water quality

*My original Diatom Forest illustration in my article “Diatom Spring” in The Meaning of Water*

This past spring, Dutch scientist Herman van Dam (Consultancy for Water and Nature) approached me for permission to use my illustration of the diatom forest in a paper he and co-authors were preparing for the Dutch journal H2O. He explained that they wanted to help familiarize water managers who read the journal with the underwater biodiversity for which my illustration would be helpful.

The Illustration

He’d seen my illustration in my article “A Diatom Spring” in The Meaning of Water. Below is a summary of my article about the diatom forest:

Attachment and colonization starts with a ‘clean’ unpopulated surface (usually scoured by turbulence in a storm or some other event or a new surface tumbled into the water). Several stages of succession take place, starting with early colonizers. The adnate Cocconeis placentula, whose frustules attach directly to the substrate, is an example of an early colonizer. When they attach to a substrate they form a biofilm (think moss in a terrestrial forest). Adnate species are eventually overgrown by taxa that produce a mucilaginous pad (e.g. Synedra) or stalk (e.g. Gomphonema). The understory layer is typically occupied by diatoms such as Fragilaria vaucheriae and Synedra radians that attach to the surface at one end (apical) of their rod-shaped frustules using a mucilaginous pad to form “rosettes” that resemble spiky understory shrubs. This allows them to protrude above the adnate taxa and take advantage of more light.

*SEM of* Synedra radians and Fragilaria vaucheriae that form rosettes as they apically attach to substrate (image by Roemer et al., 1984)

The diatoms Cymbella and Gomphonema produce long stalks that attach directly to the surface, allowing them to form a swaying canopy over the lower tier of cells of Fragilaria vaucheriae, Synedra radians and early colonizer Cocconeis placentula whose frustules attach directly to the substrate (think overstory and understory of a terrestrial forest or a marine kelp forest).

The Diatom Forest Structure

Just like trees, the canopy-forming stalked diatoms effectively compete for available light and nutrients in the water with their vertical reach. They provide the ‘overstory’ of the diatom forest’s vertical stratification. These tree-like diatoms also provide an additional surface for other diatoms to colonize (e.g. tiny epiphytic Achnanthes settle on the long stalks of Cymbella, just as lichen does on a tree trunk).

*SEM of three-week colony of* Cymbella affinis (larger diatoms on left) and Gomphonema olivaceum attached via stalks (image from Roemer et al., 1984)

The stalked diatom forest acts like a net, trapping drifting-in euplankton, such as Pediastrum sp. andFragilaria spp., which then decide to stay and settle in with the periphyton community. The mucilage captures and binds detrital particles in both lower and upper stories of the diatom forest; these, in turn, provide nutrients for the diatom forest and additional surfaces for colonization. In their work with periphyton communities, Roemer et al. (1984) found several diatoms (e.g. Diatoma vulgare, Fragilaria spp. Stephanodiscus minutula) entangled in the complex network of cells, stalks, and detritus of the diatom forest’s upper story. They also found rosettes of Synedra radians—like jungle orchids—attached to large clumps of sediment caught by the net of mucilage.

Eventually, ‘overgrowth’ occurs as the periphyton colony matures and grows ‘top-heavy’ with all this networking. The upper story of the community simply sloughs off—usually triggered by turbulence in a river from rains, storms, or dam release. This is similar to a forest fire in the Boreal forest, which creates space and light for new colonization and growth. The dislodged periphyton ride the turbulent flow, temporarily becoming plankton, and those that survive the crashing waters provide “seed” to colonize substrates downstream. Others may get damaged and form the ‘dish soap’ like suds or foam you often see in turbulent water. The proteins, lignins and lipids of the diatoms (and other associated algae) act as surfactants or foaming agents that trap air and form bubbles that stick to each other through surface tension.

*Diatoms, organics and associated detritus forms foamy ‘crema’ on the river (photo by Nina Munteanu)*

*Fragmented diatoms and organic material create a surface foam on the river (photo by Nina Munteanu)*

The Paper

The paper was published June 13, 2024, in H2O, written by Jako van der Wal, Joep de Koning and Herman van Dam, and entitled “Snel inzicht in de ecologische waterkwaliteit met diatomeeën” (Quick insight into ecological water quality with diatoms). This paper was right up my alley! As a diatom specialist and limnologist who studied them in relation to environmental conditions and perturbations, I was intrigued by the paper and gained some additional insight on diatom ecology.

Van der Wal et al. cited recent advances in DNA-based identification methods that provide fast and cheap diatom identification over the traditional method of using an optical compound microscope to observe morphological characteristics such as size, shape and ornamentations of the silicified cell wall. I can attest that this is a labour-intensive process in which I spent many hours and days hunched over a microscope during my masters research at Concordia University. This efficient DNA-identification has seen a resurgence of using diatoms as a valuable tool for water quality managers, with applications providing insight into both current and historical water conditions. The authors argue that benthic diatoms or periphyton (living on substrates such as plants, rock, sand and artificial surfaces) have been since the 1980s used as indicators of saproby, trophy, acid and salt character in, among other things, ditches and canals. For every type of water and water quality, there are diatoms that have their habitat there, write the authors. They argue that, unlike phytoplankton, fish and macrofauna, periphyton attach to a surface and hardly move; this means that effects of water quality can be demonstrated locally. Because many diatom species tolerances and intolerances are known and they reproduce quickly (over days), diatoms respond quickly to changes in the environment—much faster (often within weeks) than other ecological indicators.

Scientists and water technicians can use diatom species composition to measure perturbations by organic material, low oxygen content, eutrophication, and toxicity. Given that diatoms colonize and develop quickly, this includes unstable and damaged habitats where other indicators cannot develop, such as shipping traffic, waves or where cleaning or dredging is carried out regularly. Historical insight can be provided by diatoms, given that their silica frustules are naturally preserved in sediment.

My Own Work with Turbulence

*Periphyton biofilm (of mostly diatoms) on microscope slides left in a stream*

During my masters research in several streams in the Eastern Townships, I examined how diatoms colonized artificial substrates; how they formed productive biofilms that sustained an entire periphyton community of attached aquatic life and discovered that their pattern of colonization related to current speed and direction. I submerged glass slides (the kind people use to look at critters under the microscope) in a device in the stream and oriented them parallel or perpendicular to the current.

There are two ways an algal community grows in a new area: (1) by initial colonization and settling; and (2) by reproduction and growth. I studied both by collecting slides exposed for differing lengths of time (collecting young and mature communities) in different seasons.

I discovered that the diatoms colonized these surfaces in weird ways based on micro-turbulence. Early colonizers, like Achnanthes and adnate Cocconeis preferred to settle on the edges of the slides, where the chaos of turbulence ruled over the sheer of laminar flow. They colonized by directly appressing to the substrate, making them the first photosynthetic taxa to establish a biofilm on a clean substrate. Vadeboncoeur and Katona (2022) write that “in waved-washed surfaces, these taxa may be the only algae that persist.” I postulated that the drift velocity was reduced on the slide’s edge, where turbulence was greatest, giving drifting algae a greater chance to collide and settle on the slide over the more shear laminar flow along the slide’s central face.

Once settled, the community was more likely to grow with turbulence. Greater turbulence decreases the diffusion gradient of materials around algal cells, with a higher rate of nutrient uptake and respiration. Turbulence provides greater opportunity to an existing colony by increasing “chaotic” flow, potential collision and exchange. Turbulence is a kind of “stable chaos” that enhances vigor, robustness and communication.

Using Diatoms in Water Quality Assessments

In their paper Van der Wal et al. argued that in environmental assessment the DNA-identification is just one step in a process that looks a population structure and health. Diatoms are already used in 21 of the 27 EU countries as part of a Water Framework Directive (WFD) quality index for flowing waters and in nine EU countries for standing water. Example conditions and associated perturbations where diatoms are a particularly useful indicator include: salinity, acidity, oxygen saturation, organic load (saproby), nutrient richness (trophy), temperature, and toxicity.

Diatom Growth Forms & Deformities

Van der Wal et al. argued that in addition to the different species compositions and the related ecological indices, growth forms and deformations of diatoms are useful indicators of water quality, particularly in relation to specific toxins.

*My illustration adapted for the van der Wal et al. paper in H2O*

Growth forms of diatoms can be described as attached, short-stalked, long-stalked, mobile and living in mucous tubes (Figure 3, van der Wal et al., 2024). Each growth form has advantages and disadvantages. For example, short-stalked diatoms are more difficult to graze and long-stalked diatoms come into contact with more water, from which they can then absorb substances. Long-stalked diatoms can also absorb more light if there is a lot of competition. Mobile diatoms can adapt to changing conditions by, for example, migrating from surface to subsurface and vice versa. Diatoms in slime tubes are more difficult to prey on and respond more slowly to environmental changes.

Two frustules of Navicula *sp; the one on the right shows obvious deformities in the striations of its silica frustule (photo by van* der *Wal, H2O, June 13, 2024)*

According to Van der Wal et al., scientistis (Rimet & Bouchez) noted that long-stalked diatoms declined in waterbodies subjected to various pesticides. Falasco et al. observed diatom deformities when exposed to various toxic substances. Heavy metals were observed to cause deformities in Navicula. Nitrogen toxicity was also implicated in diatom deformities.

*Froth from diatoms and organics on the Otonabee river, ON (photo by Nina Munteanu)*

References:

Falasco, E., Ector, L., Wetzel, C.E., Badino, G. & Bona, F. (2021). “Looking back, looking forward: a review of the new literature on diatom teratological forms (2010-2020).” Hydrobiologia 848: 1675-1753.

Munteanu, N. 2022. “When Diatoms Create a Forest.” https://themeaningofwater.com. December 18, 2022.

Munteanu, N. 2023. “When Diatoms Bloom in Spring.” https://themeaningofwater.com. May 14, 2023.

Munteanu, N. 2023. “A Diatom Spring.” https://themeaningofwater.com. April 16, 2023.

Munteanu, N. & E. J. Maly, 1981. The effect of current on the distribution of diatoms settling on submerged glass slides. Hydrobiologia 78: 273–282.

Munteanu, Nina. 2016. “Water Is…The Meaning of Water.” Pixl Press, Delta, BC. 584 pp.

Poikane, S., Kelly, M., & Cantonati, M. (2016). ‘Benthic algal assessment of ecological status in European lakes and rivers: challenges and opportunities’. Science of the Total Environment 568: 603-613.

Rimet, F. & Bouchez, A. (2011). ‘Use of diatom life-forms and ecological guilds to assess pesticide contamination in rivers: Lotic mesocosm approaches’. Ecological Indicators 11: 489-499.

Roemer, Stephen C., Kyle D. Hoagland, and James R. Rosowski. 1984. “Development of a freshwater periphyton community as influenced by diatom mucilages.” Can. J. Bot. 62: 1799-1813.

Serôdio, J. & Lavaud, J. (2020). “Diatoms and their ecological importance”. In: Leal Filho, W. et al. (eds). Life below water. Encyclopedia of the UN Sustainable Development Goals (pp.1-9). Springer Nature.

Smolar-Zvanut, Natasa and Matjaz Mikos. “The impact of flow regulation by hydropower dams on the periphyton community in the Soca River, Slovenia. Hydrological Sciences Journal 59 (5): 1032-1045.

Wal, J. van der, Joep de Koning and Herman van Dam. 2024. “Snel inzicht in de ecologische waterkwaliteit met diatomeeën” H2O, 13 June, 2024.

Wood, Allison R. 2016. “Attached Algae as an Indicator of Water Quality: A Study of the Viability of Genomic Taxanomic Methods.” Honors Theses and Capstones. 306. University of New Hampshire Scholars’ Repository.

Zuilichem, H. van, Peeters, E. & Wal, J. van der (2016). “Diatomeeën als indicator voor waterkwaliteit nabij rwzi’s”. H2O-Online, 9 december 2016. https://edepot.wur.nl/401202

Nina Munteanu is a Canadian ecologist / limnologist and novelist. She is co-editor of Europa SF and currently teaches writing courses at George Brown College and the University of Toronto. Visit www.ninamunteanu.ca for the latest on her books. Nina’s bilingual “La natura dell’acqua / The Way of Water” was published by Mincione Edizioni in Rome. Her non-fiction book “Water Is…” by Pixl Press(Vancouver) was selected by Margaret Atwood in the New York Times ‘Year in Reading’ and was chosen as the 2017 Summer Read by Water Canada. Her novel “A Diary in the Age of Water” was released by Inanna Publications (Toronto) in June 2020.

Global Newswire announced yesterday that Ryan Reynolds and Blake Lively donated half a million dollars to the Canadian charity Water First Education & Training Inc. to support the locally-based hands-on skills training and education programs with indigenous communities. The program focuses on young indigenous adults in learning water science and becoming certified water operators and environmental technicians.

“One of the most fundamental challenges in Canada today is the lack of sustainable access to safe, clean water in many Indigenous communities,” writes Global Newswire. “Successive federal governments have failed to address the issue, with the likelihood of having no access to safe, clean water still far more prevalent in the lives of Indigenous Peoples, compared to non-Indigenous populations in Canada.”

At least 15%, or approximately one in six First Nations communities in Canada, are still under a drinking water advisory. Everyone has a right to safe, clean water. The water crisis in Indigenous communities is unacceptable.”
Water First

“Access to clean drinking water is a basic human right. Canada is home to over 20% of the planet’s freshwater — an abundance that’s envied around the world. There’s absolutely no reason Indigenous communities should not have access to safe, clean water. All the individuals involved, whether they are operating water systems or monitoring their local water bodies, are critical. We appreciate Water First’s focus on supporting young, Indigenous adults to become certified water operators and environmental technicians. These folks are helping to ensure sustainable access to safe, clean water locally, now and for the future. Blake and I are thrilled to support this important work.”
Ryan Reynolds

*Using a Van Dorn sampler to collect water at depth*

“Nobody understands the evolving challenges and needs more than the people who live there,” says Water First. “Drinking water challenges are complex: in some communities, local concerns may be around infrastructure, for others, source water contamination. And numerous communities have challenges recruiting and training young Indigenous adults to join the drinking water field.”

“Safe water needs skilled people”
Water First

Water First shares that Indigenous communities have identified the need for more young, qualified and local personnel to support solving water challenges. In partnership with indigenous community leaders, Water First customizes local water-focused education and training programs to align with community goals and needs. These partnerships are built on trust, meaningful collaboration and reciprocal learning.

Spencer Welling, Water First intern from Wasauksing First Nation shares, “I am doing this for myself, my family and community. It’s important to know how things are done and gives you a better appreciation for it. It’s a good career to have, which I’m sure would ease my parents’ minds knowing that. It also feels good knowing that my community will have a local water treatment operator at the plant for at least a couple decades.”

In 2018, CBC ran a story on a pilot training project that Water First ran with Indigenous youth to help tackle water challenges in their communities. The program ran as a 15-month paid internship toward ensuring communities have quality drinking water. Ten youth were involved. The training, which included week-long workshops (including mapping, traditional knowledge, and environmental science) and hands-on training at their local water treatment plants, focused towards a provincially recognized certification as a Water Quality Analyst. Certification through an exam at the Ministry of the Environment, Conservation and Parks permits them to do drinking water testing. They can receive further certification as operators through another exam.

Anyone interested in learning about Water First and its education and training programs can find out more at www.waterfirst.ngo.

Water First Education & Training Inc. (Water First) is a registered Canadian charity that works in partnership with Indigenous communities to address water challenges through education, training and meaningful collaboration. Since 2009, Water First has collaborated with 56 Indigenous communities located in the lands now known as Canada while supporting Indigenous youth and young adults to pursue careers in water science.

For more information, you can contact:

Ami Gopal
Director of Development and Communications
Water First
1-905-805-0854
ami.gopal@waterfirst.ngo

Nina Munteanu Writing Coach

H2O Publishes my Illustration of the Diatom Forest

Ryan Reynolds and Blake Lively Donate to Indigenous Education on Water Science