fbpx
Connect with us

Community

Bringing Citizen Science To Lake Pupuke

GUE diver and aquatic eco-toxicologist Ebrahim Hussain applies some serious citizen science to get to the bottom of the trouble in Lake Pupuke, New Zealand. Project Baseline is alive and kicking, thank you very much!

Published

on

by Ebrahim Hussain

I have always been passionate about aquatic ecosystems and how they work which inspired me to become an aquatic ecotoxicologist. I have always tried to document observations in an attempt to better understand environmental changes. The biggest challenge I have faced was getting my observations to organizations that are able to use them in a constructive manner. We all constantly see changes in our environments but are often unable to make a positive change.

Citizen science is a greatly underutilized resource by regulatory agencies. There are a myriad of citizen science groups that actively want to participate in the monitoring of their local ecosystems, but they lack the guidance or platform to do so. The Project Baseline Initiative provides an amazing platform for people to display their findings, and in combination with guidance from local authorities, the resulting projects can be an overwhelming success. This article will hopefully take you through my journey to improve a local lake that means a lot to me and the people who use it.

Lake Pupuke is a 186 ft/57m deep volcanic crater lake with a surface area of 110 hectares that drains a 105 hectare urban catchment in Auckland, New Zealand’s North Shore. The influence of this urban catchment on lake water quality is enhanced by the fact that the lake has no direct in and/or out flows and consequently has a high water retention time. Water enters the lake via a variety of diffuse sources (runoff, groundwater & precipitation) and exits through evaporation and intermittent drainage channels.

The lake is used for a variety of recreational purposes and is a venue for national and international events. The lake is also widely used by dive schools and boat clubs from across the region as a training facility.

A Lake Under Threat

I have been diving in Lake Pupuke since 2013, and I quickly came to realize that this lake was under threat. The water clarity had decreased, and according to the local dive schools, this deterioration had been noticed for many years prior. In the summer of 2014 a thick algal bloom developed which had not been recorded previously. The initial concern was the potential human health risk associated with algal blooms, but samples taken by the Auckland Council identified the bloom as Ceratium hirundinella which is a nontoxic species.

It was quite puzzling that even though Ceratium has always been present in the lake it had never formed large scale blooms until 2014. It was thought that this bloom was a once-off event until it occurred the following year and every summer since.


Ebrahim Hussain installing a dissolved oxygen & temperature sensor on the monitoring station. Photo by Andrew Davidson.

In an attempt to understand what had caused this change, I began looking at the Council’s long-term monitoring data, and to my surprise, I could not find anything that pointed to the exact cause of these recurring blooms.

I initially looked at temperature and nutrient loads which are the most common drivers for algal blooms and found that the lake had not been significantly warmer than previous years, and the trophic level index, while elevated, was within the same variance seen over the past ten years. However, there was no associated metadata to support any conclusions. It was clear to me that we could not fully understand what was happening in the lake through seasonal surface-based water quality sampling alone, and that regular subsurface observations were needed.

Enter Project Baseline

That is when I came across the Project Baseline Initiative, and it was the perfect platform for the type of work I wanted to conduct. The primary focus was to collaboratively work with volunteers, local communities, research organizations, and the Auckland Council to collect data that would complement the work already being done by the Council, as well as to specifically address the subsurface knowledge gaps. By doing this we are able to make use of both Council-funded and citizen science-driven data acquisition to support and inform a more holistic management strategy for Lake Pupuke.

We initially started collecting very basic data, such as visibility, temperature, and general meteorological information, but this quickly ramped up once we started noticing what was happening underwater.

Todd Kincaid & Louise Greenshields preparing the sediment coring tubes. Photo by Ebrahim Hussain.

We installed continuous temperature sensors, which log data every 15 minutes, at various depths to get a better understanding of the seasonal thermal stratification in the lake. Our data indicates that the lake usually stratifies from October until June, with an average winter temperature difference of 0.7°C between surface and bottom waters, and a summer difference of 10.2°C.

Stratification in lakes of this depth is a natural result of the surface water layers being heated by the sun. This heating causes the formation of a thermocline where the warmer water layer sits above the cooler, denser bottom water. This process separates the water column into three distinct layers, the epilimnion which is the warmest layer on the surface, the cooler metalimnion in the middle, and lastly the hypolimnion which is the coldest layer at the bottom of the lake. This separation of layers reduces the mixing of heat, oxygen and nutrients between the surface and bottom waters.

It is important to track these changes in stratification because it is directly related to the potential oxygen cycling and internal nutrient loading within the lake.

We installed continuous dissolved oxygen (DO) sensors within these distinct thermal layers to assess this oxygen cycling, and what we found was surprising. In winter the DO% on the surface ranges from 86% to 98% and gradually drops in even gradations down to about 40% at 55m. In summer the DO% ranges from 80 to 90% on the surface down to less than 3% at 55m. This is expected, but what took us by surprise was the presence of midwater anoxic layers, one near the surface between 7m-9m, and a second layer in the metalimnion between 12m-16m.  

The Results

After seeing this, we began investigating other potential DO dead zones in the lake using multi-parameter water quality meters and have since identified additional areas. There was evidence of anoxia in the macrophyte beds that surround the lake, so we deployed additional sensors, and our finding confirmed our initial assumptions with summer DO% dropping to less than 3%.

This is critical information, as anoxic sediment conditions actively promote the remobilization of nutrients which further contribute to the eutrophication of the lake and drive algal bloom formation. These conditions can also cause the release of ammonium & hydrogen sulphide which are all toxic in high concentrations.

The next question we had was what was causing this anoxia. It is natural for a lake this deep to have anoxic bottom waters during summer, but we did not know what was causing this anoxia midwater and in the macrophyte beds. The dense macrophytes stop water from freely flowing into the shallows, and there is a lot of visible organic material that is decomposing on the bed, which all contributes to the anoxia.

The increased load of organic material, composed of dead macrophytes & phytoplankton, seemed to coincide with the appearance of the algal blooms. To prove this we installed light sensors that continuously measure the photosynthetically active radiation attenuation at various depths. The data shows that at on average there is almost no usable light past 4m after 13:00 and zero light penetration past 10m during the summer blooms. This lack of light caused the macrophytes to die, and coupled with the dead phytoplankton settling down, created an influx of decaying matter on the lake bed. We now regularly conduct macrophyte extent surveys to document seasonal die back and regrowth.

Phytoplankton, Chlorophyll-a & biological oxygen demand sample bottles as well as a photosynthetically active radiation sensor ready for deployment. Photo by Ebrahim Hussain.

We knew where the additional organic material was coming from and what was causing the anoxia in both the macrophyte beds and the hypolimnion. The next question was how many nutrients are being released from these areas and what is causing the midwater anoxia. To answer this, we started a collaborative project with the Auckland Council and the Cawthron Institute.

The first step was to install sediment traps at various depths to understand how much organic material is produced midwater and how much settles down to the bed. The second step was to take a suite of sediment cores from the areas of concern we had previously identified to understand the amount of nutrient remobilization that occurs under various environmental conditions. The third and final step was to take targeted water quality and phytoplankton samples from the midwater anoxic layers to understand how/why they are formed.

Ebrahim Hussain & Tyler Ungureanu purging bottles in preparation for water quality sampling. Photo by Harry Josephson-Rutter.

The majority of the sampling required has been done except one more round of winter sediment traps. Once this has been completed, all the data will be analyzed and will fill a critical knowledge gap regarding internal nutrient cycling. This in turn will help guide the next steps for the wider project as well as inform potential mitigation measures.  

Project Baseline has provided an amazing tool to facilitate the collaboration between citizen science and local government by formalizing community-driven data collection. The Project Baseline Lake Pupuke Initiative is a proven example of how citizen science can be used to satisfy critical knowledge gaps and directly feed into regulatory strategies with the common goal of creating a better, healthier environment.


Ebrahim Hussain is an Aquatic Scientist working at the Auckland Council. He began diving when he was 12 years old and has never looked back. Hussain studied aquatic ecotoxicology and zoology at university, and it was clear that he wanted to spend his life studying these subsurface ecosystems and the anthropogenic stressors that impact them. Hussain founded Project Baseline Lake Pupuke with the goal of contributing to preserving and enhancing this natural beauty as well as encouraging others to get involved in actively monitoring their natural surroundings.


Community

Brits Brew Beer Booty

What do you get when you combine British divers’ proclivity for shipwreck exploration with their strong affinity for beer? A tasty treasure hunt on the “Wallachia” that resulted in swilling 126-year old reconstituted British beer. GUE Scotland’s detective chief inspector Andy Pilley recounts the tale.

Published

on

By

by Andy Pilley
Images courtesy of
A. Pilley

Header Image: GUE Scotland’s brewmeisters enjoying their brew (L to R) Top: Owen Flowers, Andy Pilley, Wayne Heelbeck. Middle: Steve Symington, A. Pilley, O. Flowers, Bottom: W. Heelbeck, Sergej Maciuk, S. Symington

“Give my people plenty of beer, good beer, and cheap beer, and you will have no revolution among them.”

Queen Victoria

I never thought when I started diving 10 years ago, that one day I would be able to sit down for a pint of beer with the team from GUE Scotland recreated from a brew that has been hidden under the waves for 126 years. Let me explain.

The Wallachia was a single screw cargo steamer that was owned by William Burrell & Son of Glasgow, and employed on regular trips between Glasgow and the West Indies. On 29th September, 1895 she left Queen’s Dock, Glasgow at 10am bound for Trinidad and Demerara. On board was a valuable general cargo including whisky, gin, beer, acids, glassware, and earthenware plus building materials and footwear. By 1pm that afternoon she had settled on the seabed of the Clyde Estuary after colliding with another ship in a fog bank, she was forgotten until 1977 when a local sub-aqua club rediscovered the wreck site.

The wreck of the Wallachia lies on an even keel in approximately 34 metres of water on a sandy seabed. The wreck itself is largely intact and has six holds in total, three forward and three aft. In the rearmost hold there are thousands of bottles of beer, some still inscribed with the name of the maker, McEwans of Glasgow. This is where myself and the team from GUE Scotland enter the story.

The Wreck of the Wallachia 

The Wallachia is one of the more accessible sites on the west coast of Scotland, where we carry out most of our diving. Depending on weather and tidal conditions, visibility on the wreck can be +10m/33 ft on a very good day or less than 2m/6 ft if there has been a lot of rain due to the amount of particulate in the water. Other elements to consider are the tide as this can vary in its intensity, as well as surrounding boat traffic. The wreck lies in close proximity to a ferry route and care must be taken not to dive when the ferry is closeby. However despite the challenges, the wreck is very rewarding and offers a diver plenty of places to explore and items to look at. 

The main point of interest for most has been the rearmost hold, where the bottles of whisky and beer were stored. The majority of the whisky was removed in the 1980’s however a few bottles can be found on occasion, depending where you look. What remains are thousands of bottles of beer, still with the corks and contents intact. Over the course of 2018 & 2019, the team at GUE Scotland dived on the wreck and recovered a number of bottles from the hold. 

After a chance discussion with a friend at dinner one night, I was given contact details for a company called Brewlab, which is based in Sunderland in the north east of England. Brewlab specialise in the provision of specialist brewing training, as well as laboratory services such as quality assurance, product development, chemical/microbiology testing as well as long term research options. I made contact with Keith Thomas, the Director of Brewlab, to discuss whether he would be interested in analysing the beer and investigating whether it could be recreated. Needless to say the proposal piqued his interest and arrangements were made for the bottles to be shipped to his lab.

Unbeknownst to me, the recovery of historical beers is rare, due to various sources of degradation/contamination which can affect any residual microbial cells and chemical components left in the beer that were used as part of the brewing process. So these samples are a valuable source of information on past brewing and microbiology. Over the course of 2019/2020, Keith and I kept in regular contact over the progress of the investigations and the full analysis of the beer has recently been published.

A Brewing Interest

Between 1850 and 1950, the application of scientific principles to brewing was becoming increasingly prevalent and microbiology was playing an increasingly important role. A pertinent issue in brewing microbiology around 1900 was the application of pure Saccharomyces yeast cultures developed by Hansen at the Carlsberg laboratory in 1888. These were readily adopted by continental breweries as providing more controlled production and purer beers. Application to UK brewing was, however, less positively received, in part because of the belief that British beers possessed particular flavours arising from mixed yeast cultures and, specifically, the involvement of Brettanomyces species. This was especially believed to be essential for the character of ‘stock’ ales which were matured for extended periods.

While a number of breweries did try pure culture yeasts, UK brewing was resistant to change and, with the intervention of World War I, retained its indigenous yeast cultures. Since the 1940’s a more biotechnological approach to fermentation demonstrated the value of pure culture and was progressively applied to the larger breweries developing at that time. 

During the formative period of brewery microbiology after Pasteur, brewing yeast were identified as Saccharomyces species based on morphological features of shape, filamentous propensity and spore characteristics. Non brewing, ‘wild’ yeast was recognised and termed ‘Torula’ if non-sporulating. Of these Brettanomyces strains were identified as contributing important character to stock ales. It is also clear from brewing texts that bacteria were recognised as spoilage organisms in beer, as had been initially demonstrated by Pasteur in 1863. These species were mostly categorised as bacilli and typically portrayed as rods and associated with sarcina sickness – generally producing sourness. Some studies, nevertheless, identified lactic acid bacteria as indigenous components of standard beers.

Contemporary breweries are increasingly interested in using novel microbiology, either unconventional yeast strains or mixes of species and strains for sour and natural products. Identifying the specific strains and species of yeast and bacteria present in Victorian and Edwardian beers is directly relevant to this and has particular value if cultures of authentic microorganisms can be retrieved. Reports of retrieved historic brewery microbiology are limited but hold interesting promise for identifying novel microorganisms.

The specific parameters of the analysis are contained in a published research paper, Preliminary microbiological and chemical analysis of two historical stock ales from Victorian and Edwardian brewing.”

As I mentioned, the primary objective of the analysis was to confirm whether detail could be provided on the original brewing ingredients and the fermentation microbiology. The analysis confirmed the use of Brettanomyces/Dekkera bruxellensis and Debaryomyces hansenii, which are brewing and fermentation yeasts respectively. The presence of Debaryomyces is interesting as this genus has not been noted as a historic feature of historic brewing, but has been identified in spontaneous fermentations, for example in Belgian lambic beers. Although the strain was reported to the brewing industry in 1906, it has not featured as a major contributor to beer fermentations since.



The analysis has also provided relevant information of the beer character and has confirmed that the beer recovered from the Wallachia was a stout, close to style expectations of the time and had an alcohol content of c. 7.5%. The colour gravity was high, resulting in a much darker beer however a much lower level of bitterness. Again this was typical style of the time and differs from other modern stouts.

More interestingly is the presence of various types of bacteria, which will likely have been picked up during the brewing process. The table below lists these for reference. Needless to say, historic brewing was not a sterile process in comparison to modern methods!

Bacillus licheniformisPlant and soil bacterium
Finegoldia magnaCommensal skin bacterium
Fusobacterium sp.Possible pathogenic bacterium
Kocuria roseaPossible urinary tract pathogen
Mogibacterium pumilumPossible oral cavity bacterium
Shigella sonneiEnteric pathogen
Staphylococcus epidermidisCommensal skin bacterium
Stenotrophomonas maltophiliaSoil bacterium
Varibaculum cambriensePossible pathogenic bacterium

Table 1: The bacteria found in the Wallachia beer bottles

Due to the relatively stable conditions on the wreck, being in near darkness and at a relatively cold temperature (between 6º–14ºC/43º-57ºF depending on the time of year), the live yeast structures within the beer were protected from sources of stress and allowed them to survive over the past 126 years. Luckily, Keith was able to extract these samples and begin to recultivate the yeast, specifically the Debaryomyces, with the hope of being able to rebrew the beer.

Cheers Mates

Just before Christmas, I finally received word from Keith that he had completed a trial brew and seven bottles of the brew were on their way to me. A few excitement laden days later and a nondescript box arrived at my office with the beer inside. I called the guys on our Facebook group chat to show them the case and got each bottle packaged up and sent out to them. 

A few days later, once everyone had received their sample we got together again to try the samples. There was an air of excitement after the two years it had taken us to get to this point, the most anticipated pint ever! I’m no expert in the flavour profiles of beer so you will have to forgive me for my relatively basic analysis. In summary, I got flavours of coffee and chocolate and there was a relatively low level of carbonation, which made it very drinkable. The rest of the team got similar flavours, the only complaint being there wasn’t more to try!

There will of course be slight differences in flavour since we don’t normally add the bacteria listed above as ingredients. However, the recipe we have is as close as we can make it to the original stock version.

The next steps for the project are to carry out further investigation on the characteristics of the Debaryomyces yeast strain in order to determine their suitability for fermentation and potential use in future brewing production. We are making approaches to various commercial breweries in order to discuss future commercialisation of the recipe and produce the brew on large scale. With the story behind the original recipe, we’re hopeful that the provenance would be a key selling point to consumers. It is my hope that the recovery of these samples will open up new possibilities for different types of beers to be developed, and offer something different for beer enthusiasts to try.

I have also found out that there are other types of beer to be found on the wreck, specifically an IPA style. Once we’re allowed to begin diving again, I am hoping to return to the Wallachia and recover some of these bottles so we can carry out the same analysis and keep the project moving forward.

In the mean-time, cheers!

Additional Resources:

The Brewlab Podcast, Episode 2 (March 30, 2021): Lost Beers Recreated from Shipwreck Bottles

GUE Scotland vlog -Episode 1


Andy Pilley is a Chartered Surveyor, team member of GUE Scotland, passionate wreck & cave diver and Ghost Fishing UK team diver. Andy started diving with the Scottish Sub-Aqua club in 2011 and began diving with GUE in 2018. Andy dives on the east and west coasts of Scotland where there is a rich maritime history and an abundance of wrecks to be explored. He has a passion for project diving and is developing objectives for a number of sites with the GUE Scotland team. He hopes to assist on the Mars Project and with the WKPP in the future.

Continue Reading

Thank You to Our Sponsors

Subscribe

Education, Conservation, and Exploration articles for the diving obsessed. Subscribe to our monthly blog and get our latest stories and content delivered to your inbox every Thursday.

Latest Features