“Magic is in the air … there ain’t no science here…”
And a good south wind sprung up behind;
The Albatross did follow,
And every day, for food or play,
Came to the mariner’s hollo!
‘God save thee, ancient Mariner!
From the fiends, that plague thee thus! —
Why look’st thou so?’—With my cross-bow
I shot the ALBATROSS.
And I had done a hellish thing,
And it would work ’em woe:
For all averred, I had killed the bird
That made the breeze to blow.
Ah wretch! said they, the bird to slay,
That made the breeze to blow!
An excerpt – THE RIME OF THE ANCIENT MARINER – by SAMUEL TAYLOR COLERIDGE
The Kaikoura Peninsula, on the northeast coast of New Zealand’s South Island, is in the Golden Circle – & at the foot of the world’s most spectacular stage.
The Kaikoura Canyon, 500m southeast & offshore of the peninsula, is a series of underwater canyons [some 5000 ft deep], & the foundation of the best & most accessible pelagic-birding on earth. Here, high-energy ocean convergence promotes the upwelling of nutrients – high food production & a magnet for the highest diversity of ‘tubenoses’ on the planet. There are few locales more evocative & for those passionate about the sea and the birds which call the ocean ‘home’, Kaikoura is the gateway to the Elysian Fields.
South Africa is blessed with similar *bathymetry [*’topography’ on the seabed] – further out-to-sea, admittedly, but well-travelled by fish, birds, fisheries & hardly, if at all, visited by the pelagic-birding community.
Procellariiformes (from the Latin word for procella or ‘storm’) [formerly Tubinares] or ‘tubenoses’, in this context, include the albatrosses, shearwaters, petrels and storm petrels. Roughly 125 species in 23 genera, in 4 extant families, are almost exclusively *pelagic [*open ocean]. Seabirds are widely distributed & adapted to master the winds and storms. Birds, some as light as 20g, canvass the globe, in a ceaseless quest for food returning to land only to breed; & it is on land where they are least at home & at their most vulnerable.
Ironically, by virtue of biomass & diversity, pelagic seabirds off New Zealand are more at risk of dying from the ingestion of plastic than they are anywhere else on earth.
The paradox that is Homo sapiens, or “wise man”, boggles!
Further south on islands scattered around Rakiura, “mutton-bird” chicks [Sooty Shearwater], known to Maori as titi, are harvested seasonally & eaten.
The sheep don’t care or give a bleat, apparently.
Into this crucible, guided by profit and momma’s pseudo lamb curry, Hominids, in more-or-less the same form & over millennia, have & continue to worship at the foot of Community-Heartburn – at the expense of breeding [i.e. grounded] seabirds. ‘Tradition’ [or ‘culture’], in this context, the catch-all for exploitation; & like many other ‘traditions’ the athlete’s foot of contemporary conservation & a topic for anointing, a single step at a time, another time. Fortunately, where-seabirds-go–when-they-fly-beyond-the-horizon, evades even the most dedicated foodies – (until very recently, that is). [More later]
The ocean is its own landscape; a myriad habitat divided by changes in temperature, salinity & wind. Where seabirds go, therefore, is determined by the elements that paint the canvass of life at sea.
Scientists have, for reasons of expediency rather than logic, become single-minded, neither constrained by random joy nor by the whiff of common sense.
Written in the dry parlance of scientific paper &prone to a flap in a crisis, these rolls of published mutiny, machete the ocean’s bounty at the knees. The ever present menace of the truth is hidden from free access – & the joy of discovery set adrift in cyclonic eddies of analysed data & bootstrap extrapolation. Notwithstanding, there are, indeed, a handful of ‘wise-coats’ shedding light on the dynamics that make the ocean marvellous. Their eyes burn brightly &, with the advent of technology, the onion is peeling…
The distribution of seabirds in the ocean is neither random nor linear. Just as birds are distributed preferentially on land, so too are seabirds fairly discerning in the open ocean. The Big Blue might appear homologous but there are multi-scale factors influencing habitats, seabird distribution & the foraging assemblages out at sea.
In the 18th century, Thomas Jefferson replaced his household waiters with a round revolving tray placed at the centre of his dining-table. He dubbed his invention the ‘dumbwaiter’ – as in quiet rather than two licks short of shiny. Why the dumbwaiter became ‘Lazy Susan‘ is a matter for the Susans… Whatever the reason, the Lazy Susan was designed to aid the distribution of food around the table. Wait long enough and the food comes to you & if it doesn’t get there before Grampy dips his finger in the mash – make sure you know where it turns before he gets to it.
Seabirds do the same – only their Susan is a mass of moving water on / & in which food is transported. These are the ocean currents.
The ‘ocean conveyor belt‘, in ‘Finding Nemo‘, mandatory viewing for parents, depicts sea-creatures surfing the EAC [East Australian Current] en route south to faraway reefs & bluer water on the other side. Although one of the clowns was snatched, for the most part, it’s a warm water ride… Here, as it is for all eastern boundary currents, the water nearer the ocean’s surface is warm & flows towards the poles. Conversely, deep water lurks, is cold, faces up / down-sphere – in the direction of the equator – & spills away from the poles. This spigot of hot & cold water, circumnavigating the earth in a perpetual cycle, provides loopy transport to anybody brave enough to take the plunge. To understand the flow… some science [my apologies].
From 1946 – 1962, the US government fingered the world & tested nuclear weapons in the Pacific Ocean. Their so-called Pacific Proving Grounds, which included inhabited islands in their UN-sanctioned ‘Trust Territory of the Pacific Islands’, is still contaminated today. Islanders who didn’t literally starve, then ‘relocated’ to inhospitable islands, have subsequently benefitted from approximately $750 000 000 in compensation for ‘fall-out’ exposure. That’s (a lot)… The Space Shuttle program, a bootstrap bolt-on mission, cost the American public approximately $ 196 000 000 000 – that’s [(a lot) x (2 much)] or $260 worth of ‘aliens maybe’ for a dollar’s worth of nuclear-wasted men & women, back home, on Earth. Wisdom knows it’s moniker but that’s ‘Top Secret’, of course. Mahalo!
From the mid-50s to the early-70s, the La Jolla Tritium Laboratory monitored the flow of tritium in the Pacific Ocean. Tritium is a radioactive isotope of hydrogen & a chemistry-quirk post-boom. Although the scope of their research was limited, traces of tritium were later found over vast areas of the globe. This ‘discovery’ provided early ground-truthing for the hitherto theory of a global ‘conveyor-belt’ of interconnected ocean currents; broad swathes of ocean water in constant flux, (as it turns out), but flowing along broadly predictable routes.
As our understanding of the ocean’s currents improved, the nomenclature was changed from ‘conveyor belt‘ to the Meridional Overturning Circulation [MOC] and to AMOC in the Atlantic – today’s source of de-nile; & by denial, I mean Climate Change.
In the 1990s, oceanographers discovered a 30% reduction in the AMOC over the preceding 5 decades. Most climate change models linked warmer water [meltwater] in the Labrador & Nordic Seas with a weakening in the MOC. It wasn’t long before some numpty proclaimed that earth was about to suffer an ABRUPT climate change event – & … faux climatologists featured soon thereafter as Hollywood heroes; funding-bowls in hand, dipping for seconds in the widows & orphans’ fund.
Fast forward a decade & oceanographers have found ZERO link between warmer waters at the pole and the strength of flow in the AMOC – some might say a fatal flaw in the apocalypse-tomorrow theory. Those still feeding at the trough, however, will have you whistling-Dixie in the queue for light-bulb stamps & an eco-bag for life.
Apocalypse-now Climate-theorists extrapolate the notion that meltwater [ex-ice] in the north Atlantic [ie: the Labrador Sea] will stabilise the ‘overturn’ in the high latitudes and disrupt the AMOC. The disruption would stall the northwards-flowing Gulf Stream, N. America’s warm-water Eastern Boundary Current & change the world’s heat distribution for millennia to come. More on this later.
Until very recently, oceanographers predicted that the largely wind-driven Gulf Stream flowed near / at the ocean’s surface; in a predictable manner & into the north Atlantic. There the warm waters cooled and, nearer the pole, ‘turned-over’ or *sank to great depths. Water at these depths was presumed to flow over the polar sills & into the ocean basins as the deep-water component [‘lower limb’] of the MOC. We now know that the Gulf Stream flows sub-surface & roughly northwards along the eastern seaboard of the USA before veering NE into the Atlantic to rotate in the sub-tropical gyre.
The sea surface temperature [SST] is more or less the same as the air temperature at the water’s surface. Warm water carried up-coast and into the north Atlantic by the Gulf Stream raises air temperatures & it is this natural phenom that keeps Europe long on gin & short on ice. This is why London, located @ 51.5°N, hosted the Summer Games ; and why Calgary, further south, was awarded the Winter Games . Although London is located closer to the pole, her more scantily-clad residents enjoy a clime 6° warmer, on ave., than do the people in Canada’s Calgary, located further south.
*Although the Gulf Stream is largely driven by the wind, the MOC is influenced by water densities i.e. the ocean’s thermohaline properties. Waters of different temperature [‘thermo‘] have different densities as do waters of differing salinity (salt) [‘haline‘].
More sciencey bits & bobs I’m afraid –
- Molecules in cold water slow down & ‘huddle closer’ [for warmth, presumably] i.e. – denser.
- Warmer water throws off the coverings & spreads out i.e. = less dense.
- Salty water – adds salt to the mix [volume-crowdfunding] i.e. = denser.
- Fresher water, sans the salt, means a smaller crowd i.e. = less dense.
Seawater is, therefore, more or less dense.
Sea-water expels salt when it freezes – a natural clean & rinse, and a boon for thirsty penguins in the driest desert of them all. The salts leached out in the freezing process increases the density of the water under the ice which then sinks. [i.e. denser. Pay attention!]
In the coldest climes eg. at the North Pole, +17 000 000 m3s−1 [cubic meters per second] (*17 Sv) or the volume of the Kariba Dam every 3 hours, sinks down ‘chimneys‘ to depths of 4000 m [approx.]. It’s a force of nature & terribly important, or maybe it isn’t [science, again].
In oceanography, a *Sverdrup (Sv) is a unit of flow, with 1 Sv equal to 1 000 000 cubic metres of water-flow per second. The Gulf Stream, off the coast of Newfoundland, transports water at a mean rate of +100 Sv.
It isn’t the largest current in the ocean…
The Antarctic Circumpolar Current has a mean transport of approximately 150 Sv. Our own Agulhas Current is credited with 75 Sv… but more on the Agulhas later.
Incidentally, the earth’s freshwater rivers have a combined mean rate of 1 Sv (one…), a *pee in the ocean, really. [*Mea culpa. This is, after all, a family volume]
Why the flap & what’s the big deal?
- Roughly 90% of the earth’s excess heat is transferred to the ocean. [The Gulf Stream, by way of example, transports thermal energy equivalent to the heat generated by 1 000 000 nuclear power plants…]; and
- The deep ocean is the reservoir [or ‘sink’] for approx. 45% of anthropogenic carbon dioxide – CO2.
…and there it is. The Climate Change debate, in a nut-shell, is a war of words on Hot Air.
The ‘more / less dense’ flow of the ocean’s waters; forces of temperature & salinity, are general variables DIRECTLY responsible for the globe’s health & safety agenda or, at the very least, a fairly important component in maintaining the current levels of discomfort. Those reliant on air-conditioning, TV-meals & bottled water shouldn’t worry.
What price fossil fuels?
The MOC [a variable current] moves CO2 away from the surface in the higher latitudes and into the deep ocean in the mid-Atlantic. The extent at which the MOC transports CO2 directly influences the amount of CO2 in the atmosphere.
Need I remind you that CO2 is a Greenhouse Gas i.e. the globe’s thermo-blanket?
The ocean’s CO2 sink = less greenhouse gas but more acidification in the ocean [carbon dioxide dissolved in water = carbonic acid]; a disaster for Nemo & his friends, on coral reefs, everywhere. Why you say? Corals live in their PH-balanced world of pillars, brains, tables & fans. Acidification alters this equilibrium & they don’t like it; even if their protests are conducted in stoney-silence.
Of course, the fate of the Great Barrier Reef is ‘who cares‘ for most peeps living in the North Atlantic. The emphasis, in the North Atlantic, is on understanding the fate of the ocean as a carbon dumpsite. At the root of that equation is understanding the overturning [MOC] ‘variability’. The MOC is, therefore, the globe’s waste-management-professional; earth’s unappreciated sanitation engineer & if it doesn’t come to work.. there be a lotta hot air over there, here .. everywhere.
Back to the sciencey stuff – melt-ice in the Arctic is freshening & adding advective heat to the Labrador & Irminger Seas. Physics tells us that this warmer / fresher water will linger-longer at the surface & potentially, diminish the extent of the overturning variable.
As a consequence, climate models extrapolate increasing levels of melt-ice with the eventual interruption in the overturning, cold water ‘lower-limb’ of the AMOC / MOC. If that were immediately true, the MOC would fail – less CO2 and heat would be transferred to the ocean & we’d live out the apocalypse until we drowned, froze or burned our way into the afterlife. Either way, the birding would be disappointing.
In 2014, global-talkers found some common language in #be4it’s2L8 & launched OSNAP [Overturning in the sub-polar North Atlantic Program]. It’s a welcomed collaboration, of course &, at the time of writing, yet to be Trumped.
Here’s the best bit. Until the release of OSNAP’s preliminary data, oceanographers assumed that deep water:
- was formed primarily in the sub-arctic;
- continually spilled over the sub-polar sills; &
- flowed to the ocean’s basins via the deep Western Boundary Current.
Eventually this deep water upwelled near Antarctica and, through a process of wind & mixing, traversed the globe in a single, uninterrupted 1000 year-long circumnavigation. Variation in the MOC was, therefore, on a long-time scale [i.e. millennia] and ANY disruption, however small, would paralyse the water-works.
It isn’t true!
Gliders / acoustic floats & other new technologies have revealed that the annual Sv variance is as high as 6. A factor of 6 is a very high rate of variability, particularly over 12 months. If the climate-change models held true, we’d have been outta sunscreen & blankets before Y2K.
Early OSNAP results indicate no link between higher SSTs [Sea Surface Temperatures] in the Arctic and the flow of water over the deep-water sill in the Labrador and Irminger Seas.
There is NO evidence of diminished transport in deep waters but proof, at last, that water in the Arctic is not a flawless flip-turn back to the other end of the pool. The ocean [surprise] is more complex than we thought…
Firstly, most of the water in the sub-polar region stays in the sub-polar gyre. Secondly, the Gulf Stream flows sub-surface and, although it eventually gets to the Arctic, most of the water spills into and circulates in the Atlantic’s sub-tropical gyre. There is no single MOC but a complex system of vortices, eddies, fluxes, plumes & filaments; proof again of the majesty of the sea.
More in Part 2