README. Miriam Gerhard, Alexandra Schlenker, Helmut Hillebrand, Maren Striebel. Environmental stoichiometry mediates phytoplankton diversity effects on communities’ resource use efficiency and biomass. JEcol-2021-0745. See below a list of the data files and the explanation of the content and variables included in each file. File: Mesocosm_exp_data: Includes treatments and sampling information, as well as nutrient and biomass measurements, and diversity and stoichiometry calculations of the mesocosm experiment. SAMPLE: Experimental unit number (i.e., mesocosm number) Diversity: diversity treatment as factor according to the dilution steps increasing from D1 to D6 Rin: diversity treatment as numeric and ordered by numbers according the diversity order (1 to 6) NUT: nutrient treatment as factor DATE: date of the sampling SAMPLING: sampling code (S1 = Sampling 1, S2= Sampling 2, etc) DAY: experimental day TP: Total P concentration in µmol P/L PP: Particulate organic P concentration in µmol P/L N_diss: Dissolved N concentration in µmol N/L (NOx + NH4) NO2: Dissolved NO2 concentration in µmol N/L NOx: Dissolved NOx concentration in µmol N/L NH4: Dissolved NH4 concentration in µmol N/L PN: Particulate organic N concentration in µmol N/L Real_R0: Realized richness at t0 (inoculum) Real_ID0: Realized inverse Simpson diversity at t0 (inoculum) PC: Particulate organic C concentration in µmol C/L PART_NP: Phytoplankton N:P ratio (PN/PP) CP_ratio: Phytoplankton C:P ratio (PC/PP) CN_ratio: Phytoplankton C:N ratio (PC/PN) File: Microcosm_exp_data: Includes treatments and sampling information, as well as nutrient and biomass measurements, and diversity and stoichiometry calculations of the microcosm experiment. treatment: Experimental unit number (i.e., microcosm number) div: diversity treatment as numeric and ordered by numbers according the diversity order (1 to 6) Div_fac: diversity treatment as factor according to the dilution steps increasing from D1 to D6. noNP: number of nutrient treatment (1 to 25) Ndiss: N supplied. Dissolved initial N concentration in µmol N/L (dissolved N in the mesocosm experiment at sampling 1 + supplied N in the microcosm) Pdiss: P supplied. Dissolved initial P concentration in µmol P/L (dissolved P in the mesocosm experiment at sampling 1 + supplied N in the microcosm) NPdiss: N:P supply ratio (Ndiss/ Pdiss) Ntot: Total N concentration in µmol N/L (Total N in the mesocosm experiment at sampling 1 + supplied N in the microcosm) Ptot: Total P concentration in µmol P/L (Total P in the mesocosm experiment (low nutrient) at sampling 1 + supplied P in the microcosm) POC: Particulate organic C concentration in µmol C/L PON: Particulate organic N concentration in µmol N/L POP: Particulate organic P concentration in µmol P/L PONP: Phytoplankton N:P ratio (PON/POP) Species: Realized richness at t0 (= mesocosm experiment S1) N_Fac: Nitrogen level as factor P_fac: Phosphorus level as factor File: Species_Composition: Includes the raw data of the phytoplankton species composition in the different treatments and samplings expressed as abundance (ind/mL). ID: sample code Sampling: sampling code (S0= Inoculum, S1= Sampling 1, S6= Sampling 6) Nut: Nutrient treatment – mesocosm experiment. NAs cells correspond to the inoculated communities (before being inoculated in the nutrient treatments). Day: experimental day Diversity: diversity treatment as factor according to the dilution steps increasing from D1 to D6 Row 6 to 110: Contain species abundance per sample in ind/mL File: Phyto_Diversity: Includes a summary of the calculated richness and inverse Simpson diversity in the different treatments and samplings. SAMPLE: Sample code Diversity: diversity treatment as factor according to the dilution steps increasing from D1 to D6 Rin: diversity treatment as numeric and ordered by numbers according the diversity order (1 to 6) NUT: nutrient treatment as factor. NAs correspond to the inoculated communities (before being inoculated in the nutrient treatments) DATE: date of the sampling Sampling: sampling code (S0 = Sampling 0, S1= Sampling 1, etc) DAY: experimental day Sp_Rich: Realized richness Sp_ID: Realized inverse Simpson diversity File: size_Mesocosm_exp: Includes size data of the treatments during the mesocosm experiment. Data corresponding to the first sampling (S1, day 7) are missing. Sample: sample code Sampling: sampling code (S1 = Sampling 1, S2= Sampling 2, etc) Day: experimental day Diversity: diversity treatment as factor according to the dilution steps increasing from D1 to D6. Din: diversity treatment as numeric and ordered by numbers according the diversity order (1 to 6) Nut: nutrient treatment as factor MeanSize: weighted size mean (Appendix S1, Fig. S8) SizeVar: weighted size variance (Appendix S1, Fig. S8) File: size_Microcosm_exp: Includes size data of the treatments at the end of the microcosm experiment. Sample: sample code div: diversity treatment as numeric and ordered by numbers according the diversity order (1 to 6) Div_fac: diversity treatment as factor according to the dilution steps increasing from D1 to D6 noNP: number of nutrient treatment (1 to 25) NPdiss: N:P supply ratio (Ndiss/ Pdiss) Ndiss: N supplied. Dissolved initial N concentration in µmol N/L (dissolved N in the mesocosm experiment at sampling 1 + supplied N in the microcosm) Pdiss: P supplied. Dissolved initial P concentration in µmol P/L (dissolved P in the mesocosm experiment at sampling 1 + supplied N in the microcosm) abund: cell abundance measured with the cell counter (Beckman Coulter, Z2) MeanSize: weighted size mean (Appendix S1, Fig. S8) SizeVar: weighted size variance (Appendix S1, Fig. S8)