Sonar, So Good! - Blog #3

Since we last wrote, the team has been hard at work continuing to collect multibeam data at Offshore Overfalls MCZ.

JNCC and Cefas scientific crew monitoring the multibeam data acquisition. 

In addition to the protected seabed habitats at Offshore Overfalls MCZ, the site is also designated to protect the unique underwater landscape believed to have been created over 200,000 years ago. This was around the same time that the first humans (Homo sapiens) were thought to be alive in Africa.

A deep paleochannel (“paleo” – meaning ancient) runs through Offshore Overfalls MCZ. This channel has the shape of a river bed, which means that when the first humans were alive the English Channel would have been land, allowing people to walk from France to England.

This was all set to change at the end of the last ice age, when the melting glacier produced enough water to flood this river and the surrounding low-lying land to form the English Channel that we know today. This means the paleochannel at Offshore Overfalls MCZ is rather special as it is very similar to features you might see on land, such as those created by the large volumes of water that are produced as glaciers melt in the summer. 

Map showing multibeam data collected at Offshore Overfalls MCZ during the current survey (colour ramp), overlaid on existing lower resolution (singlebeam) data (greyscale). The Offshore Overfalls MCZ boundary is shown in purple. © JNCC/Cefas

Satellite image from Google maps showing channels created by the meltwaters of an Icelandic Glacier. Notice the similar features seen at Offshore Overfalls MCZ such as the tear-drop shaped islands. © JNCC/Cefas

 Another idea about how the paleochannel was formed is that a large lake existed in the area now known as the North Sea. This lake was made up of the water from melting glaciers and burst its bank to the south, in what has been referred to as a “catastrophic flood event”. Could this flood have created the paleochannel?

The higher resolution multibeam data has enabled us to see other seabed features. These include large “underwater dunes”, which have been created by strong currents that force the sediment to form these interesting features. The largest found so far measuring over a kilometre in length. It’s not clear whether these particular underwater dunes would have been created by a catastrophic flood event or by more recent tidal currents.

Underwater dunes seen at Offshore Overfalls MCZ © JNCC/Cefas

Multibeam alone won’t reveal all the secrets of these features, but later in the survey we will be collecting sediment using a grab sampler based on what we have found with the multibeam.

For further updates before and during the survey - watch this space; follow JNCC, Cefas and the survey hashtag #CEND0119 on Twitter, or join us on Facebook.

Arriving at Offshore Overfalls - Blog #2

And we’re off! The JNCC and Cefas crew have joined the RV Cefas Endeavour and set sail for Offshore Brighton and Offshore Overfalls Marine Conservation Zones (MCZs). After a transit hugging the coastline (which provided the team with plenty of phone signal!) in exceptionally flat calm seas for January, we have arrived at Offshore Overfalls MCZ.

Our first challenge on this survey is to produce a more detailed map of what the seabed looks like at Offshore Overfalls MCZ. To do this we will be using a Multibeam Echo Sounder. Multibeam uses sonar to tell us two things about the seabed; how deep it is, and how hard it is. This is worked out by measuring how long it takes for sound to travel from the ship to the seabed and back again (i.e. the longer it takes, the deeper the water is), and by measuring how strong the returning sound signal is (i.e. harder seabed like rock will reflect more sound energy than softer seabed like mud). Due to the large size of the area within the MCZ that we plan to map, we estimate that this element of the survey will require 7.5 days to complete!

Multibeam from Offshore Overfalls MCZ survey CEND0119 © JNCC/Cefas

Multibeam data collected for the site will be used to update the existing map of seabed habitats at Offshore Overfalls MCZ. This mapping will also help the team on the ship decide where to collect grab samples and drop-frame camera images later in the trip.

For further updates before and during the survey - watch this space; follow JNCC, Cefas and the survey hashtag #CEND0119 on Twitter, or join us on Facebook.

Survey Fun Fact

The multibeam uses sound waves to “see” through even the murkiest of waters, replacing the more traditional lead weight on a rope method to provide us with colourful bathymetric pictures of the seafloor. The term bathymetry comes from the Greek meanings “Deep”(Bathy) and “Measure”(metry) and is the measurement of the depth of water in oceans, seas, lakes, rivers, and canals.

Written by Jess Taylor

New Year, New Survey - Blog #1

As Christmas approaches and the nights draw in, it’s time for another joint survey between JNCC and Cefas! Two days into 2019, staff will be heading out to survey the English Channel on RV Cefas Endeavour for 21 days. The joint team of scientists plan to visit Offshore Overfalls Marine Conservation Zone (MCZ) and Offshore Brighton MCZ. The purpose of these surveys is to build on our monitoring efforts to understand more about these important sites and provide sound management advice.

Location of the sites to be surveyed © JNCC

Offshore Overfalls MCZ has a mixture of sediment types that make up its protected features, including subtidal coarse sediment, subtidal mixed sediment and subtidal sand. The objective at Offshore Overfalls MCZ is for these features to recover to a favourable condition. This site has a depth range of 20-70m and is the smaller of the two MCZ’s being visited on this survey (593km²), making it similar to the size of the New Forest National Park (566km²). The deeper parts of the site are part of the English Channel Outburst Flood Features (Quaternary fluvio-glacial erosion features) formed more than 200,000 years ago!

More information on Offshore Overfalls can be found here.

Thornback ray at Offshore Overfalls MCZ © JNCC

Offshore Brighton MCZ has similar protected features as Offshore Overfalls MCZ, with high energy circalittoral rock and subtidal coarse and mixed sediment as protected features. This site is deeper than Offshore Overfalls ranging from 40-80m and 862km² (roughly ten times the size of Brighton).

This site has been known to have a rich community of polychaetes (worms) and significant numbers of venerid bivalve (Venus clams) and brittle stars. 

More information on Offshore Brighton can be found here.

Common starfish at Offshore Brighton Marine Conservation Zone © JNCC

To gather further information about these sites, the team will use a large variety of sampling equipment. Drop-cameras will be used to collect  high definition video and still images of the seabed and its inhabitants. The survey will also use a Hamon grab to take sediment samples from the seabed for particle size analysis and identification of the animals living within the sediment. Additionally, the team will collect multibeam bathymetry data which will provide a detailed view of the topography of the seabed.

For further updates before and during the survey - watch this space; follow JNCC, Cefas and the survey hashtag #CEND0119 on Twitter, or join us on Facebook.

#1218S final blog: Is it a whale? Is it a rig platform? No, it's land!

After 26 days at sea, the 1218S JNCC and Marine Scotland survey is complete! What a whirlwind four weeks we have had. Scientists on board the MRV Scotia have travelled nearly 3,000 kilometres, collected over 3,800 photographs, recorded over 113 hours of video footage of the seabed and collected and processed 47 grab samples from Faroe Shetland Sponge Belt NCMPA. In doing so we have met all our primary objectives for the survey!

'Ping-Pong' Tree Sponge (Chondrocladia) © JNCC/MSS 2018 

We have documented a huge variety of marine life and habitats across these sites, ranging from the deep-sea sponges of Rosemary Bank Seamount and Faroe Shetland Sponge Belt MPAs, to corals and iceberg ploughmark rocky habitats at Wyville Thomson Ridge SAC. As showcased in our previous blogs, the diversity of the marine life we have seen has been staggering!

Reflecting on this, JNCC monitoring lead for the survey and on-ship data guru Chris McCabe said, "the survey was incredibly exciting, seeing some of the extraordinary species in the deep sea of the Wyville-Thompson Ridge SAC from our camera tows was a fantastic experience".

Beautiful sunrise as the MRV Scotia approaches Aberdeen © JNCC/MSS 2018 

The data we have collected will form a crucial part of a dataset that will be used to monitor how these diverse habitats change over time.

In summary, I am glad to report that thanks to the hard work of our Marine Scotland Science colleagues, the crew and our own scientists, this survey has been a success. Please check back in with us for more survey blogging when we next go to sea, but for now we are excited to begin working up the data collected!

Welcome home! JNCC staff return from a successful survey with Marine Scotland Science © JNCC/MSS 2018

Keep an eye out for the results and progress of the data we have collected on our JNCC Twitter feed with #1218S!

Survey Fun Fact:

Did you know that the aptly-named ‘Ping-Pong’ Tree Sponge (Chondrocladia) is carnivorous? As a member of the Cladorhizidae family of carnivorous demosponges, it survives by catching small crustaceans and small fish with hook-like features covering the ball-like surfaces.

Read more here:

Nature

Deep Sea News

Written by Jessica Taylor

Images Copyright JNCC/MSS 2018

Revisiting Wyville Thomson... Fridge! Blog #6

Hello again from the 1218S survey! We have now returned to Wyville Thomson Ridge SAC to continue our sampling here following a welcome half-landing in sunny Ullapool.

Since we have been here we have found it hard to ignore the influence that the topography of the ridge has on the habitats and communities we have encountered (see Figure 1). Closely related to this, we have found much variation in the temperature of the water at the seabed surrounding Wyville Thomson Ridge. Influenced by colder Arctic water, seabed communities to the north-west of the site experience water temperatures which drop to a chilly -0.7°C (much colder than your average fridge!). A few miles to the south-east the warmer Atlantic water, itself warmed by the Gulf stream, was observed on this survey to reach a balmy 9.4°C at the seabed. Due to this, we have encountered different biological communities in different regions of the MPA.     

Ship’s sonar showing changes in bathymetry (seabed elevation) from 400 meters to 800 meters depth, reflecting the complex topology of Wyville Thomson Ridge SAC

But what of the habitats themselves? We have found that the shallower parts of the site (the ridge top and sides) seem to be dominated by cobbles, boulders and coarse sediment such as gravel and sand. In the deeper water off the ridge, we have found muddier habitats, including some consisting of hard material with a thin covering of silt.  

From our observations, these habitats all have distinct biological communities associated with them. We have found crinoids and even cold-water corals dominating similar habitats (cobble and boulder fields), while sponges have been seen on rocky surfaces throughout the site. Burrows, with as yet unknown inhabitants, were seen in the muddy areas, together with a giant Umbellulla sp. seapen!  

The images below show some examples of the range of habitats we have encountered and the animals which live there.

Potential stony reef with cold-water corals (A) and sponges and crinoids (B), cauliflower coral on gravel (C), and mud with Umbellulla sp. seapen (D)

We have also seen a plethora of mobile species from fish, captured by the underwater camera at the seabed, to marine mammals at the surface. Fish species observed include rays, chimaeras, ling and many, many red fish. During one camera tow, we were especially excited to spot two Arctic skates enjoying a nice seabed walk! This species was also sampled during the first leg of this survey; see if you can spot it on our previous blog.

Arctic skate (A) and Chimaera monstrosa (B)

Please check out @JNCC_UK on Twitter (#1218S) if you would like to see footage of the common dolphins, pilot whales and fin whale we have encountered! 

Survey Fun Fact:

The Chimaera monstrosa or Rabbitfish, is on the IUCN Red List of Threatened Species in the 'Near Threatened' category. Its favourable depth range coincides with high-levels of deep-sea fisheries making it vulnerable to capture, via methods such as trawls and bottom gillnets. A secondary threat is the increasing interest in using liver oil from this species in human dietary supplements. Read more here:

http://www.iucnredlist.org/details/63114/0

Written by Joey O'Connor & Ellen Last

Images copyright JNCC/MSS 2018

Half landing ahoy! A chance to refuel and stretch those sea legs...Blog #5

Since the last blog post the team here have been squirreling away, successfully collecting video data from all of the planned stations at Rosemary Bank Seamount and starting to collect still photos and video from Wyville Thomson Ridge. The weather has delayed us a little on this goal but we are back on track, and steaming ahead aiming to collect as much data as we possibly can before we come in to the half landing at Ullapool.


Fish assemblage from 1200m depth from the North side of Wyville Thomson Ridge in the Faroe-Shetland Channel

The half landing is anticipated by everyone by this point as stocks of chocolate bars and packs of crisps run dangerously low! Additionally, at the half landing we will be bidding farewell to our MSS and JNCC colleagues bar myself and welcoming 6 new JNCC staff to the ship. With the promise of a replenishment of the sweets and biscuits, and a chance to stretch our legs on a little less wobbly a footing, it is safe to say that everyone is looking forward to those 24 hours on dry land.



All systems go on board the MRV Scotia

After the half landing it will be a race against the clock with only 8 days left on the survey to try and gather as much data as possible from the 2 sites we plan to revisit, Wyville Thomson Ridge and Faroe Shetland Sponge Belt. The drop-frame camera system is the technology of choice for finding out all we can about the animals that live in these 2 protected areas and catching a glimpse into the world they inhabit. If the chariot footage is any indication, the staff joining Scotia are in for a real treat, the amazing footage we have already seen shows the fantastic diversity of the marine life and habitats within these 2 sites.

Written by Jess Taylor

Investigating the species of the deep... Blog #4

We have begun our depth stratified trawl transect that will take us from the warm NE Atlantic waters of the Rockall Basin, up and over the Wyville Thomson Ridge SAC and then down into the Arctic-influenced water of the Faroe-Bank Channel. We have begun the transect some 30 miles east of Rosemary Bank Seamount NCMPA and have so far undertaken a line of trawls at depths of approx.1800m, 1600m, and 1200m working north. We have encountered diverse assemblages of fish at each depth, two of which are shown below:

Fish assemblage from 1200m depth

Fish assemblage from 1800m depth

Survey Fun Fact:
There are two families of deep-sea, squaliform, sharks that are able to glow in the dark; Kitefin sharks (Dalatidae) and Lantern sharks (Etmopteridae). This phenomenon is also known as bioluminescence!  

Read more here: 
Glow in the dark sharks

Written By Jim Drewery & Ellen Last