Tuesday 11 November 2014

So long Solan Bank!

Leaving site
Two weeks have passed since we set out from Aberdeen, and following a productive stint of surveying, the sun is setting on our survey of Solan Bank Reef SCI. Having completed our work here, we are steaming for Aberdeen and looking forward to getting back to terra firma.

In total, we have recorded video and still images, and gathered information on environmental parameters at 166 stations. 

We have also used an Acoustic Doppler Current Profiler (ADCP) to collect data on the speed and direction of currents in the water column at three areas of Solan Bank. A map of the stations we’ve collected data from can be seen below.

Stations completed on 1714S survey of Solan
Bank Reef SCI

Despite losing some time to bad weather, improving conditions towards the end of the week and the persistent hard work of the crew and scientists on board have resulted in the collection of a comprehensive dataset. This can now be used to help inform the indicator work described in earlier posts.

It is with thanks to the captain and crew of the MRV Scotia and our Marine Scotland Science colleagues for their efforts on this survey that this account closes.
The scientists on board
Please check back with us soon for more survey action!
Joey and the rest of the intrepid scientists

So lan and Goodbye!

Monday 10 November 2014

Technical talk...

Another weather chart. Red indicates bad weather on the way!

As the weather sets in again, it’s the perfect time to talk about the equipment that we have been using on this survey.

The main piece of equipment that we’ve been using is the drop-frame camera. This is a welded metal frame that supports the large amount of equipment needed to enable us to view and record images of the seabed many meters below.

The Drop-frame hub: 1 - Still camera, 2- Standard video camera
3 - HD video camera, 4 - Scaling lasers.
A high resolution still image camera provides photographs to be used as ‘quadrats’ later on, and alongside sits a High Definition (HD) video camera and a backup standard definition camera. The final piece in the 4-part ‘hub’ is the laser-scaling device: four lasers set to provide a reference box
of exactly 64 x 64 mm (the official smallest size of a cobble!) that enables us to estimate the size of features and fauna on the seafloor, especially as the equipment tends to move up and down in the current and swell.

Four LED lamps situated on corners of the metal frame shine a light on the passing sponges and other fauna, enabling the video camera to record clear images in these otherwise pitch black depths. An underwater flash gun provides a high-powered burst of light to enable the stills camera to produce crisp images such as those you have seen  in earlier blog posts. The whole rig is towed behind and below the Scotia by up to 200 meters of armoured cable attached to the ship’s winch.

Not playing Pong! MSS Engineer Chris guides
the Drop-frame through the water

Wires transmitting data and commands to the camera run through the cable itself, allowing a live stream to be viewed and the camera to be ‘flown’ above the seabed. This is skilfully handled by expert Marine Scotland engineers Chris and Neil, who keep the frame in the ‘sweet spot’ to provide as close a view as possible of the habitats and species present without creating an expensive wreck on the  seabed and reefs below...

On this survey,  the frame also carries extra equipment in the form of a CTD probe and Fluoro-turbidity logger. Sitting on the top of the frame, the CTD continuously records the Conductivity (salinity), Temperature and Depth, whilst the Fluoro-turbidity logger measures how ‘clear’ the water is. This allows us to collect environmental data which may influence the differing habitats and fauna below.

The Drop-frame being deployed, with the CTD visible
on the top of the frame.

All in all, some fairly hefty equipment! Graeme

Friday 7 November 2014

Under the weather

The weather has picked up over the last few days as low pressure Atlantic weather systems form an orderly queue waiting to move our way.

Weather chart showing a low pressure system

Due to safety concerns and difficulties controlling the camera system over the seabed in heavy swell, all video sample collection has stopped. This has set in motion a busy period of data management activity as we start backing-up, checking and “folderizing” all the stills and video data collected to date. To make the most of ship time, we have taken the opportunity to collect additional information on environmental factors such as current speed/direction that may influence the type and distribution of species that we’re seeing on our ‘state-of-the-art’ TV screens. Despite the bad weather, morale remains high and breakfasts remain down.

Echosounder image of seabed showing a sharp rise in reef elevation
We have been lucky that the visibility in the area has generally been fantastic and we’ve been provided with some great images of Solan Bank reef. Preliminary viewing of the camera data suggests that the stations we’ve visited have a mix of stony reef and bedrock reef, interspersed with areas of relatively course sandy sediment. Although the reef elevation varies considerably across the site, some areas occasionally rise dramatically from the surrounding seabed (see image below), much to the alarm of our Marine Scotland colleagues as they are controlling the rather expensive drop frame camera. Nervous times indeed!

We’ve encountered a range of typical reef species over the last few days. One of the main targets of the survey has been the humble sponge, of which several examples were described in our last blog. This time we thought we’d share some of the other beasties filling our screens, including several fish species, octopus, squid, sea anemones and other epifauna some examples we’ve preliminarily identified can be seen below.

A., Conger Eel (Conger conger); B., Ray (Raja sp.); C., Squid (possibly Loligo sp.)
D., Sea Urchin (Echinus sp.) and an Edible Crab (Cancer pagurus); E., Rockling (Gaidropsarus vulgaris); F., Octopus (possible Eledone cirrhosa)

We’re off to batten down the hatches, Bye for now! Declan

Wednesday 5 November 2014

An absorbing post from our intrepid scientists....

After a rocky passage up the east coast of Scotland to Solan Bank, the swell has eased and we have made great progress with the survey. We are working like a well-oiled machine, with the usual dose of day-night shift rivalry over who has completed the most stations in a single 12-hour stint.

Our day kicks off at 00:00 hours when we begin our 12-hour night shift.  Our nocturnal team includes resident bird expert and survey ‘rookie’ Graeme, who is on his first trip, and scientist-cum-musician Megan, whose soon to be released marine concept EP has been inspired by her time at sea. The day shift takes over the reins at midday, with keen knitter Becca who, when not working, can knock up a whole pair of mittens in a few hours and fisheries man Declan, who lends a sense of gravitas to proceedings with his recently acquired  beard.

We spend most of our time in a small shipping container which houses a baffling (to the untrained eye) array of computer monitors, cables, buttons and switches. Here we control the video feed, lights and lasers to our underwater camera system, view the live footage as the camera moves along the seabed, and take notes. We are assisted by the ship’s crew who deploy and recover the gear, and the knowledgeable Marine Scotland Science engineers who help with all things technical. 

Many many monitors...
Occasionally, we leave our makeshift office to get some fresh air and help with gear deployments and recovery on the back deck. We’ve seen a nice sunrise breaking through the clouds over (the slightly alarmingly named) Cape Wrath, and watched flocks of brave migrating Redwings being buffeted in the wind as they pass on their way to the UK for winter. There are always a number of gannets gliding around the vessel, not surprisingly as the name ‘Solan’ is supposed to mean Gannet.

A gannet on the wing

We have recorded sponges at sites where they have been known to occur in the past. We have found cup-shaped ‘flabellate’ sponges that are likely to be the species Axinella infundibuliformis, which look like prawn crackers.

Two flabellate sponges either side of a blue encrusting sponge

Another common species is one we believe to be the ‘papillate’ sponge Polymastia boletiformis, otherwise known as the hedgehog sponge due to its spiky texture.

A yellow papillate sponge alongside an orange encrusting spongey friend
We have also recorded encrusting sponges in a large variety of colours. We’re not sure which species these are as encrusting sponges are generally impossible to identify accurately without a physical sample. We may have spotted the grey ‘elephant hide’ sponge Pachymatisma johnstonia too.

More news and life on the Scotia to arrive shortly...

Monday 3 November 2014

All Aboard!

Hello and welcome to the first blog from the decks of the MRV Scotia from Joey, Declan, Megan, Graeme and Becca.

Intrepid scientists hard at work....
We’re onboard with colleagues from Marine Scotland Science to collect evidence to help in the development of an ‘indicator’ as part of the UK’s obligations under the Marine Strategy Framework Directive (MSFD).  An ‘indicator’ provides information on the ‘state’ or ‘condition’ of biodiversity components, e.g. sub-tidal rock habitats.

The proposed indicator focuses on sponge and other epifauna (e.g. coral and anemone) species and is designed to spot changes in the number and type of species present in response to natural variability and human-induced pressures. Sponges and other epifauna are sensitive to environmental variability such as changes in the amount of sediment in the water column and damage from physical impacts such as fishing gear or oil and gas industry infrastructure. Ocean acidification and climate change are also likely to affect the type and quantity of species present.

The proposed indicator we are testing on this survey has two main parts:
  • Sponge morphological (body shape) diversity: Identifying individual sponge species can be very difficult due to the vast number and variation in sponges that occur in the UK and further afield. As such, spotting changes in the number and type of species present could be very time-consuming and costly. However, recognising different body shapes or ‘morphological diversity’ of sponges (see image below) is much more straightforward and quicker to do. Therefore, this could be used to detect changes in response to variations in the environment. This method has mainly been tested during inshore dive surveys and so one of the key objectives for this offshore survey is to collect data on sponge body-shapes using a drop-down camera, to test whether this approach will work in deeper waters.
  • Species composition and abundance of other epifauna communities: Epifauna is the collective term for animals that live on the surface of a substrate, in this case the sea floor and the rocky outcrops emerging from it. We can measure epifauna species composition and abundance in two ways: either by counting the total number of epifauna species or by measuring the area occupied by epifauna.

The many shapes of sponges (Berman et al 2013)

The location for our study is Solan Bank Site of Community Importance (SCI). Bedrock and stony reef are present at the site, which is fantastic habitat for sponges and other epifaunal species. Solan Bank is located approximately 50km north of Cape Wrath on the Scottish mainland. Extensive areas of bedrock outcrops with cliffs rising up to 10 metres from the surrounding seabed are found across the site. Away from the cliffs, habitat ranges from sands through to highly fissured bedrock reefs.  Hopefully there will be some interesting photos of sponges and other epifaunal species to come in the next blog.

Bye for now! Joey, Declan, Megan, Graeme and Becca.