Environmental and Experimental Botany

Raw data for statistics analyses proposed and exposed in the manuscript file.

original data of the presented result section

Cleaned data and analysis scripts including GC/MS, LC/MS, photosynthesis, plant growth, and weather data. Data are stored as .rds files which can be opened in R. Analysis scripts are as .Rmd (R Markdown) files which can be viewed in R Studio where they can be converted to Word, PDF, or HTML files for easier viewing if you wish. Data descriptions are in a README file as well as in the .Rmd files themselves.

Raw data

The quality data used in manuscript includes protein and starch quality parameters.

Rising levels of anthropogenic carbon dioxide (CO2) in the atmosphere over the past several decades has resulted in a changing climate and is projected to further fuel global climate change in future centuries. Key components of climate change in the ocean are ocean acidification (decreasing pH and carbonate ion concentration [ CO32- ]) and rising sea surface temperatures. While several studies have investigated the effect of these climatic changes on a single population, very few studies have addressed effects on populations living at the margins of their species distribution and the full distributional range. This gap in knowledge impedes the determination of detailed predictions for most species' futures. Over the course of four months, we investigated physiological changes (primary production, respiration, calcification and growth rates) of 6 populations of the intertidal ecosystem engineer and articulated coralline alga Corallina officinalis to future climatic conditions (low pH (∼7.8); T + 3 °C; as well as the combination of low pH and T + 3 °C). The populations (n = 2 per geographical location) represent the northern (Iceland) and southern (Spain) margins, as well as the centre (England) of the species distribution in the NE Atlantic. Here, we show that southern and central populations are already living closer to their thermal and stress limits, while Northern populations appear to be the most resilient to environmental changes. We present data confirming light calcification to be the most valuable physiological process which is prioritized in populations throughout the geographical gradient in the NE Atlantic. We found elevated temperature to have a greater effect on populations than pCO2. Investigating and monitoring organism physiology and structure under these extreme environmental conditions provides important information to predict their acclimatisation and resilience to future environmental conditions and potential changes in their distribution.

Cu is considered to be toxic to macroalgae at higher levels. Ocean acidification can also alter the physiological performances of macroalgae. However, little is known regarding the interactive effects of Cu and ocean acidification on macroalgae. In this study, a green tide macroalga, Ulva prolifera, was cultured at the conditions of three levels of Cu (control, 0.5 µM, and 2 µM) and pCO2 (ambient, 1000 µatm, and 1400 µatm) to investigate the responses of U. prolifera to interaction of Cu exposure and ocean acidification. The relative growth rate of thalli decreased with the rise of Cu for all pCO2 conditions except the 1000 ?atm pCO2. Compared with the control, 2 µM Cu reduced the net photosynthetic rate for all pCO2 conditions while 0.5 µM Cu only reduced it at 1400 µatm pCO2. The inhibition rate of Cu on the relative growth rate and net photosynthetic rate was reduced at 1000 µatm pCO2 but was magnified at 1400 ?atm pCO2. Contrary to growth, the dark respiration rate was enhanced by 0.5 µM Cu at ambient pCO2 and by 2 µM Cu at ambient and 1000 µatm pCO2, although it was reduced by 2 µM Cu at 1400 µatm pCO2 compared to the control. The 0.5 µM Cu did not affect the relative electron transport rate (rETR) for any pCO2 condition but 2 µM Cu decreased it for all pCO2 conditions except 1000 µatm pCO2. The mute effect of 0.5 µM Cu on the net photosynthetic rate and rETR at ambient pCO2 may be due to more Chl a and Chl b being synthesized. In addition, 2 µM Cu and 1400 µatm pCO2 led to branched thalli, which may be a defense mechanism against the stress of high Cu and pCO2. Our data, for the first time, demonstrate that a modest increase of pCO2 can alleviate the toxicity of Cu to U. prolifera whilst a further increase exacerbates it. U. prolifera can respond to the stress of Cu pollution and ocean acidification via physiological and morphological alterations.

Global change factors derived from anthropogenic activities such as increased CO2 and ultraviolet radiation (UVR) have direct impacts on the physiological responses of organisms in both terrestrial and aquatic ecosystems. We assessed in this work the mechanistic, physiological and molecular response of the unicellular chlorophyte Dunaliella tertiolecta exposed to combinatorial present (390 ppmv, LC) and future CO2 levels predicted for the year 2100 (900 ppmv, HC) and different UVR doses. Growth rates, cell esterase activity, reactive oxygen species accumulation (ROS), and 14C fixation decreased under HC compared to LC. The deleterious effects of UVR were attenuated in HC, except for decreased photosynthetic capacities. Transcriptome analysis showed different expression patterns depending on UVR and CO2 levels. PsbA, LhcII and eCA gene expression was downregulated at HC compared to LC. However, photolyase (PL) gene expression was upregulated at HC with respect LC in UVR. This suggests that HC (as opposed to LC) promoted a "low-metabolic steady state", decreasing UVR exposure-activated repair by means of protein replacement. Only PL photoreactivation was active under HC. Our data add evidence on D. tertiolecta possibly becoming more resilient to UVR exposure under future CO2 regimes, and maybe other marine unicellular chlorophytes, warranting serious considerations on the consequent ecological implications.

Extreme winter warming events in the sub-Arctic have caused considerable vegetation damage due to rapid changes in temperature and loss of snow cover. The frequency of extreme weather is expected to increase due to climate change thereby increasing the potential for recurring vegetation damage in Arctic regions. Here we present data on vegetation recovery from one such natural event and multiple experimental simulations in the sub-Arctic using remote sensing, handheld passive proximal sensors and ground surveys. Normalized difference vegetation index (NDVI) recovered fast (2 years), from the 26% decline following one natural extreme winter warming event. Recovery was associated with declines in dead Empetrum nigrum (dominant dwarf shrub) from ground surveys. However, E. nigrum healthy leaf NDVI was also reduced (16%) following this winter warming event in experimental plots (both control and treatments), suggesting that non-obvious plant damage (i.e., physiological stress) had occurred in addition to the dead E. nigrum shoots that was considered responsible for the regional 26% NDVI decline. Plot and leaf level NDVI provided useful additional information that could not be obtained from vegetation surveys and regional remote sensing (MODIS) alone. The major damage of an extreme winter warming event appears to be relatively transitory. However, potential knock-on effects on higher trophic levels (e.g., rodents, reindeer, and bear) could be unpredictable and large. Repeated warming events year after year, which can be expected under winter climate warming, could result in damage that may take much longer to recover.