Transport and Survival of Marine Tracer Phages in Topsoil at Field Conditions

TL;DR

This study investigates how marine phages move and survive in topsoil under field conditions, revealing their transport dynamics and ecological implications.

Contribution

The study provides new insights into phage transport and survival in field soils, distinguishing between retention and inactivation.

Findings

Phages were transported up to 4 times faster than deuterium due to pore size exclusion.

Infectious phage mass recoveries in pasture soil were up to 6 times higher than in forest soil.

Phage infectivity was preserved in forest soil, allowing event-driven remobilization.

Abstract

Phages are ubiquitous in soil, shaping microbial diversity
and
nutrient cycling. Phage replication requires maintaining infectivity
and finding the right host. Yet, there are limited data on phage persistence
and transport in soil under field conditions. The potential presence
of hosts enabling phage replication impedes the assessment of the
mobility of autochthonous phages in soils. In lysimeters installed
in forest and pasture topsoil, we elucidated the transport of the
tailed marine Pseudoalteromonas phage HS2 in comparison
to deuterium. Transport of infectious phages as well as numbers of
tracer phage genomes and tracer capsid-bound genomes were quantified
to account for phage retention and inactivation. Phages were transported
up to 4 times faster than the simultaneously applied deuterium tracer,
which was attributed to pore size exclusion. Retention in immobile
regions and remobilization during precipitation caused pronounced
tailing in tracer breakthroughs. High phage survival in pasture soil
resulted in mass recoveries of infectious phages that were up to 6
times higher than those in forest soil. However, long-term observations
showed that the infectivity was also preserved in forest soil, enabling
event-driven remobilization. This remobilization underscores the importance
of distinguishing between phage retention and inactivation, which
is crucial for accurately predicting phage transport dynamics and
their ecological impact in terrestrial environments.

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