The use of N fertilizers has increased worldwide in the past century. While this increased input of N has increased food productivity, it has also contributed to decreases in biodiversity, soil quality and environmental health, including increases in greenhouse gas emissions.

In this thesis, the role of plant-mediated soil legacy effects in shaping aboveground plant-insect interactions was investigated.

Promotor: J.A. van Veen, Co-promotor: E.E. Kuramae

Microbiome composition of the spermosphere and the rhizosphere of wild and modern bean accessions grown in an agricultural and a native soil from Colombia was characterized by metagenomics and cultivation-dependent approaches.

By growing in a soil plants change the biotic and abiotic properties of the soil in which they grow.

How soil microbial composition impacts structure and composition of the aboveground plant and animal communities?

De

Promotores: Prof.dr. H. van Veen & Prof.dr. W. de Boer (Wageningen University)

Promotores: J.A.van Veen, P.L.G.Klinkhamer. Co-promotor: E.E.Kuramae

How presence, abundance and enzymatic activities of AM and EM fungi differently affect soil carbon sequestration processes?

Plants and soils from natural ecosystems harbor great diversity of soil microorganisms, which could potentially contribute to the sustainability of horticulture. The knowledge about using wild plant species and soil from natural ecosystem to improve the crop health will advance the application of ecological…

The overall objectives of my thesis are to investigate the dynamics of the sorghum root microbiome and to explore the beneficial effects of the root microbiome on sorghum growth and stress tolerance.

Vinasse is a major by-product generated by the sugarcane biofuel industry. It is a source of microbes, nutrients and organic matter and often it is recycled as fertilizer.

Promotie

Promotors: Prof.dr. G.R. de Snoo, Prof.dr. G.A. Persoon, Prof.dr.ir. H.H. de Iongh

This thesis combines field and laboratory studies to address some of the most pressing questions in the field of microplastic research.

What are the global relationships between environmental conditions and abundance of distinct types of mycorrhizal fungi in soil and plant roots?

Een internationaal team van onder meer Leidse onderzoekers heeft aangetoond dat er een verfijndere methode is om oude microbiomen te bestuderen. Dat helpt archeologisch onderzoek naar de effecten van Europese kolonisatie in de Caraïben. Publicatie in Nature Scientific Reports op 13 november.

This thesis describes the genetic and prokaryotic diversity of giant barrel sponges.

Promotor: Prof.dr. W.J.G.M. Peijnenburg

Lezing, Studium Generale

1. To what extent do metallic NPs added to soil extractions change the activity, abundance, or community composition of microbes? 2. How do the effects of metallic NPs on soil microbes differ from the effects of the ions shedding from corresponding NPs?

How the global distribution of vegetation stands dominated by arbuscular and ectomycorrhizal plants relate to principle aspects of belowground carbon accumulation processes?

Vooral neerslag en bodemzuurgraad bepalen welke microben in een bepaalde habitat overleven en welke niet. Deze kennis is van belang om de biodiversiteit in stand te houden. Leidse milieukundigen werkten mee aan het onderzoek. Publicatie in Nature op 1 augustus.

Promotie

Promotie

Promotor: E.F. Smets Co-promotor: J. Geml

Promotor: E.F. Smets, Co-promotor: J. Geml

Streptomyces are bacteria abundant in soil that participate in diverse and complex interactions. These bacteria are the main producers of the antibiotics we currently use in the clinic.

The soil-dwelling, filamentous bacteria of the genus Streptomyces are renowned for their production of useful secondary metabolites including antibiotics. The work described in this thesis provides new insights on the role and regulation of antibiotic production and resistance in these bacteria.

This thesis aimed to investigate the impact of exposure dynamics, relative contributions of ENPs(particle) and ENPs(ion), and dosing regimens on the toxicity of ENPs varying in different physico-chemical properties, on the composition and functioning of soil microbial communities.

The filamentous bacteria Streptomyces are widespread inhabitants of terrestrial soils.

Promotores: Prof.dr.G.R. de Snoo and Dr. R. Heijungs

Promotie

Elk onderdeel van de kringloop op een melkveebedrijf heeft een specifieke bacterie- en schimmelsamenstelling. Dat ontdekten de Leidse postdoc onderzoeker Sofia Gomes en haar begeleiders Nadia Soudzilovskaia en Peter van Bodegom in samenwerking met het Louis Bolk instituut en Naturalis Biodiversity Centre.…

Promotie

Promotie

Herstel van de natuur op uitgeputte landbouwgrond en in natuurgebieden verloopt moeizaam. ‘Bodemtransplantatie’ kan mogelijk uitkomst bieden. Dat betoogt Martijn Bezemer, hoogleraar Ecologie van Plant-Microbe-Insect interacties. Oratie op 18 december.

Promotor: Prof.dr. G.P. van Wezel