Posts tagged ‘Marine’

This time last year I was sailing across the Great Australian Bight (the area of ocean below Australia) on the Southern Surveyor (check it out here, here and here). One cold and windy night, myself and several other scientists scrambled out onto the deck with an expensive, large, yellow, plastic float. We released it over the side of the boat and watched it as it disappeared into the night. As one of 5000 floats that scientists have released over board, it provides a way for us to continually monitor the oceans and send the data back to scientists on a regular basis via satellite. Here is a video which gives an overview of how Argo floats measure the ocean.

Exactly one year on, I’m happy to say the float is still floating! This float has spent 365 days of floating in the sea, drifting with the currents, being caught in eddies and taking observations of the ocean. Within that time it has travelled over 1845 kilometres around the Great Australian Bight.

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It has surfaced 37 times (represented by the white dots on the following map) to transmit salinity, temperature and density data back to scientists via satellite.

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Both maps are screen shots of Google Earth (red line represents 100 km) with Argo Data from here and the yellow star represents the launch location.

Temperature Profile
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The temperature profile is typical of the ocean thermocline, with a decrease in temperature as depth (sea water pressure) increases. It was warmer over the summer months at the surface but only reached a maximum temperature of 18ºC.

Salinity Profile

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The white patch between 24/6/2013 and 10/9/2013 indicates a lack of data as the Argo float was in the shallower waters  over the continental slope.

Temperature and salinity data for float WMO 5904242 was retrieved from Coriolis Operational Oceanography.

I will continue to provide updates on the adventures of this Argo float and hope it stays a float for many more years!

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One of my favourite things about reef islands and tropical beaches is the extremely white sands which disappear into bright turquoise coloured water.

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Unfortunately not all tropical beaches look like this.

Beach rock is the inconvenient rock placed between the sand and the water on many tropical beaches.

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It forms from the consolidation of tropical carbonate sands which become cemented together by the precipitation calcium carbonate from the seawater.

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There are three different coloured zones of beach rock.

The top zone (furthest out of the water) appears black as a result of a thin crust of cyanobacteria and lichen covering the  beach rock.

The middle zone is very slippery and appears pink due to a variety of cyanobacteria species.

The bottom zone (mostly submerged) is covered in a fine filamentous algae, making it green in colour.

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Pink Beach Rock  |  Green Beach Rock

The speckled and bumpy appearance of beach rock is from fish munching and scraping away at the algae and surface layer of the rock.

OLYMPUS DIGITAL CAMERABlack beach rock.

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Beach rock during low tide.

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