The Obanographers

Join us on our adventure as we head to Oban, Scotland to investigate its marine environment!

[obanographers]

Take a look at our Summary video of our time here in Oban, Scotland! :D

[obanographers]

Wildlife Sightings

Aboard RV Calanus many auks were seen with guillemots and razorbills seen throughout the day, with the penguin like birds seen mostly around nesting sites of steep cliffs. After spending the day with our eyes peeled for seals and only a brief encounter we were overjoyed to spot around half a dozen sunning their fury self’s on rocks as we looked towards the isle of Mull[JC1] .

Aboard Seol Mara the wildlife seen was the most stunning of the trip, we had 2 sightings of the white-tailed sea eagles, one stationary and one in flight. The numerous seals were much closer aboard this vessel compared to RV Calanus, their inquisitive nature bringing them close to the boat.  Other notable things were; Cormorants and Shags diving for prey, Goosanders on Loch Etive and the catching of a few dozen or so crabs of varying species from both the Jettys visited on tide practicals, abundance of crabs shown by them being caught by bacon tied on string!!!

[obanographers]

Something Fishy

        We departed SAMS around 09:45 took the half hours journey round the bendy lanes to Kames fish farm along loch Melfort.

         Situated amongst stunning scenery the fish farm wasn’t too extensive consisting of about 7 large cages for 3 species, Halibut, Salmon and Trout. As well as a hatchery within their building – a very old building at that.

         Firstly we were shown around the Rainbow Trout hatchery, it contained 123,000 fish it was staggering with very rustic container pools of corrugated metal and a water inflow/outflow system through the middle of the building!  We had arrived on vaccination day, the trout are removed from the nursery pools and placed in a bucket of anaesthetic before being placed into a vaccination machine individually. This machine injects 0.1ml of vaccine into the underside of each trout. This is quite a stressful process (it’s equivalent to half a can of coke being injected into our bodies!), but it is essential to prevent the spread of disease, ensuring healthy fish.

·         Next we were taken to the fish farm on the loch, here there were 7 cages for aquaculture, we had timed the trip awkwardly with our visit falling within the 2 month period the fishery has to stop stocking salmonids for SEPA regulation. We were however treated to an informative discussion on the equipment here, its impact and other contextual details. Halibut were present although it was the last Halibut to be produced here with the bycatch of N. Atlantic Cod being Halibut it has in recent times driven the price down to £10 per kilo with the farm producing it at £11.75 this is now completely uneconomical. So really we were very lucky to witness this inquisitive flatfish.

After Final questions and a farewell we headed back to the SAMS centre

[decaffeinatedmoonarcade-blog]

A Day in the Lab: Chemical Analysis

Today we set about analysing the samples collected from the R.V. Calanus on Monday, to do this we split into three groups of two.

Chlorophyll

Measuring the chlorophyll gives an indication of the phytoplankton concentration at depth. It would be expected to decline with depth with the decreasing light. However certain conditions can lead to a deep chlorophyll maximum developing, a chlorophyll maximum indicates the euphotic zone.

Procedure:

1.       Used exact samples of Chlorophyll to create regression graph and equation

2.       Pour the acetone from the Chlorophyll vials taken on Calanus into the test tube

3.       Place test tube into the fluorometer and read the fluorescence value on the screen

4.       After repeating each reading 5 times and entering data into spreadsheet, pour the liquid into the waste bucket

5.       Use acetone to rinse the test tube and pour into waste bucket

6.       Repeat steps 2-5 for each of the 50 Chlorophyll vials

7.       Use the slope equation in order to calculate the Chlorophyll values

Dissolved Oxygen

For the oxygen measurements, we titrated the samples with thiosulphate to allow us to calculate the dissolved oxygen concentrations for each depth. If there is stratification (no mixing) we would expect higher oxygen concentrations near the surface, decreasing with depth.

Procedure:

1.       Add 1ml sulphuric acid to each oxygen sample bottle and shake

2.       Transfer 50ml of this acidified solution to a conical flask

3.       Titrate the sample with thiosulphate until the sample is a faint yellow colour

4.       Add starch dye to darken sample colour

5.       Titrate again until sample is colourless

6.       Make a note of how much thiosulphate is used to titrate each sample to give the titration value

7.       Titrate standards and blanks for accuracy

Inorganic Phosphate

Phytoplankton uptake phosphate in its inorganic form, the measuring of its quantities in our collected samples can help to relay phytoplankton distribution throughout the water column.

Procedure

1.       Label flasks from sample 1-30 and include a ‘blank’.

2.       Filter samples and then measure 50ml into corresponding flask.

3.       5 standards made for calibration (6.45ᶮmol L-1,3.22ᶮmol L-1,1.29ᶮmol L-1,0.52ᶮmol L-1,0.26ᶮmol L-1).

4.       Use pipette to add 5ml of mixed reagent to each flask.

5.       Place in the helios spectrometer and record data produced.

6.       Plot a calibration curve of phosphate with standard concentrations. Using the equation of this line calculate your actual phosphate amounts.

Today was a good day for science.

See you next with more boating activities…. xxx

[obanographers]

Crabby Tides

Tide measurements with a side of crabsailing 

Today we measured the tides around Loch Etive at two stations, one at the SAMS jetty near the mouth of Loch Etive and one on the pier at Taynuilt about one third of the total distance along the Loch. Our aim was to measure half of a semi-diurnal cycle (around 6 hours), this data will help us investigate the propagation of the tide along Loch Etive.

At both stations we measured temperature and salinity using a handheld CTD and depth was recorded using a tide gauge with a sea bed reference. In addition to these on the jetty the strength and direction of the current was calculated using a current meter. The strength was calculated using a machine which counted the amount of times the current meter turned in 60 seconds. All of these variables were measured every 10 minutes, so we were kept very busy!

[obanographers]

The Seol Mara Voyage

Having previously decided on our stations in the middle of the loch we boarded the Seol Mara at approximately 09:00 with the conductivity-temperature-depth instrument on board being used and bringing our own castaway CTD’s for calibration. Departed after safety briefing. We stopped before Falls of Lora to deploy ctds for calibration. With strong tidal influence the CTD’s were lowered and ended up horizontal!!! Forgetting this disappointment and with the incoming tide behind us went to middle section of Loch Etive where we were profiling. After passing 2 stunning Sea Eagles perched on nearby rocks as well as passing a quiet Bonawe quarry we proceeded to deploy the Seol Mara’s CTD at our 9 Chosen sites, being so efficient and speedy we had time to include 5 station stops across the loch for a cross profile of the loch. Dodging further sea eagles and surfacing seals we returned around 16:30. 

[obanographers]

The Bottle Diaries: The RV Calanus and Me

author’s side note*: yes... we have done our blog post in the perspective of a sample bottle... so have fun enjoying this...

*Map of our CTD stations

Cloudy with a little drizzle       

 “Do you hear that?” I said to my friend, Viala, tucked snuggly in the box next to me, “I think we are going on the Calanus!”

“The Calanus? You mean the big old ship, where we get a taste of the ocean?”

It is really something that I look forward to ever since I joined the bottle crew. I have heard many wonderful stories of how they got to go out to sea and see the amazing view the boat has. Now I am ready as ever to go on this journey and hopefully be of some use.

As, we are transported onto the boat, I hear the rush of footsteps as researchers and crew stumble around to get the ship ready to fly. I was so excited, it was a new environment and I’m not ready to let anyone down just yet! As we are all fitted closely and safely, the ship starts to move and I know that this is why I came. I took a little sneak peak outside and what I see astounded me. Six students along the railings of the boat just enjoying the view and the calamity of the surrounding makes me feel very peaceful. I mean, from knowing what comes afterwards, this might just be the calm before the storm. It definitely was very quiet, just the sound of the Calanus’s song of eagerness to finally go soaring.

Then, as the ship stopped abruptly and I saw the 7 students running around the whole deck again.

*yea... here comes the action...

When the ship stopped at our first station, we all got ready to learn how everything works. First, we went up to the Bridge to find out what the CTD profile was when we lower the rosette down to near the sea floor. On the Bridge there were three big screens, one showing our boat location and track, another showing an echo sound location of what is below the boat, and a screen for the CTD data and information. When the rosette is lowered down to the bottom, we could get a clear picture of what the profiles for temperature, conductivity, chlorophyll, and oxygen would look like. This is where Mary, our principal scientists, decides at which depth we would collect water samples at, in order to make sure that Neskin bottles are shut at a suitable depth in order to get water samples at depth where there are significant changes to the water column.

*there were actually serious business going on here, definitely not as silly as this..... okay.... well we can still have fun even while working

Then, I saw a rosette of huge bottles called the Neskin brothers are slowly lowered below into the ocean by two of the ships crew. I do wish that I could be part of the Neskin brothers! They all seem so mighty and strong! I heard bangs as the Neskins are raised back out of the water.

“I heard from Captain Norman, that they are going deep into the unknown to collect samples for them young things,” O1 had said. 

One by one, we were picked out of our carriage. O1 goes out first to join the students. They released water into the O1 bottles and make sure that he is clean and filled him up to the top. How refreshing! A girl called Amy had made sure O1 had barely any bubbled left in him and sealed him up quite nicely.

Soon, it was P1 and me to go join them out with the Neskin brothers. The girl called Zoe had made sure that we were filled up proper and nice. It is really cold when she poured the water into us. I had also noticed that someone named Josh lowered a black and white coloured dish into the water, and pulled it back up, I really do wonder what that is all about?

*want to know what is lowered into the water? Go look at our video of the day as well!

Sooner that we thought, we were transported by someone named Josh into a brightly lit warm room. There we were carefully placed down. P1 is quickly put into a dark cool room under the table. Apparently, this is the place where they take samples of the water they put in us. I saw someone named Alex putting a few drops of chemicals into the O1’s water. It is very magical how suddenly the water had turned orange!

Then, he started shaking O1 around! I bet O1 probably has sea sick after this when shook around like that. Then I saw a girl named Sammi taking samples of the water in my bottle and into the beaker. Somehow, she is saving the little piece of paper and putting it into the Viala. Apparently there should be something important stored on those papers that Viala had kept safe.

This happened a few times and everyone is so busy running around the ship. There was barely enough time for lunch! Everyone was kept on pace and on track trying to keep the ship running smoothly. Soon, the day has come to an end. As the sun sets, I peeked through the lid seeing as everyone is enjoying the sun shining on the water. This is definitely an experience we would all remember…

*Mary enjoying the view of the ocean as we head back to shore after a long day’s work

-Chlorophyll 1 signing out

19.09.16

Please Check out our Calunlus Video!

[obanographers]

Loching at deep water renewal Assessment of the processes involved in deep water renewal and the atmospheric conditions that favour these events. Compare to other relevant coastal waters with a shallow sill, e.g. the Baltic Sea.

Edwards, A, Edelsten,D.J (1977) Deep Water Renewal of Loch Etive: A Three Basin Scottish Fjord ; Estuarine and coastal marine science, vol 5 ,pp 575-595. Loch Etive is a 3 basin fjord., connected to the sea by sill (300m wide, 4km long and 10-metre-deep) with this sill effecting many properties of the loch. Run off 1400km2 catchment area, Hydroelectric schemes control some but not all of runoff into loch system. The amount of runoff directly affects the salinity and density of the loch water which ultimately determine characteristics of deep water renewal. With a correlation shown concerning increased land run off and decreasing loch salinity. Salinity In April salinity highest, causing 3 haloclines to form though these disappear for end half of May. Salinity reduced in times of rainfall, affecting water stratification and deep water renewal, shallow basin of loch Etive having higher salinity at shallower depths compared to deep basin, due to sill preventing mixing of water. Surprisingly Temperature has less impact on density fluctuations and water renewal. Profile Water stagnates in the deeper basin with a second pycnocline between 30-100 metres, also within this depth lies the thermocline, around 50 metres. Beneath these boundaries physical properties alter very little. Complete Deep water renewal estimated to take 16 months with 3 main stages; Overflows of sill water, stagnation of bottom water and the stagnation of ‘new’ bottom water. Compared to renewal prevalent in times of reduced runoff concerning Loch Etive Deep water renewal occurs at times of maximum run off in the Howe sound (Vancouver), augmented by a down-fjord wind. Dickson (1973) Schinke, H., and W. Matthäus, 1998: On the causes of major Baltic inflows--an analysis of long time series. Continental Shelf Research, 18, 67–97. Journal is 4 year assessment of variables linked to high salinity water entering the Baltic sea. Distinct 2 phases to inflow events Phase 1 : Preferable conditions of high pressure and easterly winds with resulting reduced run off and precipitation. Phase 2 : Zonal winds over N. Atlantic with persistent directions lead to rise in sea level and salinity. Run off Reduced run off reduces Baltic sea level which in turn intensifies deep water current,aiding deep water renewal. Hydrological cycle in Baltic region has great influence on occurrence of inflow events, a reduction in such inflows was attributed to the increased precipitation and heightened river run off, creating higher sea levels affecting renewal rates. Relaying how atmospheric conditions affect deep water renewal.

[obanographers]

Is Fish Farming Suitable in Loch Etive?

Loch Etive, in Argyll and Bute Scotland, is a 30km sea loch with a maximum depth of 150m. Non-commercial fishing is common within the loch and there are several small scale fish farms which are currently in operation.

Fancy Words:

Sill: Sea flow barrier that restricts water flowing into an area.

Hypoxia: Deficiency of oxygen reaching the tissue.

BOD: Biochemical Oxygen Demand.

Are the physical, oceanographic features suitable for fish farming?

The short answer is yes. The loch system does provide a suitable area for fish breeding. When water is renewed, plenty of nutrients and oxygen are inputted into the loch for the local marine ecosystem. The waters in the loch are calm with little run off, this suggests that nutrients brought into the loch are likely to stay there. In addition, if run off from the loch is low, water renewal is more likely to occur (A Edwards et al., 1977).

In addition, there are fast currents described at the sill of the loch as well as by the coastline which would suggest that favourable fish farm locations would be away from these more turbulent conditions.

Are there any possible issues?

The main issue arises from a process known as hypoxia. Loch Etive has an incredibly long renewal time. This suggests that there is a possibility for the water within the loch to reach hypoxic conditions. (PA Gillibrand et al., 2007) states that lochs with the longest renewal times are at the greatest risks from reaching hypoxic conditions.

Why does this cause Hypoxia?

During water renewal, sea water contains fresh, oxygenated water which replaces the old, stagnant water in the loch. If the water is not renewed at a fast enough rate, the conditions become hypoxic for the marine organisms as oxygen is no longer readily available for respiration by the organisms.

Issues with Hypoxia theory

It is said that this model is an over-prediction. (PA Gillibrand et al., 1997) explains how lochs are just considered as rectangles which increases the uncertainty within the model. The over simplification of the model is described as causing an over prediction in hypoxic conditions. Large scale Salmon farming in some predicted hypoxic lochs occurs without hypoxic conditions ever being reached. In addition, it is stated that only 2 of the lochs out of 135 in the study may possibly reach hypoxic conditions, Loch Etive not being one of them (See Figure 7, Loch Etive is not in the highest percentage).

 Final Thoughts

There is no concrete evidence which suggests that conditions at Loch Etive have reached hypoxic conditions. The only issues that are currently present with fish farms in the loch are pollution caused by fish feed and faeces. Some of the fish farms that have been recently checked for pollution levels have been reported as dealing with the pollution in an unsatisfactory manner. As long as fish farming is approached in a sustainable way that does not pollute the water, the oceanographic features of Loch Etive should favour small scale, sustainable fish farming.

 References:

 1 A Edwards, DJ Edelsten, 1977, Deep water renewal of Loch Etive: a three basin Scottish fjord - Estuarine and Coastal Marine Science

2 PA Gillibrand, WR Turrell, 1997, The use of simple models in the regulation of the impact of fish farms on water quality in Scottish Aquaculture Elsevier

3 PA Gillibrand, CJ Cromey, KD Black, ME Inall 2007, Identifying the Risk of Deoxygenation in Scottish Sea Lochs with Isolated Deep Water Final report Scottish Association for Marine Science, Oban

4 Friends of Loch Etive, 2014, Dawnfresh’s Record on Loch Etive and Loch Awe, http://www.lochetive.org/docs/DawnfreshRecord.pdf (Last Accessed 17/09/16).

[obanographers]

Bloomin' Plankton

Coastal Plankton Blooms

Types of bloom which occur in Scottish waters

What Are Plankton

Marine plankton are the basis of what most life in the oceans is dependent upon, in fact globally they are responsible for 50% of annual primary production [2]. Plankton describes drifting, microscopic organisms which use photosynthesis and thus are found in well lit (illuminated), fresh or marine, waters [3]. Similarly to plants plankton use chlorophyll to capture sunlight, using photosynthesis to turn this into chemical energy [4]. Plankton consume carbon dioxide and release oxygen, all species photosynthesize but some consume other organisms for additional energy [4].  Plankton have a global significance in producing oxygen, for example diatoms (one sub-group of plankton) produce one fifth of the worlds oxygen [4]. Plankton are not all good however they can also produce biotoxins which can kill marine animals. This is becoming a concern in Scottish waters where aquaculture is  a major part of the economy with salmon being the biggest export from Scotland behind Whiskey. This has prompted research into the types of plankton bloom in Scottish waters and what causes these blooms.

Plankton Blooms

Plankton blooms occur when rapid growth in the numbers of one dominant species exceeds loss in numbers, this generally last a week or so [1]. Such rapid growth is possible as plankton reproduce by dividing in two [3]. These blooms occur in the euphotic zone where there is sufficient light and nutrients to allow rapid growth [1], this is below the surface as nutrients from the deep ocean rarely reach high concentrations at the surface. Blooms are associated with a discolouration of the sea surface which can be red, brown, green and yellow caused by the high concentration of this microscopic plankton and can be seen from space [1]. These blooms can occur in the oceans and lakes and freshwater rivers.  

In Scottish coastal waters plankton blooms are common, the species of plankton include Chaetoceros, Skeletonema and Pseudo-nitzschia, the latter can cause toxins to build up in shell fish, which can reach the human food chain so shell fish are routinely monitored for toxins. Karenia Mikimoto is also common and during blooms can cause wild and farmed fish mortalities. These blooms can occur anywhere along the Scottish coast and increasing effort is being put into researching predictors of harmful blooms in an attempt to limit effects on fish farms.

Environmental conditions needed to produce these blooms

The environmental conditions leading to a plankton bloom are important in predicting plankton blooms. The main environmental conditions needed for a plankton bloom are; availability of nutrients; surface irradiance levels; and a small number of predators [1].

Nutrients

The availability of nutrients has been linked to increases in rainfall, increasing runoff which can cause spikes in nutrients in coastal waters, evidence of this has been found in Japan and Norway, but not yet in Scotland [4]. Eutrophication has been heavily cited as a cause of an increase in plankton blooms in recent years, this is caused by an increase in fertiliser use on farmland and nutrient loading into aquaculture farms [3]. This could cause problems of increasing the frequency of harmful blooms in Scotland.  

Irradiance

Irradiance is important due to planktons reliance on photosynthesis for energy, blooms would not be possible without sufficient light. The effect of irradiance can be seen in the seasonal variability in plankton with a greater abundance in spring compared to winter [3]. It is also evident in the greater abundance of plankton in the euphotic zone, any deeper and growth is limited by the lack of light [1]. However it has been found to have no significant impact by some, this may indicate that abundance is driven by local factors and a variety of them [5].  

Predators

The number of predators relates to the fact that to have a bloom the population must be increasing so there must be fewer predators than normal. This is evident in findings that if blooms occur earlier in spring they are generally greater in size and this is also when less predators are present [2].  

Other

Mixing is also an important factor as it must not be too turbulent as to push plankton down below the euphotic zone [3]. But too little mixing and the thermocline will trap nutrients below the euphotic zone, which occurs in summer when blooms are less common [3]. Temperature is also found to have some influence. So in conclusion observed changes in plankton abundance implies that illumination, temperature and mixing have an effect on their growth, so when these factors are perfect rapid growth can occur.

References

[1] Purdie, D.A. 1996. Marine Plankton blooms, Chapter 6 In: Oceanography An Illustrated Guide, C.P.Summerhayes, S.A.Thorpe.  

[2] Bresnan, E., Cook, K.B., Hughes, S.L., Hay, S.J., Smith, K., Walsham, P. and Webster, L., 2015. Seasonality of the plankton community at an east and west coast monitoring site in Scottish waters. Journal of Sea Research, 105, pp.16-29.

[3] Tett, P. and Edwards, V., 2002. Review of harmful algal blooms in Scottish coastal waters. Report to SEPA, Edinburgh, 120.

[4] Lindsey, R., Scott, M., 2010, What are Phytoplankton? NASA, Available at: http://earthobservatory.nasa.gov/Features/Phytoplankton/

[5] Davidson, K., Miller, P., Wilding, T.A., Shutler, J., Bresnan, E., Kennington, K. and Swan, S., 2009. A large and prolonged bloom of Karenia mikimotoi in Scottish waters in 2006. Harmful algae, 8(2), pp.349-361.

[obanographers]

Our little blue blob of a planet has more pairs of feet walking its surface than ever before, and they all need the right balance of energy and nutrients to keep plodding on!

We already know that many people aren’t getting the food they need to live well, and we’re told the world is only going to get busier. The issue on everyone’s minds, from those going to bed hungry, all the way up to the decision-makers in the United Nations, is Food Security i.e. how do we get enough food to people, when they need it, for as long as they need it!?

I was surprised to find out that we already use 57% of our available land for producing food and even so, we’re still a long way from reaching the UN’s Global Goal of sustainable food for all! However, over the past 30 years, there’s been an increase in global food supply from the aquaculture industry - imagine farming, but in lakes or the ocean! From algae farms to our more usual fishy delicacies, this growing source of food might just be a significant part of the solution to our problem!

Now, instead of looking at the big, complex, seemingly impossible problem of feeding the world, let’s break it down into something more manageable, and slightly less intimidating. Let’s look at one of the more familiar aspects of aquaculture, fisheries. In 2012 fisheries supplied about 42% of the fish we eat, so they play a big role in global food production. In order to run a successful fishery, there are certain conditions needed to rear healthy fish in a sustainable way. For starters you need the right location with enough water and good access for transporting the fish to your plates, then you need a lot of fish food, and lastly you need plenty of oxygen in the water with not a lot of harmful chemicals!

There are quite a lot of large bodies of water in the UK, many of these are the lochs found in Scotland, which just so happens to be where I’m sitting writing this. I thought it would be a good idea to have a look at the closest loch, Loch Etive, and see how good it would be at sustaining a fishery. Since access and food are more general issues that all places would have to tackle so I’m going to look specifically at the shape of this loch, and how that might affect fish living in it.

Loch Etive is in the West coast of Scotland. It’s about 30km long, 1.4km to 1.6km wide, and has depths ranging up to 150m! But it isn’t just a big pond with a flat bottom, it’s got an interesting shape which plays a big role in how well it can support life! The scientists who monitor it have split it into an upper and lower basin. 

The most important part of water for fish, is having enough oxygen, of all of Loch Etive’s physical features, Bonawe Sill has the most influence over this factor! Salty water flows in from the sea, for shallower waters mixing occurs and oxygen is well distributed, however, when it reaches a feature like Bonawe Sill, the water is restricted and doesn’t mix as well. While some water will make it over the sill, the reduction in flow means that the upper basin doesn’t circulate very well and starts to stagnate! Oxygen is used up at the surface and as water cools it sinks deeper because it’s denser (think of it as heavier!). As the water sits at the bottom of this basin, it’s not much use to the fish as they can’t survive there. The longer the water stays there, the more likely it is that oxygen closer to the surface will be depleted as it’s used up by organisms, but isn’t replenished by circulating deep water. 

The water can sit at the bottom of the upper basin for about 16 months, which is the longest time of all the lochs in Scotland! But every so often, something interesting happens which mixes this whole system up and redistributes the oxygen again. It’s called a Deep Water Renewal event. When the tides are stronger than usual (spring tide) and bring more water flowing through the loch, it spills over Bonawe sill and rolls down the other side, mixing with the deep water as it goes.

So, in terms of creating a fishery in this loch, it seems there is potential, so long as the Deep Water Renewal events occur frequently enough to keep the oxygen well distributed throughout!

As you can see, after breaking our original Food Security problem down to the potential of a single fishery, there are a lot of different factors to consider many of which will be unique to specific locations, especially the suitability of sites based on their shape! But, for many years scientists working for places like SAMS in Scotland, and Cefas, in England have been finding out the specific dimensions of lakes and the ocean, and observing things like oxygen levels, all of which will contribute to determining the best places to put future fisheries!

Now if you’re wondering where I got my information from and want to find out more, check out the links below:

-          For more on the United Nations and their global goals www.un.org/sustainabledevelopment

-          For more on our current use of fisheries and aquaculture www.fao.org/home/en

-          For more on the future of Loch Etive www.argyll-bute.gov.uk/lochetive

And for the scientifically inclined, have a look at these:

-Edwards, A. and Edelsten, D.J. (1977). Deep water renewal of Loch Etive: a three basin Scottish fjord. Estuarine and Coastal Marine Science, 5, p575-595. DOI: 10.1016/0302-3524(77)90085-8

Swann, L. (1997). A Fish Farmer’s Guide to Understanding Water Quality. Aquaculture Extension. Fact Sheet AS-503. http://www.iisgcp.org/catalog/downlds_09/fish_farmgd.pdf. Accessed: 13/09/2016.

Austin and Inall (2002). Deep-water renewal in a Scottish fjord: temperature, salinity and oxygen isotopes.  Polar Research, 21, p251-258. DOI: http://dx.doi.org/10.3402/polar.v21i2.6485.

PA Gillibrand, CJ Cromey, KD Black, ME Inall 2007 Identifying the Risk of Deoxygenation in Scottish Sea Lochs with Isolated Deep Water Final report Scottish Association for Marine Science, Oban

[obanographers]

OUT OF BREATH: Deoxygenation in Coastal Waters

Coastal waters are becoming increasingly under threat of developing hypoxic (lowered oxygen concentrations) or anoxic (total lack of oxygen) conditions for extended periods of time. Naturally occurring deoxygenation is common in coastal waters due to the isolated nature of the waters, epescially in sille loch and fjords, and the biological oxygen demand of the marine organisms that live there.  

Causes of Coastal Deoxygenation:

Eutrophication

Rivers feeding into the coastal zones can bring waters high in nutrients, for example nitrate and phosphate, into the ocean, causing large phytoplankton blooms to develop near the coast due to the influx of nutrient rich waters. Eutrophication, as this process is known, has progressivlely worsened due to the high fertiliser inputs from agricultural land leaking into river networks. The blooms consume oxygen from the water column and as they die, sink to the sea floor, promoting oxygen depletion from their degradation. However, in regions of little agricultural land, the decreasing oxygen concentrations must have other causes. 

Phytoplankton bloom in the Baltic Sea 3 July 2001. Photo: NASA/Wikimedia

Aquaculture

Along with eutrophication, potentially another anthropogenic cause for the oxygen depletion is the development of aquaculture. The process of fish farming results in waste from the farm, in the form of fish faeces and excess feed, being released into the surrounding coastal environments, resulting in oxygen consumption as these are degraded by microbial reactions.

Upwelling

Water being moved from the deep ocean up to the continental shelf/coastal waters replenishes the coastal zones with nutrient rich but oxygen poor waters. This process occurs when winds force the surface waters out to the open ocean, allowing bottom waters on the shelf to mix vertically. However, as observed off the Oregon coast in 2008, persistant northerly winds proved problematic for the replenishment of oxygen as phytoplankton blooms thrived due to the continuous supply of nutrients but the bottom waters suffered severe oxygen depletion. Without the winds slackening, there was no oxygen replenishing to the waters leading to inhabitable conditions for life near sea bed.  

Oxygen Minimum Zones

Areas of the ocean that are too deep to mix with oxygenated waters, and therefore remain oxygen deprived are known as Oxygen Minimum Zones (OMZs). This is a naturally occuring event yet, in some cases they seem to be expanding. Water found above these zones is oxygen limited anyway, but it has been discovered recently that these oxygen concentrations have found to be decreasing. This is an issue as it is these waters that are upwelled onto the continental shelves and therefore create an uninhabitable environment for the existing marine life already present. the expansion of the zones and the depletion of waters directly above it is thought to be caused by prolonged thermal stratification, preventing the mixing of the water column.

Impacts of Coastal Deoxgenation:

Marine Life

Decreasing oxygen concentrations can be extremely damaging for marine ecosystems. The benthic organisms, unable to escape the hypoxic waters, will most ikely die off, littering the sea bed with their decaying bodies, furthering oxygen depletion as they decay. Pelagic life flees the now hypoxic/anoxic areas creating what is known as ocean dead zones. 

This expansion of oxygen depleted waters forces habitat compression, creating larger areas of ocean that cannot provide sufficient conditions to support marine life.

An increasingly common sign of a deoxygenated water in the Humboldt squid, that moves in to feed on the dead benthic organisms (Gewin, 2010).

Problems in the future?

Climate Change

Increasing global temperatures are causing warming of the global oceans. This potentially will further the deoxygenation of coastal waters as warmer waters means longer stratification periods within the water columns preventing mixing of oxygenated waters with oxygen lacking waters. Heating of the polar regions will also cause slower circulation of cold oxygen rich waters to warmer oxygen poor waters.

Food Security

Aquaculture will also put pressure on the oxygen supply as the practice expands to keep up with the increasing demand for farmed fish. Growing human populations and overfishing of wild fish means as the fish farms grow, waste leaking into the marine ecosystems increase and futher deplete the oxygen concentrations in the waters.

Equally, as agricultural practices on land expand and increase to keep up with the demand for food, fertiliser run-off will provide the freshwater inputs from the river into the oceans will increase the nutrient levels and therefore the presence of phytoplankton blooms. 

References:

Chan, F., Barth, J.A., Lubchenco, J., Kirincich, A., Weeks, H., Peterson, W.T., Menge, B.A., 2008. Emergence of Anoxia in the California Current Large Marine Ecosystem. Science. 920

Diaz, R.J. and Rosenberg, R., 2008. Spreading dead zones and consequences for marine ecosystems. science, 321(5891), pp.926-929.

 Gewin, V., 2010. Dead in the water. Nature, 466(7308), pp.812-814.

Gillibrand, P.A., Cromey, C.J., Black, K.D., Inall, M.E. and Gontarek, S.J., 2006. Identifying the risk of deoxygenation in Scottish Sea Lochs with isolated deep water. Scottish Association for Marine Science, Oban, p.37.

Picture references:

http://catastrophemap.org/wordpress/?p=5566

https://www.google.co.uk/search?q=aquaculture&biw=1920&bih=971&tbm=isch&source=lnms&sa=X&ved=0ahUKEwij0MSQ55bPAhWECMAKHd9_Bt8Q_AUIBygC#imgrc=FfQ4AC3BRLlFjM%3A

https://www.google.co.uk/search?q=humboldt+squid&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiQ5Za-5JbPAhUIBBoKHVIaBngQ_AUICCgB&biw=1920&bih=971#imgrc=kKyyvR5OLLER7M%3A

http://www.airclim.org/eutrophication

[samcatlovegood]

What’s The Costs Of Serving That Salmon On Your Plate?

The price of 1kg of Salmon sold at Tesco costs around 12 pounds, but that is not the costs I’m talking about. Recently, BBC reported that the harvest of Atlantic Salmon from Scottish fish farms declined by more than 4% to 172,000 tonnes. Aquaculture is the “farming of marine finfish or shellfish in a ‘natural’ habitat with no supplmentary food added and with minimum impact on the environment” (Read and Fernandes 2003).

Why should I care if the production of salmon is decreasing, there are other food substitutes anyway?

Not only are there less fish production but the government was concerned that the lochs and rivers surrounding the fish farms were being polluted. We have other substitutes other than salmon, but we don’t get a second choice for the environment. There are multiple environmental pressures that exist in fish farms including sustainability of fish feeds, increase in densities of sea lice, synthetic compound contamination and the input of nitrogen and phosphorus just to name a few. People tend to “fish down and farm up”, due to a depletion in fish stocks. Wild fish are decreasing in biomass, whereas farmed fish are increasing. Increasing numbers of sea lice is a challenge to many farmers as it decreases fish production. Also, sea lice may also spread from farmed fish to wild fish. Sea lice is one of the many problems that farmers would use synthetic compounds to solve, but it creates a huge impact on the environment. An open-pen environment allows chemicals to disperse to surrounding waters through treatment, spills, waste food, and fecal matter.

Ewww…

Waste is very disgusting and unhygienic, it can also be toxic to surrounding waters and ecosystems. The toxicity of the compounds may harm non-targeted organisms and cause the pathogen to develop resistance to compounds. The length of time the chemical is active is also another concerning issue with the usage of synthetic chemical compounds. One of the biggest environmental issue caused by fish farming is the release of waste into the ecosystem, which cause an increase in the concentration of nitrogen and phosphorus.

(GIllbrand et al. pg 34 2002)

“Nearly 13% of sea-bed residue samples from fish farms were higher than the environmental standard allowed.” (BBC 2012) These discharges include proteins, carbohydrates, lipids, vitamins and pigments. Fish excretory products and decaying food releases ammonia and salts of nitrate and phosphate. Waste release problems are seen as a problem from intensive farming, which uses cages or ponds with high quality artificial feeds and medication. The high levels of nitrogen and phosphorus increases phytoplankton levels which contribute to future eutrophication and algal blooms of the ocean. This is a huge problem during summertime, as there are maximum nutrient levels where temperature is high and feeding rate is high, with a maximum biomass of fish.

Is anyone doing anything to stop this?

(Scotland’s Aquaculture)

The government and many environmental agencies are trying their best to regulate, evaluate, and mitigate these issues. Voluntary best practice is encouraged in the industry. New policies are being made to create stricter control on the fish farming industries and to limit the impact it has to the environment. For example, the Scottish government is currently hoping that a new bill could encourage the proper management of fish farms and that it does not affect fishing on the Lochs and rivers. This new bill includes new legal measures for operations, stricter regulations, and an increased in fines for no compliance. Farmers may also use Locational Guidelines to assist with licensing in order to assure that the nutrient levels are within environmental standards. In Scotland, medicine or other chemical agents can’t be discharged from fish farms unless it is consented and licensed from SEPA under the Water Environment Regulations, 2005. Most farms need to be manage by legislative and regulatory measures and Codes of Conduct and Codes of Practice. The regulatory measures must consider the factors of a reasonable site selection, practices that minimize food waste and chemical usage. The Scottish Environment Protection Agency also monitors the increase of nutrients in organic waste deposition.

Okay, all I heard of is regulations,what about new methods or technology?

Well, there are new ways of farming through integrated aquaculture can be a mitigation approach to nutrient and organic matter waste from intensive aquaculture activities. This practice incorporates species from different trophic positions or nutritional levels in the same system. The output from one subsystem, which could have been wasted, would be the input to another system resulting in greater efficiency of the production of desired products under the farmer’s control. This would allow the growth of marine aquaculture as well as promoting sustainable development. The diversification of ecosystems provide stability in production efficient resource use and conservation. An example of this type of farming is rice-fish farming, where the waste from fish farms would serve as nutrients for the rice crops to grow.

(Salmon Aquaculture in 2050, 2013)

This method is dual beneficial as it reduces environmental impacts and creates other economic products at the same time. Not only is choosing the correct methods and regulations important to the sustainability of fish farming, but a good site selection can make a difference as well.

Does that have to do with why most fish farms are located in Scotland?

Yes and no, “Scotland supplies almost all the marine fin-fish farmed in the UK with a total value of approximately 375 million pounds in 2007” (UKMMAS 2010), which is pretty impressive. Scotland does provide a suitable habitat for salmon, and many other seafood to be farmed. The “production of salmon is highest in Shetland and the North West region of Scotland” (UKMMAS 2010). Aquacultural growth also depends on site availability, environmental carrying capacity and availability of investments. Through the suitable management and regulations, aquaculture could become much mroe sustainable than it is now.

So we can still enjoy our fresh range of seafood, but if we don’t act now and prevent these environmental issues to keep on happening, it would be too late for the future of many farmers and consumers that love seafood!

References:

United Kingdom Marine Monitoring and Assessment Strategy (UKMMAS) (2010), Aquaculture, Charting Progress 2 Feeder Report Productive Seas. Department for Environment Food and Rural Affairs on behalf of UKMMAS (Eds. Saunders, J. and McKie, J.) Section 3.1. 

Gillibrand,  P  et  al  (2002)  Scottish  Executive  locational  guidelines  for  fish  farming:  predicted  levels of nutrient enhancement and benthic impact, Scottish Fisheries Research Report #63. 

Read, P and T. Fernandes (2003) Management of environmental effects of marine aquaculture in Europe, Aquaculture 226, 139-163

Peel  and  Lloyd  (2008)  Governance  and  planning  policy  in  the  marine  environment:  regulating  aquaculture in Scotland. The Geographical Journal 174: 361-373

Barrington et al (2009) Integrated multi-trophic aquaculture (IMTA) in marine temperate waters. In D. Soto (Ed) Integrated mariculture: a global review. FAO Fisheries and Aquaculture Technical Paper No. 529. Rome, FAO. pp 7-46

BBC (2012, October 4) Scotland’s fish farming faces stricter controls. BBC News. Retrieved from http://www.bbc.co.uk/news/uk-scotland-scotland-politics-19829553

BBC (2016, September 12) Farmed Atlantic salmon production down. BBC News. Retrieved from http://www.bbc.co.uk/news/uk-scotland-scotland-business-37340549

Picture References:

https://salmonfarmscience.com/category/the-future/

http://aquaculture.scotland.gov.uk/

[obanographers]

Hi Obanographers!! My name is Sammi, I’m going into my second-year as an Environmental Sciences student. I have gone to the Teton Science School in Wyoming, USA, for an environmental science field trip. I am going to Mexico this summer to do some marine research as well as (hopefully) get my scuba diving license (probably not going to scuba-dive in Oban… XD). Therefore, my summer is filled with activities on the ocean. I am currently getting the hang of using MatLab. I am definitely looking forward to this trip, as it is going to be a totally different way of learning, and it is a rare opportunity to use the facilities at Oban (especially the boats!!) I think the only thing I’m not looking forward to is the long coach ride, but that is all okay when we eventually get there. I hope to see everyone soon!

[obanographers]

Hi all, my name is Mary! I study Meteorology and Oceanography at UEA. Best bit for me? The field trips!!! This picture is from the River Dart, during a trip to Slapton Ley in Devon back in first year… I’m looking forward to going to Oban (it’s my first visit to Scotland) and getting to grips with some hands on oceanography! :)