Ongoing from an earlier storyboard on taking a core sample from an Irish bog for a study of the paleoecology, we set a date to take a core sample from the lake. Except for myself, the people present are all involved in landscape study of one kind or another. Present were the organiser, Robin Lewando (paleoecologist), Robert Devoy (professor of Geography), Liam Long(local geography teacher) Niamh O’Flynn (biodiversity teacher), and myself (Author, and operator of a great cheap camera). We borrowed a rubber dingy and coring equipment from UCC (University College Cork), and another boat from a local farmer. The left tyre of the trailer collapsed on the way over… something to deal with at the end of the day.
We lay wooden pallets along the floating mat which surrounds the lake, and attach a rope to the Land Rover. You can probably see that the farthest pallet is virtually underwater, and most certainly was underwater when we stood on it…
We tied a few granny knots and threw a loop of rope out into the lake, for hauling ourselves back in over the floating mat of vegetation which surrounds the lake.
The new growth of reeds is three to four feet in height. From the remnants of last year’s reeds, you can see that they will reach up to seven feet by the summer.
The team will use the two boats for the coring, the kayak is for me. Being the photographer, I’m absent from the photographs.
The equipment is given a final check to make sure everything is present and correct.
Then the boats are launched.
Two guys in the motorboat set out first to lay a rope across the lake, and another at ninety degrees to tension the long rope. The core will be taken near the tensioning point as that spot will remain fairly stable during the coring.
The two boats are tied onto the rope, stern to stern. It is overcast when we set out, but it’s a calm, warm day, and rain isn’t forecast.
The corer consists of several parts. The grey tube is a guide, through which the corer will be operated, making sure the corer goes into the sediment at the same place each time.
The water at this level is around three meters to the surface of the sediment. The guide is pushed into the sediment, then tied to the stern of the rubber dingy.
The corer is being prepared, and will be pushed down approximately one metre deeper each time. Measurements are taken at each extraction to enable a rate of deposition to be calculated. As the sediment is anticipated to cover around ten thousand years, even an error of a few inches can make quite a difference to the analysed results.
The corer is in two parts, a rod which consists of meter-length metal pieces which screw together, and the corer itself, which is basically a hollow tube.
The first core is exceedingly wet, not having been compressed by successive layers of sediment. This will be analysed for pollen, but will also contain living organisms, which will provide a comparison to what is discovered historically, at greater depth.
This is a core of extracted sediment. It is wrapped in foil and cling film, and will be kept refrigerated prior to being cut into centimetre sections for analysis. The cores will eventually provide a historic picture of the diversity of vegetation in the area as it built up since the last ice-age. This might also provide an indication of the ways in which humans interacted with, and changed the landscape as farming took over from foraging.
Meanwhile, I paddle around the lake and take photographs of the surrounding vegetation. The ‘scum’ visible around this end of the lake is actually a raft of white flower petals, presumably from Hawthorn, which is called May Blossom in England.
On the other side of a small central island I disturbed a family of swans. I didn’t get too close as this small lake is rarely visited by people, and the swans would be unused to humans. The pen (female) swan immediately led her five signets behind some bushes.
The cob swan let out some rather distressed calls, and tried to lead me away, so I dutifully followed, and when I was far enough away, he flapped noisily back to his family.
The edges of the lake are littered with horsetails, various kinds of pondweed, and water lilies. The water lily flower buds are visible through the water, so they might be blooming in a month or so, at which point I might come back out and take a closer look at the lakeside vegetation.
From a dull beginning, the day brightened to a bright blue sky hung with fluffy white cotton-wool clouds. Perfect!
And that’s the point at which I stopped photographing. The sediment at the centre of the lake wasn’t as deep as hoped, at only four metres to the stony bed, with a small layer of glacial silt, while the core taken nearer the road was a good six metres of deposits before contacting glacial silt
The working party carried on and did another exploratory core at the edge of the lake. The deeper sections of the glacial basin turned out not to be where the lake is today, so a few more explorations delving into surrounding bog are likely. And then, of course, all that core has to be cut into centimetre slices, and examined for pollen and other microfossils. A long and arduous task. Some samples will eventually also be sent for radiocarbon dating.