Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The Sands of Time: What 30,000 Years of Sediment Can Teach US About the Changing Ocean

24.06.2013
It’s surprising what a large cylinder of ocean floor sediment can tell you about the Earth’s global climate and ocean history. At face value, it may only seem like a big cylinder of mud, but to a paleo-oceanographer it provides a much bigger picture.

A team of international scientists known as the NICOPP (Nitrogen Cycle in the Ocean, Past and Present) working group, led by Dalhousie oceanographer Markus Kienast and Eric Galbraith of McGill University, use these cylinders to measure isotopes of nitrogen on the seafloor that arise from nitrogen-rich phytoplankton sinking and collecting in the mud.

“Over thousands of years, this slow accumulation builds up a vertical record of past changes that can be sampled by taking a sediment core using a specialized ship,” says Dr. Kienast. “As you go down in the core, you go back in time.”

In a new paper, published last week in Nature Geoscience, the NICOPP working group presented the first global synopsis of available sedimentary nitrogen isotope records from throughout the world’s oceans, spanning the past 30,000 years.

“The results confirm the ocean is an effective self-regulator with respect to nitrogen, a major nutrient,” says Dr. Kienast, “but reaching equilibrium after a disturbance such as the last glacial-interglacial warming can take hundreds or thousands of years.”

That’s a concern, given the scale and speed of current anthropogenic changes. In recent years, human activity, rather than natural causes, has become the main factor in oceanic change around the world. Global warming, along with the heavy use of nitrogen-based fertilizers for agriculture, is pushing the natural ocean nitrogen cycle off balance.

“Despite its importance for all marine life, we don’t really have a good handle on how the global ocean will react to these changes,” said Dr. Galbraith. “With too little nitrogen, the ecosystem would starve. Too much, and the decay of sinking phytoplankton would use up the oxygen dissolved in ocean water, suffocating fish and other marine animals.”

This highlights the importance of research on the interplay between climate change and ocean biogeochemistry.

Previous studies on nitrogen isotopes in marine sediment records had shown signs of changes in denitrification at the end of the ice age, in some localized places. But the nitrogen isotope records are difficult to interpret from individual sites alone.

“Our research was driven by our need to provide quantitative constraints of climate change effects on the global ocean,” says Dr. Kienast.

After three years of research, the international team, composed of 35 ocean researchers, completed their goal of assembling a global network of sediment records to see the full picture clearly and compare the results with computer models of the ocean.

“This publication is not the end of it,” says Dr. Kienast. “We have a great group of enthusiastic scientists and we are looking to broaden our group and expand our research. Stay tuned.”

On his recent trip collecting sediment samples in the western tropical Pacific, Dr. Kienast was accompanied by Dalhousie MSc student Liz Kerrigan.

“If you like getting muddy, then you’ll love sediment work,” says Kerrigan. “Ultimately, this information from the sediment helps us reveal a little bit more about what’s happening in the ocean, both today and in the past”.

It is not a rare occasion for Dalhousie Oceanography graduate students to spend time at sea — it’s a key program requirement.

“A requirement that they are usually more than happy to fulfill,” says Dr. Kienast.

Regis Dudley, Communications, Faculty of Science, Dalhousie University, (902) 494-4105, regis.dudley@dal.ca

Regis Dudley | Newswise
Further information:
http://www.dal.ca

More articles from Earth Sciences:

nachricht Stagnation in the South Pacific Explains Natural CO2 Fluctuations
23.02.2018 | Carl von Ossietzky-Universität Oldenburg

nachricht First evidence of surprising ocean warming around Galápagos corals
22.02.2018 | University of Arizona

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Attoseconds break into atomic interior

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...

Im Focus: Good vibrations feel the force

A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.

By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Basque researchers turn light upside down

23.02.2018 | Physics and Astronomy

Finnish research group discovers a new immune system regulator

23.02.2018 | Health and Medicine

Attoseconds break into atomic interior

23.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>