Mangroves, the backbone of the tropical ocean coastlines, are far more important to the global oceans biosphere than previously thought. And while the foul-smelling muddy forests may not have the scientific allure of tropical reefs or rain forests, a team of researchers has noted that the woody coastline- dwelling plants provide more than 10 percent of essential dissolved organic carbon that is supplied to the global ocean from land, according to a report published 21 February in Global Biogeochemical Cycles, a publication of the American Geophysical Union.
Thorsten Dittmar at Florida State University in Tallahassee reports that mangrove plants, whose finger-like roots are known to protect coastal wetlands against the ocean and as important fish habitats, cover less than 0.1 percent of the global land surface yet account for a tenth of the dissolved organic carbon (DOC) that flows from land to the ocean. Dittmar and his colleagues at several German research institutions analyzed the carbon output from a large mangrove forest in Brazil and suggest that the plants are one of the main sources of dissolved organic matter in the ocean.
The researchers note that the organic matter that is dissolved in the world oceans contains a similar amount of carbon as is stored in the skies as atmospheric carbon dioxide, an important greenhouse gas. Dissolved organic matter is an important player in the global carbon cycle that regulates atmospheric carbon dioxide and climate.
"To understand global biogeochemical cycles it is crucial to quantify the sources of marine dissolved organic carbon," Dittmar writes. "Here we show that mangroves play an unexpected role in the global carbon cycle."
Dittmar reports that the mangrove root system slows carbon-rich leaf litter running from continental land and allows it to settle into shallow sediment, where dissolved organic matter is leached in large quantities into the coastal waters. The daily rise and fall of the tides then flushes the dissolved carbon into the open ocean (like a teabag being dipped in an out a cup). Once in the ocean, however, the intense tropical sunlight destroys some of the most delicate dissolved organic carbon molecules. But more than half of the dissolved organic matter survives the attack from sunlight or bacteria.
The authors measured the chemical signature in water samples from the massive mangrove forest in northern Brazil, using natural carbon isotopes and nuclear magnetic resonance spectroscopy--an established and common technique for determining the structure of organic compounds--to determine that mangroves are indeed a main source of dissolved organic carbon in the open ocean. In total, they concluded that the carbon exported from mangroves is approximately 2.2 trillion moles of carbon per year [2.2 x 10(12), similar to the annual Amazon River discharge], nearly triple the amount estimated from previous smaller-scale estimates of the carbon released into the ocean.
Mangrove foliage, however, has declined by nearly half over the past several decades because of increasing coastal development and damage to its habitat. As the habitat has changed, ever-smaller quantities of mangrove-derived detritus are available for formation and export of dissolved organic matter to the ocean. The researchers speculate that the rapid decline in mangrove extent threatens the delicate balance and may eventually shut off the important link between the land and ocean, with potential consequences for atmospheric composition and climate.
The research was funded by the German Research Foundation (DFG), the German Academic Exchange Service (DAAD) and The Florida State University.
Title: "Mangroves, a major source of dissolved organic carbon to the oceans"
Authors: Thorsten Dittmar, Florida State University, Tallahassee, Florida; Norbert Hertkorn, GSF-National Research Centre for Environment and Health, Institute of Ecological Chemistry, Neuherberg, Germany; Gerhard Kattner, Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany; Ruben J. Lara, Center for Tropical Marine Ecology, Bremen, Germany.
Citation: Dittmar, Thorsten; Hertkorn, Norbert; Kattner, Gerhard; Lara, Ruben J., (2006), Mangroves, a major source of dissolved organic carbon to the oceans, Global Biogeochem. Cycles, Vol. 20, No. 1, GB101210, doi: 10.1029/2005GB002570, 2006.
Contact information for author: Thorsten Dittmar: firstname.lastname@example.org or +1 (850) 645 1887
Harvey Leifert | American Geophysical Union
Water - as the underlying driver of the Earth’s carbon cycle
17.01.2017 | Max-Planck-Institut für Biogeochemie
Modeling magma to find copper
13.01.2017 | Université de Genève
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