The research group observed that the algae that displayed the most signs of stress were from the zones exposed to the most solar radiation. The results of the research have been published in the Journal of Sea Research.
Gelidium corneum is a very common alga along the Basque coast. It grows at a depth of between 3 and 15 metres, and from September onwards can be seen out of the water. It gets broken up by storms and washed up on the beaches where it forms a red carpet. On some parts of the coast, above all in transparent water zones, the fronds of the algae have turned yellowish. The researchers have identified this change as a symptom of stress.
There are more sunny days during the summer which is when the algae are exposed to increased solar radiation. However, this is not necessarily harmful, since the more light there is, the more the algae will grow. But if the light exceeds the optimum average, the algae become inhibited. After choosing algae populations located at the same depth in five zones along the Biscay coast (Kobarón, Górliz, Ogoño, Ea and Lequeitio), it was possible to observe that the algae in transparent waters were suffering greater stress. The ones under the influence of an estuary, as in the case of Górliz, are in a better condition, since the turbid waters in the zone mean that they are exposed to less solar radiation.
A stressed alga is one that cannot carry out its functions properly. The UPV/EHU researchers used certain biochemical parameters to measure the stress of the alga, and, after examining the results, came across a direct relationship between the amount of solar radiation, antioxidant activity and the C:N ratio of the alga.
The increase in solar radiation increases the alga’s photosynthesis, which happens in any plant. But above certain levels the researchers have been able to confirm that antioxidant activity decreases. In principle, the increase in solar radiation leads to greater antioxidant activity, because this is the mechanism the alga uses to manage the oxygen-free radicals generated when photosynthesis intensifies. But if solar radiation exceeds the limits, the alga suffers fatigue, cannot control the free radicals and goes into basal mode. It only carries out the functions needed to survive.
Yet there is another reason supporting the fact that the excess of solar radiation decreases antioxidant activity: ultraviolet solar radiation directly destroys the enzymes that have an antioxidant capability.
The researchers believe that the excess of solar radiation could lead to another problem. Normally, the more the amount of light increases, the greater the C:N ratio becomes, in other words, the interior percentage of nitrogen decreases. The fact is, the alga needs more nutrients (sources of nitrogen) to increase photosynthesis, and over the summer the quantity of nutrients in the sea tends to run low. So if the solar radiation is excessive, the alga will use the reserves it keeps inside it to survive. These reserves contain pigments that dye the alga red: phycolipoproteins.
If these red pigments are in short supply, the alga turns yellow. This process is similar to that which happens in deciduous trees in autumn: in order to get itself ready for the winter, the tree appropriates the reserves accumulated in the leaves and that is why the leaves turn yellow. In the case of algae, this is not adaptation that takes place on a yearly basis, but a means of protection that is activated at a given moment and could be one of the symptoms of a situation of stress. If the conditions were to deteriorate, the alga would turn white and brittle.
Transparent water is not better
Recent years have seen a fall in the amount of G. corneum algae in some spots along the Basque coast. As observed in another piece of research, the increase in the frequency of storms and big waves is linked to this loss. Likewise, the population displays a weaker appearance in areas of transparent waters, and even though the solar radiation does not directly reduce the amount of algae, it could render the algae more sensitive to possible threats and changes.
The result of the research has been published in the Journal of Sea Research. This research is part of a broader study and comes within the thesis submitted by Endika Quintano, a UPV/EHU Researcher.
About the research team
Endika Quintano (Bilbao, 1984), a Biology graduate, is a researcher in the Bentos Marino group, and is currently writing up his PhD thesis. The UPV/EHU’s Bentos Marino group set up by the Faculty of Science and Technology is dedicated to researching the quantification of coastal impacts, care of the environment and the evaluation of environmental rehabilitation.
The following Bentos Marino researchers also participated in the study alongside Endika Quintano: Unai Ganzedo, Isabel Díez-San Vicente and José María Gorostiaga-Garai. Professor Félix López-Figueroa (Photobiology Unit of the University of Malaga) participated in the study of the biochemical factors.
More articles from Ecology, The Environment and Conservation:
New rearing method may help control of the western bean cutworm
09.12.2013 | Entomological Society of America
The invasive Turkestan cockroach is displacing the oriental cockroach in the southwestern US
09.12.2013 | Entomological Society of America
The molecular architecture of three key proteins and their complexes reveals how plants fine-tune their immune response to pathogens
Plants rarely get sick in their natural environment. When the threat of infection arises, a quick decision is made about the necessary countermeasures. The course is set by a protein which forms complexes with its partner proteins for this purpose.
Jane Parker from the Max Planck Institute for Plant Breeding ...
Researchers studying speciation of butterfly orchids on the Azores have been startled to discover that the answer to a long-debated question "Do the islands support one species or two species?" is actually "three species".
Hochstetter's Butterfly-orchid, newly recognized following application of a battery of scientific techniques and reveling in a complex taxonomic history worthy of Sherlock Holmes, is arguably Europe's rarest orchid species. Under threat in its mountain-top retreat, the orchid urgently requires conservation recognition.
A lavishly illustrated publication, titled "Systematic revision of Platanthera in ...
Researchers from Brown University and the University of Hawaii have found some mineralogical surprises in the Moon's largest impact crater.
Data from the Moon Mineralogy Mapper that flew aboard India's Chandrayaan-1 lunar orbiter shows a diverse mineralogy in the subsurface of the giant South Pole Aitken basin.
The differing mineral signatures could be reflective of the minerals dredged up at the time of the giant impact 4 billion years ago, ...
In power electronics systems bonded connections create the central electrical connections between adjoining surfaces.
The quality of these bonded connections is one of the main factors that determines the reliability and availability of drive systems in electric vehicles, and hence constitutes a major design challenge for German auto manufacturers aiming to electrify their vehicles.
Now the partners participating in the RoBE (Robust Bonds in ...
International team of scientists develops new feedback method for optimizing the laser pulse shapes used in the control of chemical reactions
In many ways, traditional chemical synthesis is similar to cooking. To alter the final product, you can change the ingredients or their ratio, change the method of mixing ingredients, or change the temperature or pressure of the environment of the ingredients.
Like an accomplished chef, chemists have become very skilled ...
11.12.2013 | Information Technology
11.12.2013 | Life Sciences
11.12.2013 | Agricultural and Forestry Science
11.12.2013 | Event News
10.12.2013 | Event News
05.12.2013 | Event News