Abstract
While it is well known that severe marine summer heatwaves can cause acute and dramatic die-offs of seagrass meadows, the effect of trans-seasonal warming and winter/spring heatwaves are yet poorly understood. This study simulated a 9-months warming scenario on the common seagrass Zostera marina from winter into summer, using outdoor mesocosms, which provided near-natural conditions. The relevance of the natural temperature pattern, as well as the 3.6°C warming, and their implications were further discussed in the context of a 22-yr temperature time series of the study region. Survival of plants was high in winter independent of temperature. In spring, however, heat-treated Z. marina flowered 1.5 months earlier and experienced high mortalities. Thereafter, plant survival, growth, and pigmentation were largely comparable between temperature regimes. Yet, a comparatively high mortality occurred in ambient plants, after an abnormally warm June. Final biomass was reduced by ~ 50% in heat-treated plants. These results imply that warm winter-to-spring conditions can have severe effects on vital seagrass traits. Warming accelerates consumption of energy reserves triggering advanced flowering, similar to many terrestrial plants. Although, surviving heat-treated plants were not able to re-stock energy reserves throughout the high-light summer as inferred from low plant biomass, these seemed rather resistant to summer heatwave events.
| Original language | English |
|---|---|
| Pages (from-to) | 4112-4124 |
| Number of pages | 13 |
| Journal | Limnology and Oceanography |
| Volume | 66 |
| Issue number | 12 |
| DOIs | |
| Publication status | Published - Dec 2021 |
| MoE publication type | A1 Journal article-refereed |
Funding
We thank Nadja Stärck for pigment analysis, Anna‐Lena Kolze for biomass determination, Emi Ya and Boni de la Cruz for assisting in data collection, Martin Wahl in input in the experimental design and project coordination, and the research divers at GEOMAR for collection. This project was partly funded by GEOMAR and by the Cluster of Excellence “The Future Ocean.” The “Future Ocean” is funded within the framework of the Excellence Initiative by the Deutsche Forschungsgemeinschaft (DFG) on behalf of the German federal and state governments. M.I. acknowledges financial support of CAPES foundation (Ministry of Education of Brazil) through the Doctoral Programme (process number: 99999.001303/2015‐05). C.P. was funded by the postdoc program of the Helmholtz‐Gemeinschaft Deutscher Forschungszentren and by GEOMAR and supported through the German Research Foundation (DFG) project: The neglected role of environmental fluctuations as modulator of stress and driver of rapid evolution (Grant Number: PA 2643/2/348431475). Z. marina We thank Nadja St?rck for pigment analysis, Anna-Lena Kolze for biomass determination, Emi Ya and Boni de la Cruz for assisting in data collection, Martin Wahl in input in the experimental design and project coordination, and the research divers at GEOMAR for Z. marina collection. This project was partly funded by GEOMAR and by the Cluster of Excellence ?The Future Ocean.? The ?Future Ocean? is funded within the framework of the Excellence Initiative by the Deutsche Forschungsgemeinschaft (DFG) on behalf of the German federal and state governments. M.I. acknowledges financial support of CAPES foundation (Ministry of Education of Brazil) through the Doctoral Programme (process number: 99999.001303/2015-05). C.P. was funded by the postdoc program of the Helmholtz-Gemeinschaft Deutscher Forschungszentren and by GEOMAR and supported through the German Research Foundation (DFG) project: The neglected role of environmental fluctuations as modulator of stress and driver of rapid evolution (Grant Number: PA 2643/2/348431475). Open access funding enabled and organized by Projekt DEAL.