Monday, February 4, 2013

Sorry but no, it is not ambergris

Not ambergris but palm oil
Walking an Anglesey beach after recent gales and noticing a few lumps of a waxy substance reminded me of the several occasions in the past when similar lumps were brought in to the Bangor University marine lab in Menai Bridge by people suspecting they had found ambergris. Used as an ingredient for some expensive perfumes, ambergris is highly prized. Sometimes it sells for over £250 a gram. It always seems rather bizarre that a constituent of cosmetics applied to high maintenance human females should originate in the intestines of a sperm whale. It is secreted by the whales as a waxy substance to limit injury to the lining of the gut by the beaks of the squid they eat. When freshly ejected it is said to have a faecal smell but, after months or years of floating on the sea, microbial and photo degradation in the presence of salt-water results in lumps that are usually grey and have a musky aroma. Currents, wind and waves disperse the lumps so they may wash up far from the regions of the ocean where the sperm whales were feeding.

On the west coast of Anglesey this autumn, and quite frequently in the past, lumps of a waxy substance have washed up. A bit like ambergris these lumps are greyish white on the outside, but they are bright yellow inside. Some lumps may be quite large so they would be worth a small fortune if they really had come from a whale. Their origin, though seeming mysterious to beach walkers, has a much more mundane explanation.

As well as ships carrying the crude oil, refined fuels and chemicals passing Welsh coasts, there are others carrying various vegetable oils in bulk. These go into a range of products including processed foods, biofuels and soap. Among the vegetable oils imported to the Mersey ports are derivatives of palm oil. Following initial separation, one fraction of palm oil becomes solid and waxy at the ambient temperatures of our seas. It therefore needs to be warmed before it can be pumped from the stainless steel tanks in the specialised ships. To expedite this, heating starts while the ships are still on passage. With thermal expansion and in rough weather some of the cargo may ooze out of access hatches or vents. This then may get washed overboard becoming the waxy lumps that wash up on beaches. The lumps get pecked by birds and other shoreline scavengers but even so they may take months to disappear.

As with mineral oils, it is probably microbes that are ultimately responsible for breaking down such materials man spills into the marine environment. While not having the charisma of sperm whales and the mystic of ambergris, marine microbes, with their huge biodiversity and capacity for providing ecosystem services, should not be overlooked.   

This post was written by Ivor Rees.

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