Nutrient limitations to bacterial and fungal growth during cellulose decomposition in tropical forest soils

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

Abstract

Nutrients constrain the soil carbon cycle in tropical forests, but we lack knowledge on how these constraints vary within the soil microbial community. Here, we used in situ fertilization in a montane tropical forest and in two lowland tropical forests on contrasting soil types to test the principal hypothesis that there are different nutrient constraints to different groups of microorganisms during the decomposition of cellulose. We also tested the hypotheses that decomposers shift from nitrogen to phosphorus constraints from montane to lowland forests, respectively, and are further constrained by potassium and sodium deficiency in the western Amazon. Cellulose and nutrients (nitrogen, phosphorus, potassium, sodium, and combined) were added to soils in situ, and microbial growth on cellulose (phospholipid fatty acids and ergosterol) and respiration were measured. Microbial growth on cellulose after single nutrient additions was highest following nitrogen addition for fungi, suggesting nitrogen as the primary limiting nutrient for cellulose decomposition. This was observed at all sites, with no clear shift in nutrient constraints to decomposition between lowland and montane sites. We also observed positive respiration and fungal growth responses to sodium and potassium addition at one of the lowland sites. However, when phosphorus was added, and especially when added in combination with other nutrients, bacterial growth was highest, suggesting that bacteria out-compete fungi for nitrogen where phosphorus is abundant. In summary, nitrogen constrains fungal growth and cellulose decomposition in both lowland and montane tropical forest soils, but additional nutrients may also be of critical importance in determining the balance between fungal and bacterial decomposition of cellulose.

Detaljer

Författare
Enheter & grupper
Externa organisationer
  • University of Edinburgh
  • Smithsonian Tropical Research Institute
  • Pontifical Catholic University of Peru
  • Australian National University
  • National University of Saint Anthony the Abbot in Cuzco
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Mikrobiologi
  • Naturgeografi

Nyckelord

Originalspråkengelska
Sidor (från-till)219-228
TidskriftBiology and Fertility of Soils
Volym54
Utgivningsnummer2
Tidigt onlinedatum2017 nov 8
StatusPublished - 2018 feb
PublikationskategoriForskning
Peer review utfördJa