TRANSFER

Plankton net lrNew project

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.

Duration: 2017-2019

Funding Agency: Ministerio de Economía, Industria y Competitividad

LOOP participants: Jordi Catalan, Lluís Camarero, Marisol Felip, Berta Fueyo, Sergi Pla, Rober Sánchez.

Coordinators: J. Catalan (CREAF), L. Camarero (CEAB)

Participant institutions: CREAF, CEAB-CSIC

REPLIM

REPLIM2 lr

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.

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Atmospheric phosphorus deposition may cause lakes to revert from phosphorus limitation back to nitrogen limitation

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Time trend of DIN in the Pyrenean lake district. Box-plots showing the decreasing evolution of the distribution of DIN concentration in water from lakes in the central Pyrenees from 1987 to 2011. The box-plots show medians (line within the box), 25th and 75th percentiles (sides of the box), 10th and 90th percentiles (error bars) and 5th and 95th percentiles (circles). Data are from four synoptic surveys carried out in the years indicated on the graph; the number of lakes included (n) is also indicated.

Humans have dramatically disturbed the earth's N cycle to the point that this alteration is considered one of the most serious threats to the global ecosystem. Part of the excess N circulates through the atmosphere and is deposited with precipitation, reaching areas that would otherwise be free of direct human impact. Atmospherically deposited N has an acidifying effect on aquatic ecosystems, and most studies of N pollution have focused on this aspect.

 

However, recent research has also addressed the global impact of atmospherically deposited N as a nutrient in lakes. Recent findings indicate that increased atmospheric deposition of reactive nitrogen of human origin has caused changes in the pattern of ecological nutrient limitation in lakes in the northern hemisphere. An increase in the stoichiometric ratio of nitrogen (N) to phosphorus (P), and hence a shift from pristine N limitation to human-induced P limitation of phytoplankton growth, seems to have been driven by deposition of atmospheric N. These findings challenge the classical paradigm of lake productivity being naturally limited by P availability. However, deposition of atmospheric P may also be highly relevant.

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