In this book, one thing is abundantly clear: Tony Koslow cares deeply about the marine environments that he has studied for many years. It is not difficult to share his fascination – we have always been intrigued by the deep with its exotic creatures living in an environment so isolated and hostile to human life.

The Silent Deep provides an almost encyclopaedic coverage of the science of the deep seas. In doing so, it makes obvious how little we know. Over the past couple of decades, we have learned of hydrothermal vents and the chemosynthetic species that thrive in an environment that is highly toxic for most forms of life. However, the vents – which usually occur where tectonic plates meet – are still largely unexplored.

Koslow takes us on a tour of the various deep-sea environments. For a long time, the deep sea floor was regarded as largely barren. More recent research has shown that it supports its own thriving ecosystem. Deepwater coral reefs are home to a large number of diverse marine species. Hydrothermal vents, cold-water seeps and whale-falls all provide alternative energy sources that support their own unique ecosystems.

Most of us think the isolation of the deep sea protects it from the impact of human activity. Koslow shows that this is not the case. Threats to the ocean environment include the dumping of toxic (and sometimes radioactive) waste, the accumulation of heavy metals such as mercury and cadmium, the build-up of toxic chemicals such as PCBs (polychlorinated biphenyls) and DDT, the damage caused by offshore oil rigs and, of course, the consequences of over-fishing. The author also warns of the potential damage that may be caused by seabed mining and carbon dioxide sequestration.

The book ends with a plan for the way forward, advocating various measures to protect ocean environments – environments about which we still know little. The sentiment of the book can perhaps best be characterised by a quote from the renowned biologist E.O. Wilson: “Man is defined not by what he creates, but by what he chooses not to destroy.”