Skip to content

Technical note: The silicon isotopic composition of choanoflagellates: Implications for a mechanistic understanding of isotopic fractionation during biosilicification

Research output: Contribution to journalArticle

Original languageEnglish
Pages (from-to)4805-4813
Number of pages9
JournalBiogeosciences
Volume16
Issue number24
DOIs
DateAccepted/In press - 21 Nov 2019
DatePublished (current) - 17 Dec 2019

Abstract

The marine silicon cycle is intrinsically linked with carbon cycling in the oceans via biological production of silica by a wide range of organisms. The stable silicon isotopic composition (denoted by δ30Si) of siliceous microfossils extracted from sediment cores can be used as an archive of past oceanic silicon cycling. However, the silicon isotopic composition of biogenic silica has only been measured in diatoms, sponges and radiolarians, and isotopic fractionation relative to seawater is entirely unknown for many other silicifiers. Furthermore, the biochemical pathways and mechanisms that determine isotopic fractionation during biosilicification remain poorly understood. Here, we present the first measurements of the silicon isotopic fractionation during biosilicification by loricate choanoflagellates, a group of protists closely related to animals. We cultured two species of choanoflagellates, Diaphanoeca grandis and Stephanoeca diplocostata, which showed consistently greater isotopic fractionation (approximately-5%to-7 %) than cultured diatoms (-0:5%to-2:1 %). Instead, choanoflagellate silicon isotopic fractionation appears to be more similar to sponges grown under similar dissolved silica concentrations. Our results highlight that there is a taxonomic component to silicon isotope fractionation during biosilicification, possibly via a shared or related biochemical transport pathway. These findings have implications for the use of biogenic silica δ30Si produced by different silicifiers as proxies for past oceanic change.

Download statistics

No data available

Documents

Documents

  • Full-text PDF (final published version)

    Rights statement: This is the final published version of the article (version of record). It first appeared online via Copernicus Publications at https://www.biogeosciences.net/16/4805/2019/. Please refer to any applicable terms of use of the publisher.

    Final published version, 880 KB, PDF document

    Licence: CC BY

DOI

View research connections

Related faculties, schools or groups