Eliza continues her Australian research adventure (see Part I) where we left off… A Diary from Down Under Part II
July 7, 2016: Hello again from down under! Henna Wilckens (intern) and I are deep into processing the sediment samples we collected last month from the bottom of Sydney Harbour. From our temporary work post at the University of New South Wales, we aim to sort through each of the millions of tiny sediment grains in our frozen samples to extract anything that once wriggled, crawled, filtered, or respired. The identity and number of creepy crawly critters in our samples will help us discern whether marine communities adjacent to man-made seawalls and pilings differ from those adjacent to natural rocky shorelines. All of this is part of a project I’m doing as an NSF EAPSI fellow with my Australian host, Dr. Emma Johnston, and post-doctoral researchers in her lab (link to earlier post).
Surprising as it may be, we’ve thus far encountered a number of striking and beautiful organisms within the urban muck. July 14, 2016: In the original Star Trek, Lieutenant Spock, upon beaming down to a new planet from the Starship Enterprise, would immediately pull out a Tricoder and begin scanning the environment for life forms. Results were instantaneous, providing a comprehensive view of the surrounding ecosystem within seconds.
Though we have yet to fully see such a novel invention on Earth, I’m overwhelmed today by how close we actually are to inventing the Tricoder in real life. I spent the day in lab at the Sydney Institute of Marine Science, extracting DNA from marine sediments and their invertebrate inhabitants. Thanks to support from the IGERT Program on Ocean Change at UW and from the Applied Marine and Estuarine Ecology Lab at UNSW, the genetic material I extracted will be sequenced and matched to a database of known organism sequences, in a process called DNA barcoding.
Like DNA extractions of the old school variety, the endeavor required donning a white lab coat, goggles, and gloves, and making sure not to sneeze or shed excessively. Unlike genetic adventures past, the materials needed for the extractions were available in a self-contained kit shipped par avion from Texas — no gels or interpretation of specific sequences was needed, and the entireprocess for many 10s of samples took only a single work day (20 years ago, comparable work might have been the focus of an entire PhD).
I hope results from the day’s genetic escapades will yield helpful information about both the microbial and invertebrate community on man-made and natural shorelines in urban settings, such as Sydney. And I’m thrilled to report there is a chance that by the end of my lifetime, I could be scanning Earth’s ecosystems, Tricoder in hand, with my best interpretation of a female embodiment of Lieutenant Spock.
July 28, 2016: In the day to day here, as I commute to work, take the bus around town, and observe, I’m frequently overwhelmed by daily demonstrations of niche theory and convergent evolution in the world around me. The terrestrial flora in Sydney is of an entirely different lineage, primarily of the Myrtoideaen tribe Eucalypteae, than what I know from the Pacific Northwest. Though Eucalypts have long been present on Earth, their radiation in Australia is apparently relatively recent. Eucalypts now make up ¾ of the vegetation on this island continent, and fill nearly every ecological function that I, as a North American, attribute to other trees. For instance, coastal swamplands similar to the cypress swamps of Louisiana and Texas are here inhabited by swamp gum trees, other spp., and their Myrtoideaen cousins, the paperbark trees. Savanna and temperate grassland habitats that in the US would have scattered oaks, cottonwoods, or willows, are here are inhabited by bimble box and coolibah eucalyptus trees. The Sydney red gum is one of several Eucalypts that plays the role of North American fruit trees, providing food for fruigivores. On my commute home at night, I often get to watch enormous ‘flying foxes’, or Ku-ring-gai bats (Pteropus poliocephalus), indulging in the tree’s nectar.Eucalyptus
This, of course, is entirely tangential from my work on man-made alterations to urban shorelines in Sydney Harbour. While I know I should be entirely focused on the project that brought me here, the natural history nerd within has a hard time ignoring what Darwin and many others since found astonishing upon first traveling to the opposite hemisphere: That a similar set of ecological professions (niches) exist everywhere, and who fills them (which species) is heavily influenced by chance.
August 5, 2016: So. Many. Tiny. Cups. That’s the conclusion today after my first foray into stable isotope analysis with Henna. Though I must admit, chemistry was my least favorite subject in my early years, with a few years more wisdom, its benefits have become evident. Stable isotope analysis is a tool that allows us to measure the relative weight of carbon and nitrogen in freeze dried tissue samples. The weight of carbon helps us discern the original source of primary productivity in the tissue sample of interest. For instance, organisms that feed on suspended phytoplankton, such as diatoms, should have a different carbon isotope signal than organisms that feed on seaweed, this signal is proliferated up through each subsequent level in the food web. The weight of nitrogen in an organism’s tissue is correlated with its trophic level, or its position in the food web. Organisms that are higher order consumers such as sharks will have a heavier isotopic nitrogen signal than lower order consumers such as sea urchins.
Next, it’s off to the mass spectrometer for these little samples. Within a few weeks, we hope to have data back which give us a first look into how food web structure compares between natural and man-made shorelines in Sydney Harbor.
August 12, 2016: I’m terribly sad to be leaving this beautiful city and a new assemblage of friends and colleagues who I will forever cherish. My time at UNSW has been eye opening in so many ways, from the culture of collaboration in my host lab and department, to the suite of new critters I encountered, to the daily evidence of ecology and evolution that abound when one first becomes acquainted with life in the opposite hemisphere. My EAPSI host, Emma Johnston, has provided inspiration and ideas that will keep me motivated for much time to come. With luck, that motivation will be matched with interesting findings from the stable isotope and genetics data we’ve collected.
——————————————-All photos from Eliza’s Instagram. Follow Eliza on Instagram @eheery.
