High-resolution spatiotemporal heterogeneities of water optical properties in a large lake to infer physical and biogeochemical drivers of primary production

2020 ◽  
Author(s):  
Camille Minaudo ◽  
Daniel Odermatt ◽  
Bieito Fernandez-Castro ◽  
Hannah E. Chmiel ◽  
Sébastien Lavanchy ◽  
...  
Keyword(s):  
Optical Properties ◽  
Primary Production ◽  
Transition Period ◽  
Alternative Methods ◽  
Lake Geneva ◽  
Short Term ◽  
Large Lakes ◽  
Vertical Heterogeneity ◽  
Basin Scale ◽  
Over The Top

<p>Measuring primary production (PP) is of major importance to evaluate how lakes are recovering from eutrophication, and better constrain their role in global biogeochemical cycles. The classical sampling method involving radiolabelled carbon incubated in bottles at selected depths is associated with heavy logistics and prevents scientists from sampling the short-term dynamics of PP. Therefore, we investigate alternative methods based on oxygen sensors and optical properties.</p><p>To explore the interplay between biogeochemical and physical processes and how they are related to PP in large lakes, we have deployed since October 2018 a sophisticated autonomous profiler in Lake Geneva, Switzerland. The so-called Thetis profiler measures with a centimeter resolution backscattering and fluorescence at discrete wavelengths, hyperspectral absorption and attenuation, hyperspectral reflectance, along with temperature, dissolved oxygen and conductivity. The profiler was deployed over contrasted seasons and recorded these parameters every three hours over the top 50 m of the water column.</p><p>Observations revealed large spatiotemporal heterogeneities of optical properties as a result of seasonal and short-term (weekly to sub-daily) physical and biogeochemical processes. Diel cycles in the optical properties representing phytoplankton abundance resulted from night-time convection and grazing and production during the day. Short-lived but strong upwelling events triggered sudden disruptive shifts in the phytoplankton community composition over the fall to winter transition period which, in turn, impacted the oxygen budgets, opening the door to a better understanding of the vertical heterogeneity of PP directly from inherent optical properties. The data also features advected riverine and resuspended sediments during storms and snowmelt, and during upwelling events, respectively.</p><p>This in-situ data is now being combined with remotely sensed water quality parameters (OLCI products from Sentinel 3A and 3B) and a three-dimensional hydrodynamic model of Lake Geneva (www.meteolakes.ch) to upscale PP estimates from local to basin scale.</p>

scholarly journals Dynamics of auto- and heterotrophic picoplankton and associated viruses in Lake Geneva

2013 ◽  
Vol 10 (7) ◽  
pp. 8715-8746 ◽  
Author(s):  
A. Parvathi ◽  
X. Zhong ◽  
A. S. Pradeep Ram ◽  
S. Jacquet
Keyword(s):  
Primary Production ◽  
Western Europe ◽  
Transition Period ◽  
Critical Role ◽  
Environmental Parameters ◽  
Lake Geneva ◽  
Microbial Dynamics ◽  
Viral Lysis ◽  
Bacterial Mortality ◽  
The Impact

Abstract. Microbial dynamics has been rarely investigated in Lake Geneva, which is paradoxically the largest lake in Western Europe. From a 5 month survey, we report dynamic patterns of free living viruses, bacteria and small phytoplankton abundances in response to a variety of environmental parameters. For the first time, we fractionated the primary production to separate the contribution of different size-related biological compartments and measured both bacterial and viral production in addition to experiments conducted to appreciate virus-induced bacterial mortality. We observed marked seasonal and vertical variations in picocyanobacteria, bacteria and virus abundances and production. The contribution of picoplankton and nanoplankton production to the total primary production was high in November and spring-summer transition period respectively. The impact of viral lysis on both bacteria and picocyanobacteria was significantly higher than grazing activities. Virus-induced picocyanobacterial mortality reached up to 66% compared to virus induced bacterial mortality that reached a maximum of 34% in July. Statistical analyses revealed a complex interplay between biological abundances and/or activity with environmental factors in Lake Geneva. Our results provide new evidence on the critical role played by viruses in freshwater microbial dynamics and more globally on the functioning of the microbial food webs. This study highlights the importance of further considering this biological compartment for a better understanding of the plankton ecology of Lake Geneva, especially for modeling purposes and in a context of reoligotrophication and warming of this ecosystem.

scholarly journals Dynamics of auto- and heterotrophic picoplankton and associated viruses in Lake Geneva

2014 ◽  
Vol 18 (3) ◽  
pp. 1073-1087 ◽  
Author(s):  
A. Parvathi ◽  
X. Zhong ◽  
A. S. Pradeep Ram ◽  
S. Jacquet
Keyword(s):  
Primary Production ◽  
Western Europe ◽  
Transition Period ◽  
Environmental Parameters ◽  
Lake Geneva ◽  
Microbial Dynamics ◽  
Viral Lysis ◽  
Bacterial Mortality ◽  
Total Primary Production ◽  
The Impact

Abstract. Microbial dynamics have rarely been investigated in Lake Geneva, known as the largest lake in western Europe. From a 5-month survey, we report dynamic patterns of free-living virus, bacteria and small phytoplankton abundances in response to a variety of environmental parameters. For the first time, we fractionated the primary production to separate the contribution of different size-related biological compartments and measured both bacterial and viral production in addition to experiments conducted to quantify the virus-induced bacterial mortality. We observed marked seasonal and vertical variations in picocyanobacteria, bacteria and virus abundances and production. The contribution of picoplankton and nanoplankton production to the total primary production was high (reaching up to 76% of total primary production) in November and the spring–summer transition period, respectively. The impact of viral lysis on both bacteria and picocyanobacteria was significantly higher than grazing activities. Virus-induced picocyanobacterial mortality reached up to 66% of cell removal compared to virus induced (heterotrophic) bacterial mortality, which reached a maximum of 34% in July. Statistical analyzes revealed that temperature and top-down control by viruses are among important factors regulating the picocyanobacterial dynamics in this lake. More generally speaking, our results add to the growing evidence and accepted view nowadays that viruses are an important actor of freshwater microbial dynamics and more globally of the functioning of the microbial food webs.

Operational Model and its Validation with Drift Tests in Water Areas Around the Baltic Sea

1994 ◽  
Vol 29 (2-3) ◽  
pp. 293-308
Author(s):  
J. Koponen ◽  
M. Virtanen ◽  
H. Vepsä ◽  
E. Alasaarela
Keyword(s):  
Three Dimensional ◽  
Fast Response ◽  
Velocity Measurements ◽  
Short Term ◽  
Large Lakes ◽  
Operational Model ◽  
Water Currents ◽  
Emergency Situations ◽  
Sensitivity Tests ◽  
The Baltic

Abstract Three-dimensional (3-D) mathematical models of water currents, transport, mixing, reaction kinetic, and interactions with bottom and air have been used in Finland regularly since 1982 and applied to about 40 cases in large lakes, inland seas and their coastal waters. In each case, model validity has been carefully tested with available flow velocity measurements, tracer studies and water quality observations. For operational use, i.e., for spill combatting and sea rescue, the models need fast response, proven validity and illustrative visualization. In 1987-90, validated models were implemented for operational use at five sea areas along the Finnish coast. Further validation was obtained in model applications from nine documented or arranged cases and from seven emergency situations. Sensitivity tests supplement short-term validation. In the Bothnian Sea, it was nescessary to start the calculation of water currents three days prior to the start of the experiment to reduce initial inaccuracies and to make the coastal transport estimates meaningful.

The Marine Environment

2017 ◽  
Author(s):  
N. Penny Holliday ◽  
Stephanie Henson
Keyword(s):  
Primary Production ◽  
North Atlantic ◽  
Physical Environment ◽  
Seasonal Cycle ◽  
Physical Processes ◽  
The North ◽  
Basin Scale ◽  
The North Atlantic ◽  
Physical Features ◽  
Growth Distribution

The growth, distribution, and variability of phytoplankton populations in the North Atlantic are primarily controlled by the physical environment. This chapter provides an overview of the regional circulation of the North Atlantic, and an introduction to the key physical features and processes that affect ecosystems, and especially plankton, via the availability of light and nutrients. There is a natural seasonal cycle in primary production driven by physical processes that determine the light and nutrient levels, but the pattern has strong regional variations. The variations are determined by persistent features on the basin scale (e.g. the main currents and mixed layer regimes of the subtropical and subpolar gyres), as well as transient mesoscale features such as eddies and meanders of fronts.

scholarly journals Extradition Between the UK and Ireland After Brexit—Understanding the Past and Present to Prepare for the Future

2020 ◽  
pp. 002201832097753
Author(s):  
Gemma Davies ◽  
Paul Arnell
Keyword(s):  
Transition Period ◽  
Alternative Methods ◽  
Good Friday ◽  
The United Kingdom ◽  
Good Friday Agreement ◽  
The Future ◽  
Close Relationship ◽  
The Republic ◽  
The Uk ◽  
The Eu

The Republic of Ireland and the United Kingdom have a long, close and difficult history. The most recent phase of which dates from 1998 and the conclusion of the Good Friday Agreement. Since 1921, however, there has been unique practice between Ireland and the UK as regards the transfer of accused and convicted persons from one to the other. Indeed, there has been a special and close relationship between the two in that regard; albeit one not without difficulties. In recent times EU Justice and Home Affairs measures and the Good Friday Agreement have supplemented and strengthened the relationship. These include, since January 2004, the European Arrest Warrant (EAW). The EAW has been particularly important in streamlining the extradition process between the Ireland and the UK. This phase of history and co-operation is coming to an end. The UK’s membership of the EU has now ceased, and a transition period during which the UK remains part of the EAW will end on 31st December 2020. The extradition relationship between the two is therefore facing a considerable challenge. There are several options open to Ireland, the UK and the EU as a replacement. Time, political will and the interests of third states, however, may well stand in the way of the conclusion of an agreement that optimally serves the interests of all parties and criminal justice. This paper considers the origins of extradition between the UK and Ireland and the alternative methods of extradition open to the UK and Ireland after Brexit. Consideration is given to the likely operation of a Norway-Iceland style agreement and whether such an agreement will be in place by the end of the transition and, if it was, whether its terms are likely to be sufficient for the needs of Ireland and the UK. The possibility of a bilateral arrangement on extradition between Ireland and the UK is also explored. Underlying the discussion is the critical point that the future extradition relationship must retain its ‘special’ characteristics, and therefore maintain the trust and good will that has developed over the years and given rise to an effective extradition relationship between the two countries. In other words, the lessons of history must be remembered.

scholarly journals Family and childcare support public expenditures and short-term fertility dynamics

2013 ◽  
Vol 60 (3) ◽  
pp. 347-364 ◽  
Author(s):  
Cosmin Enache
Keyword(s):  
Birth Rate ◽  
Crude Birth Rate ◽  
Low Fertility ◽  
Alternative Methods ◽  
Public Expenditures ◽  
Short Term ◽  
Wide Range ◽  
Policy Measures ◽  
Support Policy ◽  
Cash Benefits

In a period of very low fertility, effective family and childcare support policy measures are needed. From a wide range of instruments available to government intervention, we focus on public expenditures effects on short-term fertility. Using a sample of 28 European countries in a panel framework, we found that there is a small positive elasticity of crude birth rate to cash benefits related to childbirth and childrearing provided through social security system. Different public services provided to ease the burden of parents and all other benefits in kind, means or non-means tested, are found to be insignificant. These results are robust to alternative methods of estimation. Controlling for country heterogeneity by religion and by culture, some particularly interesting differences in birth rate determinants were highlighted as well.

scholarly journals Photosynthesis-irradiance parameters of marine phytoplankton: synthesis of a global data set

2017 ◽  
Author(s):  
Heather A. Bouman ◽  
Trevor Platt ◽  
Martina Doblin ◽  
Francisco G. Figueiras ◽  
Kristinn Gudmudsson ◽  
...  
Keyword(s):  
Primary Production ◽  
Broad Band ◽  
Marine Phytoplankton ◽  
Production Model ◽  
Initial Slope ◽  
Model Parameters ◽  
Data Set ◽  
Spatial Coverage ◽  
Basin Scale ◽  
Marine Primary Production

Abstract. The photosynthetic performance of marine phytoplankton varies in response to a variety of factors, environmental and taxonomic. One of the aims of the MArine primary Production: model Parameters from Space (MAPPS) project of the European Space Agency is to assemble a global database of photosynthesis-irradiance (P-E) parameters from a range of oceanographic regimes as an aid to examining the basin-scale variability in the photophysiological response of marine phytoplankton and to use this information to improve the assignment of P-E parameters in the estimation of global marine primary production using satellite data. The MAPPS P-E Database, which consists of over 5000 P-E experiments, provides information on the spatio-temporal variability in the two P-E parameters (the assimilation number, PmB, and the initial slope, αB, where the superscripts B indicate normalisation to concentration of chlorophyll) that are fundamental inputs for models (satellite-based and otherwise) of marine primary production that use chlorophyll as the state variable. Quality-control measures consisted of removing samples with abnormally-high parameter values and flags were added to denote whether the spectral quality of the incubator lamp was used to calculate a broad-band value of αB. The MAPPS database provides a photophysiological dataset that is unprecedented in number of observations and in spatial coverage. The database would be useful to a variety of research communities, including marine ecologists, biogeochemical modellers, remote-sensing scientists and algal physiologists. The compiled data are available at https://doi.org/10.1594/PANGAEA.874087 (Bouman et al., 2017).

scholarly journals Alternative methods for Salt free / Less salt short term preservation of hides and skins in leather making for sustainable development – A review

2019 ◽  
Vol 2 (1) ◽  
pp. 46-52 ◽  
Author(s):  
Venkatasubramanian Sivakumar ◽  
Resmi Mohan ◽  
Chellappa Muralidharan
Keyword(s):  
Sodium Chloride ◽  
Environmental Concern ◽  
Treatment Method ◽  
Alternative Methods ◽  
Waste Streams ◽  
Short Term ◽  
Leather Processing ◽  
Disposal Option ◽  
Patent Literature ◽  
Ultra Filtration

During the leather processing, large quantities of the salt as sodium chloride, about 30-50 % (% w/w on raw weight) is applied for short term preservation of hides and skins, which subsequently leaches out from the skins/hides and end up in waste streams. This raises a serious environmental concern as well as total dissolved solids (TDS) problem in the wastewater, for which there is no viable treatment method available. Remediation measures such as Reverse Osmosis (RO) or Ultra Filtration (UF) could only separate salt from these waste streams and end up as salt sludge, which necessitates Secured Land Fill (SLF) for disposal option. There are some concerns for SLF as it requires Land area as well as possible leaching due to highly soluble nature of Sodium chloride. Therefore, there is a pressing need for developing an alternative methods for Salt free / Less salt short term preservation of hides and skins. In this regard, Research and Development work is being carried out worldwide and several reports are available. Therefore, it would be beneficial to review and analyze the salt free alternative preservation methods. Even though, some reviews on this topic has been reported earlier, they have not taken into account the patent literature available on this subject. The present paper reviews various alternative methods for Salt free / Less salt short term preservation of hides and skins, taking into account both patent and other publications on this subject.

Sign in / Sign up

Export Citation Format

Share Document