Above: The ISIS ROV which we will be using to explore the black smokers with. For more information on ISIS click HERE

ABOVE: A black smoker - click HERE for more information

Above: Our work area will be around South Gergia and the South Sandwich islands

Introduction

So this promises to be one of the most exciting cruises we have done for a very long time and the excitment has been mounting over the last few months. The scientific party will be using the deep diving ISIS ROV to study life around Hydrothermal Vents known as "Black Smokers".

Ok what are Hydrothermal vents? Hydrothermal vents are fissures in the ocean floor that leak hot, acidic water. The size of the openings range from less than half an inch to more than six feet in diameter. The largest vent is called TAG (Trans Atlantic Geotraverse) and is about the size and shape of a football stadium. The openings spew out jets of hot brine (up to 350°C) at velocities of up to five metres a second. These brines are complex solutions containing lots of elements leached from the rock formations that they have transversed. As they are often black in colour these vents are sometimes also referred to as 'Black Smokers'.

These vents are normally found along the crest a of mid ocean ridge, a 46,000 mile long chain of mountains that wraps around the earth. They tend to form in linear zones a few kilometres long by a few hundred metres wide. A few vents have also been found at seamounts (Seamounts are isolated submarine elevations of at least 700m of volcanic origins). Hydrothermal vents are normally found at depths of greater than one mile. Lots have been found on the East Pacific Rise, an underwater mountain range about 500 miles southwest of Alcapulco and particularly close to the Galapagos Islands. The vents we will be studying are located near the South Sandwich Islands in the Southern Ocean

Ok, we know what they are and where you will be looking - how do they work? Ok, Vents are formed where the planets crustal plates are slowly spreading apart and magma is welling up from below to form mountain ranges known as mid ocean ridges. Cold seawater percolates down through jointed and permeable rocks and descends to the lower reaches of the sheeted complexes, two to three miles deep. (Magma collects in magma chambers underground and finds its way through a systems of dykes to the surface where it forms a volcano. These sheeted dykes are known as sheeted complexes). The heated brines ascend and produce pervasive alteration (metamorphism) of the rocks with which they come in contact. The heated brines then shoot out as jets (up to 350°C) and boiling is prevented by the high hydrostatic pressures of the overlying sea water.

Ok the big questions - why are they important? Well firstly, these hydrothermal vents pump a lot of minerals into the sea and surrounding seabed. Large scale precipitations of sulphides, particularly those of zinc, iron and copper are common. These precipitates build up mounds and chimneys like tubes around the vent, these vents can 'grow' up to 10 metres tall.

However, these ore deposits associated with these are not the only reason why these vents are important. Previous studies have found that the areas around the hydrothermal vents support a huge variety of life in an area where no sunlight penetrates. These besties process the minerals spewed from the hydrothermal vent into energy a process known as chemosynthesis . The life found in these places is unique. It was once thought that nothing could survive the harsh combinations of toxic chemicals, high pressures, high temperatures, and total darkness at these vents. However, scientists have discovered huge tube worms up to 4 feet tall anchored to the sea floor as well as mussels, shrimps, clams and crabs. The fact that these animals are unique and we also know very little about them makes them so important. Around the vents enormous amounts of bacteria live and breed, they can withstand higher temperatures than any other organisms. The study of this bacteria and creatures is of great importance. Some scientists have suggested that if life exists on other planets it may be similar to the bacteria found at these vents which survives in such extreme heat and is not reliant on the sun. This hardiness has also made them attractive to researchers who are developing heat-stable enzymes for genetic engineering as well as culturing bacteria designed to break down toxic waste and a whole range of other potential applications

This cruise will start on January 7th - come and join in the excitement