Bring on the solstice on GBI! We’ll be celebrating solstice in a few days – my favourite day of the year, because it's all uphill from there! Mystery pallet What a surprise to be driving along Sandhills Road on the way to our swim at Medlands and see this! Considering the Golden Bay cement works closed in the 1980s, how a pallet from at least 30 years ago came to be on Great Barrier Island is quite a mystery! This time it was a crab! And I can still see and feel the grab marks on my thumb! It may have been one of these, which I selected from 48 possible suspects in “Coastal Crabs: a guide to the crabs of New Zealand". I chose the paddle crab because it’s common, it’s the colour I caught a glimpse of as it aqua-jogged off, well, crabwise, on four of its five pairs of legs (the fifth pair wields the enlarged pincers), it’s widespread around New Zealand in the surf zone on sandy sheltered and open coasts, AND it’s described as “very aggressive”! I learned that "many crabs are scavenging omnivores, eating any plant or meat scraps they come across. Some species are particularly aggressive and prey upon other invertebrates, and occasionally the odd human finger may get nipped if it comes too close.” Indeed! But the way things are going, I’m glad there are still creatures to be encountered out there! Plastic bag free GBI Taking their lead from Golden Bay’s groundbreaking Bag Ladies of over a decade ago, whose fun-but-serious campaign resulted in the declaration of Collingwood as New Zealand’s first plastic-shopping-bag-free town, the group Wastewise Aotea is implementing their brilliant plan for replacing plastic shopping bags on the island with cloth bags. Golden Bay Bag Lady Nicola Basham, third from left, with MP Damien O’Connor, Helen Clark, Prime Minister at the time, and Colleen Trotter, co-owner of the Collingwood General Store – the first plastic shopping bag free shop in New Zealand! The group put out a call to the community for preloved cloth shopping bags. These were given to the shops for “swap-a-bag” – come in to shop, choose a bag, use it and keep it for future shopping or, for variety, exchange it for another one. Then, after putting out a call for donations of fabric, the group started monthly bag-sewing gatherings at the art gallery, or anyone wanting to sew bags at home can collect fabric, cotton and a pattern at any time. The volunteer-made cloth bags are for sale at the gallery as a fundraiser. Gradually all the used and new reusable bags will come into circulation and next thing you know, no more plastic bags on GBI! We meet our 300th person! Every next hundred takes longer than the last (7 months for the first 100, then 9 months, then a year), but we made it to our next milestone! Karen Walker was the lucky winner of a Janene’s Ice Dreams voucher – yummy treats made right here in Okupu facebook.com/JanenesIceDreams. Karen is an artist and volunteer at the gallery who’s lived for 30 years on a secluded ridgetop in Puriri Bay, Tryphena. Exhibits at the gallery are usually works by one artist or created for a theme decided by the coordinator and the Arts & Heritage Trust. This month's theme was birdlife of Aotea/Great Barrier Island, and here’s one of Karen’s paintings, a pied stilt. MESSENGER Mission to Mercury, 2004-2015 (MESSENGER = Mercury Surface, Space Environment, Geochemistry and Ranging) Thanks to the Night Sky group and a talk by resident astronomer Ann Sprague, now retired, we now know a bit more about Mercury, and so will you! Ann's a spectrographer – analysing the spectrum of emitted light to deduce the properties of whatever is emitting it, so she was an important member of the mission team, one of whose goals was to find out just what the planet and its atmosphere consist of. Moonless Mercury, the smallest planet, about a third the size of Earth and the closest to the sun, zips around its small orbit in just 88 Earth days, but its rotation takes 59 Earth days! That’s one long day! Mercury has the greatest temperature range in the solar system – the side close to the Sun reaches 427°C, while the other drops to -183°C. An artist’s image of MESSENGER Earth and Moon from orbit around Mercury The spacecraft blasted off in 2004, began orbiting and photographing in 2011, and came to a violent end with an intentional crash onto the surface at about 4 km per second. The impact site: Considering its slow rotation so close to the sun, you may be surprised to know there’s ice on Mercury. Ann explained that the deep floors and walls of craters near its poles are always shaded and much too cold for swimming! It was the suspicion that ice is present that got the mission funded, she said, because ice means water and water could mean life. A whole lot of people went to a whole lot of trouble and expense to identify these water ice deposits in eternally shaded regions within impact craters around Mercury's north pole. Mercury's surface has been shaped by the impact of large objects forming craters, by volcanic lava flooding the surface, and by the planet's crust shifting in response to cooling and contracting. Both folks at NASA and the audience at Ann’s talk were amazed to find that Micky Mouse and the Cookie Monster had dropped by in the distant past, and that at least one little crater seemed very happy to be alternately boiled alive and frozen solid! At last we got to Ann’s speciality: using spectroscopy to study “volatiles” – chemical elements and compounds with low boiling points found in a planet's or moon's crust or atmosphere. Mercury is surrounded by an extremely thin envelope of gas, so thin it’s not an atmosphere but an “exosphere". Unlike the atmospheres of Venus, Earth and Mars, the molecules don't collide with each other but bounce around on the surface. Seven elements have been found in Mercury's exosphere: hydrogen, helium, oxygen, sodium, potassium, calcium, and, as discovered by Messenger (Yay, Ann!), magnesium. The hydrogen and helium are in the solar wind – the gas streaming from the Sun. The other elements are likely from crash-landed comets or meteors, or maybe from surface rocks. Vaporisation of rocks upon impacts, evaporation of elements from surface rocks in the hot sun, sputtering by solar wind or ions in Mercury's weak magnetic field, or volatiles coming up from the planet's interior are all ingredients in the recipe. The colours show the different elements comprising Mercury. That’s all fine, but with all the urgent problems in need of solving here on Earth, I think it’s all a giant waste of human, material, financial and energy resources! Back on our wee island on Planet Earth…. The return of Ridge to Reef Three down, five to go! I never imagined it would take two years to share info about all eight presentations we attended back in 2015! Today thanks to a recent initiative on the Barrier that resulted in the return of fish to Awana Stream after a 30-year absence, I thought I’d share what we learned about freshwater fish. Tom Mansell: Freshwater fish – “Bring back the whitebait!” Tom is a council stormwater engineer who’s been on a mission around Auckland to eliminate barriers to the whitebait’s annual upstream journey. He reviewed the dire situation of these freshwater fish, a peril that many of us have heard or read about before. Like all species threatened by human activity, whitebait (the juvenile forms of the five Galaxiidae species) would love nothing more than to carry on in their ecological niches and produce abundant new generations as they’ve always done. But destruction of their spawning grounds and freshwater habitats, agricultural run-off and other pollution, and too many people taking too many of them are threatening their survival. Some are as badly threatened as the kiwi. Of the five species, only the lifecycle of the inanga is fully understood. Females lay their eggs in estuary vegetation around the high-water mark on a very high tide (a “spring tide”). Males fertilise the eggs, releasing so much milt (sperm) that inanga are known as “cowfish” because of the milky water. Most adults die after spawning. The eggs remain moist for weeks among the vegetation. When another spring tide reaches the eggs, the larvae hatch. The outgoing tide carries them to sea, where the hatchlings spend the winter, feeding on small crustaceans. In spring, the whitebait make their way upriver to live and grow in freshwater habitats. By autumn the mature adult fish are ready to swim back downriver to spawn in the estuaries. They live only one year. Once again, for flora and fauna (including people!) the Barrier is a refuge. The estuaries are mostly unaltered and relatively pure, many stream mouths are inaccessible, the human population is small, a voluntary fishing code of conduct is in place, and most previous barriers to the whitebait’s upstream journey on the island have been mitigated. One barrier that hadn’t been removed was a flow-gauging weir installed in Awana Stream by NIWA (National Institute for Water and Atmospheric Research) in the late 1980s. All this time fish were blocked from swimming upstream and completing their lifecycle along about 19 km of the stream’s isolated habitat. Several months ago the large concrete structure was removed by a team of local contractors, the Rural Fire Service and DOC. The scene didn’t look so good when work was in progress…. … but once the water cleared, juvenile native fish soon began to return from the ocean, and as they occupy their freshwater habitats over time, their population numbers will rebuild. Yippee! Surfer’s paradise Most of the time the end of Oceanview Road is deserted, but big swells on the east side of the island bring the surfers out of the woodwork and into their wetsuits. Catching the waves at the east coast beaches…. Medlands, photo by Aotea Boardriders Club Kaitoke, by Stray Possum Lodge Awana Whangapoua, by Soul O'Reilly Dune-top picnic A perfect blue sky day to celebrate our 32nd “official” anniversary. Next month is our real anniversary – 45 years! Rainbow cloud Rainbow over Medlands, photo by Sam Rodney-Hudson (same scene I sent a few months ago, better photo!)
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