These files contain the data recorded from a mesocosm experiment conducted in Bergen, Norway 2022 which assessed the effect of simualted mineral-based (silicate or calcium) ocean alkalinity enhancement (OAE) on diatom silicification. Ten mesocosms were used in total, divided into two groups either the silicate- or calcium based group and alkalinity was increased by either 0, 150, 300, 450 or 600 µmol L-1 above natrually occuring levels. The PDMPO-fluorescence (an appropriate proxy for silicification) of diatoms was recorded on eight seperate days during the experiment. Accompanying data includes measured; macronutrients (nitrate, nitrite, phophate, silicate), total alkalinity, biogenic silica in the water column and sediment trap.

To investigate how the unavoidable physical and chemical perturbations associated with Ocean Alkalinity Enhancement (OAE) could influence marine plankton communities and how potential side-effects compare to impacts of climate change, we conducted 19 ship-based experiments in the Equatorial Pacific, examining three prevalent OAE source (NaOH, olivine, and steel slag) and their impacts on natural phytoplankton populations. Our experiments simulated realistic and moderate alkalinity enhancements between 29-16 μmol kg-1. The monitored parameters included total chlorophyll-a concentrations, macro nutrients, trace elements, total alkalinity, Fv/Fm, pH,and flowcytometry.

The main purpose of the study was to gain a greater understanding of the chemical and biological characteristics of sites in the D'Entrecasteaux Channel and offshore of the Derwent Estuary between North West Bay and Betsey Island. Four transects were completed on the 5th and 6th of April 2022 to achieve this. A SBE 55 ECO Water Sampler Conductivity, Temperature and Depth (CTD) Rosette was used to collect depth, temperature, conductivity, salinity, density, dissolved oxygen, pH, turbidity, fluorescence and pressure data. Water samples collected at three depths using Niskin bottles were used to obtain discrete measurements of oxygen, pH, alkalinity and phosphorous at sea, and discrete measurements of chlorophyll-a, ammonia, NOx, nitrite, nitrate, phosphate and silicate in a laboratory setting. A plankton tow net was used to roughly measure the abundance of plankton at each site and a Secchi disk was used to discern the Secchi depth.