Tag Archives: Ocean Acidification

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

Where the wild things roam: Dispersal, connectivity, marine protected areas, and my PhD project

 

In my last post I mentioned that I am starting a PhD.  I promised to tell you a little more about what my research will be looking at, so here we go!

The project outline

My research comes very broadly defined already – the work’s raison d’être if you like.  Here it is:

“Movement and dispersal connects marine populations, allowing restoration of depleted local populations by immigrants that renew genetic diversity. Although Canada’s Oceans Act prioritizes ‘linking Canada’s network of marine protected areas (MPA)’, connectivity has not weighed significantly in MPA network design in Canada. This study will optimize regional marine connectivity among protected areas in the Atlantic region by determining optimal locations for new MPAs and evaluating how commercially important species would be representative in the entire MPA network. To model species distribution based on larval dispersal, fishery pressure, and climate change, we will use 3-D ocean circulation models. Then, based on metapopulation theory, we will develop novel spatial network algorithms to optimise the number and spatial connectivity between MPAs under current and future scenarios of climate and fishery pressure that may alter larval supply”.

Sounds complex?  Yep, for me too. Continue reading Where the wild things roam: Dispersal, connectivity, marine protected areas, and my PhD project

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.

Ocean acidification could impede Chilean abalone’s ability to self-right

Abalone.  they aren’t the prettiest of things, but they are a popular food choice.  They are also an ecologically important species, so understanding how they may react to ocean acidification is an important consideration.

It seems under many species that use calcium carbonate to to build their shells (and indeed corals who use it for building their ‘skeletons’) will find it more difficult to gather the minerals they need to do so under increasing acidification.  How badly they are affected is species specific, so finding out that the Chilean abalone Concholepas concholepas (also known as loco) calcification rates aren’t adversely altered isn’t unheard of.  Turns out, that acidification has another affect on these molluscs….their ability to self-right after dislodgement.

In this open access paper, Dr Patricio H. Manríquez from the Instituto de Ciencias Marinas y Limnológicas in Chile and colleagues report that as our oceans become increasingly more acidic the  young abalone find it easier to get off their backs on on their front.  This is a really important skill.  These critters attach themselves to rocks in often high-energy wave environments.  That means its rough and wild, and they are always at risk from being knocked off a rock.  Now their shells are great at protecting them from a range of predators but when their soft, tasty underbelly is exposed there isn’t much they can do to protect themselves.

The story doesn’t end there though.  It seems the speed at which these critters self-right is partly determined by the presence of predators.  If a predator is present, then they will self-right much faster then when it is absent.  Of course they need to know a predator is present initiate this faster self-righting and unfortunately under acidic conditions, the ability of juvenile loco to detect predators is reduced.

So what’s the future for the loco in light of ocean acidification?  Well, its a little hard to tell.  This paper demonstrates that there is no one simple response to changes in ocean chemistry.  Some species will most certainly fare better than others, and some species will do better in some respects, and worse in others. And of course there are the knock-on effects, like how will the predators of these loco do in the face of changing behaviours of their prey?

Since the paper is open access, why not have a read of it yourself

Image: Photographic sequence (A–H) illustrating self-righting behavior in the gastropod Concholepas concholepas.  Taken from the paper.

Social-ecological vulnerability of coral reef fisheries to climatic shocks

Just as climate change is altering reef-associated species behaviour, ecology , and community structure below the water, so it too is impacting those on land.  That includes people.  The FAO have taken a look at the socio-ecological impacts of climate climate change and ocean acidification on a human community in Kenya that utilizes reefs for their livelihoods and survival.

Here’s the blurb from the FAO:

“This [FAO] circular examines the vulnerability of coral reef social-ecological communities to one effect of climate change, coral bleaching. The objective was to develop and test in Kenya a community-level vulnerability assessment approach that incorporated both ecological and socio-economic dimensions of vulnerability in order to target and guide interventions to reduce vulnerability.

In addition to a range of direct threats such as siltation, overfishing and coral disease, coral reefs are now threatened by climate change. Climate impacts on coral reefs and associated fisheries include:
increasing seawater temperatures;

  • changes in water chemistry (acidification);
  • changes in seasonality;
  • increased severity and frequency of storms, which affect coral reef ecosystems as well as fisheries activities and infrastructure.

Coral bleaching and associated coral mortality as a result of high seawater temperatures is one of the most striking impacts of climate change that has been observed to date. As warming trends continue, the frequency and severity of bleaching episodes are predicted to increase with potentially fundamental impacts on the world’s coral reefs and on the fisheries and livelihoods that depend on them.

The analysis presented in this circular combined ecological vulnerability (social exposure), social sensitivity and social adaptive capacity into an index of social-ecological vulnerability to coral bleaching. All three components of vulnerability varied across the sites and contributed to the variation in social-ecological vulnerability. Comparison over time showed that adaptive capacity and sensitivity indices increased from 2008 until 2012 owing to increases in community infrastructure and availability of credit. Disaggregated analysis of how adaptive capacity and sensitivity varied between different segments of society identified the young, migrants and those who do not participate in decision-making as having both higher sensitivity and lower adaptive capacity and, hence, as being the most vulnerable to changes in the productivity of reef fisheries.”

The full report is open access.

Image: Toka Panda spear fishes for reef fish, Santupaele village, Western Province, Solomon Islands. Taken by Filip Milovac.  WorldFish/Flickr (CC BY-NC-ND 2.0)

Study highlights under-appreciated benefit of oyster restoration

Chesapeake Bay has a long history of fishing – and overfishing.  Oysters were a commercially important species even as far back as the 14th century, and centuries of overexploitation have left the Chesapeake devoid of the rich oyster reefs that once existed there, and consequently altered the ecosystem making conditions difficult for many other species – including commercially harvested ones.  This is not just because they are part of the food chain, but because they are ecosystem engineers.  Not only do oyster reefs provide a hard substrate for many other species to live on and around, but they are tenacious filter feeders, cleaning up the water of the bay.  It makes sense to instigate oyster restoration projects – not just as a means of providing a food source but also to reverse the degradation of the ecosystem.  Unfortunately it is not always that simple, especially where conditions have degraded so dramatically that oysters may simply no longer be able to thrive in areas they once inhabited.

A recent study by Professor Waldbusser and colleagues suggests that one reason for degradation – ocean acidification – can also be buffered by oyster reefs.  The idea is simple.  Acidic waters mean oyster shells ‘dissolve’ and as they do so, release an alkaline salt that buffers the acidity levels.  The problem today is that there aren’t that many dead oyster shells left in the Chesapeake because when we harvest them, most of the shells aren’t returned to the bay, and the buffer is heavily reduced.

For those with access to the journal ‘Ecology’, the original paper can be found here http://dx.doi.org/10.1890/12-1179.1