EEB Seminar: October 23rd

 

This upcoming Thursday, University of Waterloo’s Dr. Josh Neufeld will talk on how
 

A perfect storm of scientific serendipity implicates Thaumarchaeota in global vitamin B12 production
 

at 12:30 in the EEB lounge (BioSciences 4338)
 
lake

Vitamin B12 (cobalamin) is a complex metabolite and essential cofactor across many branches of life, including most aquatic algae. Eukaryotic algae and other cobalamin auxotrophs rely on environmental cobalamin supplied from a relatively small set of vitamin-producing prokaryotic taxa. Although several bacteria have been implicated in cobalamin biosynthesis and associated with algal symbiosis, the involvement of Archaea in cobalamin production is poorly understood; the Thaumarchaeota had not been implicated in cobalamin synthesis prior to this research. Based on the discovery of a complete thaumarchaeal cobalamin pathway in the metagenome of an aquarium biofilter, we hypothesized that Thaumarchaeota, which are ubiquitous and abundant in aquatic environments, play an important role in cobalamin biosynthesis within aquatic ecosystems. To test this hypothesis, we examined cobalamin synthesis genes across sequenced thaumarchaeal genomes and over 50 metagenomes from a diverse range of marine, freshwater, and hypersaline environments. Our analysis demonstrates that all available thaumarchaeal genomes possess cobalamin synthesis genes, predominantly from the anaerobic pathway, suggesting widespread genetic capacity for cobalamin synthesis. Furthermore, although bacterial cobalamin genes dominated most surface marine metagenomes, thaumarchaeal cobalamin genes dominated metagenomes from polar marine environments, increased with depth in the marine water column, and displayed a potential seasonality with increased winter abundance observed in time-series datasets (e.g., L4 surface water in the English Channel). Our results suggest niche partitioning between thaumarchaeal, euryarchaeal, proteobacterial, and cyanobacterial cobalamin genes across all metagenome datasets analyzed. Analyses of available soil metagenomes also implicate Thaumarchaeota as relatively abundant cobalamin producers in terrestrial habitats. These results provide strong evidence for specific biogeographical distributions of thaumarchaeal cobalamin synthesis genes, expanding our understanding of the global biogeochemical roles and keystone services provided by Thaumarchaeota.
 
josh
 
Josh Neufeld is an Associate Professor in the Department of Biology at the University of Waterloo. As a microbial ecologist, Josh combines cultivation-based and molecular approaches for studying biogeochemical cycling in aquatic, terrestrial, and host-associated environments.

His website can be found here (https://uwaterloo.ca/biology/people-profiles/josh-d-neufeld) and he communicates via Twitter (@joshdneufeld).

EEB Seminar: October 16th

This upcoming Thursday, our very own Dr. Virginia Walker will talk on
 

There may be more to nanoparticles than meets the eye
 

at 12:30 in the EEB lounge (BioSciences 4338)
nano

There is no doubt that engineered nanoparticles (NPs) found in a variety of consumer goods are technologically valuable. However, we need to understand their potential toxicity so that the costs and benefits of their near-ubiquitous applications can be evaluated. The chance discovery that Julie’s mum had purchased one of those NP-discharging clothes washers has given me wanderlust. I have journeyed to Paul’s arctic site for soil samples, visited the med school’s “mouse house”, paid several visits to Emma’s ‘roboguts’ in Guelph, and dusted off my own fruit fly bench. I have even inveigled Pranab, Niraj and Laura to join me in this obsession. Although the quest will continue, for now, our molecular and physiological evidence suggests that there may be more to NPs than meets the eye, and that perhaps we should exercise some caution before using them ‘frivolously’.

Walker

EEB Seminar: October 9th

Dr. Arthur E. Weis will talk on

Phenology as Habitat Choice in Plants: How and why the when of germination and flowering determines the what and who of fitness impacts, everywhere

at 12:30 in the EEB lounge (BioSciences 4338)
 

Correctly timing the transitios-arven-fieldn from one life history stage to the next is key to individual survival and reproduction. The date of a transition has no intrinsic fitness impact. Rather, selection on the timing of birth, dispersal, reproduction, dormancy, etc., arises because individuals that transition at different times experience different temporal segments of the general environment. Climate, resource availability, and exposure to enemy/mutualistic/competing species can change predictably over the course of the seasons. Individuals occupying different temporal segments can have predictable fitness differences. In addition, differences in transition time also expose individuals to different segments of the social environment.

In populations that are heterogeneous for phenology, some sets of individuals are more likely to interact than others. Partitioning total selection on phenology into components caused by the general and social environment is fraught with difficulty. The temporal general and social environment are inevitably correlated. Further, phenological traits by necessity impose confounding genotype-environment correlations. I will present three experiments with Brassica rapa that manipulate these correlations to examine components of selection on germination and flowering time. One manipulates the length of the growing season to examine the fitness function for flowering time. A second contrasts selection on flowering time through female and male function by breaking the genetic correlation between mates (eliminating assortative mating). A third reveals that asymmetric competition between early and late germinants gives rise to individual and group components of selection.

 
After 19 years in southern California, Dr. Weis returned to the land of four seasons to take directorship of the Koffler Scientific Reserve at Jokers Hill. He lives at the reserve and has a research laboratory there. His main lab and greenhouse space are on the main campus of U of T, where Dr. Weis is a professor in the Department of Ecology and Evolutionary Biology.

Recently, Dr. Weis has become interesteart_weisd in the selective pressures imposed by climate change. In California, his lab used the “resurrection paradigm” to demonstrate a rapid adaptive response by field mustard, a winter annual, to an extended drought. At KSR he is continuing to work on the evolution of phenology to lengthening growing seasons.

The Weis lab website can be found here.

EEB Seminar: October 2nd

Changhai Zu will talk on

Population ecology and age demographics of black bass in the Bay of Quinte and Lake Ontario sampled through competitive fishing events

at 12:30 in the EEB lounge (BioSciences 4338)
 

Recreational fishing indirectly contributes over 2.5 billion dollars annually to the economy in Ontario. A major aspect of recreational fishing that has gained widespread popularity is competitive tournament fishing. Bass are among the most popular sport fish species, yet very little is known about adult populations of bass from large water bodies like the Bay of Quinte and Lake Ontario. With the number of tournaments held on large water bodies on the rise, it is important for us to understand as much about these bass populations as possible in order for us to keep these fisheries sustainable. Hundreds of fish are regularly weighed in at any given tournament which also makes tournaments ideally suited as a sampling tool. In an ongoing three year study, a large amount of biological information has been collected from tournament fish. This seminar will focus on what we have learned about the biology of black bass in Lake Ontario and the Bay of Quinte by sampling and tagging tournament fish.

changhai

 
 
Changhai Zhu completed his undergraduate degree in Biology in 2012 and is currently finishing his M.Sc. degree in Biology at Queen’s University, supervised by Dr. Tufts. His research focuses on age and growth of Smallmouth and Largemouth Bass in eastern Lake Ontario, and how tournaments affect bass ecology in large lake systems.

The Tufts lab webpage can be found here.

EEB Seminar: September 25th

Dr. Nalini Puniamoorthy will talk on
 
Sexual selection, sperm competition and incipient speciation in a widespread dung fly, Sepsis punctum (Sepsidae)
 
at 12:30 in the EEB lounge (BioSciences 4338)
 

Nalini2-2Theory predicts that males have limited resources to invest in reproduction, which they must allocate to mate acquisition as well as insemination and competing for fertilizations. Because adaptations to both episodes of selection may be costly, trade-offs are predicted to arise between traits that influence pairing success and those that enhance fertilization success (Parker et al. 1997). Using fitness component assessments, I demonstrate that sexual selection for large male body size accounts for a geographic reversal in sexual size dimorphism (SSD) in a widespread dung fly Sepsis punctum (Diptera: Sepsidae), where males are larger than females in Europe (EU) and females are the larger sex in North America (NA). Additionally, I address continental variation in mating behavior and internal reproductive morphology in light of phylo-geographic information to assess differential allocation in reproductive traits.

sepsidae32

Dr. Nalini Puniamoorthy is an evolutionary biologist, interested in sexual selection and the role it plays in driving speciation. She is currently a postdoc at Syracuse University where she is working on comparative studies of size, behavior and morphological traits in a family of flies known as Sepsidae (Diptera).

Her website can be found here.

Welcome to our first EEB seminar of the new term: September 18th

Our very own terrestrial ecosystem ecologist, Dr. Paul Grogan, will talk to us about

Mentors and mentoring

at 12:30 in the EEB lounge (BioSciences 4338)

Almost all of us (stpaul2udents as well as faculty) are mentors in some way. Mentoring, like teaching, is a core activity for many scientists (and in related ways for most other professions), and yet few of us have had any formal training in either. Most of us plod along, subconsciously drawing on our own experiences of being mentored, and “learning by our mistakes”. Guidelines on the goals of mentoring, and how it can best be achieved are extraordinarily rare in the literature. In this seminar, I will offer some reflections on the process of mentoring in science, and in particular I will focus on how each of us might develop and improve our own mentoring. I anticipate that the discussion will be of just as much interest to those in the audience who consider themselves primarily as mentees, since it should provide useful insights into the process that they are going through.

Dr. Paul Grogan has been with the Queen’s Department of Biology for the past 11 years. He recently participated in a celebration of his own Ph.D. supervisor’s (Prof. F.S. (Terry) Chapin – U.C. Berkeley and U. Alaska Fairbanks) contributions to science and society that resulted in the following publication: Grogan, P, Eviner, V., and Hobbie, S.E. 2013. The Qualities and Impacts of a Great Mentor – and How to Improve your own Mentoring. Bulletin of Ecological Society of America 94:170–176. Open access at http://dx.doi.org/10.1890/0012-9623-94.2.170.

Dr. Grogan’s lab website can be found here.

EEB Summer Break

The EEB seminar series is taking a break over the summer. We will return in the Fall with our first seminar taking place on September 18th.

In the meantime, if you have suggestions for speakers for the fall and winter terms, please do not hesitate to email us.  Scheduling will be done in a largely first-come, first-served fashion so the best way to get your speaker in is to let us know as soon as possible.

 

Thank you – and see you in the Fall,

EEB Committee