Marine biologist from Warnemünde presents indicator for the state of foodwebs in the Baltic Sea on the basis of long-term data series on the composition of spring blooms
The European Union declared it their target to re-establish a „good ecological status“ in European seas by 2020. Quite a challenging task! But what actually is a good ecological status?
Like of us humans, the „state of health“ of an ecosystem cannot be defined by one single factor only. It is important to take all basic functions into account. Therefore, in total eleven so called descriptors were defined. „Eutrophication“ is such a descriptor to describe the state of the ecosystem, „food web stability“ another.
The quality of the food web in the Baltic Sea and how it can be determined is subject of two articles by Norbert Wasmund, phytoplanktologist at the Leibniz Institute for Baltic Sea Research Warnemünde, recently published in the international open access journal „Frontiers in Marine Science“. He describes a new indicator basing on relatively simple measurements and simultaneously applicable as an indicator for eutrophication: the diatoms/dinoflagellates index - in short: the dia/dino index.
Once the days get longer in spring, the seas and oceans experience the so called spring bloom: microalgae use the energy of the sun light in order to build up organic substances by means of basic elements as carbon, nitrogen and phosphorus. In the course of a few days to weeks, the microorganisms reproduce themselves very rapidly.
In the Baltic Sea, these organisms mainly belong to the groups of diatoms and dinoflagellates. They are essentially responsible for the foundation of a food pyramid upon which nearly all other forms of marine life depend and on the top of which marine mammals and human beings are positioned. The dia/dino index describes which of the two groups dominated the yearly spring bloom. This in turn is decisive for organisms preying them: Diatoms with a relatively heavy silica shell sink to the seafloor immediately after their death.
Thus, beside the zooplankton preying them in the surface waters, the zoobenthos at the seafloor, too, benefits from this food source. Dinoflagellates are lighter and do not sink to the seafloor after their death in such a rapid way as the diatoms do. In the consequence, zooplankton can benefit from them for a longer time, but nearly nothing is left to feed the zoobenthos. Norbert Wasmund explains: “If diatoms dominate the spring bloom, more parts of the food web take profit than if dinoflagellates are the major group. So, this simple relation provides us with a good measure to describe the state of the food web“.
As a benchmark for a good ecological status in the Baltic Sea serve the environmental conditions in the first half of the 20th century. Fortunately, we can already rely on observational data from this time, when the environmental damage can be regarded as negligible.
Phytoplankton data from the Baltic Sea exist since the beginning of the 20th century. Therefore, calculating the respective historical status of the dia/dino index is possible. Norbert Wasmund summarizes the results: “It turned out that under the early conditions, diatoms always dominated the spring bloom. It was as late as in the 1980ies, when dinoflagellates became the dominant group of the spring bloom, indicating poor conditions for the food web.” Since the turn of the millennium the values of the dia/dino index improved again. Whether this is an enduring or just a short-term change can easily be tracked down by means of the data systematically collected in the frame of the HELCOM monitoring programme and therefore continuously at hand for calculating the index.
The state of the food web is just ONE aspect when assessing the ecological status. The Helsinki Commission currently elaborates a holistic assessment, which integrates all eleven descriptors. A first version comprising the years 2011 – 2015 is already available under https://stateofthebalticsea.helcom.fi.
The referred articles are available under:
Wasmund, N., Kownacka, J., Göbel, J., Jaanus, A., Johansen, M., Jurgensone, I., et al. (2017). The Diatom/Dinoflagellate index as an indicator of ecosystem changes in the Baltic Sea. 1. Principle and handling instruction. Front. Marine Sci. 4:22. https://doi.org/10.3389/fmars.2017.00022
Wasmund, N. (2017). The Diatom/Dinoflagellate Index as an Indicator of Ecosystem Changes in the Baltic Sea. 2. Historical Data for Use in Determination of Good Environmental Status. Front. Mar. Sci. 4:153.
Dr. Norbert Wasmund, IOW, phone: +49 381 5197 212,
Dr. Barbara Hentzsch (press and media officer), IOW, phone: +49 381 5197 102, E-mail: firstname.lastname@example.org
IOW is a member of the Leibniz Association with currently 91 research institutes and scientific infrastructure facilities. The focus of the Leibniz Institutes ranges from natural, engineering and environmental sciences to economic, social and space sciences as well as to the humanities. The institutes are jointly financed at the state and national levels. The Leibniz Institutes employ a total of 18.100 people, of whom 9.200 are scientists. The total budget of the institutes is 1.6 billion Euros. (www.leibniz-association.eu )
Dr. Barbara Hentzsch | idw - Informationsdienst Wissenschaft
Reducing manure and fertilizers decreases atmospheric fine particles
30.10.2017 | Max-Planck-Institut für Chemie
Flagship species could help protect freshwaters
26.10.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
The Fraunhofer Institute for Laser Technology ILT and Rapid Shape GmbH are working together to further develop resin-based 3D printing. The new “TwoCure” process requires no support structures and is significantly more efficient and productive than conventional 3D printing techniques for plastic components. Experts from Fraunhofer ILT will be presenting the state-funded joint development that makes use of the interaction of light and cold in forming the components at formnext 2017 from November 14 to 17 in Frankfurt am Main.
Much like stereolithography, one of the best-known processes for printing 3D plastic components works using photolithographic light exposure that causes liquid...
A team of researchers led by Prof. Wolfram Pernice from the Institute of Physics at Münster University has developed a miniature abacus on a microchip which calculates using light signals. With it they are paving the way to the development of new types of computer in which, as in the human brain, the computing and storage functions are combined in one element.
Researchers at the universities of Münster, Exeter and Oxford have developed a miniature “abacus” which can be used for calculating with light signals. With it...
Extremely short electron bunches are key to many new applications including ultrafast electron microscopy and table-top free-electron lasers. A german team of physicists from Rostock University, the Max Born Institute in Berlin, the Ludwig-Maxmilians-Universität Munich, and the Max Planck Institute of Quantum Optics in Garching has now shown how electrons can be accelerated in an extreme and well-controlled way with laser light, while crossing a silver particle of just a few nanometers.
Of particular importance for potential applications is the ability to manipulate the acceleration process, known as a swing-by maneuver from space travel, with...
Cancer cells can reactivate a cellular process that is an essential part of embryonic development. This allows them to leave the primary tumor, penetrate the surrounding tissue and form metastases in peripheral organs. In the journal Nature Communications, researchers from the University of Basel’s Department of Biomedicine provide an insight into the molecular networks that regulate this process.
During an embryo’s development, epithelial cells can break away from the cell cluster, modify their cell type-specific properties, and migrate into other...
30.10.2017 | Event News
23.10.2017 | Event News
17.10.2017 | Event News
03.11.2017 | Physics and Astronomy
03.11.2017 | Earth Sciences
03.11.2017 | Physics and Astronomy