Scientists have long believed that the distribution of plants within a marsh is a passive adaption in which species grow at different elevations because that's where conditions like soil aeration and salinity best meet their needs.
But this team found intertidal marsh plants in Italy's famed Venetian lagoon were able to subtly tune, or adjust, their elevations by producing different amounts of organic soil, and trapping and accumulating different amounts of inorganic sediments as part of a complex interplay with the environment.
"Our study identifies the visible signature of a two-way feedback occurring between the vegetation and the landscape," said Marco Marani, professor of ecohydrology at Duke's Nicholas School of the Environment and Pratt School of Engineering. "Each species builds up the elevation of its substrate to within a favorable range for its survival, much the way corals in the animal kingdom do."
The finding may help scientists better predict marsh ecosystems' resilience to climatic changes such as sea level rise.
"Obviously, this is not a conscious choice on the part of the plants," Marani said. "It's a natural mechanism -- how marshes work. We just didn't understand it in such detail until now."
The study appears this week in the early online edition of the Proceedings of the National Academy of Sciences.
The team used numerical modeling to visualize the dynamic interactions of marsh ecosystems over time, and tested the models against detailed topographical surveys of elevations and distributions of plant species in the Venetian lagoon.
"We've been studying this same marsh for 15 years and, as in similar studies around the world, we were using GPS technology with an accuracy of plus or minus one centimeter in elevation," Marani explained. For the new study, they used a more precise surveying instrument, an electronic theodolite, which measure elevations accurately to within less than one millimeter. "It allowed us to observe differences so subtle that they went unnoticed before," he said.
The differences in substrate-building capabilities between species are often minute, but they allow each species to stabilize the soil within different stable states, or layers, in the marsh. Some species prefer elevations at or below mean sea level; others prefer higher elevations that are less often inundated.
"Interestingly, our models and surveys show that plants make trade-offs when colonizing within their preferential ranges," Marani said. "Entire sections of a species' vegetation patch often are located above the elevation needed for its maximum biomass productivity." This gives it a bit of margin to compensate for external fluctuations, such as the rates of relative sea level rise or sediment availability.
"Essentially," he said, "the species hedges its bet by trading maximum productivity for greater long-term stability."
Scientists have long known that biodiversity plays an important role in a marsh ecosystem's long-term health and survival, "but this paper provides a clear causal link suggesting how and why," he said. "The take-home message is that the more species you have colonizing different levels within a marsh, the more resilient to abrupt change the marsh as a whole will be."
He said that marshes in which an invasive species, such as cordgrass, has pushed out other species will be less resilient to climatic changes.
Marani's co-authors on the new study are Cristina Da Lio and Andrea D'Alpaos of the University of Padova, Italy.
CITATION: "Vegetation engineers marsh morphology through multiple competing stable states," Marco Marani, Cristina Da Lio and Andrea D'Alpaos. Published week of Feb. 11, 2013 in the early online edition of the Proceedings of the National Academy of Sciences. DOI - 10.1073/pnas.1218327110
Tim Lucas | EurekAlert!
Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel
Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
23.05.2018 | Life Sciences
23.05.2018 | Physics and Astronomy
23.05.2018 | Life Sciences