Category Archives: Climate Change, Acidification, & the Oceans

What the GBRMPA chair DID NOT say about my coral bleaching article

In April 2016 I submitted an article to The Marine Professional – a publication of the Institute of Marine Engineering, Science & Technology (IMarEST) focusing on the mass bleaching event that had hit the Great Barrier Reef at the time.  In their September 2016 issue, The Marine Professional featured a comment from a reader, in which he stated that he shared the article with Dr. Russell Reichelt – chair of the Great Barrier Reef Marine Park Authority.  The reader alleged that  Dr Reichlet told him that the article “contains some accurate things mixed with half truths and alarmism”.

A number of  coral reef, marine biology, and climate scientists have been in touch to express their concern about Dr Reichelt’s alleged comments on my article.  After liaising with Dr Reichelt’s office*, I am pleased to be able to set the record straight on what he did – or rather did not say.

*I did contact Dr Reichelt directly, but he replied via his office not directly.

After corresponding with Dr Reichelt’s office to determine where the “half truths and alarmism” were in the article, I have been informed that, whilst Dr Reichelt recalls the article being brought to his attention, he never made any such comments about the article.  In fact, he hadn’t even seen the article to comment on in the first place.  He has since read the piece and agrees that it is factual.

I have not attempted to contact the reader to find outwhere his comment came from.

Below is a copy of the article I submitted to The Marine Professional.   For those who want to see the article after it has been through their editorial process, please see the June 2016 edition of The Marine Professional.

Continue reading What the GBRMPA chair DID NOT say about my coral bleaching article

Climate Change Impacts on Kenya’s Fishery-dependent communities

 We now have a number of scientific studies that tell us how climate change is altering coral reef ecosystems, but how will these changes impact on communities that depend on them for their livelihood?  According to Joshua Cinner of James Cook University in Australia and colleagues from around the world, that answer depends more on the  community capacity for adaptation than its location.

Fishery-dependent communities in Kenya are not in a great situation.  Their reefs were heavily affected by a massive bleaching event in 1998 that has been linked to an extreme El Niño event and have not necessarily recovered as well as we might hope, and Kenyan reefs are likely to face increasing amounts of climate-related stress into the future.  Across three years, Cinner and co surveyed 15 ecological sites associated with 10 coastal communities along the Kenyan coast.  Using a range of ecological indicators of vulnerability of these reefs, they linked up the ‘health’ of the ecosystems with the vulnerability of the human communities that depend on them. Continue reading Climate Change Impacts on Kenya’s Fishery-dependent communities

A tale of two penguins

The Antarctic Peninsular is regarded as one of the fastest warming regions in the Southern Hemisphere.  It might seem small to you, but the increase in air temperature of around 2.8 degrees Celsius is resulting in some big changes.  According to the British Antarctic Survey some 25,000 square kilometres of ice has been lost from ten floating ice shelves, 87% of glacier termini have retreated, seasonal snow cover has decreased.  What exactly these sorts of changes mean for the inhabitants and seasonal visitors to the Peninsular is a question researchers are desperately trying to get a handle on.  The way each species reacts to this changing environment is likely to be very different, even among closely related species. Continue reading A tale of two penguins

A practical solution to species range changes detection?

With rapidly warming ocean regions comes changes in marine species distributions.  Understanding and monitoring these changes is important for managing biosecurity threats as well as management of existing and changing living marine resources.  Detecting range changes in the marine environment is difficult and expensive.  For many species, assessment simply has not taken place.  To combat this data gap and assist managers in directing limited research resources, Dr Lucy Robinson, research fellow at the Institute for Marine and Antarctic Studies (IMAS) and colleagues suggest a new method – rapid screening assessment that uses a variety of sources.

Development of the method, which was recently published in Global Environmental Change , focused on waters off the east coast of Tasmania, and area where over the past 50 years warming has been nearly four times greater than the global average.  Using field data from a number of sources, primarily from the citizen science program Redmap Australia, 47 species were assessed for range expansion.  Categorising species based on confidence in their range expansion, 8 species – 6 fish species, a lobster and an octopus species –  were categorised with a ‘‘high’’ confidence of potentially extending their ranges.  These species, the researchers argue, are the ones that should be prioritised for impact assessment, with those falling in the “medium” and “low” confidence categories coming after.

The paper is behind a paywall, but if you have access (or want to buy a copy) you can find it here http://dx.doi.org/10.1016/j.gloenvcha.2014.12.003

Image:  The rainbow cale (Heteroscarus acroptilus) is one of the species assessed in this study.  The assessment had “high” confidence in a potential range extension for this beautiful fish.  This particular beauty is a male in breeding colouration. Credit Richard Ling/Flickr (CC BY-NC-ND 2.0)

Rivers and streams on the Greenland ice sheet a major contributing factor to global sea level rise

Meltwater runoff from the Greenland ice sheet, which covers 80% of the country, is a major contributing factor to global sea level rise.  The processes by which melting water reaches the ocean is still a subject of research, with most studies focusing on large chunks of ice that break off the ice sheet forming icebergs, or on large lakes which can abruptly drain.  Recently, a study lead by Dr Laurence Smith, Professor and Chair of Geography, and Professor of Earth, Planetary, and Space Sciences at University of California revealed that the network of 523 rivers and streams flowing on top of the Greenland ice sheet may be draining as much – if not more meltwater through sinkholes, than the other two processes combined.

The research team utilised remote sensing, remotely controlled boats equipped with specially designed instruments, and helicopter flyovers to map the network of rivers and streams, and collect data on water flow.  Alongside the importance of rivers and networks, the study also indicated that discharge from the Isortoq River, one of the largest rivers on the ice sheet, is lower than expected given the amount of water flowing down it.  Where and how this ‘missing’ water is being captured under the surface is not yet understood, but is contrary to models used by the Intergovernmental Panel on Climate Change, which assumes all meltwater goes into the ocean.  The study will help researchers refine climate models, ultimately developing better global sea level rise projections.

The paper which was published in PNAS is open access.

Image:  Supraglacial river networks represent an important high-capacity mechanism for conveying large volumes of meltwater across the Greenland Icesheet surface.  Taken direct from the paper.

News from the life aquatic

There are three great open access papers out this week that I want to share. Three! But which to share? Well why not all three. Here’s a quick round-up of some of the latest research in ocean science. Best served with a nice slice of your favourite treat.

Can you tell what (species) it is yet?
Every time we explore life in the deep sea we find more and more creatures that bioluminensce. Around 80% of all eukaryotic life in waters below 200 meters are thought to have this ability. In this study by Matthew Davis of The University of Kansas (USA) and fellow researchers, it emerges that diversity of species (species richness) in deep sea fish groups may be influenced by photophores – light emitting cells on the body of fish. The researchers work found that some lineages of the lanternfishes (Myctophidae) – which are made up of over 250 species – have photophores with species-specific patterns. This means species can clearly be identified from one another. This diversification seems to have happened after the evolution of the lanternfishes photophores some 73 – 104 million years ago. As diversification of photophores occurred, so too did speciation.  http://dx.doi/10.1007/s00227-014-2406-x

 

Where the young turtles swim
We watch baby turtles hatch and make their way into the open ocean. We watch them when they show up in coastal waters years later as ‘teenagers;. But where do they go when they are growing up? That is what Kate Mansfield of the University of Central Florida and fellow researchers set about to discover for loggerhead turtles (Caretta caretta) . 17 young turtles – all between 3.5 and 9 months old and reaching a maximum length of just 18 cm were tagged with small solar-powered satellite transmitters. And what an adventure these guys had. Staying mostly at the surface, these critters were found enjoying a wide area of the ocean past the continental shelf, – with one turtle travelling up to 2,672 miles! What was particularly surprising for the researchers was that they didn’t just hang out in gyre-associated currents – sometimes they went off exploring
http://dx.doi10.1098/rspb.2013.3039

 

I’m sure there used to be people living there
With changing climate comes changing sea levels. And for many areas that means a sea level rise. In this study by Ben Marzeion from the University of Innsbruck (Austria) and Anders Levermann from Potsdam University (Germany), looked at all 720 UNESCO World Heritage Sites to see what increasing sea levels would mean for them. The researchers decided to take a not-too unrealistic prediction of 3 degrees Celsius above pre-industrial levels in the next 2000 years. Under this scenario, their models indicated that 136 sites (19%) would be impacted by sea level rise. Doesn’t sound too bad, on the grand scheme of things but those sites do include key heritage areas like the Sydney Opera House, the Tower of London, and Independence Hall. Check out some visualisations from The Weather Channel, created using ‘Drown your Town’. But the researchers didn’t stop there. They also looked at how much of the current human population would be impacted by sea level rise. The same scenario indicated that 7% of the world’s population is living on land that will be undersea within 2000 years. Around 60% of those affected live in just 5 countries – China, India, Bangladesh, Vietnam, and Indonesia. Sobering thoughts for the future.  http://dx.doi:10.1088/1748-9326/9/3/034001

 

Image: ‘Drown your Town’ used on Cape Town, South Africa (50m rise – possibly a little extreme!). Credit: Drown your Town

Studying the climate past

We know that our climate isn’t static.  Over the billions of years our planet has been rotating around the sun, it has undergone periods when it is very very cold (glacial periods) and periods when things are warmer (interglacial periods).  We are sitting in an interglacial period right now.  This one is called the Holocene, and is one of 5 major interglacials that scientists have identified.  Today technology is allowing us to record all sorts of data – both at a global scale and at a local scale – about the weather and climate.  As this technology improves, so does the quality and quantity of information we can capture.  Even before technologies such as satellite remote sensing were around, people have kept long-term records of the weather they have experienced.  These records can be used to reconstruct the historical climate.

But what about measuring oceanographic variables?  Today we have an array of tech to do this for us – like satellites, buoys, and autonomous vehicles providing all sorts of data on global and more fine-scale oceanographic conditions.  Before this technology?  Back in the 1700’s Benjamin Franklin (yep – one of the ‘founding fathers of the United States’ – he was a scientist too) had to use much simpler methods…dipping a thermometer into the ocean and recording the readings he got.  Franklin’s experiment is one of the earliest empirically-derived sea surface temperature datasets we have.  These readings are very much a one-shot deal – not something we can use in isolation to figure out what the average sea surface temperature was during that time, at the location he took them.  So how can we find out what historic ocean-climate was?  Turns out that there are all sorts of clever ways.  Here’s a couple of examples from science papers that have come out over the past couple of weeks.

Foraminifera are pretty awesome.  The single-celled critters that make up the order foraminifera are found in all marine environments, and have been pootling about since the Cambrian period (that’s around 541–485 million years ago).  Whilst they vary in size and shape, foraminifera all have something quite important to paleooceanographers…a shell.  Shells are constructed from calcite, but also trap impurities from the water.  It was one of these impurities in particular that Oscar Branson  of the University of Cambridge in the UK, and his fellow researchers from the US and Japan were interested in for their study – magnesium.  As the shells of these tiny critters grow, the magnesium forms growth rings (rather like tree rings), and these bands appear for every day of that individual’s life.  So what’s the link with ocean temperature you ask?  Well it seems that the level of magnesium in these bands is related to water temperature.  The more magnesium a band has, the warmer the ocean was where that critter happened to be.  When these foraminifera die, they end up on the sea floor (or stay there if they are benthic), handily leaving their shells behind with those magnesium bands stored.  So, take a core sample (the different layers from these cores can be dated), take out the shells and bobs-your-uncle you have a record of ocean temperature for the life of those individuals.  And because these guys have been around for quite some time, their collective remains can give us an indication of what the ocean temperature were like in the very very…very distant past.  Sounds simple right?  Well it’s not quite that easy.  Each one of these bands is tiny.  On the nanometer-scale tiny, and not really visible with standard microscopes.  This was a job for the Advanced Light Source synchrotron – a huge particle accelerator that “produces light in the x-ray region of the electromagnetic spectrum that is one billion times brighter than the sun” .

Pretty cool right!  Well so is the next paper.

Plankton aren’t the only ‘paleoproxies’ that are used for figuring out what the temperature of the oceans used to be.  Shayne McGregor of the The University of New South Wales in Australia and colleagues recently reconstructed ENSO over the past 600 years.  ENSO – the El Nino Southern Oscillation – is the variation of sea surface temperature and surface air pressure over the tropical east Pacific.  You’ll most likely have heard of El Nino and La Niña years.  ENSO has a huge impact on weather patterns.  If you live on the east coast of Australia, you may be more familiar with how this can play out – cyclone activity, flooding, droughts….  The strength and frequency of ENSO events shows multi-decadal variability, but understanding the long-term changes in frequency and magnitude of these events is a little more tricky.  That’s because the technology to measure these events in the detail needed hasn’t been around long enough (around 150 years).  So to figure out anything past this, we need to use these paleoproxies.  For historic El Nino sea surface temperature data, these proxies tend to come in 3 flavours – tree rings, sediment cores and corals.  When scientists have tried to reconstruct ENSO patterns, they usually combine each individual proxy and then figure out what ENSO was doing.  Makes sense right?  The problem is that the reconstructions from these proxies don’t always line up perfectly, with a number of discrepancies between the dates of the measurements, causing issues with combining them together.  What Shayne and the rest of the team did is perhaps a little less intuitive.  They calculated ENSO activity based on each proxy individually, and then combined those activities to provide a reconstruction.  It seems to have worked well.  The team ran a number of simulations and compared it to more the recent measurements of ENSO.  These measurements have been taken from oceanographic monitoring instruments, so we can safely say they are pretty robust, and a great candidate for testing historical models against.  So what has this more robust reconstruction of ENSO told us?  Well it seems that if we look over the past 600 years – from the 1400s up to 2009, the most active 30 -year period was between 1979 – 2009.  These results aren’t the result of researchers arbitrarily choosing a 30-year window just to ‘show something’ either.  The 30-year sliding window was chosen to focus on that multi-decadal variability.

Well it’s all very fascinating stuff this ‘what the ocean used to be like’ but…so what?  Well if we can reconstruct how the oceans used to be, and figure out how systems (biological, ecological, physical, chemical…) responded to those conditions then we can improve the predictions we make about our future climate.  This knowledge in turn can help us mitigate – and crucially adapt to – our ever-changing environment.

The paper by Shayne McGregor and co looking at ENSO variations was published in the journal Climate of the Past .  The paper is open access.

The paper by Oscar Branson and co looking at the foraminifera shells is published in the journal Earth and Planetary Science Letters. This paper is also open access (hurrah!).

If you fancy finding out a little more about foraminifera, UCL have produced a nifty little site which goes into all sort of details.   The Natural history Museum in the UK have also put some really cool foraminifera posts up on their Micropaleaeontology blog. 

Image: Baculogypsina sphaerulata (Starsand Foraminifera) from the Great Barrier Reef.  Image taken by Martin Langer of  the University of Bonn

Ocean warming hotspots

7303056092_552b121015_o

This little chap is a Sally Lightfoot crab (Grapsus grapsus).  Sally Lightfoot’s can be found on the west coast of South America, Central America, and Mexico, but this critter in particular lives on the Galápagos Islands – or as they are officially known Archipiélago de Colón.  These islands are home to 95 living endemics species (species found nowhere else), and famed for the now-deceased giant tortoise ‘Lonesome George’ and Charles Darwin’s work on Galapagos mockingbirds and finches which eventually gave rise to his seminal book On the Origin of Species as well as its biodiversity and outstanding beauty both on land and in its seas.  Unfortunately for our Sally Lightfoot, those seas are due to get warmer….a lot warmer. Continue reading Ocean warming hotspots

The science is clear, but what will we do to take better care of our ocean?

 Something has gotten researchers, NGO’s and concerned citizens shouting this week…well aside from the US Government shutdown…

“When an alarm bell rings over a threat to our ecological security, governments must respond as urgently as they do to national security threats; in the long run, the impacts are just as important.”  ~  Trevor Manuel, Co-chair of the Global Ocean Commission and Minister in the South African Presidency

“The world has grown too crowded to sustain the selfish pursuit of narrow national or business interests without regard for the impacts on others.”  ~ Professor Callum Roberts, University of York, UK.

In the face of changing coral reefs, how will dependent communities react?

We now have a number of scientific studies that tell us how climate change is altering coral reef ecosystems, but how will these changes impact on communities that depend on them for their livelihood?  According to Joshua Cinner of James Cook University in Australia and colleagues from around the world, that answer depends more on the  community capacity for adaptation than its location.

Fishery-dependent communities in Kenya are not in a great situation.  Their reefs were heavily impacted by a massive bleaching event in 1998 that has been linked to an extreme El Nino event and have not necessarily recovered as well as we might hope, and Kenyan reefs are likely to face increasing amounts of climate-related stress into the future.  Across three years, Cinner and co surveyed 15 ecological sites associated with 10 coastal communities along the Kenyan coast.  Using a range of ecological indicators of vulnerability of these reefs, they linked up the ‘health’ of the ecosystems with the vulnerability of the human communities that depend on them.

The authors found only a marginal difference in the vulnerability of reefs that were heavily fished, under community co-managed fisheries closures, or no-take National Marine Parks, with heavily fished reefs looking like they may be most vulnerable.  How this impacted on their associated human-communities varied considerably, with some communities faring better than others.  Some of this variability depended on the type of species fishers were targeting, with fishers using traps and beach seine nets are expected to see a decline in their catch.  But we are an adaptable species, and some coral creatures – particularly herbivorous fish – may increase in abundance as a response to changes in the reef*.

But not every community is able to adapt to the changing conditions well.  There are a whole host of reasons why a community may not be able to adapt.  For the fishers themselves, switching gear to catch a different species isn’t necessarily that easy.  Fishing equipment isn’t cheap, and these guys aren’t exactly rolling in it.  Then we have whole communities that are almost solely dependent on reef fisheries.  For these guys, their adaptive capacity is even more limited, because there simply isn’t the option to switch to another source of livelihood.  In essence, communities that are more ‘generalist’ are better able to adapt to changing conditions than those which are ‘specialist’.

So where does this leave the Kenyan communities when having to deal with the changing conditions they are facing?  The authors maintain that “adaptive capacity is perhaps the component of vulnerability most amenable to influence, and may be a useful focus for adaptation planning”.  This is a good point.  We can’t necessarily halt the degradation that reefs have been experiencing on a time-scale that is meaningful to these communities, but we can work towards supporting communities increase their capacity to adapt to change.

Lumping ‘poor communities’ together when thinking about climate change impacts doesn’t really cut it – even within the same geographic area there is considerable variation with regards to the impacts of climate change and more importantly how those communities can respond to that change.

The paper is published in the open access journal PLoS ONE

Image: Small-scale fishers on the coral reef surrounding Siquijor island, Philippines.  Credit Rebecca Weeks/Marine Photobank

* Herbivorous fish may increase because algae often grow over dead coral.  So, as reefs become degraded and the coral dies off, there will be more food for herbivorous fish and we may very well see a shift in the state of the ecosystem in those areas.  Nothing is certain though, and we will have to wait to see how that scenario actually plays out.