Effects of temperature on the behaviour and metabolism of an intertidal foraminifera and consequences for benthic ecosystem functioning

• Published in: Scientific reports Vol. 11; no. 1; pp. 4013 - 14
• Main Authors: Deldicq, Noémie, Langlet, Dewi, Delaeter, Camille, Beaugrand, Grégory, Seuront, Laurent, Bouchet, Vincent M. P.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 17-02-2021; Nature Publishing Group; Nature Portfolio
• Subjects: 704/158/2165; 704/158/2445; 704/158/856; Biodiversity and Ecology; Biogeochemical cycles; Chloroplasts; Climate Change; Ecological function; Ecosystem; Environmental Sciences; Foraminifera - metabolism; Foraminifera - physiology; Geologic Sediments - microbiology; Heat waves; Herbivores; High temperature; Humanities and Social Sciences; Locomotion; Marine Biology - methods; Marine sediments; multidisciplinary; Organic matter; Science; Science (multidisciplinary); Sediments; Temperature; Temperature effects; Tides
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-021-83311-z

Heatwaves have increased in intensity, duration and frequency over the last decades due to climate change. Intertidal species, living in a highly variable environment, are likely to be exposed to such heatwaves since they can be emerged for more than 6 h during a tidal cycle. Little is known, however, on how temperature affects species traits (e.g. locomotion and behaviour) of slow-moving organisms such as benthic foraminifera (single-celled protists), which abound in marine sediments. Here, we examine how temperature influences motion-behaviour and metabolic traits of the dominant temperate foraminifera
Haynesina germanica
by exposing individuals to usual (6, 12, 18, 24, 30 °C) and extreme (high; i.e. 32, 34, 36 °C) temperature regimes. Our results show that individuals reduced their activity by up to 80% under high temperature regimes whereas they remained active under the temperatures they usually experience in the field. When exposed to a hyper-thermic stress (i.e. 36 °C), all individuals remained burrowed and the photosynthetic activity of their sequestered chloroplasts significantly decreased. Recovery experiments subsequently revealed that individuals initially exposed to a high thermal regime partially recovered when the hyper-thermic stress ceased.
H. germanica
contribution to surface sediment reworking substantially diminished from 10 mm
3
indiv
−1
day
−1
(usual temperature) to 0 mm
3
indiv
−1
day
−1
when individuals were exposed to high temperature regimes (i.e. above 32 °C). Given their role in sediment reworking and organic matter remineralisation, our results suggest that heatwaves may have profound long-lasting effects on the functioning of intertidal muddy ecosystems and some key biogeochemical cycles.