Friday 30 October 2015

All things small and wriggly

This time it's good morning from the day shift! Having collected and sieved 157 Hamon grab samples from East of Gannet and Montrose Field NCMPA and 50 from Norwegian boundary Sediment Plain NCMPA we are getting very familiar with a few of the animals in the mud.

The grab collects about 25 litres of seabed sediments and deposits it in a large tray. This sediment is then sieved with running water to remove the finer sediment leaving behind shells, stones and any animals.

Seabed sediments straight from the grab (left) and the animals, stones and shells that remain after sieving © JNCC, 2015. 

The sieves so far have contained an assortment of worms, clams, urchins, hermit crabs, brittlestars and sea pens. Among the empty shells present in the sediments, we are finding lots of tusk shells (Scaphopods), which are molluscs commonly found in the offshore muddy sediments but rarely seen along a beach.  Large numbers of the empty bivalve shells have a small perfectly round hole through the shell.  It is likely these have been eaten by predatory snails which bore through the shell to reach the animal inside.

 Bivalves, hermit crabs and tusk shells have all been sighted in grab samples © JNCC, 2015.

Many of the grabs contain small brittle stars (see image below). These have five arms which, as their name suggests, are fragile and easily break off.  This helps the brittle star escape from predators, and the brittle star is able to regrow the lost arm. They also use these arms for feeding, where they hold their arms up off the seabed in the water to collect passing food particles.

Brittle star collected in a grab sample © JNCC, 2012.

The Norwegian Boundary Sediment Plain NCMPA grab samples have been muddy sand and we have regularly found heart urchins, or sea potatoes as they are more commonly called. These bury into the sediment using their spines and feed on particles that fall to the seafloor.  Today, one grab contained a large, fist-sized, purple heart urchin (Spatangus purpureus).

Purple heart urchin (Spatangus purpureus) © JNCC, 2015. 

We are currently taking advantage of some good weather to do some video work, but are looking forward to getting back to the sieving soon.

By Karen and Beckie

Thursday 29 October 2015

Sea pens and quahogs – the mysterious world of offshore mud

Good morning from the night shift! We’re now about half way through our survey and have settled into life onboard the good ship Scotia, where disadvantages include getting up at midnight and advantages include having a full English breakfast for lunch!

On this survey we are investigating the habitat ‘features’ for which the two nature Conservation Marine Protected Areas (NCMPAs) we are visiting have been designated: the ocean quahog and ‘offshore deep sea muds’. We are gathering an initial dataset on these features which will inform future monitoring and assessment. The goal is to determine whether there are any changes to these features over time.

Arctica islandica captured using high resolution photography © Becky Hitchin, 2015

You’ve already heard a little about the amazingly long-lived Ocean Quahog, or Arctica islandica for latin speakers (see previous blog post). This clam is typically found buried in sandy and muddy sediment with two feeding tubes called siphons peaking out above the seabed surface.  These siphons are pretty tiny and, although they can be captured using high resolution photography (see picture above), they are very difficult to spot using the underwater camera sledge. It is, therefore, far more effective to record the quahogs using a seabed sediment sampler. Encouragingly, we have already found evidence of quahogs, and have collected both live specimens and many shells in our grab samples.

The living ocean quahog shells are brown in colour whereas the dead ones tend to be mostly white. Any live specimens found within the grabs are measured and photographed by the scientists onboard before being returned to the sea. The shells recorded so far have ranged in size from very small juveniles of less than 1 cm in diameter to adults of up to about 8 cm.

The ‘offshore deep sea mud’ habitat is associated with communities of sea pen (a type of soft coral that grows in the shape of a quill) and large burrowing crustaceans such as Nephrops norvevicus, also known as scampi or the Norway lobster. We have three common species of sea pen in the UK – Pennatula phosphorea which is a very distinctive red feather, Virgularia mirabilis which is straight and upright with white polyps, and Funiculina quadrangularis which is very tall, bowed at the top, and found in deeper waters.

Sea pen images captured using a camera sledge: Pennatula phosphorea (top picture) and Virgularia mirabilis (left in bottom picture) next to another Pennatula. © JNCC/MSS, 2015

As the camera sledge descended for our first tow, we were happy to see a large number of Pennatula sea pens spread across the seafloor, interspersed with a few Virgularia. All our video transects so far have shown evidence of sea pens, and at some stations we have also found high numbers of burrows with the occasional Norway lobster sticking its head out. It is likely that burrows are found in the areas with a higher proportion of mud rather than sand, but we will have to wait for the results of the particle size analysis of the sediment samples to confirm.

We’d better get back to work!

By Megan and Yessica

Monday 26 October 2015

Of (Sea) Mice and Mud

Greetings all from the deck of the Marine Research Vessel (MRV) Scotia, where we are currently surveying in the East of Gannet and Montrose Field (EGM) and Norwegian Boundary Sediment Plain (NSP) Nature Conservation Marine Protected Areas (NCMPAs) with our Marine Scotland Science colleagues.

Sunrise on the MRV Scotia © JNCC, 2015.
This first week has gone by quite quickly and has been spent adapting to ship life, where we work in 12 hour shifts to ensure the ship is able to collect scientific data around the clock. As we have spent a good deal of time this year planning this survey, I have really enjoyed this week and the opportunity to get out into the field to test the preparation work completed back in the office!

We have been very lucky with weather so far on this trip, with only 8 hours of ‘downtime’ experienced so far. This, in combination with our hard working crew and scientists, has allowed us to successfully complete almost 200 stations, using the large Hamon grab (pictured below). We hope to complete another 80 or so large Hamon grab stations and 60 camera sledge transects to help our colleagues monitor these sites, providing the good weather continues.

Morning breaks over the Hamon Grab (left) with sieves at the ready (right). © JNCC, 2015.

If you are new to our survey blog you will find earlier posts which detail what the Hamon grab and camera sledge are and how we deploy and operate these.

We have encountered mostly fine-grained, muddy material in our samples, which have contained a plethora of seabed dwelling animals including marine worms, brittlestars, sea potatoes (Echinocardium cordatum), sea pens (Pennatulacea sp.), a sea mouse (Aphrodita aculeata) and some crustaceans. Once aboard, the Hamon grab samples are sieved to remove material smaller than 1mm, and preserved for further analysis back in the laboratory.

 Just a few preserved seabed samples! © JNCC, 2015.

Unfortunately, we have had to dispose of three samples to date and redeploy the grab a second time as the hagfish present in these three samples would not have allowed us to ‘process’ the remainder of the sample. The threat posed by the all-consuming slime of the sampled hagfish is generally sufficiently convincing for marine scientists to redeploy sampling equipment in the hope of obtaining a more accommodating sample!

We have also managed to find specimens of Arctica islandica (also known as the ocean quahog), which is the protected feature common to both sites we will visit on this survey, in our samples. More about that later; now it is time to get back to those sieves... 

By Joey O'Connor 

Tuesday 20 October 2015

JNCC are back at Sea!

Teams from JNCC and Marine Scotland Science are aboard the RV Scotia, in the seas to the east of Scotland, embarking on a cruise to conduct the first monitoring surveys within two offshore Nature Conservation Marine Protected Areas (NCMPAs). Our enthusiastic scientists will spend two weeks collecting seabed samples and photographic data from East of Gannet and Montrose Fields NCMPA and Norwegian Boundary Sediment Plain NCMPA.  These sites have been designated for two features; ocean quahog aggregations (including sands and gravels as their supporting habitat), and offshore deep sea muds.

East of Gannet and Montrose Fields NCMPA and Norwegian Boundary Sediment Plain NCMPA location

The ocean quahog (Arctica islandica) is a large and extremely long-lived species of clam which is typically found beneath the surface of sandy sediments. Ocean quahog are an important food source for several species of fish, including cod, and can live buried deep in the sand for long periods of time without food or oxygen to escape predators. Arctica islandica hit the headlines in recent years for being the world’s oldest animal ever recorded. An individual was collected from the seabed off the coast of Iceland in 2006 that was eventually aged by scientists as 507 years old (link to article). The scientists that collected the clam named it ‘Ming’, after the Chinese Ming dynasty that ruled over China when the animal was born. This means that Ming was four years old when Leonardo da Vinci painted the Mona Lisa and born only 7 years after Columbus first sailed to the Americas!

Arctica islandica and Leonardo da Vinci's Mona Lisa © Creative Commons

Offshore deep sea muds are relatively stable environments which typically support communities of burrowing megafaunal species, such as the commercially important Norway lobster (Nephrops norvegicus), and populations of fragile sea pens.

Large amounts of data are needed to accurately sample the sediment communities at these sites. Weather permitting, the team hope to collect at least 270 seabed samples across the two sites for ocean quahog, with extra camera work where deep sea muds are found. This data will form the first point in a monitoring time-series, which will allow JNCC to monitor the rate and direction of long-term change in ocean quahog aggregations and offshore deep sea mud communities.