"It takes a village to finish (marine) science these days" Paraphrased from Curtis Huttenhower (the Human Microbiome project) The rapidity and complexity of climate change and its potential effects on ocean biota are challenging how ocean scientists conduct research. One way in which we can begin to better tackle these challenges is to conduct community-wide scientific studies. This study provides physiological datasets fundamental to understanding functional responses of phytoplankton growth rates to temperature. While physiological experiments are not new, our experiments were conducted in many laboratories using agreed upon protocols and 25 strains of eukaryotic and prokaryotic phytoplankton isolated across a wide range of marine environments from polar to tropical, and from nearshore waters to the open ocean. This community-wide approach provides both comprehensive and internally consistent datasets produced over considerably shorter time scales than conventional individual and often uncoordinated lab efforts. Such datasets can be used to parameterise global ocean model projections of environmental change and to provide initial insights into the magnitude of regional biogeographic change in ocean biota in the coming decades. Here, we compare our datasets with a compilation of literature data on phytoplankton growth responses to temperature. A comparison with prior published data suggests that the optimal temperatures of individual species and, to a lesser degree, thermal niches were similar across studies. However, a comparison of the maximum growth rate across studies revealed significant departures between this and previously collected datasets, which may be due to differences in the cultured isolates, temporal changes in the clonal isolates in cultures, and/or differences in culture conditions. Such methodological differences mean that using particular trait measurements from the prior literature might introduce unknown errors and bias into modelling projections. Using our community-wide approach we can reduce such protocol-driven variability in culture studies, and can begin to address more complex issues such as the effect of multiple environmental drivers on ocean biota.

File List EPAdata.txt Description The EPAdata.txt file is a tab-delimited ASCII file. The file contains data on phytoplankton species richness and environmental variables of 540 lakes and reservoirs distributed across the continental USA. The lakes and reservoirs were sampled from 1973-1975 as part of the National Eutrophication Survey conducted by the U.S. EPA. Column definitions and checksum values: Name of waterbody State Type of waterbody (lake or reservoir) Latitude, SUM = 20585.85475 Longitude, SUM = -51798.3929 Altitude (in km), SUM = 304.5463 Lake area (in km2), SUM = 25453.51 Lake depth (in m), SUM = 4945.149999 Number of sampling days, SUM = 1592 Chlorophyll concentration (in mug/L), SUM = 11718.22239 Total nitrogen (in mg/L), SUM = 705.6529752 Total phosphorus (in mg/L), SUM = 70.3631407 Temperature (in °C), SUM = 10188.35764 Secchi depth (in m), SUM = 885.1552689 Species richness (number of phytoplankton species), SUM = 15875 There are no missing values. Copyright: CC-0

Supplementary statistical methods. Copyright: CC-0

Supplemental figures showing environmental covariation and species-specific responses to environmental predictors. Copyright: CC-0

Coefficient estimates for the 25-species occurrence model, the 13-species abundance model, and the 13-species occurrence model. Copyright: CC-0

light Copyright: CC-0

nutrients Copyright: CC-0

tower3 Copyright: CC-0

tower6 Copyright: CC-0

phys_and_stoich Copyright: CC-0