Most of the team have now arrived on Ascension and are getting straight into work. Yesterday (Monday 20th August) new arrivals were somewhat groggily taking their first dives just hours after touching down on Wideawake Airfield. First order of business was trialling the sampling methodology for transects along the seabed during which species counts would taken.
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Dr Judith Brown gives a rundown of safety guidelines for the team to follow while diving in this remote location.
Image: Pieter van West
These early dives were done in English Bay, a sheltered beach with easy access and relatively calm waters so everyone could check out their gear and make sure all was in good working order. The weather was overcast with passing showers, but occasionally the sun broke through in full tropical strength.
Under the direction of Dr Simon Morley some team members also began to set up the lab in the offices of the Ascension Island Conservation Dept. complete with collapsible aquaria for climate change experiments. We still need to address the issue of transporting fresh seawater to the office everyday to keep the experiment running over the 3 weeks. Today, Simon and Dr Wetjens Dimmlich embarked on a scavenger hunt around the island following any rumour of containers which might hold water. Eventually, after scouring the local rubbish tip unsuccessfully they had to give up and now need to work on a new plan for getting water to the fish tanks.
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The boiler of the Derby, sunk in 1929.
This morning’s dives were on the wreck of the Derby, a steel hulled steam trawler which was used to transport guano from Boatswain Bird Island. She was moored in English Bay but sank together with other small vessels during heavy rollers in January 1929. She lies off a reef in about 9m of water and involved more transect work and also photography of marine life near the wreck. This proved challenging in the swell, and was made more difficult by the countless urchins found in almost every crevice so any handholds or potential spots to kneel had to be carefully considered before committing yourself to it. In the meantime the subject generally decided not to wait around and had swum away. It’s likely that capturing images of the fish life is going to prove quite a lot more frustrating than anticipated.
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The bow section of the Derby.
While other team members were either diving or driving around Ascension in futile quests for water containers, Dr’s Pieter van West and Alexander Arkhipkin enjoyed a very memorable tour by Jolene and Natasha of Ascension Island Conservation. Shelly Beach is a location accessible only by 4wd vehicle and a half hour hike through a lava field. This used to be the site of a large sooty tern colony numbering in the hundreds of thousands of birds, but this was wiped out by feral cats. Rock pools are found here, separated from the sea by 100m of lava platform but replenished with seawater through underground fissures. These pools appear to contain ecosystems probably found nowhere else. Of particular interest are two unique species of shrimp (Procaris ascensionis and Typhlatya rogersi) living in these interconnected network of rock pools.
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Procaris ascensionis, one of the extremely rare and protected species of shrimp found only on Ascension Island.
Image: Pieter van West
It may be that the shrimp are the most vulnerable species on the planet, found only in these pools and only on Ascension Island and are completely protected to the extent that we are only permitted to look but not touch. In addition to the shrimp Peter noticed other distinct species of algal and invertebrate life which may be worth further investigation. Unfortunately this visit to the rock pools was only a short one as the main object of the excursion was to collect oysters required for another study. A return visit to these pools will no doubt occur later in the trip with the underwater cameras to collect a full record of the species existing there.