Plankton net lr

Keys to understand the transfer of the atmospheric forcing to the dynamics of lacustrine plankton

The footprint of global change shows up in multiple indicators. As evidence accumulates, some paradoxes also emerge. At multiannual time scales, one intriguing aspect is why some ecosystems seem to follow more closely indicators of general atmospheric dynamics (e.g., CO2 increase, hemispheric mean annual temperature) than the local weather and deposition records. Pathways of mechanistic causality must exist that explain the apparent paradox. Probably, they are related to processes of a different characteristic reaction and renewal times. One of the systems in which the phenomenon has been observed is the plankton of remote lakes. The TRANSFER project aims to address this issue and provide an integrated view of the transfer of atmospheric fluctuations to the planktonic system of lakes in remote areas to understand the apparent paradoxes.



A network of observatories of ecosystems (lakes and peatbogs) sensitive to the climate change in the Pyrenees

REPLIM is a network of scientific centers and managers specialised in the dynamics of high mountain lakes and peatbogs and their relationship with Climate Change (CC). Pyrenean lakes and peatbogs are iconic elements of our landscape, and sensitive to recent climate change. REPLIM will implement a Pyrenean network of observatories of lakes and peatbogs designed to undertake the challenge of evaluating the CC impact on the high altitude areas and to provide robust scientific data to develop policies of mitigation and adaptation.



The lake district concept in the ecological understanding of high mountains

Sets of lakes in the landscape are known as lake districts. The objective of this project is to demonstrate that the lake district acts as a regional functional ecological unit. The hypothesis is that ecological properties, beyond the simple addition of smaller units (lakes), emerge from the densification of lakes in a region. They could result among others from topographical restrictions, border effects, directional environmental gradients, stochastic colonizing patterns, concatenation of dominant biogeochemical processes.


Study of the effects of nitrogen deposition increase on the lakes of the Pyrenees

The acceleration of industrialization since 1950s resulted in a progressive increase of nitrogen forms that can easily be easily assimilated by living organisms (e.g. NH4+: NO3-). Currently reactive nitrogen has duplicated natural levels existing just less than a century ago in our planet. As some compounds are easily volatile, reactive nitrogen has spread beyond human activity areas and, in greater or smaller degree, is affecting relatively remote zones through increase of ammonium and nitrate in the deposition.


Pilot study for the use of stable and radioactive isotopes in monitoring and long term ecological research (LTER) in the aquatic ecosystems of the National Parks

In this project, we aim to implement a protocol for the use of the measurement of natural levels of several stable and radiactive isotopes with a view to monitor the biogeochemistry of surface waters as indicators of the ecological functioning of high mountain catchments. These new techniques would be included in the monitoring programme running since 2004 in the Aigüestortes National Park. The objectives are: 1) to design and test in a pilot study a monitoring protocol including isotopes; 2) to determine the isotopic composition, its range and mode of variation, for a suite of compounds that are substrates of several environmental processes of interest and are thus relevant to the interpretation of the isotopic composition of the products resulting from these processes; 3) to identify which processes have a greater weight on the ecological and biogeochemical functioning of the catchment, and therefore warrant more attention in a long term monitoring; and 4) to propose an optimized design based on the results of the project.


Livestock effects on the lakes of Aigüestortes and Sant Maurici Lake National Park: nitrogen inputs and eutrophication risk

 High mountain landscapes do not escape the effects of the increased nitrogen atmospheric deposition caused by human activities during the last few decades. In addition to this, livestock grazing on high mountain natural pastures during the summer might modify the quantity and composition of nutrient load entering lakes, thus affecting production rates in these ecosystems. The present proposal seeks to evaluate the effects of livestock on lakes in the Aigüestortes and Sant Maurici Lake National Park, and to assess the eutrophication risk posed by livestock as it interacts, perhaps synergistically, with increased nitrogen deposition rates. Our proposal suggests addressing these questions at three distinct spatial and temporal scales. At the scale of the lakescape, we propose to build statistical models linking livestock pressure, atmospheric deposition, and lake and catchment characteristics with in-lake nutrient concentrations and stoichiometry. At the lake and catchment scale during the entire ice-free season, we seek to analyse in greater detail the effects on the biomass, composition, and activity of plankton, including Archaea and Bacteria. Finally, at the individual lake scale, we propose to analyse the local effect of livestock on the composition and biomass of algal and macrophyte communities, and on microbial activity.


Interaction between climate and human impacts on vegetation changes in the National Park of Aigüestortes i Estany de Sant Maurici throughout the last 15,000 years.

The project aims to study the effects of climate, human activities and their interaction on vegetation changes in the National Park of Aigüestortes i Estany de Sant Maurici throughout the last 15,000 years. Palaeoecological and archaeological techniques are combined to: reconstruct the climate at secular time scales; reconstruct vegetation changes; establish the beginning of human presence and the fluctuations of its impacts on vegetation; and eventually to analyse the interactions between climate, vegetation and human use of high mountains. For managing purposes, the study is completed by: analysing past history as reference for current changes; valuating the National Park archaeological heritage in the context of the human history in the mountains; and producing outreach materials (iconography and visiting itineraries) for dissemination of the history of nature-human interaction in the mountains.


Coupling of the C and N hydrobiogeochemical cycles in high mountain catchments during intense hydrological episodes, estimation of its relative importance in the yearly mass balances and possible implications of climate change

In this project, we aim to study the processes affecting the biogeochemistry of carbon and nitrogen, as they are reflected in the changes produced in the chemistry of the waters draining mountain catchments. This is a continuation of a previous project. The detailed objectives are: 1) To estimate the rates of CO2 sequestration in weathering reactions; 2) To establish the links between the cycles of C and N in the catchments; 3) To improve and adapt the distributed hydrological model TETIS to the features of high mountain catchments; and 4) To forecast the effects of climate change on the biogeochemistry of C and N in high mountain catchments. To undertake this, it is proposed to increase both the space and time resolution of the hydrobiogeochemical monitoring that is presently being carried out. This will allow us to identify the contribution of each hydrological compartment to the stream flow, to detail the spatial heterogenity of these compartments, and to assess the relevance of the abrupt hydrological events (floods anf thaw) in the leaching of solutes from the catchment to the rivers.


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