Laura Marín-Samper
Marín-Samper
Laura
Javier Arístegui
Arístegui
Javier
Giulia Faucher
Faucher
Giulia
GEOMAR - Helmholtz Centre for Ocean Research Kiel
GEOMAR
Leila Kittu
Kittu
Leila
Maarten Boersma
Boersma
Maarten
Alfred Wegener Institute for Polar and Marine Research, Bremerhaven (1986-2013)
AWI
Ulf Riebesell
Riebesell
Ulf
KOSMOS 2023 Helgoland mesocosm study on ocean alkalinity enhancement: Microbial metabolic rates
PANGAEA
Data Publisher for Earth & Environmental Science
dataset
Ocean alkalinity enhancement (OAE) is a marine carbon dioxide removal (mCDR) approach that can also mitigate ocean acidification. However, its biological impacts are expected to depend on the magnitude, timing, and dilution of alkalinity additions. To investigate these factors, a mesocosm experiment simulated hydrated lime additions using two six-level alkalinity gradients (up to ΔTA 1250 µmol kg⁻¹): one with immediate full-column mixing and another with mixing delayed by two days. These treatments simulated rapid (e.g. from a moving vessel in open ocean) and slow (e .g. point source or land-based applications in poorly mixed environments)dilution scenarios, representing different hydrodynamic conditions that may occur following real-world alkalinity additions. Gross production (GP), net community production (NCP) and community respiration (CR), determined from in vitro oxygen production and consumption, together with chlorophyll a, were monitored over a 35-day period. Spring bloom initiation was delayed non-linearly at low fCO₂, with reduced absolute and biomass-normalized production occurring in treatments exposed to fCO₂ below ~70 and 30 µatm respectively. These findings indicate that phytoplankton communities may be generally resilient to realistic OAE scenarios while helping to define ecologically relevant fCO₂ thresholds for safe OAE deployment.
Microbial metabolic rates under ocean alkalinity enhancement: A step towards a safe operating space
Communications Earth & Environment
in press
journal article
DAM CDRmare - RETAKE, GEOMAR
Federal Ministry of Education and Research
BMBF
Network of Leading European AQUAtic MesoCOSM Facilities Connecting Mountains to Oceans from the Arctic to the Mediterranean
Horizon 2020 of the European Commission
OceanNETs: Ocean-based Negative Emission Technologies
data points
Type of study
type
Event label
Day of experiment
day
Time
DATE/TIME
Identification number
Mesocosm number
Treatment: dilution type
Dil_Treat
treatment
Treatment: alkalinity, total
µmol/kg
Delta_TA
total
Molar Concentration
Treatment
Sample code/label
Respiration rate, oxygen, community
µmol/l/day
CR: Community Respiration (amount of oxygen respired in the dark)
respiration rate
oxygen
Reaction Rate
Net community production of oxygen
net community production
NCP
Gross community production of oxygen
Balance
GPR: Metabolic Balance = GCP/CR
balance
Depth, description
depth
description
metabolic rates; ocean alkalinity enhancement; Ocean Alkalinity Enhancement (OAE); Phytoplankton; Primary production
access rights needed
text/tab-separated-values
text/html