CIE Seminar Series 2015 – Marine microbial ecology: From drops of seawater to ocean basins

Justin SeymourSPEAKER: Assoc Professor Justin Seymour, ARC Future Fellow, Ocean Microbiology Group Leader, Plant Functional Biology & Climate Change Cluster, University of Technology Sydney
DATE: Friday, 29th May 2015
LOCATION: Melbourne-Burwood Campus, The new Burwood Corporate Centre (BCC), Level 2, Burwood Highway frontage building (please report to reception)
TIME: 12:00 noon
Seminar will also be video linked to the following campuses: Geelong Campus at Waurn Ponds, Room ka5.303; and Warrnambool Campus, Room G1.01 (Percy Baxter LT)

ABSTRACT: Microorganisms form the foundation of the marine food-web and are the engine-room for the ocean’s major biogeochemical cycles. Consequently, the composition and function of these microbial communities strongly influence the productivity of fisheries and governs the ocean to atmosphere exchange of climatically important gases.

The ecological and biogeographical dynamics of these important marine microbial populations are controlled by diverse biotic and abiotic process operating over a continuum of spatiotemporal scales.

Our work has shown that large-scale oceanographic features including currents, eddies and up-welling events determine the composition and functional capacity of microbial assemblages across regional scales.

At these large-scales, recurring biogeographic trends in community-level characteristics are linked to specific physical and biological characteristics of the environment. However, from the perspective of an individual microbe, large-scale environmental gradients and seasonal cycles are inconsequential.

The world of a microbial cell is defined within a fraction a single drop of seawater, over time-frames of seconds to hours. Surprisingly, at this microbial scale physical and chemical gradients are often more pronounced than over regional scales. This results in a markedly patchy microbial seascape, which with the aid of microfluidic-based experimental platforms, we have been able to demonstrate is efficiently exploited by foraging microbes.

Within this microscale world, marine microbes use foraging behaviours that sometimes mirror those of macroorganisms, and ultimately influence marine chemical cycling processes.

I argue that processes occurring at this microscale represent true microbial ecology, while the study of microbial patterns over larger oceanographic scales represents microbial biogeography, rather than ecology.

A comprehension of how the composition and functional capacity of important marine microbial assemblages are affected by and affect biotic and physicochemial features of the environment at both the ocean-scale and the microscale is fundamentally important for understanding the function of the ocean, both now and in a climate change influenced future.

BIO: Justin is an ARC Future Fellow and the leader of the Plant Functional Biology and Climate Change Cluster (C3) Ocean Microbiology Group at UTS.

Appointments with guest speaker may be made via Peter Macreadie