I explored the Antarctic deep seas for Blue Planet II – and it was like going back 350m years

Ooooh. Image: BBC.

“It has always been our ambition to get inside that white space, and now we are there the space can no longer be blank,” wrote the polar explorer Captain Scott, on crossing the 80th parallel of the Antarctic continent for the first time in 1902. Fast-forward more than a century – and the deep ocean floor around Antarctica still offers a “white space”, beyond the reach of scuba divers, only partially mapped in detail by sonar from ships and seldom surveyed by robotic vehicles.

So I jumped at the chance to join a team from the BBC on an expedition to the Antarctic Peninsula for Blue Planet II, to help them as a scientific guide. Thanks to the crew of the research ship Alucia, we dived in minisubmarines to 1km deep in the Antarctic for the first time. And while we didn’t face anything like the physical hardships endured by early polar explorers on land, those dives did give us the opportunity for some unique science.

The deep ocean around Antarctica is a special place for several reasons. Because Antarctica is pushed down by the weight of its ice sheets, the submerged continental shelf around it is deeper than usual, around 500-600m deep at its edge rather than 100-200m deep. It’s also cut by even deeper channels close inshore, some plunging more than 1km, scoured out by larger ice sheets in the past. So although the continent itself is remote, we can reach the deep ocean close inshore here – handy for us diving in minisubmarines, despite the need to dodge icebergs.

Giant sponges found in the deep waters of the Antarctic. Image: BBC NHU.

There’s a gateway to the deep for marine life here too. Some deep-sea animals come into much shallower depths than usual around Antarctica, because the water temperature near the surface is similar to the cold temperatures elsewhere in the deep ocean. And in the past, shallow-living ancestors of some deep-sea animals spread out across the deep oceans from the Antarctic, via this cold gateway between the shallows and the deep.

One of my favourite animals that we saw on dives was the octopus Graneledone antarctica, whose ancestor ventured down from the shallows around 15m years ago, when the water temperature at the surface cooled to the same chilly temperature as the deep. Her descendants then spread out across the abyss like wagon-train pioneers, giving rise to several different species of deep-sea octopus found around the world today. Some stayed behind, however, becoming the species that we saw.

The ocean around Antarctica is also the lungs of the deep. Much of the life-giving oxygen in deep waters across the world begins its journey from the atmosphere here. As seawater freezes around the white continent in winter, it leaves behind very cold and salty water that sinks and flows into the depths of the Atlantic, Indian and Pacific Oceans – even the deepest water in the ocean, at the bottom of the Marianas Trench 14,000km away, came from here. As this deep water flows out from the Antarctic, it carries oxygen, dissolved from the atmosphere at the surface. So the Antarctic is where the world’s deep oceans breathe in – and its waters are among the most oxygen-rich on our planet.

Another of my favourite animals from our dives takes advantage of those oxygen-rich waters: giant sea-spiders, with legspans up to 40cm across. Sea spiders lack a respiratory system, which usually limits their size, but can grow much larger in the oxygen-rich conditions here.


‘Ancient ocean ecosystems’

Diving in the Antarctic is also a journey back in time, to glimpse what ancient ocean ecosystems were once like. Fish dominate as predators in most marine ecosystems today, but few fish species can cope with the -1.5℃ conditions where we were diving. The “ice dragonfish”, Cryodraco antarcticus, is a notable exception, however, and another of my favourite animals – with antifreeze proteins that stop its blood from icing up. Its blood is also clear, without any of the oxygen-carrying haemoglobin that gives ours its red colour – in the cold waters, enough oxygen dissolves directly in the fluid of the fish’s blood to keep it alive.

But there are few fish with remarkable adaptations like the ice dragon, and so invertebrates have diversified to dominate as predators in the deep ocean here, just as they did throughout the oceans more than 350m years ago. A final favourite from our dives epitomises that: the Antarctic sunstar Labidiaster annulatus, which is a relative of the familiar five-armed starfish. Nicknamed “the Death Star” by those inside the subs who watched its behaviour, it has up to 50 arms and grows larger than a dinner plate. It uses those arms like fishing rods, holding them up off the seabed to snag passing krill, thanks to tiny pincers on its skin that snap shut when anything brushes past them. Unlike other starfish, Labidiaster can wave its arms to catch prey here because there are relatively few predatory fish to chew them off.

A feather star dances in the deep waters of the Antarctic Sound. Image: BBC NHU.

The ConversationOverall, seeing the deep Antarctic sea floor close-up from our minisubs should help us to understand how “dropstones” shape the pattern of life here. “Dropstones” are car-sized boulders that fall from passing icebergs – they provide “islands” of rocky habitat for filter-feeding species which otherwise don’t get a look-in on the soft mud of the Antarctic seafloor. But where the dropstones settle depends on the undersea terrain. As we found on our dives, they slide down steeper undersea slopes, actually scraping off marine life. But if you’re at the bottom of a gully, then lots of dropstones end up there, giving a major boost to local biodiversity. That pattern of life is hard to see from samples collected by nets or trawls in the past, so our first minisub dives to 1km deep in the Antarctic should help to make that “white space” no longer such a blank.

Jon Copley is associate professor in ocean exploration & pbblic engagement at theUniversity of Southampton.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

Was the decline in Liverpool’s historic population really that unusual?

A view of Liverpool from Birkenhead. Image: Getty.

It is often reported that Liverpool’s population halved after the 1930s. But is this true? Or is it a myth?

Often, it’s simply assumed that it’s true. The end. Indeed, proud Londoner Lord Adonis – a leading proponent of the Liverpool-bypassing High Speed 2 railway, current chair of the National Infrastructure Commission, and generally a very influential person – stood on the stairs in Liverpool Town Hall in 2011 and said:

“The population of Liverpool has nearly halved in the last 50 years.”

This raises two questions. Firstly, did the population of the City of Liverpool really nearly halve in the 50 year period to 2011? That’s easy to check using this University of Portsmouth website – so I did just that (even though I knew he was wrong anyway). In 2011, the population of the City of Liverpool was 466,415. Fifty years earlier, in 1961, it was 737,637, which equates to a 37 per cent drop. Oops!

In fact, the City of Liverpool’s peak population was recorded in the 1931 Census as 846,302. Its lowest subsequent figure was recorded in the 2001 Census as 439,428 – which represents a 48 per cent decline from the peak population, over a 70 year period.

Compare this to the population figures for the similarly sized City of Manchester. Its peak population also recorded in the 1931 Census as 748,729, and its lowest subsequent figure was also recorded in the 2001 Census, as 392,830. This also represents a 48 per cent decline from the peak population, over the same 70 year period.

So, as can be seen here, Liverpool is not a special case at all. Which makes me wonder why it is often singled out or portrayed as exceptional in this regard, in the media and, indeed, by some badly briefed politicians. Even London has a similar story to tell, and it is told rather well in this recent article by a Londoner, for the Museum of London. (Editor’s note: It’s one of mine.)

This leads me onto the second question: where have all those people gone: London? The Moon? Mars?

Well, it turns out that the answer is bit boring and obvious actually: after World War 2, lots of people moved to the suburbs. You know: cars, commuter trains, slum clearance, the Blitz, all that stuff. In other words, Liverpool is just like many other places: after the war, this country experienced a depopulation bonanza.


So what form did this movement to the suburbs take, as far as Liverpool was concerned? Well, people moved and were moved to the suburbs of Greater Liverpool, in what are now the outer boroughs of the city region: Halton, Knowsley, St Helens, Sefton, Wirral. Others moved further, to Cheshire West & Chester, West Lancashire, Warrington, even nearby North Wales, as previously discussed here.

In common with many cities, indeed, Liverpool City Council actually built and owned large several ‘New Town’ council estates, to which they moved tens of thousands of people to from Liverpool’s inner districts: Winsford in Cheshire West (where comedian John Bishop grew up), Runcorn in Halton (where comedian John Bishop also grew up), Skelmersdale in West Lancashire, Kirkby in Knowsley. There is nothing unique or sinister here about Liverpool (apart from comedian John Bishop). This was common practice across the country – Indeed, it was central government policy – and resulted in about 160,000 people being ‘removed’ from the Liverpool local authority area.

Many other people also moved to the nearby suburbs of Greater Liverpool to private housing – another trend reflected across the country. It’s worth acknowledging, however, that cities across the world are subject to a level of ‘churn’ in population, whereby many people move out and many people move in, over time, too.

So how did those prominent images of derelict streets in the inner-city part of the City of Liverpool local authority area come about? For that, you have to blame the last Labour government’s over-zealous ‘Housing Market Renewal Initiative’ (HMRI) disaster – and the over enthusiastic participation of the then-Lib Dem controlled city council. On the promise of ‘free’ money from central government, the latter removed hundreds of people from their homes with a view to demolishing the Victorian terraces, and building new replacements. Many of these houses, in truth, were already fully modernised, owner-occupied houses within viable and longstanding communities, as can be seen here in Voelas Street, one of the famous Welsh Streets of Liverpool:

Voelas Street before HMRI implementation. Image: WelshStreets.co.uk.

The same picture after HMRI implementation Image: WelshStreets.co.uk. 

Nonetheless: the council bought the houses and ‘tinned them up’ ready for demolition. Then the coalition Conservative/Lib Dem government, elected in 2010, pulled the plug on the scheme. 

Fast forward to 2017 and many of the condemned houses have been renovated, in a process which is still ongoing. These are over-subscribed when they come to market, suggesting that the idea was never appropriate for Liverpool on that scale. 

At any rate, it turns out that the Liverpool metropolitan population is pretty much the same as it was at its peak in 1931 (depending where the local borough boundaries are arbitrarily drawn). It just begs the question: why are well educated and supposedly clever people misrepresenting the Liverpool metropolis, in particular, in this way so often? Surely they aren’t stupid are they?


And why are some people so determined to always isolate the City of Liverpool from its hinterland, while London is always described in terms of its whole urban area? It just confuses and undermines what would otherwise often be worthwhile comparisons and discussions. Or, to put it another way: “never, ever, compare apples with larger urban zones”.

In a recent Channel 4 documentary, for example, the well-known and respected journalist Michael Burke directly compared the forecast population growths, by 2039, of the City of Liverpool single local authority area against that of the combined 33 local authority areas of Greater London: 42,722 versus 2.187,708. I mean, what bizarre point is such an inappropriate comparison even trying to make? It is like comparing the projected growth of a normal sized-person’s head with the projected growth of the whole of an obese person, over a protracted period.

Having said all that, there is an important sensible conversation to be had as to why the populations of the Greater Liverpool metropolis and others haven’t grown as fast as maybe should have been the case, whilst, in recent times, the Greater London population has been burgeoning. But constantly pitching it as some sort of rare local apocalypse helps no one.

Dave Mail has declared himself CityMetric’s Liverpool City Region correspondent. He will be updating us on the brave new world of Liverpool City Region, mostly monthly, in ‘E-mail from Liverpool City Region’ and he is on twitter @davemail2017.