Stable Isotope Applications in Marine Ecosystem Dynamics

Stable isotope analysis has become a cornerstone method for unraveling energy flow and trophic interactions within marine ecosystems. By measuring the ratios of heavy to light isotopes of carbon and nitrogen in biological tissues, researchers can infer primary production sources, quantify trophic positions and trace nutrient pathways from phytoplankton through zooplankton to higher predators. Advances in isoscape modelling have enabled spatially and temporally explicit maps of baseline isotopic compositions, revealing how environmental gradients, seasonal cycles and anthropogenic pressures shape food‐web structure at local to global scales. Applications range from assessing benthic–pelagic coupling and cross‐ecosystem energy exchange to detecting long‐term shifts in predator diets and ecosystem responses to climate variability. These insights inform sustainable management of fisheries, conservation of vulnerable species and predictions of marine carbon cycling under changing ocean conditions.

Research from Nature Portfolio

Recent studies have applied natural‐abundance stable isotopes to characterise seasonal and size‐structured food‐web dynamics in coastal plankton communities. By sampling mesozooplankton across winter, spring and autumn, isotopic niche metrics revealed a pronounced springtime expansion in carbon source diversity linked to phytoplankton blooms, whereas low‐productivity seasons were dominated by mixed pelagic and benthic inputs. Bayesian mixing models further elucidated predator feeding strategies, showing size-selective prey preferences during productive periods and opportunistic generalism in leaner months. The work highlights how bottom-up processes at the base of the food web propagate through higher trophic levels, underlining the value of isotope approaches for understanding seasonal energy fluxes and ecological resilience.

Stable Isotope Applications in Marine Ecosystem Dynamics publication trend

The graph below shows the total number of articles in stable isotope applications in marine ecosystem dynamics across all publications each year (not limited to Nature Index journals).

Technical terms

δ13C and δ15N: Ratios of stable carbon and nitrogen isotopes in tissues, indicating carbon sources and trophic enrichment respectively.

Isoscape: A spatially explicit model of isotopic variation across a landscape or seascape.

Mixing model: A quantitative approach that estimates the proportional contributions of multiple dietary sources to a consumer’s isotopic signature.

Trophic position: The relative level an organism occupies in a food web, inferred from nitrogen isotope enrichment with each trophic transfer.

References

1. Insights into planktonic food-web dynamics through the lens of size and season. Scientific Reports (2024).
2. Cross‐ecosystem trophic structure and benthic–pelagic coupling: Effects of depth, body size, and feeding guild. Limnology and Oceanography (2025).
3. Spatial models of carbon, nitrogen and sulphur stable isotope distributions (isoscapes) across a shelf sea: An INLA approach. Methods in Ecology and Evolution (2019).
4. Temporal dynamics in zooplankton δ13C and δ15N isoscapes for the North Atlantic Ocean: Decadal cycles, seasonality, and implications for predator ecology. Frontiers in Ecology and Evolution (2022).