Monitoring the Oceans from Space MOOC

As your self-appointed education officer and fellow perpetual student, it is my duty to inform you of an upcoming MOOC on the Futurelearn platform, entitled “Monitoring the Oceans from Space“. In the five weeks of the course,  which starts on 24 October, you will learn about using satellite data to monitor the health of the oceans. You will also learn how to access some of the ocean monitoring data that is collected every day about weather phenomena, icebergs, sea levels, ocean temperature, and more. If you’re into creating your own visualisations or crunching numbers yourself, this should appeal.

The course is presented by EUMETSAT and was developed by Imperative Space in partnership with Plymouth Marine Laboratory, the National Oceanography Centre (Southampton), CLS France and NASA JPL.

Read more about the MOOC here, and register here.

Here’s a trailer:

Regular service on this blog should resume in the forseeable future; it’s been a heck of a year, so forgive us!

A new ocean MOOC starting on Monday!

Online learning with SDI
Online learning

This one snuck up on me. Starting on Monday 25 April (yes, this Monday), a massive open online course (MOOC – remember those?) about science-based solutions to challenges facing the world’s oceans becomes available to the curious. It’s a collaboration between Kiel University in Germany, its GEOMAR Hemholtz Centre for Ocean Research and “cluster of excellence” (I don’t know!) The Future Ocean, and the International Ocean Institute.

The course syllabus is comprehensive and spans 10 weeks of online study. You will cover topics from oceanography, marine biology, and geology. The aspects of the course related to humans include ocean governance, human-ocean interactions, changes happening along our coastline, and – most importantly – solutions from marine spatial planning to ecosystem management.

It looks very comprehensive and unmissable if you’re a marine freak. Go to oceanmooc.org to learn more and sign up. For your own privacy, protection and future access (and this applies to every website that offers you the option, not just this one) don’t sign in with your facebook, linkedin or other credentials. Make a new account using your email address, and create a new password.

Get to it.

Colour fronts in False Bay

Colour front seen from Sunny Cove on 27 November 2015
Colour front seen from Sunny Cove on 27 November 2015

Perhaps you have wondered what causes the patterns of strange coloured water in False Bay during the summer months. Perhaps you have dived in it, and wondered why sometimes you can’t see your hand in front of your face! Wonder no more – I am here to help.

Colour fronts

Frequent visitors to and residents of the shores of False Bay will observe that at certain times of the year, the ocean is marked by bands and arcs of sharply contrasting coloured water. This phenomenon is known as a colour front. In oceanography, a front is the interface or boundary between two separate masses of water. In this case, the water masses are easy to discern, because they are of different colours. There are usually other characteristics of the water on each side of the front that differ, too. Fronts are either convergent (the water masses are moving towards each other) or divergent. The presence of marine debris (like pieces of kelp) at the front boundary suggests that it is convergent.

Causes of colour fronts in False Bay

Prior to 2005, there was much conjecture about the causes of these fronts (including the usual pollution bugbear), but little evidence to support any of the theories. By sampling, the fronts were found not to be caused by pollution, or by plankton blooms in the surf zone. It was known that a colour front was most likely to occur in False Bay after a period of southerly or south easterly wind lasting a few days. October and November seem to be prime months for the phenomenon.

When a large, obvious colour front arose near Simon’s Town in November 2005 with milky green water on one side, and darker blue-green water on the other, researchers from UCT and IMT sprang into action, sampling the water on each side of the boundary so that they could measure its characteristics. Speed is of the essence in these situations; colour fronts can disappear quickly. The one in the picture below is busy decaying – notice the smudged boundary.

Colour front in north western False Bay on 13 November 2014
Colour front in north western False Bay on 13 November 2014

Measurements revealed that the milky green water overlaid the clearer, bluer water, down to a depth of 11-12 metres (this will vary from front to front). The milky water did not extend to the ocean floor.  Scuba divers around the Cape Peninsula will be familiar with the experience of diving through two or more layers of water, with varying turbidity (clarity) and temperature! (Here is picture of Tony and Christo diving near Oudekraal in the Atlantic that shows what the boundary between two layers of water can look like.)

The researchers found that the milky coloured greenish water was full of fine, almost neutrally buoyant particles of calcium-rich sediment. The green-blue water contained much less calcium, but relatively more silicon, which would suggest the presence of diatoms (a kind of phytoplankton – you can think of them as teeny tiny plant-like organisms) or sand in the water. The origins of the calcium-enriched sediment in the milky water are interesting: one source is from the shallows (less than 30 metres deep) of north western corner of False Bay, where the ocean floor is made up of rocks that are rich in calcium carbonate (such calcrete and limestone), some areas covered by a thin layer of sand.

Milky-white water near Swartklip on 29 November 2014
Milky-white water near Swartklip on 29 November 2014

The second probable origin for the particles of calcium-rich material is the interface between the sea and the land at the northern end of False Bay. The cliffs at Wolfgat/Swartklip at the head of the bay are made of calcrete, and at Swartklip the beach narrows to the extent that the cliffs erode directly into the water when the sea is high. Strong southerly winds create a wide (of the order of one kilometre) surf zone at Muizenberg and Strandfontein; a spring tide also adds to ideal conditions for the generation of a colour front.

The temperature of the milky water was found to be slightly (0.4 degrees Celcius) higher than the green-blue water. This measurement will also vary from front to front. The researchers speculate that the temperature difference could be because the milky water originated in the surf zone, which is shallower and therefore warmer, or because the high concentration of suspended particles in the milky water caused greater absorption of heat from the sun.

Colour front at Smitswinkel Bay on 24 October 2014
Colour front at Smitswinkel Bay on 24 October 2014

Summary

Here’s the tl;dr: strong southerly and/or south easterly winds, perhaps coupled with spring tide conditions, set up a very wide surf zone along the northern end of False Bay, which disturbs the sediment on the ocean bottom and drives the waves further up the beach than usual. Particles of buoyant calcium carbonate from the sea floor and eroded from the cliffs at Swartklip are lifted up into the water column, changing its colour to a milky-green shade. Wind-driven circulation patterns in the bay push the front from its original location in a southerly direction, towards Simon’s Town.

What to do?

Contrary to what your friends on social media may claim, not all colour changes in the ocean around Cape Town can be attributed to a giant sewerage plume. Hardly any of them can, in fact. In summer, the reason for the ocean looking green, red or even brown is likely to do with a plankton bloom of some description, or related to suspended sediments (as in this case) or other naturally arising material in the water. Instead of using this as an opportunity to become hysterical on the internet, how about celebrating the incredibly dynamic system that we can observe, living near the ocean? Drive up a mountain next to the ocean and take in the spectacle from on high. Dip your face in the water and see what it does to the viz. Take some pictures for posterity. And – if you don’t know what’s causing it – try to find and question someone who does know, like a scientist, or consult a good non-fiction book, to find out some facts.

If you’d like to read more about colour fronts in False Bay, take a look at this scientific paper (pdf), which I used as source material for most of this post. The paper is called A Prominent Colour Front in False Bay: Cross-frontal structure, composition and origin

Article: Wired on rising sea levels

An article on Wired.com reveals the strange – and frankly terrifying – progress of sea level rise on planet earth. Summarising a scientific paper in Geophysical Research Letters (which makes this post a meta-meta analysis), the article describes how historical patterns of sea level rise and fall have decoupled. Typically, sea level rises in one oceanic basin and sink in an adjacent one, but since 2000 sea levels in the southern hemisphere have increased across the board. The change seems linked to changing wind patterns, which are related to climate change.

Does this kind of change in the environment interest you? Check out Ocean of Life for some more scary changes happening to our oceans. And read the Wired.com article here.

Article: Wired on giant ocean eddies

Scientists have discovered giant eddies, 100 kilometres across, making their leisurely way across the world’s oceans. The rotational effect extends up to a kilometre below the ocean’s surface. They are quite beautiful when visualised (if you were in one you probably wouldn’t notice – they move very slowly). Wired.com covered this discovery in an article last year.

Read the Wired article here. Bear in mind that the colours in the maps represent height of the ocean surface, not temperature!

If ocean circulation interests you, I cannot recommend Flotsametrics highly enough. You should also check out NASA’s Perpetual Ocean, and their global sea surface temperature and currents map. The Gulf Stream is also quite informative.

Bookshelf: Flotsametrics

Flotsametrics and the Floating World- Curtis Ebbesmeyer & Eric Scigliano

Flotsametrics
Flotsametrics

I found Flotsametrics to be a profound and moving memoir slash ocean science book. Curtis Ebbesmeyer is an oceanographer who cut his teeth in the oil industry, and later moved to private consulting. His late-life interest in beachcombing, and reading the debris he finds in order to chart the paths of ocean currents, was sparked by a question his mother asked him upon reading about a shipment of Nike shoes that had burst out of its container and floated all over the world.

The chapters of Flotsametrics are organised chronologically and by theme, and Ebbesmeyer mingles his life story with revelations about the oceanographic discoveries and projects he was part of at each stage. Cadavers, bath toys, messages in bottles (lots of these), drifting Japanese junks (seriously fascinating!), hockey gloves, sneakers, sea beans, and plain old garbage give up secrets of ocean circulation.

I stopped and re-read several parts of the book, particularly in the chapters that dealt with the death of Ebbesmeyer’s friends and family members. His meditations on releasing his loved ones’ ashes into the ocean gyres are quite beautiful and profound, notwithstanding an alcohol-fuelled incident in which he and a group of friends flush another friend’s ashes down a toilet in Seattle!

Thanks to Rochelle, I came across this article about a shipment of nautical-themed Lego that spilled out of a container 17 years ago, and is washing up (still) in Cornwall. Ebbesmeyer is lending his expertise here, as well. There is a New York Times review of Flotsametrics here, and one from The Guardian here. If you have to choose between Flotsametrics  and Moby Duck, which deals with some overlapping themes, I would recommend Flotsametrics a thousand times over. The author actually has something (many things) to say!

Get the book here (South Africa) or here or here.

Bookshelf: The Fluid Envelope of Our Planet

The Fluid Envelope of Our Planet: How the Study of Ocean Currents Became a Science – Eric L. Mills

The Fluid Envelope of Our Planet
The Fluid Envelope of Our Planet

This beautifully-titled book is a slow moving history of physical oceanography, tracing the contributions and occasional theoretical dead ends that, over the decades, have led us to our current understanding of ocean circulation. Eric Mills has a special interest in the history of the marine sciences, and – rather than get bogged down in too much explanation of the underlying processes – focuses here on the history and development of the science. His account is not normative in the sense that I sometimes didn’t know why a particular scientist’s ideas were wrong (not being a particularly hardcore student of physical oceanography), and he concentrates on providing a historical account.

The arrangement of the book traces the history of oceanography around the globe, from Canada to Berlin to Monaco to Scandinavia, and finally to the United States. I didn’t realise just how mathematical the field is. Mills makes clear the immense challenges in doing empirical oceanographic studies of the deep sea, which may be a contributing factor to the rate of development of the theoretical side of the science.

Mills provides interesting detail of the protagonists in his story, lifting them out of history as the often quirky individuals that they were (much as Trevor Norton does in Stars Beneath the Sea – although this is a more serious historical work). I enjoyed the fact that Columbus Iselin, Director of the Woods Hole Oceanographic Institute, complained in 1939 that:

The main difficulty with oceanography is that the Lord made the ocean too big and this is the chief obstacle, which we must use our collective ingenuity to overcome.

Mills’s writing is detailed and a pleasure to read. There are comprehensive references as well as a list of the canonical textbooks in the field, at the end of the book. I’d recommend this book to you if you have a special interest in the history of science.

You can get a copy of this book here or here. South Africans can find it here.

Bookshelf: Mapping the Deep

Mapping the Deep: The Extraordinary Story of Ocean Science – Robert Kunzig

Mapping the Deep
Mapping the Deep

Robert Kunzig won the Aventis Science Book of the Year award in 2001 for this book (the 2011 winner was The Wavewatcher’s Companion!). It is an absolutely fantastic piece of science writing, charting the state of the art in ocean science as well as the historical processes that led us to where we are today (or were in 2000).

Kunzig mostly used scientific papers and interviews with the scientists themselves as his primary sources, making complex mechanisms understandable without loss of information in the transmission.

The first few chapters of the book deal with the challenges of finding out what the ocean floor looks like, and of representing it in a useful way. Those beautiful maps of the ocean floor that I pored over in the atlas as a child, or in Sylvia Earle and Linda Glover’s wonderful Ocean: An Illustrated Atlas aren’t as precise as you may think they are – we often repeat the aphorism about how little of the ocean we have explored – but conveniently forget that this also precludes us from making detailed maps of it. The United States Navy probably has the most comprehensive sea floor maps, but they aren’t sharing.

Kunzig devotes several chapters to the type of life found in the ocean – he is not so much concerned with coastal as pelagic life forms, and devotes many fascinating pages to hydrothermal vent communities without once mentioning Robert Ballard. I experienced serious job envy reading about the blue water diving that Bill Hamner did to collect and study pelagic marine organisms such as jellies and plankton.

The influence of humans on the ocean’s environment is the subject of the next few chapters. There is a terrible, compulsively readable chapter about the New England cod fishery that was so convincingly destroyed, even with the assistance of government scientists. The final sections of the book deal with climate change and the ocean.

You can read other reviews of the book here and here. Here’s some of Kunzig’s writing, to give you a taste of what this book is like.

If you’re in South Africa, get a copy of the book here, otherwise try here or here. This is an updated edition of The Restless Sea, so don’t buy that one!

Bookshelf: The Gulf Stream

The Gulf Stream: Tiny Plankton, Giant Bluefin, and the Amazing Story of the Powerful River in the Atlantic – Stan Ulanski

The Gulf Stream
The Gulf Stream

Stan Ulanski is an academic with a special interest in the Gulf Stream, both as an oceanographer and meteorologist, and as a keen angler. I was drawn to this book because it reminded me of a book I took out of the school library when I was twelve, also about the Gulf Stream. I remember devouring that book, and have been trying to find it again for much of my adult life. I haven’t succeeded, and this isn’t it.

The Gulf Stream is a fast flowing, warm current that runs from the Carribbean up the east coast of the United States, past Canada, and across the Atlantic Ocean. It is responsible for about ten percent (popular opinion has always held this number to be higher, but it’s not) of the warming of England’s climate, transporting heat from the tropics up into northern latitudes. At the surface, where its flow is fastest, it can move at up to 9 kilometres per hour and the water in the current may be ten degrees warmer than the water surrounding it. Oceanographer/cartographer Matthew Fontaine Maury called it a “river in the ocean”, as it is so distinct from the water surrounding it:

There is a river in the ocean. In the severest droughts it never fails, and in the mightiest floods it never overflows. Its banks and its bottom are of cold water, while its current is of warm. The Gulf of Mexico is its fountain, and its mouth is in the Arctic Sea. It is the Gulf Stream.

The Physical Geography of the Sea, 1855

Ulanski divides his book into three parts. The first section provides an oceanography lesson, as well as a history of how we came to know what we know about ocean circulation. The second section, which I felt could have been beefed up significantly, has a chapter on the plankton, sargassum weed and other small life in the current, and another dedicated to bluefin tuna. I know from Richard Ellis’s tuna book how incredible these creatures are, and I felt that Ulanski could have made more of them. (He may have felt that since tuna have been so extensively eulogised, he has nothing to add – fair enough.)

The final chapter of the second section grated my goat and I struggled to read it – it’s about fishing, a sport of which Ulanski is a keen proponent, and profoundly smug (he “feels no remorse”). I cannot understand sport fishing  (or hunting) of any kind: if you’re going to release the animal after fighting it, exhausting it, and injuring it, what have you achieved? The inflicting of a prolonged, possibly fatal wound on a creature at a significant disadvantage to you in your motorised boat with expensive fishing tackle and crafty lures? How manly. We can appreciate how marvelously put together earth’s creatures are without damaging them with our ego in the process. (I realise that other people feel differently, with equal forcefulness.)

Ulanski concludes with an examination of the history of the exploration and colonisation of the New World, both aided and impeded by the Gulf Stream. It seemed that at times he wanders far from his main subject, but it is instructive to be reminded of what was involved in crossing an ocean before the advent of GPS and the creation of detailed charts. The section on piracy is fabulous and created in me a strong urge to re-watch Pirates of the Caribbean.

While my personal preference would be for a heavier focus on the oceanography and marine biology of the Gulf Stream, Ulanski is quite right to include a comprehensive section exporing humans’ relationship to this massive current. It has shaped the settlement and economies of all the lands adjacent to it.

Here’s an incredible visualisation of ocean currents – you can see the Gulf Stream prominently in the Atlantic. What is it like to be adrift on the Gulf Stream? Find out here.

The Perfect Storm deals with the 1991 nor’easter, a storm (not uncommon in the western United States) generated by the interaction of the warm water of the Gulf Stream with atmospheric phenomena. The Gulf Stream is the “weather-maker” of the western Atlantic, according to the author, and these interactions between the current and the atmosphere will become increasingly important and explosive as the global climate changes (and let me clarify, the change has come about because of human behaviour).

If you’re in South Africa, get the book here, otherwise here or here. For an even more wide-ranging view of the Atlantic ocean (minus the marine biology), check out Simon Winchester’s Atlantic.

Video (TED): Enric Sala on pristine ocean ecosystems

Have you seen what Kingman Reef looks like? If not, today’s your lucky day. Kingman Reef is a triangular reef in the middle of nowhere (the northern Pacific Ocean). It is considered to be one of the very few practically untouched marine environments that we have left. The proliferation of coral is remarkable, and apex predators (mostly sharks) make up 75-85% of the fish biomass there.

In this TED talk, ecologist Enric Sala shows what untouched marine environments look like (turns out the accepted idea of the “normal” number of sharks for a reef is a bit on the low side), and mounts a spirited defence for no take marine reserves.

Look out for Sylvia Earle in the audience!