A team led by Patrick Martin of the National Oceanography Centre has shown that a species of planktonic marine alga can rapidly change the chemical composition of its cell membranes in response to changes in nutrient supply. The findings indicate that the process may be important for nutrient cycling and the population dynamics of phytoplankton in the open ocean.
Tiny free-floating algae called phytoplankton exist in vast numbers in the upper ocean. Through the process of photosynthesis, they use the energy of sunlight to produce organic compounds required for growth, which draws large amounts of carbon dioxide down from the atmosphere. However, they also need other nutrients such as phosphorus, which is chronically scarce in many oceanic regions.
"We are interested in the adaptations of phytoplankton living in regions where nutrients are in short supply," explained Patrick Martin.
Under normal growth conditions, the cell membranes of phytoplankton contain phosphorus-based lipids called phospholipids. However, it has been appreciated for some time that phytoplankton can exchange their membrane phospholipids with non-phosphorus lipids when phosphorus is in short supply. This substitution saves the cells some phosphorus, which can then be used for other important growth processes such as making new DNA.
"Until now, it has been unclear how rapidly phytoplankton cells are able to change the phosphorus composition of their membranes, and hence whether this process is important over the life-time of individual cells" said Patrick Martin.
To address the issue, he and his collaborators from Woods Hole Oceanographic Institution (WHOI) in the United States performed growth experiments with a species called Thalassiosira pseudonana, which biologists use as a model species representative of a very important group of phytoplankton called diatoms.
They found that when the diatoms were starved of phosphorus their membrane phospholipids were replaced with lipids lacking phosphorus over a couple of days. Moreover, when the diatoms were re-supplied with phosphorus, they rapidly renewed the phospholipid content of their cell membranes, removing the lipids lacking phosphorus.
"Our research now shows that this substitution, at least in the alga we studied, can take place within 24 hours, and is clearly a physiological response by individual cells to the phosphorus concentration in their environment – as opposed to a longer-term adjustment over successive generations," said Patrick Martin.
The researchers also show that when cells have ample phosphorus, their phospholipids contain a surprisingly large amount of phosphorus. Therefore, if these cells suddenly encounter low phosphorus conditions, they have quite a substantial phosphorus reserve in their lipids, which might be significant for supporting further growth.
"Phosphorus concentrations in the ocean can be locally enhanced by physical features such as eddies in the water, and rapid remodelling of lipid membranes might allow phytoplankton to exploit such conditions," said Patrick Martin.
The researchers are Patrick Martin (NOC), and Benjamin Van Mooy, Abigail Heithoff and Sonya Dyhrman (WHOI). The work was conducted while Patrick Martin visited Woods Hole on an exchange programme last autumn.
This research was funded by the United States' National Science Foundation and by the Graduate School of the NOC in Southampton.
Publication: Martin, P., Van Mooy, B. A. S., Heithoff, A. & Dyhrman, S. T. Phosphorus supply drives rapid turnover of membrane phospholipids in the diatom Thalassiosira pseudonana. ISME J. (published online, 16 December 2010).
Dr Rory Howlett | EurekAlert!
Understanding animal social networks can aid wildlife conservation
23.06.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
Making Oceans Plastic Free - Project tackles the problem of plastic pollution in the oceans
31.05.2017 | Leibniz-Zentrum für Marine Tropenforschung (ZMT)
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
23.06.2017 | Physics and Astronomy
23.06.2017 | Life Sciences
23.06.2017 | Information Technology