Tag Archives: oceans

Pumice and chips

Last June I spent some hours on the Sunshine Beach … here is the blog  I posted to my Facebook friends at the time. Yesterday’s beach walk inspired me to re-post it here.

I got back from the beach and spent a few hours looking into plastic pollution. I’d read about the Pacific, west of California, being turned into a giant garbage dump bigger than Texas but was astonished to spot large numbers of plastic chips amongst what looked like pumice pebbles right here on Sunshine Beach.

Receding king tides had left small drifts of pumice interspersed with tiny blue and green shards.

Pumice and plastic chips on Sunshine Beach

Pumice and plastic chips on Sunshine Beach

and nearby a bigger bank.

Having begun reading up about Capn Charles Moore’s sailings a few years ago to the N Pacific Gyre on the Alguita http://www.vice.com/toxic/toxic-garbage-island-1-of-3

I found more on volcanic eruptions in the nearby South Pacific.

There are no active volcanos in Australia! However, newspapers reported major pumice strandings along the Queensland Sunshine Coast in mid April 2013. The most likely source was recycling along coast from earlier arrivals that had first come ashore in 2007 from a Tongan eruption.

There was one in my collection from yesterday. About 3=4 mm in diameter.

Pumice from the Home Reef eruption that began early-to-mid August 2006 reached the eastern Australian coast in March 2007. A substantial stranding of the pumice in mid-April extended for more than 1,300 km along the Queensland and northern New South Wales coast. Pumice ‘clasts’ or stones ranged in size from 1-4 cm in diameter, with the largest ‘clasts’ up to 17 cm in diameter. A visit to Home Reef in February 2007 revealed a pumice mound barely visible over the waves.

Pumice raft

Research now shows that such eruptions can disperse marine life more effectively than ocean currents alone. Studies demonstrated that large rafts transported over 80 species collected on a +5000km journey from the eruption locality to the Barrier Reef over 8 months.


The same author reports a similar sequence of events in 2001-2 and other writers researching pumice layers from midden excavations on NSW coast suggest that it has been going on for thousands of years.

Whilst reports mention the marine hitch-hikers they say little about rafts picking up plastic waste too. I wondered how these became mixed with the pumice. Were they local waste, carried into the sea through storm drains and subsequently ground by beach action. I didn’t see much evidence of on-going waste deposit on the Beach so perhaps this was just a collection zone for the little bits floating out on the ocean?

This afternoon, curiosity got the better of me. Here is my collection (along with some pumice and shell) from a sparse 2 metre drift randomly chosen. The little round white one next to the coin is the raw material from which plastic objects are moulded. There were 17 different blues and greens and 2 reds, never mind the black and whites. I imagined quite a heap just from my little area. I imagined a large heap of plastic objects from all over the pacific of which these shards were a small percentage, and now distributed along countless beaches and sea floors.