The Matcha Lagoon has expired

It’s 12:30 p.m. You’ve just finished a grueling three-hour lecture or bombed a 100-item midterm exam, all because the university will not cancel face-to-face classes unless the heat index hits 42°C. All you want is a quiet spot by the Lagoon to eat your lunch and relax for a while. 

​But as you went to the usual budget-friendly eating place of PUPians, you’re met with a view that looks like something out of a café promo… but smells like the inside of a sewer… 

The Matcha Lagoon is the campus’s favorite recurring meme. But for those trying to relax in between classes or enjoy a meal nearby, it’s a literal sensory crisis. It looks like a premium, 0% sugar latte, but the sharp, sulfurous "rotten egg" punch hitting your nostrils is a reminder that this isn't a cafe. It’s a biological crime scene.

The ingredients

​To understand why the Lagoon looks like a venti-sized matcha latte, we have to look at the "recipe" simmering in the Sta. Mesa heat. This isn't just dirty water; it’s a textbook case of eutrophication, a process in which water becomes overly enriched with minerals.

Figure 1. Biogeochemical Stages of Eutrophication

The "base" for this brew is a mixture of Nitrogen (N) and Phosphorus (P). These act as the primary fuels for aquatic growth, or what we call “nutrient pollution.” It is like the "syrup pumps" of the disaster. In an urban setting like Polytechnic University of the Philippines (PUP), these likely seep in from campus runoff and decaying organic matter. In a stagnant system, they act as fuel for Harmful Algal Blooms (HABs).

​The bartender behind the counter is the Manila Heat Index. As the sun beats down on the Pylon, it "steams" the water, turning the lagoon into an outdoor bioreactor. This triggers a population explosion of cyanobacteria. These organisms multiply exponentially, serving as the "matcha powder" that gives the drink its vibrant, opaque color.

Figure 2. Intensive cyanobacteria bloom at the PUP Lagoon (May 7, 2025).

​Photo by Jannine Lagbawan

This is not a healthy growth. Research from recent studies explains that this film acts as a "lid," blocking sunlight and preventing natural aeration, a neon-green seal that is effectively suffocating everything beneath it.

Bad brew

​The science of the "matcha" isn't just about the ingredients, but how the heat "stirs" the system. According to the Urban Heat Island effect, concrete-heavy campus environments trap and intensify heat far more effectively. When the heat index reaches the danger level, the Lagoon functions as a heat sink, maintaining the water at temperatures that accelerate the fermentation of this toxic "brew.”

​A 2018 study in Nature Climate Change highlights that rising temperatures are a primary driver of these blooms. Heat reduces water viscosity, allowing the bacteria to float to the surface faster to form that thick film.    

The thick green film acts like a “lid”, sealing the water off from the air. This causes hypoxia, where the oxygen levels in the water drop to zero.

​Beneath this "lid," bacteria use up all the remaining dioxygen (O₂) to decompose the dead algae. Once the oxygen is gone, the lagoon turns anaerobic. The "good" bacteria die, and a different type takes over that doesn't need air. Instead of breathing, they break down waste by releasing Hydrogen Sulfide (H₂S), the gas responsible for that "rotten egg" smell.

Aside from that, there are also sightings of floating dead tilapia in the neon-green waters, serving as "bio-indicators" of anoxia, a state of zero oxygen. These bodies are the final proof that the bacteria have completely suffocated the water, and the biological confirmation that the lagoon is now physically incapable of supporting life.

Aftertaste 

The performative "matcha" meme has officially reached its expiration date. What was once a recurring campus joke has curdled into a biological and political crisis that the PUP community can no longer afford to laugh off. 

At what point does the Matcha Lagoon stop being a campus meme and start being a sign that the university is no longer a safe or healthy "sanctuary" for the students forced to stay here?

​PUP Sentral na Konseho ng Mag-aaral (SKM) Councilor Michael Dave Bolima emphasizes that while the water was never pristine, the current state has reached a level of decay that needs no further elaboration. 

He describes the stench as literal and inescapable, a sentiment echoed by students, who find the situation alarming given its proximity to campus food stalls. For a student body already braving extreme heat in classrooms with failing ventilation, this rotting ecosystem is the breaking point.

​The film covering the water is the physical manifestation of systemic neglect. Bolima argues that the quality of education is inseparable from the state of the campus:

​"For years, we have been demanding for a more spaces, healthy environment, and quality education. Kasabay n'yan [ay] ung call natin for a well-ventilated and climate ready facilities. Kasi kaaakibat dapat ng quality education [ay] ang maayos na lagay ng pasilidad o pamantasan na nagiging sanctuary namin sa panahon na gusto namin mag-aral. Hanggang ganito ang danas ng mga estudyante sa PUP, hinding-hindi magiging quality ang edukasyong ibinibigay sa'min."

The Matcha Lagoon is the lungs of PUP, and right now, they are suffocating. It is no longer a joke or a meme. The neon-green film, the stench curling from its surface, the floating corpses of tilapia, the thick layer choking everything beneath, it all screams of a campus pushed to its limits. 

Students walk past it every day, carrying the weight of three-hour lectures in classrooms that bake under the sun, struggling through midterms while the very lungs of their university gasp for air. When the lungs are clogged, the whole body suffers. Classrooms, walkways, eating areas, and even spaces meant for quiet study should nurture learning, creativity, and rest. 

Instead, they have become extensions of a neglectful system, where decay is the only thing thriving. This rot is the record of years of underfunding, proof that when a university is starved of resources, its very environment begins to reject the students it was meant to protect. 

The call is urgent and undeniable: we deserve spaces that are safe, ventilated, climate-ready, and truly livable. Clean water, clean air, functional facilities, these are not luxuries; they are necessities. PUP must transform its campus into a sanctuary, or risk letting decay define the very education it promises.

Article: John David Parol

Graphics: Yvonne Gacillos