The Dark Zone - what lives below Just another Extreme marine habitats site Fri, 17 Dec 2010 12:18:29 +0000 en hourly 1 Introduction Fri, 10 Dec 2010 18:59:13 +0000 Maria Taylor Continue reading ]]> Below 1000m no sunlight can penetrate, creating a zone of total darkness, uninterrupted except by the occasional blue-green glow of bioluminescence or the rare passage of a submersible. From here to 4000m is the dark zone, also known as the aphotic or bathypelagic zone. The pressure is 101 atmospheres and greater, with cold constant temperatures of around 6-2oC and low oxygen levels (Byatt et al. 2001). The only input of nutrients is the marine snow, which is the organic detritus from the more productive shallower waters falling through the water column. In this harsh environment it is difficult to believe that anything can survive here, which is exactly what was believed until the late 19th century, when the HMS Challenger expedition in 1872 succeeded in discovering life to 5,500m (Robison 2009), challenging our ideas of the deep sea forever.

It is only relatively recently that we have developed the technology that allows us access to these areas, although it is expensive to run expeditions exploring the depths. Despite this, investigations into the deep have become more frequent in recent years, yet are still few, with less than 1% of the deep oceans having been explored (Robison 2009). Due to the difficulty in surveying these depths and the sparse distribution of organisms, our knowledge of what exactly lives down there is severely limited and our information on the organisms that we do know to exist is restricted, as we are unable to observe behaviour and retrieving specimens can prove to be problematic. Currently we are not even able to estimate the biodiversity of this environment due to our lack of knowledge (Robison 2009).

This website will explore the species that we have discovered and how they are adapted to live in, what we consider, an extreme environment. It will also investigate the threats to the deep sea ecosystem and explore what can be done to protect them.

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