Affiliation:
1. Horn Point Laboratory University of Maryland Center for Environmental Science Cambridge Maryland USA
2. Marine Advisory Program Virginia Institute of Marine Science Gloucester Virginia USA
3. Maryland Sea Grant College College Park Maryland USA
4. Earth and Planetary Sciences Johns Hopkins University Baltimore Maryland USA
Abstract
AbstractMarine snow and other particles are abundant in estuaries, where they drive biogeochemical transformations and elemental transport. Particles range in size, thereby providing a corresponding gradient of habitats for marine microorganisms. We used standard normalized amplicon sequencing, verified with microscopy, to characterize taxon‐specific microbial abundances, (cells per litre of water and per milligrams of particles), across six particle size classes, ranging from 0.2 to 500 μm, along the main stem of the Chesapeake Bay estuary. Microbial communities varied in salinity, oxygen concentrations, and particle size. Many taxonomic groups were most densely packed on large particles (in cells/mg particles), yet were primarily associated with the smallest particle size class, because small particles made up a substantially larger portion of total particle mass. However, organisms potentially involved in methanotrophy, nitrite oxidation, and sulphate reduction were found primarily on intermediately sized (5–180 μm) particles, where species richness was also highest. All abundant ostensibly free‐living organisms, including SAR11 and Synecococcus, appeared on particles, albeit at lower abundance than in the free‐living fraction, suggesting that aggregation processes may incorporate them into particles. Our approach opens the door to a more quantitative understanding of the microscale and macroscale biogeography of marine microorganisms.
Funder
Maryland Sea Grant, University of Maryland
National Science Foundation
Subject
Ecology, Evolution, Behavior and Systematics,Microbiology