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

Fiona Sharp, You Will Be Sorely Missed

As you have likely heard, we’ve lost one of the irrepressible and much-loved characters in the tech and diving medicine community, 55-year old Australian anesthesiologist and diving physician Fiona Sharp.

Published

on

By

By Rosemary E Lunn
Header photo by Catherine Meehan. Fiona in Sodwana Bay.

Fiona at BonaireTek. Photo by Michael Menduno.

One of the colorful characters in the field of diving medicine died tragically in a rebreather diving accident on Thursday, October 17, 2019. Fifty-five-year-old, Australian diving physician and anesthetist Dr. Fiona Sharp, MBBS, FANZCA, was found unresponsive on a reef at 24 m/80 f. She had been solo diving on a rebreather, and she was discovered with her mouthpiece out. Fiona was medevaced but did not regain consciousness. The incident occurred on the last day of Fiona’s diving trip to Bonaire, located in the Leeward Antilles, Carribean Sea. It was the week after Bonaire Tek. Fiona enjoyed deep rebreather diving and was known to be a bit of a maverick.

“We are shattered.” Bruce and Lynn Partridge, Shearwater Research.

Fiona at AsiaTek. Photo by Michael Menduno.

The disturbing news of Fiona’s death rocketed around the world in a few hours. Many people from the diving medicine and technical diving communities expressed their dismay and distress at Fiona’s death. She was gregarious, fun-loving, irrepressible, and generous. Fiona was a friendly colleague and we had dived together a few times. I wrote a heartfelt tribute about Fiona’s bulldozer attitude to life and diving, and this was published by X-Ray Mag. It includes a myriad of voices from around the globe and amply illustrates just how well-loved she was by her colleagues and friends. 

“Fiona was an individual. She did what she wanted. She did what she loved. She was very much her own person, and drove us mad at times. Fiona was down to earth, had a massive heart, a huge personality, and was very dear to all of us. She will be greatly missed.

Dr. Catherine Meehan

Fiona Sharp was born in May, 1964, in Perth, Australia, and she was bright! She attended Mercedes College Perth, where she was “Dux” in her graduating year. [Dux: from Latin for ‘leader,’ the term that is now used in Australia and New Zealand to indicate the highest-ranking student in a specific achievement). 

Fiona in Sodwana Bay. Photo by Catherine Meehan.

After leaving high school, Fiona studied medicine at the University of Western Australia where she graduated in 1989 as a Bachelor of Medicine and Bachelor of Surgery (MBBS UWA). After serving an internship in Perth in 1989, followed by a year as a junior Resident in Sydney, Fiona moved to England where she gained her Diploma of Anaesthesia (DA) in 1992, whilst working as a Senior House Officer in Anaesthetics in Southend, Essex.

Fiona then returned to Australia and commenced specialist Anaesthetics training. In 2000, she flew once again to the UK where she spent five years practicing diving medicine at DDRC Healthcare (Diving Diseases and Research) in Plymouth. During this period, she was awarded a Fellow of the Australian and New Zealand College of Anaesthetists (FANZCA) Fellowship in 2004.

At the time of her death, Fiona Sharp was working at the Fiona Stanley Hyperbaric Medicine Unit (FSHHMU) in Perth, Western Australia. She had been in post since it opened in November 2014. Prior to that, she was employed at the HMU at Fremantle Hospital from 2007 to November 2014. (The department then relocated to the newly built department at FSH).

Fiona at an event with the Hyperbaric Technicians and Nurses Association. Photo courtesy of Catherine Meehan.

Whilst writing this, I spoke to Fiona’s family and asked: “why medicine?” They responded,

“If you are really smart at school, you are expected to be an architect, a lawyer, or a doctor. Medicine appealed to her; however, it was possible that she could have become a vet because the family did have a lot of animals.”

Fiona’s family

“She was nuts, about everything. But especially about diving.” 

Dirk Peterson

Fiona got into diving in her late teens after trying skydiving and scuba diving. Water prevailed and she learned to dive when she was 18 years old. She was a PADI Divemaster, cave certified and qualified to dive the Inspiration, Evolution, SF2, Drager Dolphin, Mark VI Poseidon, and JJ-CCR rebreathers. 

Fiona with Dr. Neal Pollock, Rosemary Lunn, and Dr. Richard “Harry” Harris at Rebreather Forum 3. Photo courtesy of Rosemary Lunn.

You cannot ever say that diving was her hobby. It was her all-encompassing great passion. Fiona recently told her older sister that she felt happiest when she was underwater. It was therefore natural that she would take an active interest in diving medicine, and she became a fixture at all the major diving medical or tech conferences. SPUMS, UHMS, EUBS, HTNA, as well as EUROTEK, OzTek, Rebreather Forum 3 and other diving industry events. These helped keep her current and educated in this niche sector. 

Fiona loved the diving, diving medicine, and the camaraderie around the bar. She was regularly first up and last to bed. Most often, Fiona could be heard well before she was seen on land and underwater!! She was well-loved by her colleagues at these events and, as many have said, the SPUMS Conference won’t be the same without her. I think she attended at least 17.” 

Dr. Neil Banham, Fiona Stanley Hospital

Fiona’s first South Pacific Underwater Medicine Society (SPUMS) Conference was at Layang, Layang island, in Malaysia in 1999,  a venue well suited to her type of diving because it was deep. It was at a later SPUMS, in 2008, that Fiona’s diving would change. Dr. Catherine Meehan takes up the story. 

I met Fiona at a SPUMS meeting about 20 years ago. In 2008, I chartered the ‘Golden Dawn’ liveaboard. Ten of us flew into Alotau in Papua. New Guinea. and we sailed and dived our way across to Kimbe Bay, West New Britain, to join the SPUMS annual scientific conference. There was a rebreather on board and Fiona had a guided rebreather dive. She enjoyed it so much that she dived with it for the rest of the week. I believe this was one of her earliest experiences rebreather diving, and I think that she embarked on her passion for diving rebreathers shortly afterward.

Catherine and Fiona would regularly dive together, at least two or three times a year, all over the world.

We did a lot of conferences and diving together. We were most recently in South Africa diving Sodwana Bay. She was dressed in her vibrant orange drysuit so it was easy to see where she was, doing her own thing. It was tough cold water diving, but she was very hardy and didn’t miss a dive, even when her suit leaked. It is a good lasting memory of her.”

It was like she had been shot out of a cannon when she entered a room.

Joanna Mikutowicz, DiveTech


Fiona Sharp never did anything by halves, and this is amply demonstrated by a classic Fiona story that her older sister Donna regaled to me.

Many years ago Fiona rang me up and said, ‘I have got two tickets to the rugby game on Friday night, do you want to come with me?’ I thought, ‘Why not?’ One of our kids plays rugby at school. I rocked up at the game and she said to me, ‘Here is your ticket. Don’t worry about paying. And by the way, these tickets are not just for tonight’s game. They are season tickets’.”

She goes on: 

“We ended up supporting the Western Force, a professional Perth-based rugby team, for the next twelve years and watched them play Super Rugby against New Zealand and South Africa. What I found ironic was that I went to nearly every game. I think Fiona missed more games than any of us because she was away diving so much.

Fiona Sharp drew no quarters when it came to life and diving. I only met her a few times, but she left an aircraft carrier shipwreck-sized impression on my psyche and we remained in contact.”

Laura James, Environmental Campaigner, Underwater Cinematographer

Many divers have been generous with their Fiona stories. Todd and Tiffany Winn of Silent O Solutions reached out to me with another classic Fiona tale and said I could share it. When Fiona decided you would be friends, the recipient really didn’t stand a chance. 

Fiona’s reputation as ‘difficult’ preceded her, and our first encounter with her was memorable, to say the least. It was in San Diego for an in-water recompression symposium and training event in 2014. She exceeded my expectations. I believe she only told me I was completely mistaken two or three times. I conceded two of three and agreed to disagree on the third. She had an uncanny ability to defuse my ire with a wry smirk. As she had already decided we’d be friends, I had little say in the matter.

Tiffany Winn
Fiona before a dive in Bonaire. Photo by Michael Menduno.

Tiff liked Fiona immediately and loved her unflinching honesty and authenticity. Fiona threatened to visit us on Maui on one of her transits across the globe, but unlike nearly everyone else she called and texted for a month straight, ironing out the details, and sure enough, one day, showed up. We loaded up our little boat for its maiden voyage, and Tiff and Fifi had a girl’s day rebreathering all by themselves. We had a beautiful day and a fabulous sunset. We will remember her fondly and often, and will miss her dearly.”

Todd Winn

It is only right that I leave the last words to her family. I was told that Fiona had wanted to climb Mount Everest, but she suffered so badly with altitude sickness, that she just about made it to base camp and no further. Fiona was always willing to take a risk, and push herself. Apparently she competed in triathlons in her early 20’s, and she liked challenges. Everyone who came into contact with her soon found out she had a very dry sense of humor.

Fiona didn’t like cheap champagne or wine. It had to be good quality and lots of it, and she always brought home two bottles of whiskey from every trip for her father.

Donna Sharp

Fiona was close to her family. She is survived by her mother, three sisters, a brother, and 18 cousins. She was an “oh so very proud” aunt to 13 nieces and nephews. Typically big-hearted and kind, Fiona had planned to take a nephew to Antarctica this November. You mad as a box of frogs lady, you will be missed. 

The author is very grateful for the assistance of the Sharp family and Dr. Neil Banham, Director of Hyperbaric Medicine at Fiona Stanley Hospital in writing this tribute. 


Dive industry fixer, Rosemary E Lunn (“Roz”) is the Business Development Director at The Underwater Marketing Company. This British firm specializes in providing marketing, communications, social media and event management for the “tecreational” and technical diving industry. Rosemary is a PADI IDC Staff Instructor, BSAC Advanced Instructor, Trimix, and CCR diver. Before moving into the public relations field, she worked as a professional recreational instructor, safety diver, and underwater model underwater and appeared on the History Channel and National Geographic documentaries. She established TEKDiveUSA and organized Rebreather Forum 3 on behalf of AAUS, DAN, and PADI. In 2008, Rosemary co-founded EUROTEK, the European advanced and technical diving biennial conference. She is a respected and prolific diving author, an SSI Platinum Diver, an Associate Member of the Women Divers Hall of Fame, and sits on the SITA Board (Scuba Industry Trade Association).

Continue Reading