Wednesday, July 16, 2008

signing off for 2008

Today's blog brought to you by:
Darlene Lim

Photo: Darlene sectioning microbialite at Pavilion Lake
Photo credit: Bill Taylor

A Summary of Phase II of our 2008 field season – great field science, and tired so-longs for now

With the departure of the Deepworkers from Pavilion Lake on July 3rd, came the arrival of a new crop of researchers to move the project into the second phase of field operations. From July 4-11th, the PLRP was engaged in science diving activities in Pavilion and Kelly lakes. These dives were primarily to support the PLRP geobiological investigations. During these dives, water, microbialite, sediment, and microbial mat samples were collected for a variety of analyses (geochemical, microscopic, mineralogical, molecular, organic, thin section and taxonomic). Some ground truthing of the Deepworker waypoints of interest was conducted, however given the long list of science items we had to check off, we decided to leave much of the ground truthing to another expedition next year. A subgroup of the geobiology team spent 3 days investigating ponds on the Cariboo plateau, which are viewed as geochemical book ends to our understanding of carbonate precipitating environments. Greg Druschel from the University of Vermont conducted micro-electrode analyses to help with our understanding of the sediment redox chemistry in these ponds and Pavilion Lake. As well, Alfonso Davila from NASA Ames used a portable Raman spectrometer to investigate organic signatures in the microbialites and the mats from the various lakes and ponds.

Bekah Shepard spent hours diving in 10-20 feet of water investigating the unusual mat morphologies in the shallow regions of Pavilion Lake. While scouring the lake for interesting slime, as she puts it, Bekah discovered depressions in the shallows that had the distinct odor of hydrogen sulfide (that horrid rotten egg smell), indicative of the presence of sulfate-reducing bacteria. This led to water samples and pH data being collected from these points of interest. Bekah and Harry Bohm also discovered a region of incoming groundwater in Pavilion Lake. PLRP members have been on the hunt for a recognizable input point for groundwater for years, however given the low, diffuse flow throughout most of the lake, this find has eluded us – until now. The spring was located in the shallows, and was visually and thermally apparent to divers. This will most certainly be a region we will return to in the future to sample the groundwater for limnological and isotopic analyses. With the discovery of this spring, we hope to better understand how to locate others in the lake, and to determine whether or not the groundwater is an important contributor to the development of microbialites in Pavilion Lake.

The UBC-GAVIA team conducted mapping work at Pavilion and Kelly lakes, and added to their growing data base of sonar and photographic images from these two sites. Their research, along with that of Geoff Mullins from Simon Fraser University, has been the backbone of our understanding of Pavilion Lake’s physical characteristics. The SONAR maps produced by Geoff provided high-resolution remote sensing data that was used to plan Deepworker dives throughout Pavilion Lake. Water samples and pH profiles were also collected from a series of other regional lakes and ponds as part of the PLRP’s long-term limnological monitoring program in the area.

Throughout all of these science activities, the PLRP had the privilege of hosting Bill Taylor, a high school physics teacher from California, who was embedded with the team for the duration of Phase II. His enthusiasm, humor, and energy were infectious, and I know that his students will benefit greatly from all that he learnt while in the field with us.
We had an incredible team that made the 2008 field season possible. All supported each other through long, hot days, and late, tired nights. It was amazing to watch in action, and such a privilege to be a part of. Thank you again to the Ts’kw’aylaxw First Nations people, Pavilion Lake Community, B.C. Parks Service, and in particular to Mickey and Linda Macri, and Ron and Lorna Cook, for the incredible support and encouragement. As well, thank you to the Canadian Space Agency CARN program, NASA ASTEP and Spaceward Bound programs, Nuytco Research, McMaster University and the National Geographic Society for funding our PLRP endeavors over the years.
This is our final report for the 2008 field season. Thank you to everyone who has been following our adventures – stay tuned for more to come in 2009.
July 14, 2008

Wednesday, July 9, 2008

Science week/Tuesday

Circa 1970's beer can with microbialite growth recovered from Pavilion Lake

Carol Turse

Science week continues with some of the team completing more dives at Pavilion Lake, some continuing to prepare samples for transport back to the lab and the remainder taking field trips to nearby lakes for additional observations and sampling.

• Dives completed at the Herms, top of the mounds, Willow Point, Three Poles and the South Basin. A chimney sample was taken from Willow Point. A beer can was retrieved with microbialite growth. A preliminary investigation identifies the can label as the type of can that might have been distributed in the 70's.
• Gavia completed 7.5 hours of investigation in Kelly Lake
• Additional mat samples were obtained at Pavilion Lake South Basin and Willow Point
• Samples and readings were taken from Good Enough Lake, Clinton Lake and Probe Lake.
• Tuesday night’s science meeting discussed Phoenix findings and its relevancy to the work here. Alfonso led the discussion. In an amusing side note, Bill Taylor, Alfonso’s STAR teacher assistant for the summer, shared his observation of the role of graduate students in the Pavilion Lake work. He commended them for their work in tackling the ‘stinky lakes’ by doing the messy physical work of retrieving the samples, Gavia and other ‘up close and personal’ aspects of science research.
• The dry ice arrived today – there is a good quantity. The samples will be completed, packed and shipped Thursday.

Monday, July 7, 2008

Another martian twist at the PLRP

Alfonso Davila

It's about to get really nasty. Tomorrow some of us are heading to the Basque Lakes, a group of lakes characterized by a high concentration of magnesium-sulfate salts, which at this time of the year precipitate here and there and everywhere, forming small brine pools. Bacteria feed on these sulfate salts, leaving behind a collection of sulfide minerals and gases. Getting your nose too close to these pools will engrave long-lasting, stinky memories in your brain. Watch your step, or they may leave long-lasting stains on your boots and trousers too. Nothing in these black and white smelly ponds will be of interest to your eyes, unless your interests lie in finding out if life was ever present on Mars.
Magnesium sulfate salts, mainly epsomite (MgSO4-7H2O) and its dehydrated twin kieserite (MgSO4), are the most common evaporitic minerals identified on Mars so far. They have been found in the vast flat lands of Meridiani Planum and in the steep walls of Valles Marineris. These minerals are a window into a period of the history of Mars when liquid water was stable and abundant on the surface. In the Basque Lakes, magnesium sulfate salts are breakfast for many microorganisms, which in turn are lunch for others and so on down the menu. To many of you the resulting ecosystem may not be the prettiest expression of mother nature's masterpiece, but perhaps the simplicity of a mathematical equation will change your mind:

Mg-sulfate + H2O + Life on Earth = Mg-sulfate + H2O + X on Mars

Figure out X and you may find beauty. This is one of the many equations that justify Mars analogue research. It is based on the fact that there is many places on Earth that resemble Mars today or sometime in the past. Pavilion Lake may be an example. The Basque Lakes may be another. Studying these analogue environments brings us a step closer to understanding Mars, its evolution and its potential for life. It helps us guiding and designing the next robots that will be sent to Mars, and are the perfect grounds for testing the instruments that they will carry, or the life support systems that humans will use themselves one day. This year we brought a portable version of one of these instruments: a Raman Spectrometer. We use the Raman to identify special compounds within bulk samples that are of interest for one reason or another. Organic compounds are one example, sulfate salts are another. The working principle of a Raman Spectrometer is the same as bouncing a ball against something. Bounce it against a concrete wall and it will come right back at you. Bounce it against a pillow and it will come back much more slowly (or it won't come back at all!). After bouncing the ball many times against many different things, you may be able to recognize the type of material you are hitting just by seeing how fast or slow the ball is coming back to you. A Raman does not throw balls but instead it shines a laser into the sample. After interacting with the sample the laser comes back with a different wavelength (wavelength shift), the equivalent to the speed of our ball. Organic compounds and sulfate salts induce characteristic shifts on the laser, which can be easily identified on the screen of the computer attached to the Raman. This way we hope to be able to easily identify any sulfate salts and organic compounds in the lakes. I can almost smell them...

Monday - July 7

Carol Turse prepares speciman

Science week continues to go well.

• Bekah led two dives into the South South Basin. The group found signs of springs, mats, algae and other formations. The microbialites were small and large cone shaped formations and continued into the shallow water.
• Allyson dove Three Poles and brought up mat samples.
• Greg, Alfonso and Emily went to the Basque Lakes where they took samples from the 5 ponds in the area.
• Dirk hiked the fault zone and came down through the Willow Creek area observing rock formations and compositions
• Zena finished with ALL the submersible tapes. In addition she scanned all diver logs. A huge job - now complete.
• The remainder of the team prepared specimens and packed equipment for tomorrow’s visit to nearby lakes

Smooth Sailing - Day 2 Science

Allyson Brady and Darlene Lim prepare samples.
Photo by Carol Turse

Operations continue to go smoothly, we are still a day ahead of schedule!

1. Retreived samples at 35' and 85' near Three Poles for the seasonal study.
2. Sampled water chemistry from yesterdays 'TOP' mat area
3. Retrieved Licor and Thermisters from Three Poles science transect
4. Sampled core from 106' at Willow Cove with microelectrode probe
5. Conducted observation dive at Three Poles
6. Completed night dives to sample at Three Poles and Willow Point
7. Conducted additional microelectrode analysis of mats and structures with some interesting findings and results
8. Water samples taken from Kelly Lake and Pear Lake

Science Continues with Bacterial Gossip

Carol Turse, Graduate Student
School of Earth and Environmental Sciences
Washington State University

photo by Emily Taylor

One of the big mysteries in the history of life on our planet is the evolution of organisms from unicellular to multi-cellular life. This transition occurred during the Cambrian Explosion and neither the conditions nor the critical variables are clearly understood. To make matters even more interesting, transitional forms are poorly represented in the fossil record. However, we are extremely lucky to have Pavilion Lake and the microbialites found here as putative transitional forms. These microbialites support a wide variety of bacteria including Cyanobacteria such as Fischerella sp., Pseudoanabaena sp. and Synechoccus sp. These bacterial species have been shown to engage in cell-to-cell signaling (bacterial gossip), more commonly called quorum sensing. This quorum sensing could be extremely important in understanding the evolution of organisms on Earth as well as those that might exist on other planets.

Today I prepared four sets of microbialite samples from two different locations on the lake. The first three sets were from the Three Poles sample site and were collected at 36ft, 42ft and 84ft. I froze small pieces of these samples for later analysis via mass spectrometer and placed the rest in small beakers of a slightly acidic solution. This solution will dissolve the calcium structure allowing me to suspend the remaining microbes in a gelatin-type mix. The different sections of the microbial community can then be isolated from the gel and the DNA extracted for analysis. Another set of samples from Willow point was already suspended in gelatin, so I isolated all the layers in that sample for DNA analysis. In the past I have found several of the genes for quorum sensing in the microbial DNA and I hope this round of samples continues the trend!

Sunday, July 6, 2008

Voltammetric microelectrode

Greg Druschel and Ben Cowie lower the microelectrode to the microbialite field

by Greg Druschel
Department of Geology
University of Vermont

Sediment porewater redox chemistry in lakes reflects the activity of microorganisms that utilize oxygen, nitrate, manganese, iron, and sulfate, giving deeper sediment porewater a different chemical signature compared to the water column. Of particular note for our research, sediment porewater organisms include sulfate reducers that generate hydrogen sulfide as a product of their metabolism. At Pavilion Lake, the location of microbialites is highly heterogeneous and they have an interesting morphology, including vent-like structures that are often associated with flow in other systems. The ‘vent’ structures observed with the microbialites have not thus far been noted to be associated with any detectable flow, but it has been hypothesized that diffuse flow may be an important part of these structures. Allyson Brady and Greg Slater have found evidence in the microbialites themselves for sulfate reducing bacteria, further suggesting that these organisms may be somehow linked to microbialite formation and morphology. We are investigating if this diffuse flow may cause upwelling of porewaters, or mixing of groundwaters with deeper porewaters, that may contain low concentrations of hydrogen sulfide or other reduced forms of manganese or iron associated with sediment porewater microbes. Hydrogen sulfide reactions may additionally change the pH of the water and potentially cause changes in carbonate precipitation, and some microbialites have been observed to include bands of different colors often associated with iron and manganese precipitates which can also affect water chemistry and associated carbonate precipitation or dissolution. We are using voltammetric microelectrodes that can measure oxygen and hydrogen sulfide (in addition to iron, manganese, and many other sulfur forms) to investigate if any of these reduced chemical forms may be present in and around the vent structures.

Yesterday, Greg Slater and Dale Andersen carried a sampling pole with a voltammetric microelectrode down to a field of microbialites at 70 feet deep in the 3 Poles region of Pavilion Lake. The electrode was attached to a potentiostat and computer on a pontoon boat where I was constantly monitoring the computer screen for changes in redox chemistry at the tip of the microelectrode. Dale and Greg placed the sampling pole in the sediment and placed the voltammetric microelectrode (a little smaller than the size of a small pencil) inside 5 different microbialite vent structures at different levels and outside the microbialites to see if there were any changes in redox chemistry associated with diffuse flow through the microbialite structures. The redox chemistry within these 5 vents was no different than the redox chemistry outside the vents, which was fully oxygenated. Our hypothesis that the occurrence and morphology of the microbialites is affected by a link with sediment porewater chemistry was not supported by measurements at these sites, but we shall keep thinking, working, and looking to unlock the secrets of these fascinating formations!