We are proud to share that our TipESM Researchers have published a new paper on 10 October 2025.

Dees, P., Fröb, F., Arellano-Nava, B., Johns, D. G., and Heinze, C.: A novel multispecies approach for the detection of regime shifts in a plankton community – a case study in the North Sea, Ocean Sci., 21, 2397–2417, https://doi.org/10.5194/os-21-2397-2025, 2025.

The physical environment both above and below the ocean surface has changed dramatically during the last century. Changes in the marine environment induced by increased greenhouse gas emissions and direct resource exploitation include increased ocean temperatures, decreased salinity and pH, and theremoval of apex predators. The risk of ecological regime shifts occurring has similarly increased.

A variety of methodologies to identify regime shifts have already been used in the North Sea, which has become a critical case study for the analysis of regime shifts in a semi-enclosed water body.

The North Sea is regarded as a case study in part due to the operation of the continuous plankton recorder, which has provided detailed abundance records of phyto- and zooplankton for over 60 years. Here, the study proposes a new methodology to calculate the likelihood of regime shifts for each month between 1958 and 2020. This unique model produces a single time series of regime-shift likelihood from sequential abundance data for more than 300 plankton species. The study shows the model’s ability to identify past regime shifts by comparing it with previous, less automated methodologies.

The authors have validated the model for use in the North Sea by estimating the frequency of false positives and false negatives. Results from the model indicate evidence for three periods of high regime-shift likelihood in various parts of the North Sea: between 1962 and 1972, between 1989 and 1999, and from 2002 to 2015.

These periods are consistent with previous estimates of North Sea regime shifts, and the study discusses possible applications of the model’s output of a single time series.