Diminished growth and vitality in juvenile Hydractinia echinata under anticipated future temperature and variable nutrient conditions

Daniel Tschink,Michael Winklhofer,Laura Eickelmann,Yvonne Schadewell,Cora Kohlmeier,Bernd Blasius,Julia Strahl,Gabriele Gerlach

doi:10.1038/s41598-021-86918-4

Abstract

In a warming climate, rising seawater temperatures and declining primary and secondary production will drastically affect growth and fitness of marine invertebrates in the northern Atlantic Ocean. To study the ecological performance of juvenile hydroids Hydractinia echinata we exposed them to current and predicted water temperatures which reflect the conditions in the inter- and subtidal in combination with changing food availability (high and low) in laboratory experiments. Here we show, that the interplay between temperature stress and diminished nutrition affected growth and vitality of juvenile hydroids more than either factor alone, while high food availability mitigated their stress responses. Our numerical growth model indicated that the growth of juvenile hydroids at temperatures beyond their optimum is a saturation function of energy availability. We demonstrated that the combined effects of environmental stressors should be taken into consideration when evaluating consequences of climate change. Interactive effects of ocean warming, decreasing resource availability and increasing organismal energy demand may have major impacts on biodiversity and ecosystem function.

Highlights

In a warming climate, rising seawater temperatures and declining primary and secondary production will drastically affect growth and fitness of marine invertebrates in the northern Atlantic Ocean
Colony area and polyp number were lower at the higher temperature (21 °C) combined with insufficient food availability (Figs. 1, 2; Supplementary Tables 2 and 3)
In scenario 1, the juvenile growth rates were highest at high food (HF)/18 °C and lowest at low food (LF)/21 °C (Fig. 2), with a reduction by 77% in area growth rate (p < 0.001, Table 1, Fig. 2a) and by 72% in polyp growth rate (p = 0.013, Table 1, Fig. 2b) (Supplementary Tables 2 and 3)

Summary

Introduction

In a warming climate, rising seawater temperatures and declining primary and secondary production will drastically affect growth and fitness of marine invertebrates in the northern Atlantic Ocean. While the effects of changing water temperatures on benthic and pelagic ectotherms have been investigated in recent decades (e.g.18–20), temperature-nutrient interactions in temperate marine ectotherms have received little attention. Their ecological consequences are difficult to assess, due to the complexity of the organism—environment interactions and of the interacting physiological and ecological processes underlying stress resistance, resilience and acclimation/adaptation of marine organisms to predicted environmental c hanges[21]. In the intertidal, temperature fluctuations caused by tides may increase temperature stress in the future and potentially intensify the effects of temperature-nutrient interactions on marine organisms

Methods

Results

Conclusion