22 research outputs found
Organic matter from Artic sea ice loss alters bacterial community structure and function
Continuing losses of multi-year sea ice (MYI) across the Arctic are resulting in first-year ice (FYI) dominating the Arctic ice pack. Melting FYI provides a strong seasonal pulse of dissolved organic matter (DOM) into surface waters; however, the biological impact of this DOM input is unknown. Here we show that DOM additions cause significant and contrasting changes in under-ice bacterioplankton abundance, production and species composition. Utilization of DOM was influenced by molecular size, with 10-100 kDa and >100 kDa DOM fractions promoting rapid growth of particular taxa, while uptake of sulfur and nitrogen-rich low molecular weight organic compounds shifted bacterial community composition. These results demonstrate the ecological impacts of DOM released from melting FYI, with wideranging consequences for the cycling of organic matter across regions of the Arctic Ocean transitioning from multi-year to seasonal sea ice as the climate continues to warm
Hydrocarbon removal and bacterial community structure in on-site biostimulated biopile systems designed for bioremediation of diesel-contaminated Antarctic soil
Genetic signatures indicate widespread antibiotic resistance and phage infection in microbial communities of the McMurdo Dry Valleys, East Antarctica
The McMurdo Dry Valleys of Antarctica support
extensive yet cryptic microbial communities but little
evidence for ‘top-down’ herbivory control. A question
therefore arises as to how standing microbial biomass is
regulated. Here, we present results from a survey of soil and
rock microbial community metagenomes using the GeoChip
microarray that demonstrate antibiotic resistance and phage
infection are widespread. We interrogated a range of dry
valley locations from maritime to extreme inland sites.
Antibiotic resistance genes were identified in three categories:
beta-lactamases, tetracycline and vanomycin plus a
range of transporter genes. Frequency of recovery generally
reflected microbial diversity, with greatest abundance
among Halobacteria, Proteobacteria and the photosynthetic
bacteria (Chlorobi, Chloroflexi and Cyanobacteria). However,
no clear differences between locations and soil/rock
communities were apparent. Phage signals were also recovered
from all locations in soil and rock communities. The
Leviviridae, Myoviridae, Podoviridae and Siphoviridae were
ubiquitous . The Corticoviridae occurred only in moisturesufficient hyporheic soils, the Microviridae occurred only in
maritime and hyporheic sites and an unidentified group
within the order Caudovirales occurred only at dry inland
sites. We postulate that widespread antibiotic resistance
indicates potential inter-specific interaction and that phage
signals indicate possible ‘bottom-up’ trophic regulation in
the dry valleys.http://link.springer.com/journal/3002016-02-28hb201