Etiqueta: jordi sardans
A study involving three CREAF researchers has found that plants with low nitrogen and phosphorus concentrations in their leaves do not reproduce every year to enable them to reproduce on a huge scale in years in which conditions are right. Oaks, holm oaks and beeches are examples of trees that behave in such a way.
Published in the journal PNAS (Proceedings of the National Academy of Sciences), a study to which the Spanish National Research Council (CSIC) and CREAF have contributed has revealed that the time for which forests retain carbon has fallen by between 0.2% and 0.3% every year in recent decades. Plant mortality is rising due to higher carbon dioxide (CO2) levels and, in particular, warming and droughts. The time in question, which is termed carbon turnover time, is a relevant factor in climate change projections as it is indicative of carbon sinks’ capacity to retain carbon.
Mean male height in countries with a high level of GDP is 23 cm greater than in countries with a low level, a difference that has risen by 1.5 cm over the last 30 years. Thanks to a more varied diet rich in animal products, the annual nitrogen and phosphorus intake of people in wealthy countries is practically twice that of those in poor countries.
A new study led by Josep Peñuelas and published in Nature Ecology and Evolution reveals that CO2 abundance in the atmosphere no longer has a powerful fertilizing effect on vegetation. The greening that has been observed in recent years is slowing and this will cause CO2 levels in the atmosphere to rise, thus increasing temperatures and leading to increasingly severe changes in climate.
An extensive review of studies and databases reveals that drought and an increase in temperature are already causing species substitutions, greater aridity, higher forest fire risk, lower soil fertility, and lower water availability, among other negative impacts.
Freshwater ecosystems near densely populated areas have levels of phosphorus which are very high and out of balance with nitrogen levels. This has resulted in altered ecosystem functioning, lower water quality, and has made water conservation more difficult.
Scientists identify the 13 most important research challenges to face global change in the Mediterranean region3 de February 2015J.Luis Ordóñez
Scientists consider it key to understand why droughts kill so many trees and the influence of local forest histories on tree mortality. They also warn that we know very little about the joined effects of different disturbances on each ecosystem, and highlight the necessity to plan research projects covering more time and space.