Friday 7 August 2015

Farewell!

The Jelly Farm Cruise 2015 is sadly now at an end!

The end of the cruise with the team at Sævråsvåg. Pictured: Magnhild Torper, Silvia Hess, Graihagh Hardinge, Andrew Sweetman, Leon Pedersen, Elisabeth Alve. 


Over the course of the week a series of deep-sea samples were collected, which will be analysed at various institutions affiliated with the Jelly Farm Project. 

Thanks to everyone who followed us on this journey. 

See you next year for the next Jelly Farm cruise!


Deploying sediment traps in Masfjorden

Solvik in Sævråsvåg


Today marks the final day of sampling for the Jelly Farm cruise 2015! 

The Masfjorden sediment trap was deployed to 480 m. Like the Lurefjorden trap, a new sample bottle will be automatically switched every 14 days, and then the trap collected after a year on the sea floor. Scavenger traps containing mackerel bait were also deployed, as the yo-yo frame yesterday did not haul up any scavengers. The sample net with attached traps brought up a few hagfish, which were bagged and frozen for isotope analysis. 

Priming the acoustic releaser for the sediment trap.
300 kg chain to weigh down the trap.
Deploying the floats for the Masfjorden sediment trap. Pictured: Graihagh Hardinge and Andrew Sweetman.
Successful deployment! Pictured: Andrew Sweetman.


Last night of the cruise!

'Team Dan Gelbart'. PIctured (left to right): Leon Pedersen, Andrew Sweetman, Silvia Hess, Elisabeth Alve, Magnhild Torper and Graihagh Hardinge. 

The team celebrated their last night of the cruise in the Kjelstraumen vertshus and enjoyed some fine dining (in not-so-fine clothing) near to where Solvik was docked in Sævråsvåg.  

Thursday 6 August 2015

Yo-yo camera work on Masfjorden

Staying the night in the tranquil Sævråsvåg to collect equipment for the Solvik. 
Today a series of transects to photograph the sea floor in Masfjorden took place, using the yo-yo camera in 3 different depth zones. Starting points for the transects were selected randomly for each depth, and photographs were taken in 10 metre intervals (50 photographs for each depth area). 

Lowering the yo-yo camera in Masfjorden.
Jellyfish tentacles caught in the yo-yo camera net upon surfacing. 


Image of sea floor at Masfjorden (480 m depth). Pictured: Stichopus holothurian. 


Image of sea floor at Masfjorden (480 m depth). Pictured: Ctenophore and rat-tail fish (Family: Macrouridae). 


Lowering the yo-yo frame complete with scavenger traps.

Wednesday 5 August 2015

Sediment coring in Masfjorden

The landscape between Lurefjorden and Masfjorden transitioned from open, exposed waters to glassy fjords surrounded by high mountain walls. En route, there were a number of fish farms which represent a common industry for the area, and also an oil refinery plant at Statoil Mongstad (pictured).  
Masfjorden is an area abundant in fish, with no mass aggregations of Periphylla. Shallow water species, however, including Cyanea capillata, were sighted. Masfjorden has a maximum depth of approx.. 480 m, and is composed of a series of basins, which is unlike the gradually sloped trough of Lurefjorden.)
Today marks the first day of sampling in Masfjorden, a fjord with a similar maximum depth to Lurefjorden (approx.. 480 m), but with no mass aggregations of Periphylla jellyfish. As such, a comparison can be made between the fjords to determine the effects of the jellies on the two systems.

Sediment coring to determine foraminifera composition was performed by Silvia Hess, Elisabeth Alve and Magnhild Torper from the University of Oslo. The cores will be dated to determine the rate of sediment deposition in the area, which as of yet has not been established. 

Magnhild Torper, Elisabeth Alve and Silvia Hess from the University of Oslo.
Elisabeth Alve extracting a Masfjorden sample from the Gemini corer.
Making initial assessments of the samples.
Magnhild Torper with 1 cm sliced sediment samples. These will be frozen for analysis post-cruise.

Imaging the sea floor

Lurefjorden was photographed in two sites in Lurefjorden; a deep site (440 m), and a shallow site (200 m). Both were along linear transects, with image intervals of 10 m.

The deep site recorded a number of jelly falls, which will be analysed in greater detail post-cruise. The shallow site recorded an array of deep-sea fauna but no jelly falls; despite a number of Periphylla being caught in the net when the yo-yo frame was surfaced. 

Yo-yo camera frame with two Periphylla caught in the net. Depth approx. 200 m. 
The high-resolution images captured by the Nikon camera mounted in an Ocean Imaging Systems housing unit can provide a habitat map of the sea floor, as well as providing an indication of the extent of jelly detritus transferred to the benthos. 
Yo-yo camera image of a Periphylla jellyfish being consumed by an anemone. Depth 440 m. 
Yo-yo camera image, depth approx. 200 m. Laser dots allow for size referencing.
Yo-yo camera image, depth approx. 200 m. 

Tuesday 4 August 2015

Deployment of sediment trap in Lurefjorden

The weather was not particularly inviting to start with
Today the McLane Time Series Sediment Trap was deployed, to a depth of 450 m. This trap, with a honeycombed structure to slow the settling of material, will allow any jellyfish particulate matter to be quantified using isotope signature analysis, and also determine overall particle flux. The trap consists of a funnel to catch the particulates, as well as a series of sample bottles to contain the material, which will be changed every 14 days. After a year, the attached KumQuat acoustic release transducer will be triggered which releases the weighted trap, which then floats to the surface to be collected.  

The chain link weight to keep the trap on the sea floor for a year. Attached to the weight is the battery-powered acoustic release transducer, which when triggered will separate from the weight and float to the surface. Pictured: Andrew Sweetman.
McLane Time Series Sediment Trap, with sample bottles at the bottom. A programmed computer on-board switches the sample bottle every 14 days. 

Lowering the sediment trap into the water. The top is honeycombed in order to slow the deposition of sediment. 
Lowering the floats into the water, which are attached to the sediment trap. Pictured: Andrew Sweetman, Graihagh Hardinge and Leon Pedersen. 

Monday 3 August 2015

Sampling deep-sea scavengers in Lurefjorden

A calm morning for sampling deep sea fauna in Lurefjorden.
Today on-board the MS Solvik, a further 100 images of the sea floor along a linear transect were taken, with a high-resolution photograph produced every 10 metres. 

Traps were also baited in order to collect some deep-sea scavengers. These traps were constructed from 1.5 litre plastic bottles, and lowered to a depth of 450 m. After a duration of 45 minutes, a haul of hagfish (Class: Myxini) were brought to the surface, and bagged for isotope analysis post-cruise. 


Scavenger traps: Fizzy drink bottles cut to create an inescapable funnel, and baited with mackerel that has been left to 'stew' for a while...
Sample net with scavenger bait around the outside.
Hagfish bagged prior to on-board freezing. Post-cruise, these will be analysed to determine the isotopic signature. 

Sunday 2 August 2015

Yo-yo camera work in Lurefjorden

Today the final adjustments of the yo-yo camera frame were made, including installing the camera and flash, which are triggered automatically when the weight reaches the bottom of the fjord. High resolution images of the deep sea can be gathered this way, using the winch aboard the MS Solvik to systematically take photos along a randomly selected linear transect. Using the yo-yo camera system, any Periphylla that have perished and sunk to the sea floor - also referred to as jelly falls - can be tracked, giving an indication of the extent of jelly falls within the fjord as a whole. 

Andrew Sweetman making final adjustments to the yo-yo frame. 

Yo-yo frame aboard MS Solvik, which is mounted with a Nikon camera, and Ocean Imaging Systems protective housing, which can protect the camera up to 6000 m deep. 

Lowering the yo-yo frame into the water.

Mapping the yo-yo frame being raised and lowered along the 0.5 km transect. Here the frame was lowered 50 times every 10 metres. 
The netting from the yo-yo frame also doubles as a sample net for collecting Periphylla. Pictured: Graihagh Hardinge and Andrew Sweetman

Saturday 1 August 2015

Sediment coring in Lurefjorden

Sediment coring took place in Lurefjorden to determine how a jelly-dominated ecosystem can influence the foraminifera composition within the fjord. Comparisons will be drawn between Lurefjorden, where the jellies are, and Masfjorden, a fjord with no Periphylla. Cores were taken today from 3 different sites in Lurefjorden, at depths of 444 m, 350 m and 200 m. 

Selecting sample locations, using equipment on-board the MS Solvik
Elisabeth Alve hosing down the sediment corer.
Magnhild Torper and Silvia Hess with a sample taken from 444 m deep.  
Selecting 1 cm sections of the core, to be analysed post-cruise for composition changes with depth. From this, it can be possible to determine the sediment accumulation rate of the fjord, which has not previously been explored. Pictured: Magnhild Torper, Silvia Hess and Elisabeth Alve. 

Jellies found!


At a depth of approx. 400 m, a vertical daylight tow brought up 10 large Periphylla jellies, and 1 small medusa. From here, various morphological measurements were noted down, and tissue removed for laboratory analysis post-cruise. 

Jellies being hauled to the surface using the net constructed by Leon Pedersen. 
Periphylla are covered in red pigment, porphyrin, which degrades when exposed to light, killing the jellies. 
Periphylla can reach considerable sizes, and weigh up to a kilo.




Aliens of the deep: Periphylla jellyfish within Norwegian fjords

Periphylla periphylla jellyfish. Image credit: Christian Skauge.


Periphylla periphylla are mesopelagic jellyfish typically found up to depths of 4000 m in the open ocean. However, in various Norwegian fjords, these jellies are found at much shallower depths due to enhanced light attenuation from the dark, nutrient-rich waters coming in from the Norwegian Trench. In Lurefjorden in particular, Periphylla have reached vast abundances, due to the shallow sill of the fjord (approx. 20 m), resulting in the jellies becoming trapped. Here, the jellies rule, and Periphylla are the top predator, as visual predators such as fish cannot hunt in the abnormally dark waters. 

Periphylla jellyfish are well-recognised in the Lurefjorden area, due to their abnormally high abundances. Pictured: Leon Pedersen's speedboat, which is named after the deep-sea jellies. Leon has captained a number of  cruises that have focused on Periphylla and jelly falls. 

Prepping the cruise equipment

The final preparations for the cruise took place at Leon Pedersen’s workshop in Florvaag. Here the yo-yo camera frame, designed by Leon and Andrew Sweetman, is being assembled and finalised, ready to house the camera system which can operate up to 6000 m deep. The camera system is automatically triggered when the weight is lowered to the sea floor, producing a series of high-resolution images along a transect . See Sweetman & Chapman (2011) for full description of the yo-yo system. 
Yo-yo camera frame, constructed by Leon Pedersen (pictured) and Andrew Sweetman.
The floats, which will attach to the sediment traps in order to gauge the flux of jellyfish particulate matter, have a depth rating of 6700 m, which should be more than sufficient for the depths of Lurefjorden (max. 444 m) and Masfjorden (max. approx. 500 m)! The floats consist of a thick glass sphere encased in a hard plastic shell, and are kept separate in case of implosion.

Andrew Sweetman prepping the sediment trap floats and flag. 

Floats and mooring to keep the glass spheres isolated. Floats produced by Woods Hole Oceanographic Institute. 
For the sampling of Periphylla periphylla jellyfish within Lurefjorden, two nets were assembled. Periphylla will be sampled in order to gather morphological measurements on board the MS Solvik, and frozen for future jelly fall studies. Small quantities of tissue will be dissected for analysis at the Natural History Museum London, and the National Oceanography Centre Southampton. 

Large sample net, constructed by Leon Pedersen, for sampling Periphylla jellyfish. 

Graihagh Hardinge stitching together a small sample net for scooping out Periphylla jellyfish.