Titre du document / Document title

The role of marine biota in the evolution of terrestrial biota : Gases and genes : Atmospheric composition and evolution of terrestrial biota

Auteur(s) / Author(s)

RAVEN J. A. ⁽¹⁾ ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

⁽¹⁾ Department of Biological Sciences, University of Dundee, Dundee DD1 4HN, ROYAUME-UNI

Résumé / Abstract

There is greater biodiversity (in the sense of genetic distance among higher taxa) of extant marine than of terrestrial 02-evolvers. In addition to contributing the genes from one group of algae (Class Charophyceae, Division Chlorophyta) to produce by evolution the dominant terrestrial plants (Embryophyta), the early marine 02-evolvers greatly modified the atmosphere and hence the land surface when the early terrestrial 02-evolvers grew. The earliest terrestrial phototrophs (from geochemical evidence) occurred 1.2 Ga ago, over 0.7 Ga before the Embryophyta evolved, but well after the earliest marine (cyanobacterial) O₂ evolvers (3.45 Ga) and marine eukaryotic O₂ evolvers (2.1 Ga). Even by the time of evolution of the earliest terrestrial O₂-evolvers the marine O₂-evolvers had modified the atmosphere and land environment in at least the following five ways. Once photosynthetic O₂ paralleling organic C burial had satisfied marine (Fe²⁺, S^2-) reductants, atmospheric O₂ built (1) up to a considerable fraction of the extant value (although some was consumed in oxidising terrestrial exposed Fe²⁺ ) and (2) provided stratospheric O₃ and thus a UV-screen. (3) CO₂ drawdown to ∼20-30 times the extant level is attributable to net production, and burial, of organic C in the oceans (plus other geological processes). Furthermore, (4) their production of volatile organic S compounds could have helped to supply S to inland sites but also (5) delivered Cl and Br to the stratosphere thus lowering the O₃ level and the extent of UV screening.

Revue / Journal Title

Biogeochemistry   ISSN 0168-2563   CODEN BIOGEP 

Source / Source

Congrès
International Symposium on Environmental Biogeochemistry N^o12
1997, vol. 39, n^o 2 (105 p.)  (4 p.3/4), pp. 139-164

Langue / Language

Anglais

Editeur / Publisher

Springer, Heidelberg, ALLEMAGNE  (1984) (Revue)

Mots-clés anglais / English Keywords

Cyanobacteria ; Algae ; Vegetals ; Earth atmosphere ; Carbon dioxide ; Oxygen ; Gas exchange ; Biological productivity ; Photosynthesis ; Biological evolution ; Biodiversity ; Bacteria ; Thallophyta ; Biogeochemical cycle ; Marine environment ; Terrestrial environment ;

Mots-clés français / French Keywords

Cyanobacteria ; Algae ; Végétal ; Atmosphère terrestre ; Carbone dioxyde ; Oxygène ; Echange gazeux ; Productivité biologique ; Photosynthèse ; Evolution biologique ; Diversité biologique ; Bactérie ; Thallophyta ; Cycle biogéochimique ; Milieu marin ; Milieu terrestre ;

Mots-clés espagnols / Spanish Keywords

Cyanobacteria ; Algae ; Vegetal ; Atmósfera terrestre ; Carbono dióxido ; Oxígeno ; Intercambio gaseoso ; Productividad biológica ; Fotosíntesis ; Evolución biológica ; Diversidad biológica ; Bacteria ; Thallophyta ; Ciclo biogeoquímico ; Medio marino ; Medio terrestre ;

Localisation / Location

INIST-CNRS, Cote INIST : 21005, 35400006837208.0020