Growth strategies of a model picoplankter depend on social milieu and pCO2

Phytoplankton exist in genetically diverse populations, but are often studied as single lineages (single strains), so that interpreting single-lineage studies relies critically on understanding how microbial growth differs with social milieu, defined as the presence or absence of conspecifics. The properties of lineages grown alone often fail to predict the growth of these same lineages in the presence of conspecifics, and this discrepancy points towards an opportunity to improve our understanding of the factors that affect lineage growth rates. We demonstrate that different lineages of a marine picoplankter modulate their maximum lineage growth rate in response to the presence of non-self conspecifics, even when resource competition is effectively absent. This explains why growth rates of lineages in isolation do not reliably predict their growth rates in mixed culture, or the lineage composition of assemblages under conditions of rapid growth. The diversity of growth strategies observed here are consistent with lineage-specific energy allocation that depends on social milieu. Since lineage growth is only one of many traits determining fitness in natural assemblages, we hypothesize that intraspecific variation in growth strategies should be common, with more strategies possible in ameliorated environments that support higher maximum growth rates, such as high CO(2) for many marine picoplankton

Evolutionary temperature compensation of carbon fixation in marine phytoplankton

The efficiency of carbon sequestration by the biological pump could decline in the coming decades because respiration tends to increase more with temperature than photosynthesis. Despite these differences in the short-term temperature sensitivities of photosynthesis and respiration, it remains unknown whether the long-term impacts of global warming on metabolic rates of phytoplankton can be modulated by evolutionary adaptation. We found that respiration was consistently more temperature dependent than photosynthesis across 18 diverse marine phytoplankton, resulting in universal declines in the rate of carbon fixation with short-term increases in temperature. Long-term experimental evolution under high temperature reversed the short-term stimulation of metabolic rates, resulting in increased rates of carbon fixation. Our findings suggest that thermal adaptation may therefore have an ameliorating impact on the efficiency of phytoplankton as primary mediators of the biological carbon pump

Enhanced biofilm formation aids adaptation to extreme warming and environmental instability in the diatom Thalassiosira pseudonana and its associated bacteria

These files contain all data necessary to create the figures published in "Enhanced biofilm formation aids adaptation to extreme warming and environmental instability in the diatom Thalassiosira pseudonana and its associated bacteria". In most cases, these are also the data that were used for analysis. Raw data and R code are available from the author upon request. Sequencing data will be available From GenBank in due course (accession numbers will be added to the zenodo file descriptor). 1. File "20180930_biofilm_trajectories" contains the evolutionary trajectories of biofilm forming cells. The column names are as follows: 'count' for number of cells, 'size' is a unites ImageJ estimate, '%area' gives the area of the cover slip that had biofilm growth, 'date' is the date of the measurement and was used for internal purposes only, 'temp' is the selection temperature , 'nutrient' gives the nutrient status with n+ for nutrient replete and n- for lower nutrient status, 'week' for week of the experiment. Evoplas indicates whether the measurement was for the evolved samples in their selection environment ('evo', assay temperature is the same as selection temperature) or whether it was an assay for plasticity ('plas' , assay at a temperature other than the selection temperature). assay details the assay temperature. These data can be used to re-create and analyse Figure 3. (Figures 1 and 2 are conceptual figures; i.e there are no data associated) 2. File "20180930Ability_to_form_biofilms" contains data for analysing whether a naive planktonic sample presented with a coverslip grows in a biofilm as well as a sample selected to form biofilms. Column names are the same as above, apart from the 'ability [...]' column, which is the ratio of biofilm growth of a biofilm-selected sample compared to a naive sample. Values >1 indicate that the biofilm selected samples grew larger biofilms faster than a planktonic samples subjected to the same conditions. These data are for Figure 6. 3. File "20183009_biofilm_characterise" contains the data for Figure 4, i.e. information on cell size, chlorophyll a content, and bacterial load. The column names are as follows: trait is for either cell diameter in µm ('size'), chlorophyll a content ('chlorophyll'), or bacterial load. Selection temp is the selection temperature and nutr, the nutrient regime with full for full f/2 media and deplete for 1/3 of f/2 media. in 'sampletype' p is for planktonic cells, bf for the biofilm cells, and pbf for planktonic cells sloughed off the biofilm. Traitvalue is for the trait values. Size in µm, chlorophyll in pg per cell, and bacterial load in % of total biomass

Data from: Plasticity predicts evolution in a marine alga

Under global change, populations have four possible responses: ‘migrate, acclimate, adapt or die’ (Gienapp et al. 2008 Climate change and evolution: disentangling environmental and genetic response. Mol. Ecol. 17, 167–178. (doi:10.1111/j.1365-294X.2007.03413.x)). The challenge is to predict how much migration, acclimatization or adaptation populations are capable of. We have previously shown that populations from more variable environments are more plastic (Schaum et al. 2013 Variation in plastic responses of a globally distributed picoplankton species to ocean acidification. Nature 3, 298–230. (doi:10.1038/nclimate1774)), and here we use experimental evolution with a marine microbe to learn that plastic responses predict the extent of adaptation in the face of elevated partial pressure of CO2 (pCO2). Specifically, plastic populations evolve more, and plastic responses in traits other than growth can predict changes in growth in a marine microbe. The relationship between plasticity and evolution is strongest when populations evolve in fluctuating environments, which favour the evolution and maintenance of plasticity. Strikingly, plasticity predicts the extent, but not direction of phenotypic evolution. The plastic response to elevated pCO2 in green algae is to increase cell division rates, but the evolutionary response here is to decrease cell division rates over 400 generations until cells are dividing at the same rate their ancestors did in ambient CO2. Slow-growing cells have higher mitochondrial potential and withstand further environmental change better than faster growing cells. Based on this, we hypothesize that slow growth is adaptive under CO2 enrichment when associated with the production of higher quality daughter cells

Data for Figure 2

Columns in data file contain - evoplas (evolved plasticity), iniplas (initial plasticity), as well as - evoplassd and - iniplassd (standard deviations pooled here for three biological and three technical replicates). clade - A,B,C,D - clade as found by ITS sequences

Data for Figure 1

Description: columns in csv file contain data as follows: ecotype - lineage of Ostreococccus. Initial plasticity - plasticity as measured at t0. Response - fitness response as measured at t400. for calculation see main manuscript and SI. whichresp - indicates whether response was measured in ancestral or selection environment. sdini and sdresp are standard deviations for plasticity at t0 and fitness response at t400 respectively. Here, they are pooled for 3 biological and 3 technical replicates. clade - clade A,B,C,D based on ITS sequences. year and culturing for year of isolation and culturing method at the Roscoff culture collection respectively. wherefrom: sampling depth as factor. Pst0 and growtht0 - are photosynthesis and growth rates at t0 (foldchange PS and foldchangegrowth are foldchanges thereof). Figure legend: (a–d) Lineages with higher ancestral plasticity evolve more. Direct and correlated responses to selection plotted as a function of plasticity in oxygen evolution rates before evolution (ancestral plasticity). For all panels (a–d), different shapes represent mean values for each lineages ± 1 s.e. For each lineage n = 3. Dashed line indicates no response to selection. Panel (a) (selection in FH, assay at 1000 ppm CO2): ancestral plasticity in FH evolved lineages predicts up to 47% of the evolutionary response (F2,13 = 210.67, p < 0.001). FH populations evolve slow growth in response to high pCO2. Panel (b) (selection in SH, assay at 1000 ppm CO2): with no selection for plasticity, a linear relationship using ancestral plasticity as the only explaining variable is not statistically significant (p = 0.63). Still, most lineages evolve lower growth rates (range from −0.31 to −0.08, mean −0.15 ± 0.12). Panel (c) (selection in FH, assay at 430 ppm CO2): ancestral plasticity is a significant nonlinear predictor of the correlated response to selection (F2,13 = 563.38, p < 0.0001). Lineages from FH increased their growth rate at ambient pCO2 the most when their ancestral plasticity was high (increase in growth of 0.12–0.30, mean 0.19 ± 0.05). Panel (d) (selection in SH, assay at 430 ppm CO2): lineages selected in SH had a negative correlated response, and the relationship between ancestral plasticity and the correlated response to selection was significant (F2,13 = 22.28, p < 0.01), though best described by a nonlinear fit (p-values and r2 reported on the panels are for linear regression)

data for Figure 3

Data in columns is organised as follows: growthdif - foldchange difference of growth rate in selection environment compared to control environment. selected assay - selection environment and assay environment, e.g. 1000fluc 1000ppm lineages have been selected at fluctuating 1000ppm CO2 (FH in main manuscript) and were measured at 1000ppm CO2 (mean ppm in their selection environment). ecotype - lineage of Ostreococcus . forwhat - trait considered. Here, growth rate. hl - high or low pCO2. ls - long term or short term response

Smelling danger - alarm cue responses in the polychaete Nereis (Hediste) diversicolor (Müller, 1776) to potential fish predation.

The harbour ragworm, Nereis (Hediste) diversicolor is a common intertidal marine polychaete that lives in burrows from which it has to partially emerge in order to forage. In doing so, it is exposed to a variety of predators. One way in which predation risk can be minimised is through chemical detection from within the relative safety of the burrows. Using CCTV and motion capture software, we show that H. diversicolor is able to detect chemical cues associated with the presence of juvenile flounder (Platichthys flesus). Number of emergences, emergence duration and distance from burrow entrance are all significantly reduced during exposure to flounder conditioned seawater and flounder mucous spiked seawater above a threshold with no evidence of behavioural habituation. Mucous from bottom-dwelling juvenile plaice (Pleuronectes platessa) and pelagic adult herring (Clupea harengus) elicit similar responses, suggesting that the behavioural reactions are species independent. The data implies that H. diversicolor must have well developed chemosensory mechanisms for predator detection and is consequently able to effectively minimize risk

Presence of a resident species aids invader evolution

Phytoplankton populations are intrinsically large and genetically variable, and interactions between species in these populations shape their physiological and evolutionary responses. Yet, evolutionary responses of microbial organisms in novel environments are investigated almost exclusively through the lens of species colonising new environments on their own, and invasion studies are often of short duration. Although exceptions exist, neither type of study usually measures ecologically relevant traits beyond growth rates. Here, we experimentally evolved populations of fresh- and seawater phytoplankton as monocultures (the green algae Chlamydomonas moewusii and Ostreococcus tauri , each colonising a novel, unoccupied salinity) and co-cultures (invading a novel salinity occupied by a resident species) for 200 generations. Colonisers and invaders differed in extinction risks, phenotypes (e.g. size, primary production rates) and strength of local adaptation: invaders had systematically lower extinction rates and broader salinity and temperature preferences than colonisers – regardless of the environment that the invader originated from. We emphasise that the presence of a locally adapted species has the potential to alter the invading species’ eco-evolutionary trajectories in a replicable way across environments of differing quality, and that the evolution of small cell size and high ROS tolerance may explain high invader fitness. To predict phytoplankton responses in a changing world, such interspecific relationships need to be accounted for

Data from: Plasticity predicts evolution in a marine alga

Under global change, populations have four possible responses: ‘migrate, acclimate, adapt or die’ (Gienapp et al. 2008 Climate change and evolution: disentangling environmental and genetic response. Mol. Ecol. 17, 167–178. (doi:10.1111/j.1365-294X.2007.03413.x)). The challenge is to predict how much migration, acclimatization or adaptation populations are capable of. We have previously shown that populations from more variable environments are more plastic (Schaum et al. 2013 Variation in plastic responses of a globally distributed picoplankton species to ocean acidification. Nature 3, 298–230. (doi:10.1038/nclimate1774)), and here we use experimental evolution with a marine microbe to learn that plastic responses predict the extent of adaptation in the face of elevated partial pressure of CO2 (pCO2). Specifically, plastic populations evolve more, and plastic responses in traits other than growth can predict changes in growth in a marine microbe. The relationship between plasticity and evolution is strongest when populations evolve in fluctuating environments, which favour the evolution and maintenance of plasticity. Strikingly, plasticity predicts the extent, but not direction of phenotypic evolution. The plastic response to elevated pCO2 in green algae is to increase cell division rates, but the evolutionary response here is to decrease cell division rates over 400 generations until cells are dividing at the same rate their ancestors did in ambient CO2. Slow-growing cells have higher mitochondrial potential and withstand further environmental change better than faster growing cells. Based on this, we hypothesize that slow growth is adaptive under CO2 enrichment when associated with the production of higher quality daughter cells.Schaum, C. Elisa; Collins, Sinéad (2014), Data from: Plasticity predicts evolution in a marine alga, Dryad, Dataset, https://doi.org/10.5061/dryad.gf06