# Short-term responses of temperate and subarctic marine diatoms to Irgarol 1051 and UV radiation: Insights into temperature interactions

## TL;DR

This study examines how temperature affects the impact of a chemical and UV radiation on marine diatoms from different regions.

## Contribution

The study reveals that higher temperatures can reduce the negative effects of Irgarol and UV radiation on diatoms.

## Key findings

- Irgarol and UV radiation significantly inhibit the photochemical performance of marine diatoms.
- Higher temperatures reduce the inhibitory effects of Irgarol and UV radiation on temperate and subarctic diatoms.
- Temperate diatoms show a stronger interaction between temperature and stressors compared to subarctic species.

## Abstract

Phytoplankton face numerous pressures resulting from chemical and physical stressors, primarily induced by human activities. This study focuses on investigating the interactive effects of widely used antifouling agent Irgarol 1051 and UV radiation on the photo-physiology of marine diatoms from diverse latitudes, within the context of global warming. Our findings clearly shown that both Irgarol and UV radiation have a significant inhibitory impact on the photochemical performance of the three diatoms examined, with Irgarol treatment exhibiting more pronounced effects. In the case of the two temperate zone diatoms, we observed a decrease in the inhibition induced by Irgarol 1051 and UVR as the temperature increased up to 25°C. Similarly, for the subarctic species, an increase in temperature resulted in a reduction in the inhibition caused by Irgarol and UVR. These results suggest that elevated temperatures can mitigate the short-term inhibitory effects of both Irgarol and UVR on diatoms. Furthermore, our data indicate that increased temperature could significantly interact with UVR or Irgarol for temperate diatoms, while this was not the case for cold water diatoms, indicating temperate and subarctic diatoms may respond differentially under global warming.