By Joanna Wolstenholme
Sudbury, on first inspection, is a rather bland, spread-out mining town, inhabited by many, many trucks (most of them blue). When I first arrived, to help out on a project run by Andrew Tanentzap, I have to say I was a little underwhelmed. However the more you explore, the more remarkable the town becomes. It is one of the few areas of the world where remediation has really worked, and the next generation will inherit a greener and cleaner city than the one that their parents inherited. This remarkable change, from a barren ‘moonscape’ caused by years of acid rain (Sudbury was once the largest point source of sulphuric oxide fumes in the world, thanks to the extraction of large amounts of nickel from many mines in the area), to an area with burgeoning first generation forest cover, and recovering lakes, is a great success story that the area can be immensely proud of.
With its industrial heritage, Sudbury, with its 330 lakes, makes an idea experimental location for a research group dealing in ecosystems and global change. Our test lake, Daisy Lake, is perfectly set up for studying the effects of terrestrial influences on aquatic ecosystems, as along its length the shores and wetlands have been remediated to various degrees. One section has been limed (spread with calcium carbonate, neutralising the otherwise very acidic soils) and so the growth is relatively lush, and the trees, although young, are not stunted. Other areas, closer to the smelter at the far end of the lake, are far more barren; bare, stained rock predominates, with a few stunted trees.
In Daisy, we were studying eight stream deltas, each with very different personalities. At each site Andrew’s post-doc Erik and I collected algae samples (through a variety of fairly low tech contraptions, more of which later), sediment samples, water samples, and used the Floroprobe and BenthoTorch (two very expensive, high tech contraptions) to characterise the algal species found in the littoral zone (water near the edge of the lake) and benthic layer (the area at the top of the sediment) respectively. This all sounds very easy in theory, but in practice (as with any fieldwork, as I came to learn) things were far harder and more complicated… and often involved some rather novel solutions. If nothing else, this placement has certainly given me plenty of opportunities to stretch my problem solving skills!
My first job was to build umpteen algae-collectors, which were incredibly scientific looking plastic tubes with cut up swim floats attached, from which 6 microscope-slides dangled from fluorescent string. These floated on the surface, but we also sank clay pot holders tied to bricks, as another surface for algae to grow on. We left these in the lake (on a beautiful sunny day) at each of the deltas and then returned to collect them 3 weeks later. After those three weeks had passed, We set out early, trying to avoid a storm that was due around lunchtime, only to find that between two boats we only had one working fuel cable. Great. So we towed each other around the lake, with our little motor struggling along at a snail’s pace. Whilst the clay pot holders had proven attractive to algae at most of the sites, trying to scrape the algae off the pot and into a rather narrow-necked falcon tube proved difficult. However, these still looked like our best bet, as the microscope-slide contraptions had only a thin layer of algae on each slide – we may actually have just built elaborate feeding platforms for the algae-eating zooplankton! The rain set in in earnest after we had got through just half the sites, and the wind got up – heavy rain whilst trying to scrape algae off clay plates tends to complicate things somewhat! Eventually though, we made it around all the sites, collected all the contraptions, and the rain stopped. Fieldwork is great fun, but the weather makes such a difference, especially when you are out on a very exposed lake!
On a more high-tech note, we also made use of two fancy algae-counting probes – the Fluoroprobe (which detects the level of various algal species in the water column) and the BenthoTorch (which, as the name suggests, measures benthic algae growing on the top of the sediment). Both were a little baffling to start with; their comprehensive manuals detailing many things, but not necessarily the answers to what we actually needed to know! After several dry runs measuring the amount of algae on Erik’s office floor, we took them out to the lake, and used them at each of the deltas three times between when we deployed the contraptions and when we scooped them up. The unseasonal amount of rain that Sudbury was experiencing, however, complicated things, and meant that in some sites Erik had to swim down to the sediment with the Benthotorch, as we couldn’t reach it from the boat. Holding the boat still enough to steady the Benthotorch whilst it was measuring was also a challenge, especially on windy days – we often resorted to having one person standing on submerged logs holding the boat still, whilst the other measured! Again, something which sounds easy in theory, but when you are out on a lake, at the mercy of the elements, often proves more complicated…
As well as working on Daisy with Erik, I also helped Andrew collect additional data for a project looking at the interplay between terrestrial and lake ecosystems. This meant going out to 6 other lakes around Sudbury, and six down in the Muskokas, to collect water samples, use the fluroprobe, and deploy and collect the microscope slide contraptions. Key to the project was collecting clean leaf and algal samples, to go off for stable isotope analysis, to allow Andrew to calculate the influence of the terrestrial systems surrounding the lakes were having on the lake ecosystems. In order to grow clean algal samples without the influence of terrestrial DOM, we collected water from each of the lakes, then filtered it into jars and re-inoculated each jar with a small amount of unfiltered lake water, from which wehoped the algae would regrow. Again, simple in theory, but in practice involved hours and hours of standing by a vacuum pump, watching water drip, drip, drip through a filter. One night, on a field trip down to the Muskokas, we actually ended up filtering outside a Best Western hotel, so as not to set the fire alarms off! Safe to say we got many odd looks. However, the field trip down to the Muskokas was one of the best perks of the summer. We went down in September, almost at the peak of the colours changing, and had two lovely dry but crisp days. Driving down dirt tracks through beautiful forest, to find beautiful lakes to paddle out into was great fun, and a real adventure! It definitely offset the tedium of filtering.
At the end of my seven weeks here I am very sad to be leaving. It was a great experience, with plenty of messing about on boats, and exploring new places. I have learnt a lot about the complications of fieldwork, how to solve problems on the fly with limited supplies, and just what really goes on behind those dry-sounding ‘Materials and Methods’.