. Buffle, translators S.P. Kounaves, A. Kounaves and R.S. Altman

https://www.carey.biol.vt.edu/wp-content/uploads/2013/09/Carey_2012_Water-Res.pdf

Eco-physiological adaptations that favour freshwater cyanobacteria in a changing climate

. SURFEX is a new externalized land and ocean surface platform that describes the surface fluxes and the evolution of four types of surfaces: nature, town, inland water and ocean. It is mostly based on pre-existing, well-validated scientific models that are continuously improved. The motivation for the building of SURFEX is to use strictly identical scientific models in a high range of applications in order to mutualise the research and development efforts. SURFEX can be run in offline mode (0-D or 2-D runs) or in coupled mode (from mesoscale models to numerical weather prediction and climate models). An assimilation mode is included for numerical weather prediction and monitoring. In addition to momentum, heat and water fluxes, SURFEX is able to simulate fluxes of carbon dioxide, chemical species, continental aerosols, sea salt and snow particles. The main principles of the organisation of the surface are described first. Then, a survey is made of the scientific module (including the coupling strategy). Finally, the main applications of the code are summarised. The validation work undertaken shows that replacing the pre-existing surface models by SURFEX in these applications is usually associated with improved skill, as the numerous scientific developments contained in this community code are used to good advantage.

/pdf/the-surfexv7-2-land-and-ocean-surface-platform-for-coupled-261aoq10jv.pdf

The SURFEXv7.2 land and ocean surface platform for coupled or offline simulation of earth surface variables and fluxes

Strong climate-related secular trends are apparent in a 52-yr long (1947–1998) uninterrupted series of monthly temperature profiles fromLake Zurich, a large, deep (136 m), temperate lake on the Swiss Plateau. Decadal mean water temperatures have undergone a secular increase at all depths, reflecting the high degree of regional warming that occurred in the European Alpine area during the 20th century. From the 1950s to the 1990s, high warming rates (∼ 0.24 K per decade) in the uppermost 20 m of the lake (i.e., the epi/metalimnion) combined with lower warming rates (∼ 0.13 K per decade) below 20 m (i.e., in the hypolimnion), have resulted in a20% increase in thermal stability and a consequent extension of 2–3 weeksin the stratification period. In common with many other parts of the world, 20th-century climate change on the Swiss Plateau has involved a steep secular increase in daily minimum (nighttime) air temperatures, but not in daily maximum (daytime) air temperatures. With respect to both secular change and decadal-scale variability, the temporal structure of the temperature of the surface mixed layer of Lake Zurich faithfully reflects that of the regional daily minimum air temperature, but not that of the daily maximum. The processes responsible for longer-term changes in the temperature structure of the lake therefore act during the night, presumably by suppressing nighttime convective cooling of the surface mixed layer. Application of a one-box heat exchange model suggests that the observed secular changes in thermal structure are due to shifts in the nighttime rate of emission of infrared radiation from the atmosphere and in the nighttime rates of latent and sensible heat exchange at the air-water interface. The increase in hypolimnetic temperatures is mainly a result of the increased prevalence of warm winters in Europe.

/pdf/impact-of-secular-climate-change-on-the-thermal-structure-of-4sbrv4h5pr.pdf

Impact of secular climate change on the thermal structure of a large temperate central european lake

Twenty-five years of extensive water temperature data show regionally coherent warming to have occurred in Alpine rivers and streams at all altitudes, reflecting changes in regional air temperature . Much of this warming occurred abruptly in 1987/1988. For brown trout populations , the warming resulted in an upward shift in thermal habitat that was accelerated by an increase in the incidence of temperature -dependent Proliferative Kidney Disease at the habitat's lower boundary. Because physical barriers restrict longitudinal migration in mountain regions, an upward habitat shift in effect implies habitat reduction, suggesting the likelihood of an overall population decrease. Extensive brown trout catch data documenting an altitudinally dependent decline indicate that such a climate-related population decrease has in fact occurred. Our analysis employs a quantitatively defined reference optimum temperature range for brown trout , based on the sinusoidal regression of seasonally varying field data.

Consequences of climatic change for water temperature and brown trout populations in Alpine rivers and streams

A unique data set of 50 years of monthly temperature profiles from Lake Zurich, a normally ice-free lake located on the Swiss Plateau, allowed the one-dimensional numerical k-« lake model ’’S IMSTRAT’’ to be calibrated (1948‐ 1957) and validated (1958‐1997). Hindcasts of temperature profiles agree excellently with the measured data. Both interannual and intraannual variations in thermal structure are reproduced well during the entire 50-yr simulation, thus demonstrating the stability and good prognostic qualities of the model. Simulations conducted with raised and lowered air temperatures (Tair) suggest that an increase in Tair will lead to an increase in lake water temperature at all depths. In comparison to the continuous modeling approach taken in this study, the commonly employed discontinuous modeling approach (with no heat carryover during winter) substantially underestimated the degree of long-term hypolimnetic warming that can be expected to result from an increase in Tair. Thus, whereas the discontinuous approach yields valid predictions for strictly dimictic lakes that are ice-covered each winter, heat carryover during winter makes a continuous approach necessary in lakes like Lake Zurich that are only facultatively dimictic. The significant degree of hypolimnetic warming found in this study suggests that the response of facultatively dimictic lakes to increases in Tair is likely to differ from that of the strictly dimictic lakes modeled in other investigations. In Lake Zurich, an increase in Tair is predicted to result in more frequent suppression of deeply penetrative winter mixing events, with a potentially negative impact on the lake ecosystem.

/pdf/modeling-50-years-of-historical-temperature-profiles-in-a-1xl8o2fscg.pdf

Modeling 50 years of historical temperature profiles in a large central European lake

The fate of particle reactive substances in a surface aquatic system is controlled by both geochemical and physical parameters. Scavenging processes in Lake Biel (Switzerland) have been studied using the anthropogenic tracer 60 Co. This isotope originates mostly in dissolved form from the Muhleberg nuclear power plant and is transported 18 km down by the River Aare to the lake. Radionuclide data from sediments, combined with inventory calculations, indicate that between 30% and 55% of the discharged 60 Co is transferred to sediments. Scavenging efficiency is higher during the winter period than during summer, in spite of higher particle fluxes during the summer. An intrusion model, based on buoyancy calculations, predicts that Aare water, including its radionuclide load, remains in the epilimnion during the warm period; thus, mixing is restricted to only a fraction of the lake volume and the residence time is reduced to 1 week. Buoyancy in the summer is controlled mostly by temperature. During winter, when the lake and Aare waters are close to 4°C, the higher dissolved load of Aare water increases its density and forces it to intrude into deeper sections of the lake, increasing the residence time and thus the time available for adsorption and particle settling. The predictive capability of the model was tested for the summer period using a fluorescent dye (uranin) to track Aare water from the inflow to the outflow of the lake. Higher fluxes of both particles and associated radionuclides in deep sediment traps confirm the results of the intrusion model for the winter period. Comparison between modeled and measured 60 Co activities in lake water at the end of the winter validates the credibility of the intrusion model further. This combined geochemical and physical approach may be applied to transport modeling of radionuclides and of any particle reactive substance, inorganic or organic.

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1999.44.1.0196

Importance of lacustrine physical factors for the distribution of anthropogenic 60Co in Lake Biel

The fate of particle reactive substances in a surface aquatic system is controlled by both geochemical and physical parameters. Scavenging processes in Lake Biel (Switzerland) have been studied using the anthropogenic tracer 60 Co. This isotope originates mostly in dissolved form from the Muhleberg nuclear power plant and is transported 18 km down by the River Aare to the lake. Radionuclide data from sediments, combined with inventory calculations, indicate that between 30% and 55% of the discharged 60 Co is transferred to sediments. Scavenging efficiency is higher during the winter period than during summer, in spite of higher particle fluxes during the summer. An intrusion model, based on buoyancy calculations, predicts that Aare water, including its radionuclide load, remains in the epilimnion during the warm period; thus, mixing is restricted to only a fraction of the lake volume and the residence time is reduced to 1 week. Buoyancy in the summer is controlled mostly by temperature. During winter, when the lake and Aare waters are close to 48C, the higher dissolved load of Aare water increases its density and forces it to intrude into deeper sections of the lake, increasing the residence time and thus the time available for adsorption and particle settling. The predictive capability of the model was tested for the summer period using a fluorescent dye (uranin) to track Aare water from the inflow to the outflow of the lake. Higher fluxes of both particles and associated radionuclides in deep sediment traps confirm the results of the intrusion model for the winter period. Comparison between modeled and measured 60 Co activities in lake water at the end of the winter validates the credibility of the intrusion model further. This combined geochemical and physical approach may be applied to transport modeling of radionuclides and of any particle reactive substance, inorganic or organic.

Gerrit Goudsmit

Papers

Modeling 50 years of historical temperature profiles in a large central European lake

Importance of lacustrine physical factors for the distribution of anthropogenic 60Co in Lake Biel

Importance of lacustrine physical factors for the distribution of anthropogenic 60 Co in