Displaying items by tag: Algal Bloom
Wastewater overflows from Ringsend’s over-capacity treatment plant have made algal blooms in Dublin Bay much more likely, says one marine expert.
Speaking to The Green News, Karin Dubsky of Coastwatch Ireland said overflows from Ringsend which have occurred after heavy rainfalls provide the right nutrient-rich environment for algae to prosper.
Afloat.ie readers will remember the ‘orange slick’ seen on south Dublin beaches this past summer — and this past week the Shelly Banks adjacent to the Ringsend plant was blanketed in rotting seaweed many mistook for raw sewage.
But capacity issues at Ringsend are only one facet of the the problem, according to Dubsky.
“It’s not just one big Ringsend discharge as the treatment plant is struggling, it’s all those smaller stormwater overflows mixed with sewage water which are discharging right at high watermark onto the shore,” she said.
The Green News has more on the story HERE.
It’s understood that hundreds if not thousands of fish including brown trout, juvenile salmon and bream may be affected by a fish kill on a tributary of the Bandon River in Co Cork.
IFI says it attended the site on Monday evening (26 August) following a report from a local angler — and initial investigations point to “a significant algal bloom” as the cause.
“Efforts are ongoing to assess the extent of the fish kill and an aerial survey of the lake is underway,” IFI adds.
“Cork County Council has taken water samples from the lake and river and is liaising with Inland Fisheries Ireland in their investigation.”
Bristling with sensors and state-of-the-art technology, the German research vessel RS Heincke completed a circumnavigation of UK and Ireland this August in a month-long survey.
A team of six Irish phytoplankton, biotoxin and oceanographic scientists joined the survey, which was conducted by the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research in collaboration with the Marine Institute and the University of Oldenburg Institute for Chemistry and Biology of the Marine Environment.
A total of 75 stations were surveyed using instrumentation aboard the ship, which was primarily designed to investigate Azaspiracid toxins produced by a number of micro-planktonic species of the family Amphidomataceae.
“This research is important for us as Ireland remains the most affected country in the world by shellfish poisonings caused by toxins produced by these species,” said Joe Silke, senior scientist on the survey from the Marine Institute.
These toxins, which were first discovered 23 years ago during routine monitoring of Irish shellfish, have resulted in annual temporary closures of Irish shellfish production areas, with resulting economic loss from loss of sales and markets.
Recent research has identified that the Amphidomataceae, unlike many other toxic algae, are pelagic plankton found in the open sea to the west of Ireland. These can accumulate in specific cases of currents and wind direction, creating toxin problems in the shellfish production bays along the West coast.
This was the first time that near real-time analysis was possible underway due to the advanced equipment available for the survey, including a fully equipped chemistry lab capable of measuring and identifying trace levels of toxin produced by the plankton using a liquid chromatography mass spectrometry instrument. Only 30 minutes after taking plankton samples aboard a full characterisation of the toxins present was possible with this equipment.
The team of scientists on board were able to confirm the presence of these phytoplankton at several offshore and nearshore stations, and collected an integrated data set comprising oceanographic, bio-optical, meteorological, plankton and sediment data accompanied by taxonomic determinations, toxin measurements and DNA analysis.
“Having the capability to carry out near real-time analysis of microscopic plankton while at sea to reveal the species present and their toxins is a huge leap forward in opportunities for our research programmes,” Silke said.
Simultaneous research activities included taxonomic analyses of the filtered plankton. Scientists used high resolution microscopy, further supported by real-time analyses of the plankton using molecular biological technology designed to recognise the DNA fingerprint of individual species.
Automated instruments on board such as a FerryBox carried out physico-chemical analysis of underway water, and a Flow-Cam carried out automated particle measurements and image analysis of phytoplankton samples. Full bio-optical properties of the water were measured using instruments on the ship measuring spectral properties both above and in the water.
In the course of the survey, several other blooms of algae were detected along the oceanographic fronts traversed by the ship’s track. These included large blooms of the usual late summer phytoplankton that we commonly see in coastal waters. These comprised mostly diatoms and dinoflagellates, such as Dinophysis acuta that produce DSP shellfish toxins, and Karenia mikimotoi that can cause fish and invertebrate mortalities if it accumulates in coastal areas.
The survey also revealed several species of Azadinium, the target group for this survey. These included some rare species, and some that have not been recorded previously in Irish waters.
One unexpected observation in the plankton net hauls was the diverse and frequent observation of microplastic particles in the same size range as the phytoplankton. While the survey was not looking for these in particular, it was evident that their occurrence is more widespread than observed in previous surveys in offshore waters, and would also appear to be diverse in nature based on shape and colour.
The European Food Safety Authority stated recently that plastic particles of this nature are less likely to pass to humans through fish, because the they do not pass through the intestine into other tissues of finfish, and the digestive tract is normally discarded. They may, however, pass to the food chain through filter-feeding shellfish species where the GI tract is consumed.
The sizes of particles observed on this survey would lend support to this, although the risk of exposure to humans and its consequence on health requires more research.
#Shellfish - Predicting risk and impact of harmful algal bloom events that cause impact to the shellfish aquaculture sector (PRIMROSE) is a new €2.7-million marine science project led by the Marine Institute.
The project is funded by the Interreg Atlantic Area Operational Programme and includes 10 research and SME partners from five countries along the Atlantic Arc from southern Spain to the Shetland Islands.
During the next three years, the PRIMROSE project will form a network of scientists and industry members to produce an inter-regional toxin and microbiological advisory and forecasting capability to the European aquaculture industry.
“The project will produce applications based on reusing existing monitoring data, modelled coastal hydrodynamics, satellite and other novel aerial observations, meteorological, historical and recent trend data to predict and give early warning of toxic blooms and elevated microbiological events,” said project coordinator Joe Silke, from the Marine Institute.
“This will allow fish and shellfish farmers to adapt their culture and harvesting practices in time, in order to reduce potential losses.”
The Marine Institute will implement the lead role of co-ordinating the project and ensure that all the work packages, actions, deliverables and results are achieved.
Already a strong partnership approach has been established during the project preparation. By consolidating and further developing the regional knowledge capital that exists, the consortium is confident of a successful outcome.
Partners will participate in a suite of six work packages and will develop a sustainable product that will be largely automated to predict and produce regular published reports for the long term once the project is finished.
In recent years, there has been much discussion of satellites being able to track surface algal blooms. Understanding biological phenomena in the ocean requires a complex approach, though there is some merit in using satellite derived chlorophyll images to delineate high biomass near surface algal blooms.
Much cutting edge harmful algal bloom research work has focused on subsurface profiles, where certain species are present in thin layers of limited geographical extent often associated with strong density interfaces. Phytoplankton blooms, micro-algal blooms, toxic algae, red tides, or harmful algae, are all terms for naturally occurring phenomena.
Clearly, in order for a toxic, harmful algal bloom, or a microbiological forecast to be realistic, physical factors including changes in water column structure and transport pathways are necessary.
“PRIMROSE is the next step towards providing an operational advisory service by integrating physical oceanographic drivers with a variety of biotoxin, phytoplankton count and microbiological data,” said Silke. “A distributed advisory service and a network of thematic experts distributed across the participating countries will then network to provide regular advisory products and forecasts of impending toxic and harmful algal events.”
PRIMROSE brings together experts in the areas of modelling, Earth observation, harmful algal bloom and microbiological monitoring programmes and end users to assemble a number of key data sets and build upon and explore new forecasting options.
The consortium includes three UK partners (Seafood Shetland, Scottish Association for Marine Science and Plymouth Marine Lab) two Irish partners (Marine Institute and Bantry Marine Research Station), one partner in France (IFREMER), three in Spain (AZTI, Instituto Oceanographico Espanol and AGAPA) and one in Portugal (Institute Technico Superior/University of Lisboa).
The Marine Institute recently issued a recruitment call for a data analyst and project co-ordinator for the PRIMROSE project, as previously reported on Afloat.ie.
The bloom was detected two weeks ago using satellite images and information provided by the Environmental Protection Agency (EPA) and Wexford County Council.
The Marine Institute has analysed a number of samples from the algal bloom and has identified the species as Phaeocystis pouchetii, a common species that has caused blooms along the east coast several times in previous years. The species causes discolouration of the water, and foaming on the beach in windy conditions.
Joe Silke of marine environment and food safety services at the Marine Institute emphasised that the species is not directly harmful to humans either through swimming or from consuming fish that have been exposed to the bloom.
Beaches remain safe despite any discolouration of water, though the production of foam, and in some extreme cases anoxia, can result in marine organism mortalities.
However, unlike last summer's destructive algal bloom on the west and north coasts that was responsible for significant fish and shellfish kills from Galway to Donegal, fish mortalities caused by this particular species in previous Irish blooms have not been observed, as wild fish tend to avoid the bloom. This may explain the low catches reported by sea anglers on the east coast in recent weeks.
Several fishermen have also reported clogging of nets in recent weeks, which may be caused by the decaying bloom sinking to the seafloor.
Algal blooms are commonly detected over the summer months in coastal areas. It is likely that this particular bloom will dissipate in in the next week or so and will be replaced with the normal succession of microalgae that form the bottom of the food chain in the sea.
#algalbloom – After impacting on the marine wildlife along the north west coast for the past month, the algal bloom of Karenia mikimotoi has finally began to subside. The bloom severely affected areas of the North West from Mayo to Donegal and in certain areas down along the rest of the West coast. It impacted on coastal marine life in these areas and resulted in considerable mortalities of fish, shellfish and other coastal invertebrates. The most recent satellite imagery and seawater samples analysed by the Marine Institute show a significant decrease in the concentration compared to recent weeks.
Mr Joe Silke of the Marine Institute stated, "These blooms are part of the natural summer marine flora, and occasionally they form these exceptionally high blooms. Karenia mikimotoi is a common species in all European waters and dense bloom have been detected many times in the past. This recent bloom is similar in impact and duration to one which we experienced in 2005, and is most likely due to a combination of environmental conditions and ocean currents providing optimal conditions on the continental shelf. The accumulation of the bloom against the coastline with tidal and coastal currents causes very dense concentrations to occur. Mortalities in marine organisms particularly those living on or near the bottom are due to the algae affecting their respiratory systems and this is compounded by low oxygen in the water, particularly as the bloom is decaying."
While the bloom of this species is not known to harm humans directly, dead marine life was washed up on the shoreline, even requiring Local Authorities to temporarily close two beaches in Donegal. Discoloured reddish - brown water were observed along large expanses of the coast line. In several areas, oyster farms reported losses between 20 to 80% in some sites and farms stocking juvenile oysters also reported significant mortalities with many deciding to defer putting out new stock until the bloom passes. Other areas affected included Galway Bay, and while no mortalities were reported in this region, a shellfish hatchery in the area reported difficulty in settlement of their shellfish larvae. Local sea anglers have reported low fish catches along west and northern coasts and in some areas a complete absence of any fish. This is mainly due to fish avoiding the bloom when they can. Lobster and Prawn fishermen have also reported very poor catches in the Donegal area.
Indications from satellite and modelled data last week showed the bloom was moving back out to sea, and the latest cell counts of samples analysed in the Marine Institute today show that the bloom is has reduced significantly in the west Donegal and Sligo regions as it was last week, but it is still present Galway Bay. The Marine Institute's monitoring programme will continue to sample and monitor the bloom and post updates on our website at marine.ie and on local radio.
The algae responsible, karenia mikimotai, occurs naturally in Ireland's coastal waters during the summer months and his harmless to humans, but contains a "toxic irritant" that damages the gills of fish, shellfish and other marine species.
Low-level samples were first detected in May but in the last two weeks it has grown into a dense bloom from Donegal to Mayo, with high levels now being recorded in Galway Bay, according to the Marine Institute's Joe Silke.
"In Donegal the bloom was so dense that there were many reports of discoloured red or brown water in some areas and several areas have reported dead marine life washing up on the shoreline, requiring local authorities to close certain beaches,” he said.
"The bloom affects species that live on or near the sea bed so we are seeing flatfish, lugworms and some shellfish getting washed up on the beaches."
The image evokes memories of the notorious 'red tide' that killed wild fish and shellfish along the west coast in 2005.
Meanwhile, the Marine Insitute said there are "some indications" that the bloom may be moving back out to sea, as observed in the latest satellite images and modelling data.
"However, cell counts of samples analysed in the Marine Institute... show that the bloom is still of the same density in the Donegal and Sligo regions as it was last week."