A University of Florida scientist and other researchers have found that plants in Hawaii have the ability to acclimate to big changes in rainfall in at least one important respect – how they get nutrients. The plants largely rely on one form of the vital nutrient nitrogen in moist areas. But in the still wetter terrain that characterizes some rainforests, they switch to another form of nitrogen that becomes more available in those conditions.
The findings, reported in paper set to appear this week in the online edition of the Proceedings of the National Academy of Sciences, present a notable exception to the commonly held idea that tropical plants are highly specialized in their own little environmental niches – and thus very sensitive to disturbances of those niches.
That could be good for the plants because climate change is expected to radically alter rainfall patterns in the tropics. But it comes with a caveat: Nutrient uptake is only one of many ingredients in plant life. Other unrelated changes that accompany a warming climate could still affect plant distribution and growth, such as those that hold sway over pollinators, insect predators or invasive plants.
"These plants should be able to do OK in terms of their nitrogen nutrition, even with the climate changing," said Ted Schuur, a UF assistant professor of ecology and one of four authors of the paper. "But of course, we only studied one group of organisms and one mechanism in this study" and plants depend on many different mechanisms to coexist, some of which may also change with changing rainfall.
The scientists researched plant growth at six sites on the slopes of Mount Haleakala, a volcano on the island of Maui. The sites were ideal because they share the same species, elevations and soils but have vastly different rainfall. The wettest rainforest sites receive an astonishing 196 inches of rain annually, while the driest sites in this study get about 79 inches.
"That's the range of rainfall you might find across the entire tropics, but that would usually be over hundreds or thousands of kilometers," Schuur said. "I can visit all of these forest sites in a single day."
The scientists analyzed nitrogen isotopes in the soil and leaf samples of four plant species at each site. They learned that drier soils contained more nitrogen in the form of nitrate, while wetter soils contained more nitrogen in the form of ammonia. Isotopic analysis of the plants revealed that they switched from nitrate to ammonia "abruptly, and in unison" once the rainfall reached a certain level.
"There's an abrupt change halfway through the rainfall gradient, and they all switch to this other form for their nutrition," Schuur said.
That's a surprise partly because of the uniformity of response, he said. Such uniformity sharply contrasts the conventional notion that tropical plant species coexist by adopting widely different strategies to getting what they need. At least with regard to nitrogen uptake, all the Hawaiian plants acted the same -- and at the same time.
" … This does not support the idea that natural selection has caused species to diverge into highly specialized niches for nitrogen consumption," the PNAS paper says.
That's a positive sign considering that as the Earth warms, some areas of the tropics are widely expected to be wetter, some drier. So, at least one of dozens of variables that will change with precipitation changes – nutrient uptake – might not affect tropical plants. That said, plenty of others could, Schuur said.
Ted Schuur | EurekAlert!
Reducing household waste with less energy
18.01.2017 | FIZ Karlsruhe – Leibniz-Institut für Informationsinfrastruktur GmbH
Joint research project on wastewater for reuse examines pond system in Namibia
19.12.2016 | Technische Universität Darmstadt
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
18.01.2017 | Power and Electrical Engineering
18.01.2017 | Materials Sciences
18.01.2017 | Life Sciences