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The origins of Cayman's sand - Marnie Laing, Cayman Islands' National Trust - 1 May 2006

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Year 11 John Gray Recyclers Attend Awards Function on Disney Cruise Line - 23 June 2006
Dogs Kill Endangered Blue Iguanas, Botanical Gardens, Grand Cayman - 7 June 2006
Year 11 John Gray Recyclers Win Jiminy Cricket Challenge 2006 - 6 June 2006
John Gray Recyclers have Recycling Global Reach - "Carribean Current" - 1 June 2006
The origins of Cayman's sand - Marnie Laing, Cayman Islands' National Trust - 1 May 2006
Caribbean Coral Threatened by Warming Seas - 24 April 2006
John Gray Recyclers Agape Park Project in the News - 16 February 2006
CaymanNewNews Article on Grand Cayman's Landifll problems following Hurricane Ivan - 18 January 2006
Decline in World Population of Molluscs - 10 January 2006
JGR in the News - Students, businesses get together to help environment - 7 December 2005
UNEP - Global Warming forces Pacific Islanders to move - 6 December 2005
John Gray Recyclers Target Six-pack Holders - 2 December 2005
Cayman Islands Dept of Environmental Health join John Gray Recyclers at Reading Fair - 30 November
Wednesday 30 November marks end of record 2005 hurricane season
Coral Reefs Facing Crisis - 30 November 2005
JGR In the News - Plastic Six-Pack holder Recycling in Grand Cayman - 18 November 2005
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JGR Blog - Cayman Islands' Turtles survive wild Wilma - 1 November 2005
JGR Blog - Erosion a major problem from Hurricane Wilma - Cayman Islands - 1 November 2005
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JGR Blog - IUCN Article on Climate Change Destruction of World's Coral Reefs - 25 October 2005
JGR Blog - Cayman Islands' Conch/Whelk Season starts 1 November and closes on 30 April 2006
JGR Blog - Turtle Tracking of Cayman Islands' Turtles - 24 October 2005
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JGR Blog - Important Cayman Islands' Recycling Information from C I Dept of Environmental Health
JGR Blog - 14 November 2003 - We've got the Baby Blues
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JGR Blog - 19 - 23 October 2003 - the Blue Iguana Programme of the Cayman Islands' National Trust
JGR Blog 29 Sept - 3 Oct 2003 - We continue to track our Grand Cayman turtles in Central America
JGR Blog 22 - 26 Sept 2003 - Tracking our Grand Cayman Sea Turtles
JGR Blog - 18 Sept 2003 - John Gray High School Club Fair
JGR Blog - 15 - 19 Sept 2003 - Opening of Stephen Jared Youth Centre
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Check out this article in the "Caymanian Compass"

The origins of Cayman’s sand

 

Sunday 30th April, 2006   Posted: 22:47 CIT   (03:47 +1 GMT)

Where does Cayman’s beautiful white sand originate?

Believe it or not, from a colourful parrotfish and green algae!

Reef grazing fish

Reef grazing fish, such as parrotfish, produce a significant amount of sand found on the beaches.

From a distance, all sandy beaches look the same. But if you take a closer look, you will find they are all very different. Every grain of sand is unique in colour, texture, and shape, depending on what it is made from and where it lives on the beach. Sand is created from either rocks or sea animal remains, such as fragmented shells.

The floury soft coral sand found on the majority of Cayman’s beaches comes, almost entirely, from the coral reef community. This type of sand is biogenic – sands made of the skeletal remains of plants and animals. This is the main reason why our sand is so much finer and softer than the sand found on most continental beaches, which comes from terrestrial sources such as weathering rocks.

Most of our sand is created by wave and current energy acting on the coral reef as coral, calcareous green algae (algae with a hard exoskeleton), the shells of various sea creatures and sea urchin spines are gradually broken down into sand sized grains. Calcified green algae, particularly the Halimeda spp., are especially important as a major contributor of marine sediments.

The white sand is largely composed of the sun–bleached and eroded calcium–carbonate remnants of calcareous green algae. This calcified sand is deposited from natural expiration and consumption by some marine animals, such as the sea urchin species Clypeaster rosaceus and parrotfish.

Reef grazing fish, such as parrotfish, produce a significant amount of sand found on the beaches. Parrotfish get their names from their parrot–like mouths and they have strong teeth that resemble a parrot’s bill. These strong, sharp teeth allow parrotfish to scrape algae from rocks and corals. Parrotfish also bite off pieces of coral, grinding up the coral ‘skeleton’ to eat the tiny coral polyps or algae. But the parrotfish can’t digest the ground–up skeleton therefore this passes through their digestive systems to be excreted as ‘sand’! A single parrot fish can produce tons of soft white sand during its lifetime.

Parrotfish are not shy and are regularly seen while snorkelling or diving. Often you can hear the sound of their beaks scraping against the coral before you even see them! You may even see them relieving themselves of the indigestible portion of their meal in the form of sand that will settle slowly to the bottom of the sea.

Protect Cayman wildlife! For more information, to share your knowledge or if you would like to get involved with the many activities in the National Trust’s Know Your Islands Program, please visit www.nationaltrust.org.ky, or contact info@nationaltrust.org.ky or 949–0121

John Gray Recyclers have Recycling Global Reach - "Carribean Current" 1 June 2006