Marine Life

Just keep swimming

This little critter is a limpet.  From the photo they may not look like the most exciting of creatures.  If you’ve ever been down to the coast and taken a look at them yourself… your opinion may not have changed.  They don’t seem to move around a lot, or do a lot.  Of course looks can be deceiving.  Under that shell is the limpet’s squishy body – and their big, muscular foot which, alongside a pretty amazing adhesive secretion, they use to cling onto rocks and other hard surfaces.  Anyone who has ever had a go at trying to get a limpet off a rock knows how good a grip they can have.  This fabulous foot isn’t just used to stop them from drying out when the tide leaves them exposed to the air, or keep pesky predators (or nosy humans) at bay.  Limpets are grazers, feeding on tiny algae on the surface of rocks with their raspy “tongue” (called a radula).  See that empty space behind the limpet in the photo?  That’s where it’s been grazing.  Once they have grazed an area they need to find more food.  That foot gets to work, and along moves the limpet, munching up all the algae in its path.  Some limpet species even appear to have a home – a particular crevice that they return to just before the tide will expose them to the air.

But this isn’t a post about how amazing limpets are.  This is a post about animal movements in the ocean.. Or at least 3 different types of animal movement.  Some of them move a lot further than you think.  Yes, even limpets.

Continue reading “Just keep swimming”

Conservation & Sustainable Management, Marine Life, PhD / Graduate School

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”

Marine Life

What 415 million year old fossil plankton tells us about heavy metal pollution and extinction

These weird looking things are plankton – from the genus Ancyrochitina to be a little more precise.  They are also fossils – approximately 415 million old, from a period known as the late Silurian.  That’s pretty cool in itself (at least I think so), but what makes this really interesting is that the individual on the left is malformed, whilst the one on the right is ‘normal’.  What is even more interesting than that, is that these malformations coincide with the initial stages of extinction events.

Led by Thijs Vandenbroucke (researcher at the French CNRS and invited professor at Universiteit Gent | Ghent University) and Poul Emsbo (US Geological Survey), an international team of researchers have taken a look at these malformed (known as ‘teratological’) fossil plankton.  They wanted to find out what was causing these malformations. Continue reading “What 415 million year old fossil plankton tells us about heavy metal pollution and extinction”

Conservation & Sustainable Management, Marine Life

A brighter future for the shy albatross

Predicting the future is a tricky business.  As then United States Secretary of Defence Donald Rumsfeld famously said “There are known knowns. These are things we know that we know. There are known unknowns. That is to say, there are things that we know we don’t know. But there are also unknown unknowns. There are things we don’t know we don’t know” .  Then there is the interactions between all the variables that determine the outcome of a particular event.  However, few things work in isolation and species decline often results from the accumulation of different stressors.  If we want to put in place conservation management measures that are effective in the long term, then we need to be able to put our known (and measurable) stressors together and figure out what, cumulatively they mean for our potentially at risk species.

The shy albatross (Thalassarche cauta) is an endemic to Australia, breeding on just three Tasmanian islands, including the aptly named Albatross Island.  The albatross of Albatross Island have a long history of human interest.  In the early 19th century adult albatross were extensively hunted for their feathers and egg, taking their numbers down from an estimated 11,100 pairs to just 400.  The population is now recovering, but still faces a number of possible threats.  High on this list are two issues – changing climatic conditions, and the accidental capture of the albatross in longline and trawl fisheries.  To understand just what the combined impact of these stressors could mean for this vulnerable bird, Robin Thomson and colleagues from CSIRO Marine and Atmospheric Research​​​, together with the Tasmanian Government Department of Primary Industries, Parks, Water and the Environment (DPIPWE) put together a model that can hopefully direct management to ensure these birds survive in the long term.

Continue reading “A brighter future for the shy albatross”

Marine Life

The travelling life of the tiger shark

At 9 foot long, not including the tail, tiger shark (Galeocerdo cuvier) Harry Lindo is not exactly on the small side.  It’s not Harry’s size that is exciting scientists and shark enthusiasts, nor a photograph taken in 2009 by Ian Card showing a shark – suspected to be Harry, trying to eat a 150 lb juvenile tiger shark off the coast of Bermuda.  Between 2009 and 2012 researchers tagged 24 tiger sharks with satellite transmitters in the Challenger Bank, which lies just off Bermuda in the Atlantic Ocean.  In study lead by James Lea (The Guy Harvey Research Institute, Nova Southeastern University Oceanographic Center) and team of international collaborators, those shark movements have been compiled and analysed.  Harry, it turns out, is one heck of an ocean wanderer.  In just over 3 years Harry swam over 44,000 kilometres – that’s more than the circumference of the Earth (just over 40,000 kilometres).  Harry’s track is the longest recorded for a tiger shark, and probably the longest ever published for any shark species.

Continue reading “The travelling life of the tiger shark”

Marine Life

Cool critter of the month: the chambered nautilus (Nautilus pompilius)

Phylum: Mollusca

Family: Nautilidae

Where do they live?
These ocean dwellers can be found throughout the Pacific and Indian Oceans.  As it turns out, there are two sub-species of (Nautilus pompilius).  Nautilus pompilius polpilius is the larger of the two subspecies.  These guys can be found in the Andaman Sea down to Western Australia in the Indian Ocean, and from southern Japan down to Northern Australia in the Pacific.  Nautilus pompilius suluensis has a much more restricted range, staying in the Sulu Sea between Malaysia and the Philippines.

Continue reading “Cool critter of the month: the chambered nautilus (Nautilus pompilius)”