Science & Nature

elizabethwatsonillustration.com

Vitalii Hulai/Shutterstock

DRAWN TO THE LIGHT

RED UNDERWING (Catocala nupta) Gillian Nash

This striking, fast-flying large moth with a wingspan of up to 80mm is found throughout England and Wales and most frequently seen in southern counties. It is, however, an uncommon species in Dorset, although its status nationally has improved with a rise in numbers over recent years, in particular with an increase in more northerly sightings.

Sometimes found on house walls or wooden surfaces such as fence posts resting by day, its highly diffuse black and grey tones provide exceptionally efficient camouflage until disturbed, when the warning red and black hindwings are revealed as it flies to seek safety elsewhere, out of sight of predators. These vividly coloured hindwings are rapidly hidden by the forewings as it settles in another hiding place.

The adult moths are nocturnal and can sometimes be seen nectaring on buddleia flowers. On the wing from August through to autumn, red underwing moths can be found in many habitats, including gardens, parks, woodland, riverbanks and unimproved wild areas. Eggs are laid singly to overwinter in crevices in the bark of its foodplant tree species, which include a variety of poplars and willows. In early summer the newly hatched, night-feeding larvae grow rapidly on a diet of leaves, and when fully developed pupate within a cocoon in a sheltered place, often on the ground among decaying fallen leaves and other debris, or in a crevice on its foodplant tree trunks. The adult moth emerges in late summer.

MARVELLOUS MERLINS

Alex Hennessy, Dorset Wildlife Trust

The smallest European falcon and the UK’s smallest bird of prey, the merlin, is not much larger than a blackbird. Despite their diminutive size, merlins are impressive hunters, feeding on small birds including meadow pipits which they chase in flight, keeping low to the ground. Their small size and agility also allow them to ‘hang’ in the breeze as they pursue their prey. Merlins can’t be found in Dorset all year round but do visit coastal areas in autumn and winter. They retreat south when their usual habitat of upland moorlands between Shetland and south-west England become too cold. In the winter British breeding merlins are also joined by migrants from Iceland in search of warmer weather. They are a thrilling bird to keep watch for during the winter months, when birdwatching is made easier by the bare tree branches, so increasing visibility. Wintering merlins favour coastal marshes and lowland farmland, indeed they have been spotted at Portland in previous years.

Merlin nests are most often found on the ground, often concealed in heather. The ground is ‘scraped’ by the female and lined with twigs, bracken, heather and other vegetation found nearby. When eggs are laid, the male and female share incubation duties (although not equally – the female spends more time incubating than the male). How will you know when you’ve spotted a merlin? They can look quite similar to a female kestrel but are much smaller. Merlins are blue-grey on top, with a grey head and orangey-cream underparts that are streaked in black. Females are mainly grey-brown, with dark streaking underneath. Merlins have blunt tails and compact, broadbased wings with pointed tips. Their beaks are hooked and dark in colour, fading to a lighter yellow or grey as they meet the head, with relatively large dark eyes. Merlins are a protected species, and are Schedule 1 listed in the Wildlife and Countryside Act. It is an offence to disturb them during their breeding season without a licence. UK merlin numbers crashed towards the end of the 20th century, and while the population has been in recovery in recent years, they are still scarce, likely due to habitat loss and an increase in disturbance.

Merlin Facts

• Mated pairs of merlins will often hunt together, catching their prey in co-operation. • Merlins often perch in an elevated position when hunting, such as tree stumps and nearby rocks. In some areas, they have been recorded using sheep for this very purpose. • Merlin nesting behaviour has started to change somewhat since the 1970s. At this time merlins began nesting in conifers, at the edge of plantations and hunting in the nearby open ground.

BEEZANTIUM

Paula Carnell, Beekeeping Consultant, Writer & Speaker

Unexpectedly, especially for this time of year, I had a rather large job added to my list when I was contacted about some bees after their home in an ancient oak tree lost one of its branches in high winds. I agreed to take a look, with no idea how big, or accessible the colony would be. Thankfully Gareth, who’d called me, had a cherry picker to hand as the bees were about 30ft up and REALLY exposed! If they remained there much longer, wasps would invade and steal their honey and with no protection from the weather their survival looked bleak. On closer inspection, they were calm, busy protecting what turned out to be two large combs of brood. The bees cover the brood in the wax comb to keep them warm, and nurse them ready for hatching, because if they get chilled the larvae will perish. I had to find a way of removing them intact and as quickly as possible.

The first plan was to return with my adapted Bee Hoover, one of my best investments, bought a few years ago as it really helps when extracting colonies of bees in awkward places. It attaches to my ‘Hetty’ hoover, with a clever grill which reduces the suction and prevents the bees from ending up inside the machine. A large box contains the bees safely, ready for transportation to their new home. The suction is gentle, so it takes a while to vacuum up around 80,000 bees! By removing most of them and keeping them inside the box, the combs were revealed ready to be cut away and placed in further boxes to transport. I’d arrived at 5pm, a good time as the bees were returning home to settle after a day of foraging. An earlier start could have left many bees stranded after our removal. By 8pm most of the flying bees were now in my Bee Hoover box.

Experienced bee team member Kerry then arrived to lend a hand. I was getting tired so fresh eyes and brains were very welcome! Gareth remained on the ground whilst Kerry and I returned back up to the colony to

start removing the comb. The non-flying nurse bees had now covered the brood combs and so we carefully cut them away and placed them in two large containers – bees, comb and honey altogether. It was messy work, and as night drew in, we were very grateful for the head torches Gareth had to hand. By 9.30pm we had two full boxes of bees and comb, and the Bee Hoover, full of bees and off we headed to the Newt.

In the new Beezantium, there is a fabulous, large log hive made by Matt Summerville and it was still uninhabited. Working in the dark with our head torches, Kerry and I carefully pulled out the brood and honeycomb, placing it inside the log hive. There were bees and honey everywhere, so we worked as quickly as we could. We had to think how we could get all the flying bees, still in the Bee Hoover into the hive, which was high up, even with my ladder. With everyone else in bed, we had to adapt! We managed to balance the hoover with its entrance unplugged above the hive, protected it with sheets and decided the remaining bees and honey had to wait until daylight.

Despite getting back home two hours past my usual bedtime, I was hot and ‘buzzing’, eager to share my adventure with Greg before I could contemplate sleep. During the night I was wondering how to save the bees stuck in the honey as they’d drown if left too long. At around 2am it came to me to place the comb and honey in a large container over a sieve; the honey would then drain off the bees leaving them free to fly into their new home. Back at the Beezantium, before the wasps awoke and transferring the bees and honey into large honey drums with sieves, I looked to see how many bees had made it into the log hive. We had no idea if we’d caught the queen amongst the masses of bees hoovered and scooped up. Only time will tell.

The next morning, the bees had cleaned up the wax comb, mainly filling their bellies, and a very small amount had made it into the tank. Although disappointed as we hadn’t saved or tasted any for ourselves, it was absolutely essential for their survival that they had as much of their honey as possible. There were of course casualties during the move, not least Kerry, who despite wearing double gloves, suffered a sting on each forefinger.

WEARING CARE FOR THE PLANET ON YOUR SLEEVE

Peter Littlewood, Director, Young People’s Trust for the Environment

Increasing numbers of young people are becoming aware of the impacts of the fashion industry on our planet. It’s the second biggest global polluter after the energy industry. That’s in part because most of the cheap clothing that gets heaped under the label of ‘fast fashion’ is made in factories where the labour is at its cheapest – China, India and Bangladesh for example – and in these countries, most of the electricity that powers the factories comes from coal-fired power stations. As we ’re all becoming acutely aware, coal is the worst kind of fossil fuel, producing up to double the amount of greenhouse emissions, when compared with natural gas, to produce the same amount of energy. And that’s not even taking into account the working conditions that many workers in these countries have to endure.

Transporting clothes across the planet is a further source of carbon emissions. The amount of water used in making clothes is staggering. In 2017 for example, the fashion industry used almost 79 billion cubic metres of water – that’s enough to fill a staggering 32 million Olympic-sized swimming pools. That seems almost impossible, but cotton, a staple of the fashion industry and the fabric worn in some form or other by most of us every day, comes from a very thirsty plant. It can take up to 2,700 litres of water to produce the cotton needed for a single t-shirt, and up to 10,000 litres to produce the cotton for a pair of jeans. To give a sense of perspective, that would supply someone with drinking water for more than nine years!

Synthetic fibres like rayon and viscose come from

Sirirak kaewgorn/Shutterstock

plants, with around 70 million trees being cut down each year to create wood-based fibres for clothing. And oil-based materials like nylon, acrylic and polyester shed up to 1,900 microscopic fibres – ‘microfibres’ – every time they’re washed. Microfibres are too small either to be seen by the human eye, or to be filtered out by our water treatment plants. 72% of tap water sampled from various locations in the UK was found to contain microfibres, whilst globally, that figure increased to 83%. It is thought that microfibres make up around 35% of all the plastics in the world’ s oceans. You can now get a wide range of activewear that has been made using recycled marine plastics, which seems like a good idea. And it is – to a point – but as there is no capacity to recycle them at the end of their useful life, they are merely delaying the journey to landfill or incineration, rather than closing the loop on truly sustainable clothing. Cheap fashion items tend to be made to be disposable. It’s the whole point with fast fashion: buy it cheap, wear it a few times and when you get fed up with it, throw it away. A typical family throws away around 30kg of clothes each year, of which only about 15% is recycled or donated. The rest ends up in landfill or is incinerated.

So, how can we do things better? Should we all just give up and stop wearing clothes? Absolutely not! It’ s a horrifying thought! But if we all try to buy fewer, but better-quality clothes that we wear more often, that would be a great start. Buying used clothes is becoming quite a trend too, and it’s an area where young people have really taken the lead. If you’re not wanting to make money from your cast-offs, then taking your clothes to the local charity shop is a great way to recycle them and to start making a difference. You can pick up some fantastic bargains in charity shops too and Oxfam even has its own online clothing store at online.shop.oxfam. org.uk, where you can pick up not just used clothing, but accessories and even jewellery too.

If you have the time, there is money to be made by selling your clothes. eBay is an obvious choice for this, but there are other, more specialist websites that are becoming popular places to both buy and sell ‘pre-loved fashion’. Sites like Depop (depop.com) and Vinted (vinted.co.uk) are excellent places to both sell the clothes you’ve got tired of and to pick up some new ones at bargain prices. Reviews for these sites are patchy though, so I’d recommend you do some research of your own before taking the plunge! But there are other specialist sites for different markets too. If you’re looking to buy some bargain clothing for your children (and they do have a habit of growing out of things very fast!), try a site like Kidclo (kidclo. com), which defines itself as a super-easy way to ‘recircle’ your children’s clothes.

This is by no means a comprehensive guide, but if you ’d like to make more environmentally-responsible choices on what you wear, here are some first steps you can take: reduce the number of clothes you buy, keep and wear your clothes for longer, recycle them when you don’t wear them anymore, and try to buy more used clothing. It’s not going to solve all the problems, but small steps made by lots of people add up to big changes!

HOT ROCKS IN EDEN

Rob Bygrave, Sherborne Science Cafe

Willyam Bradberry/Shutterstock

In June 2012, Guy Macpherson-Grant of EGS Energy gave a talk to the Science Café in which he outlined the attempts to exploit deep geothermal energy as a source of carbon-free energy, in the context of declining oil supplies, particularly low-sulphur types. Developments and projects operating in France and Germany at the time were described and key findings of the Sinclair Knight Merz (SKM) report were discussed.

The SKM report stated that geothermal energy is widely spread around the UK with ‘hotspots’ in Cornwall, Weardale, Lake District, East Yorkshire, Lincolnshire, Cheshire, Worcester, Dorset, Hampshire, Northern Ireland and Scotland;

Deep geothermal resources could provide 9.5GW of baseload renewable electricity – equivalent to nearly nine nuclear power stations – which could generate 20% of the UK’s current annual electricity consumption;

Deep geothermal resources could provide over 100GW of heat, which could supply sufficient heat to meet the space heating demand in the UK. Cost reduction potential is also exceptionally high.

Despite this significant potential, the UK support regime was uncompetitive with other European countries.

At the time of the talk EGS was looking in the South West for areas of accessible granite and where the rock was already fractured to provide a wider volume of

Cooling Tower Power Plant

Cup Rock

Ground water aquifer

Cup rock Geothermal reservoir

Heat source

Designua/Shutterstock

hot rock; Heat transfer occurs along a channel through which water runs. The depth of the rock affects the temperature of the water at the surface and at 4 to 5 kilometres the temperature is about 180ºC.This enables the generation of electricity by steam turbines. It also provides low grade surplus hot water which can be used to heat homes in the locality.

The geology of parts of Cornwall was considered suitable for the application of the techniques developed by EGS Energy. In addition, there was sufficient water in the area to provide a reservoir for the system. In order to determine the area where the initial EGS Plant would be established, EGS undertook an analysis of geological data and a suitable site was identified at the Eden Project.

In collaboration with the Eden Project EGS Energy were due to build the UK’s first geothermal power plant generating both heat and electricity. With a capacity of 4MWe and the ability to generate around 95% of the time, it was to produce enough electricity to supply Eden and the equivalent of around five thousand households, as well as heating for the biomes and potentially some district heating (depending on economics and logistics). It was anticipated that power would be delivered from late 2013 dependent on many factors: planning permission, drilling rig availability, drilling progress, and so on.

Questions from the group raised concerns about extraction and disposal of pollutants, potential problems similar to those from “fracking” and low overall efficiency.

UPDATE 2021 - EGS WORLDWIDE Our planet is still very hot. In fact, 99.9% of our Earth exists at a temperature greater than 100ºc. Therefore the Earth itself is an abundant source of renewable energy. It will never run out – unlike fossil fuels.

Geothermal energy can be harvested from the crust, which is 15-35 miles thick over land, in several different ways. The most common sources of underground heat are used to either generate electricity, or heat water for domestic or commercial use. There are four main sources being used around the world today: hot water, steam, hot rocks and magma. The latter is molten rock which is found deeper in The Earth’s crust and breaks through when volcanoes erupt releasing larva.

This source of energy is sustainable and constantly renewed. It also a relatively clean although there is some small release of greenhouse gases such as carbon dioxide into the atmosphere, and some toxic minerals will reach water supplies. However, a conventional coal-fired power station releases about five times as much CO2 as an equivalent geothermal plant and filtration processes can collect the minerals.

The use of these sources is increasingly significant around the world and the data below indicates the most recent developments.

Top 10 Geothermal Countries 2019

U.S. Indonesia

2,133

Installed Capacity in MWe Year-End 2019 Total 15,406 MW

Source: ThinkGeoEnergy Research (2020)]

3,676

Other

1,025

Japan

601 755

1 GW Country Club 1,918 Philippines

1,526

1,005 Turkey

Iceland

861 944 963 New Zealand Kenya Italy Mexico

sherbornesciencecafe.com

___________________________________________ Tuesday 26th October 7.30pm The Ryewater Farm Butterfly Project in Holnest– A Talk by Wren Franklin Raleigh Hall, Digby Road, Sherborne DT9 3NL sherborne.scafe@gmail.com