Data_Sheet_1_Metabolic Responses of Subtropical Microplankton After a Simulated Deep-Water Upwelling Event Suggest a Possible Dominance of Mixotrophy Under Increasing CO2 Levels.PDF

• Main Authors: Mayte Tames-Espinosa, Ico Martínez, Vanesa Romero-Kutzner, Josep Coca, María Algueró-Muñiz, Henriette G. Horn, Andrea Ludwig, Jan Taucher, Lennart Bach, Ulf Riebesell, Theodore T. Packard, May Gómez
• Format: Dataset
• Language: unknown
• Published: 2020
• Subjects: Oceanography; Marine Biology; Marine Geoscience; Biological Oceanography; Chemical Oceanography; Physical Oceanography; Marine Engineering; ocean acidification; mesocosms; nutrient fertilization; subtropical North-Atlantic; potential respiration; plankton metabolism; mixotrophy; North Atlantic; Ocean acidification
• Online Access: https://doi.org/10.3389/fmars.2020.00307.s001; https://figshare.com/articles/Data_Sheet_1_Metabolic_Responses_of_Subtropical_Microplankton_After_a_Simulated_Deep-Water_Upwelling_Event_Suggest_a_Possible_Dominance_of_Mixotrophy_Under_Increasing_CO2_Levels_PDF/12285668

In the autumn of 2014, nine large mesocosms were deployed in the oligotrophic subtropical North-Atlantic coastal waters off Gran Canaria (Spain). Their deployment was designed to address the acidification effects of CO 2 levels from 400 to 1,400 μatm, on a plankton community experiencing upwelling of nutrient-rich deep water. Among other parameters, chlorophyll a (chl-a), potential respiration (Φ), and biomass in terms of particulate protein (B) were measured in the microplankton community (0.7–50.0 μm) during an oligotrophic phase (Phase I), a phytoplankton-bloom phase (Phase II), and a post-bloom phase (Phase III). Here, we explore the use of the Φ/chl-a ratio in monitoring shifts in the microplankton community composition and its metabolism. Φ/chl-a values below 2.5 μL O 2 h −1 (μg chl-a) −1 indicated a community dominated by photoautotrophs. When Φ/chl-a ranged higher, between 2.5 and 7.0 μL O 2 h −1 (μg chl-a) −1 , it indicated a mixed community of phytoplankton, microzooplankton and heterotrophic prokaryotes. When Φ/chl-a rose above 7.0 μL O 2 h −1 (μg chl-a) −1 , it indicated a community where microzooplankton proliferated (>10.0 μL O 2 h −1 (μg chl-a) −1 ), because heterotrophic dinoflagellates bloomed. The first derivative of B, as a function of time (dB/dt), indicates the rate of protein build-up when positive and the rate of protein loss, when negative. It revealed that the maximum increase in particulate protein (biomass) occurred between 1 and 2 days before the chl-a peak. A day after this peak, the trough revealed the maximum net biomass loss. This analysis did not detect significant changes in particulate protein, neither in Phase I nor in Phase III. Integral analysis of Φ, chl-a and B, over the duration of each phase, for each mesocosm, reflected a positive relationship between Φ and pCO 2 during Phase II [α = 230·10 −5 μL O 2 h −1 L −1 (μatm CO 2 ) −1 (phase-day) −1 , R 2 = 0.30] and between chl-a and pCO 2 during Phase III [α = 100·10 −5 μg chl-a L −1 (μ atmCO 2 ) −1 (phase-day) −1 , R 2 = ...