Delta-C-13; δ13C

Measure for the enrichment of the stable carbon isotope 13C in the food web

Carbon has two stable isotopes, 13C and 12C. They differ in their atomic masses and can therefore be detected separately by means of mass spectrometry (isotope ratio MS). The lighter isotope 12C is more frequent constituting 98.9% of the total carbon whereas 13C contributes only with 1.1%.

In nature, the ratio of 13C to 12C depends mainly on the photosynthesis efficiency of plants.
The lighter isotope 12C reacts faster and its enzymatic transformation is more rapid. This leads to an enrichment of the heavier isotope 13C in organisms. This enrichment progresses in the food web.

The differences between ratios are normally small. They are considered in relation to one another using the so-called δ-notation (δ13C), the values being expressed as per mille (‰). An increase in δ13C indicates an increase of 13C accumulation in the sample.
The δ13C values of organisms are influenced by their immediate environment and their food and can therefore provide information on the origin of samples and the nutrition of organisms.
In aquatic ecosystems, the δ13C value can be used to distinguish between the two major energy sources – attached algae and detritus on the one hand and phytoplankton on the other. This helps to assign organisms either to the littoral or the pelagic food web.


Zebra mussel Common mussel species as invasive animal in rivers and lakes with high information level for water pollution
Bream Bioindicator in rivers and lakes
Suspended particulate matter Fine insoluble mineral or organic particles in the water phase
Common bladder wrack Common brown alga of the coastal areas of the North and Baltic Sea
Blue mussel One of the most important edible mussel species common in the North and Baltic Sea
Eelpout As the only viviparous fish in German nearshore waters, it is a bioindicator in nearshore coastal marine ecosystems.
Herring gull Inshore, the herring gull mainly feeds from the sea: upon fish, mussels, and crabs.
Common spruce A major primary producer in semi-natural and anthropogenic affected ecosystems.
Pine A major primary producer in semi-natural and anthropogenic affected ecosystems.
Lombardy poplar A deciduous tree typical of ecosystems close to dense conurbations and an indicator for the characterisation of the immission situation during the vegetation period.
Beech As the most dominant deciduous tree species in Central Europe, it plays a significant role in most nearly natural and also anthropogenically influenced forest ecosystems up to an altitude of 1100 m.
Roe deer, one-year-old The roe deer is the most common of the larger herbivores (first order-consumer) to be found in the wild in Europe.
Feral pigeon A pigeon species home in nearly every city.
Earthworm (Aporrectodea longa) As an organism living at ground level, it is a major driver of the decomposition of organic material (e.g. plant litter).
Earthworm (Lumbricus terrestris) As an organism living at ground level, it is a major driver of the decomposition of organic material (e.g. plant litter).
Soil Soil is livelihood and biosphere for humans, animals, plants and soil organisms. All the substances brought in are transported, transformed and/or accumulated in the soil.

Sampling area

BR/NP Berchtesgaden The only high mountains national park in Germany and an area of the Limestone Alps with international relevance
Saarländischer Verdichtungsraum Important, old-industrialised conurbation in Germany.
Bornhöveder Seengebiet Main water divide between the North- and Baltic Sea
Rhein Longest river in Germany
NP Bayerischer Wald Germany's first national park
NP Vorpommersche Boddenlandschaft National Park in the largest brackish water (Bodden) habitat of the world.
BR/NP Wattenmeere National park in the world largest connected sand and mud flats.
Elbe Fourth largest river basin in Central Europe
Verdichtungsraum Halle-Leipzig Region in the chemical triangle of Central Germany
NP Harz Germany's largest forest national park
Solling Second highest and largest low mountain range in Northern Germany
BR Pfälzerwald Germany's largest connected forest area in a range of low mountains
Oberbayerisches Tertiärhügelland The Upper Bavarian Tertiary Uplands are a part of the Southern German Molasse Basin
Donau Second largest river in Europe

Sampling period

1991 - 2019