Short-term responses to ocean acidification: effects on relative abundance of eukaryotic plankton from the tropical Timor Sea

Anthropogenic carbon dioxide (CO2) emissions drive climate change and pose one of the major challenges of our century. The effects of increased CO2 in the form of ocean acidification (OA) on the communities of marine planktonic eukaryotes in tropical regions such as the Timor Sea are barely understo...

Full description

Saved in:
Bibliographic Details
Published inbioRxiv
Main Authors Rahlff, Janina, Khodami, Sahar, Voskuhl, Lisa, Humphreys, Matthew, Stolle, Christian, Pedro Martinez Arbizu, Wurl, Oliver, Ribas-Ribas, Mariana
Format Paper
LanguageEnglish
Published Cold Spring Harbor Cold Spring Harbor Laboratory Press 03.05.2020
Subjects
Acidification
Bacillariophyceae
Biodiversity
Carbon dioxide
Climate change
Community composition
Emissions
Food webs
Plankton
rRNA 18S
Tropical environment
Timor Sea
Online AccessGet full text

Cover

More Information
Summary:Anthropogenic carbon dioxide (CO2) emissions drive climate change and pose one of the major challenges of our century. The effects of increased CO2 in the form of ocean acidification (OA) on the communities of marine planktonic eukaryotes in tropical regions such as the Timor Sea are barely understood. Here, we show the effects of high CO2 (pCO2=1823±161 μatm, pHT=7.46±0.05) versus in situ CO2 (pCO2=504±42 μatm, pHT=7.95±0.04) seawater on the community composition of marine planktonic eukaryotes immediately and after 48 hours of treatment exposure in a shipboard microcosm experiment. Illumina sequencing of the V9 hypervariable region of 18S rRNA (gene) was used to study the eukaryotic community composition. Down-regulation of extracellular carbonic anhydrase occurred faster in the high CO2 treatment. Increased CO2 significantly suppressed the relative abundances of different eukaryotic operational taxonomic units (OTUs), including important primary producers. These effects were consistent between abundant (DNA-based) and active (cDNA-based) taxa after 48 hours, e.g., for the diatoms Trieres chinensis and Stephanopyxis turris. Effects were also very species-specific among different diatoms. Planktonic eukaryotes showed adaptation to the CO2 treatment over time, but many OTUs were adversely affected by decreasing pH. OA effects might fundamentally impact the base of marine biodiversity, suggesting profound outcomes for food web functioning in the future ocean. Competing Interest Statement The authors have declared no competing interest.
DOI:10.1101/2020.04.30.068601