Assessing the impact of ocean acidification and irradiance on phytoplankton bloom development and DMS production in the Arctic

A Bioassay incubations of 10 days was carried out in Northern Baffin Bay in summer 2015 with the intent on simulating conditions encountered by blooming phytoplankton in a progressively acidified Arctic Ocean (6 levels of decreasing pH) submitted to light fields typical of either under-ice (low-light) or open ocean (high-light). The experiment was conducted at station BB-3 (71°24.373'N - 70°11.269'W) on August 6th 2015. The initial acidification was conducted following procedures described in "Guide to best practices for ocean acidification research and data reporting", adding strong acid (HCl 0.02N) and bicarbonate (NaHCO3 0.3N) in our bags. Added volumes of bicarbonate and acid were calculated by manipulating the carbonate system with the software CO2sys in order to fully mimic 'natural' ocean acidification: rise of the total inorganic carbon with constant alkalinity. Although alkanities after initial acidification were not entirely similar due to manipulation biases and the difficulty in properly controlling the concentration of added solutions of NaHCO3 and HCl, target pHs were achieved (note however that these data are not corrected for m-cresol purple dye bias and alkalinity). In order to mimic in situ light fields, we added a mesh on the incubator thereby reducing the incident light. Moreover we added a second 300µm nitex mesh on the bags assigned to the low light treatment: those were already covered with one Mylar D film (which cuts UV-B radiation) and one 300µm nitex mesh which allowed approximately 40% of incident light to pass. The transmittance for the high light treatment was 80%: these bags were not covered by neither mesh nor mylar. After filtering the AN rosette water with a 200µm nitex mesh in order to remove mesozooplankton grazers, we filled 12 bags of 10 liters and followed the evolution of each bag by subsampling every day during 10 days. The following variables were monitored: pH, DIC, Alkalinity, Salinity, Temperature, Nutrients, chla, Phytoplankton taxonomy, cytometry, HPLC, total DMSP, dissolved DMSP, dimethylsulfoxide, DMS, FR/RF.

Metadata Access
Creator Lizotte, Martine;Thomas, Helmut;Tremblay, Jean-Eric;Hussherr, Rachel;Levasseur, Maurice;Tortell, Philippe;Miller, Lisa;Mucci, Alfonso
Publisher Canadian Cryospheric Information Network
Contributor Université Laval / Québec-Océan
Publication Year 2016
Rights Limited
Language English
Discipline Environmental Research
Spatial Coverage (72N,70W)
Temporal Coverage Begin 2015-07-10T11:59:59Z
Temporal Coverage End 2015-08-20T11:59:59Z