By Daniel de la Calle
Same day the Census For Marine Life made public the results of those ten years of research (read October 16th blog post) the BBC broadcast a new documentary narrated by David Attenborough and titled “The Death of the Oceans?”.
The hour long film shows the outstanding marine footage we have come to expect from BBC documentaries, but the tone this time is more bleak and apocalyptic. Never before has David Attenborough shown his concerns and doubts about the future.
Right from the start a scientist warns us that “we are talking now about an unnatural ocean”, while another immediately adds that “there is no question that humans are ecosystem engineers right now”, “there are no places on earth where humans are not impacting the ocean environment”. Some seconds later Professor Jeffrey Bolster, of the University of New Hampshire, vehemently tells the camera: “the living ocean is very fragile and don’t for a minute believe that we can’t screw it up much more than it is today”.
The documentary centers around the two direst threats to the oceans and the life within them:
1 Overfishing. Historic numbers show a considerable worldwide decline in captures. Mr. Attenborough’s voice over laments that “in 2003 researchers from the census published a paper in the science journal Nature comparing fish numbers of those of 1950. What they concluded was that in a little over 50 years 90% of top predators such as tuna, shark and marlin had been fished from the sea.” Another interviewed scientist explains how, even though we have learned to think of food chains, the truth is that most marine ecosystems are more like a food web, with complex and yet unknown interconnections amongst the different animals, if we take one or several players out the consequences are uncertain.
This section of the film ends with with David Attenborough’s words: “In one of the most disturbing pieces of research commissioned by the Census, the question was asked ‘how much longer can our oceans tolerate the present level of commercial fishing?’ The answer was simple and stark: If present trends continue, commercial fishing as we know it will have collapsed by the year 2050”.
2 Mr. Attenborough again: “There are habitats that are facing a threat the implications of which scientists are only just beginning to work out. The cause of this concern is an environmental impact with the potential to be every bit as disastrous for reefs as rising sea temperatures: Ocean Acidification.”
Right after we are shown some fascinating research Professor Ove Hoegh-Guldberg, of the University of Queensland, and his team are carrying out in Australia, monitoring corals living in the wild, but artificially placed under different and precise levels of CO2 in the water. Over the past years he has been witnessing how these marine animals are already under much stress: “We are seeing very large responses from coral reefs, we are seeing large scale mortality events and scientists are now recording the decline in the calcification that’s going on reefs. And this is not seen in hundreds and hundreds of years of records.” He believes “there’s really two things we have got to do: the first is we have to limit further increases in CO2, because we know those futures don’t have corals in them, we’ll rapidly exceed the known conditions for coral reefs. But the second thing we gotta do is treat reefs better on a local scale, we gotta reduce the overfishing, reduce the pollution, sedimentation and so on and if we do that, we will have corals survive the century.”
Overall, it was a strange sensation to hear about ocean acidification from Mr. Attenborough’s voice, not that it didn’t make complete sense for him to talk about it. When the venerable wise man finished with the words “to my mind acidification is the biggest threat to oceans today. Even if we stopped our carbon emissions now it will be many centuries before the oceans return to full health” I felt deeply touched, legitimated and absurdly proud.