Abraham U. Morales-Primo

Facultad de Medicina, Universidad Nacional Autónoma de México, Hospital General de México, Mexico City, Mexico.

E-mail: aump.puma (at) gmail (dot) com

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Marine ecosystems play a vital role in maintaining the planet’s stability. They contribute to temperature regulation, carbon dioxide absorption, storm and flood mitigation, and serve as habitats for an immense variety of species (Barbier, 2017). These ecosystems also provide essential services that directly benefit humanity. The exploitation of marine natural resources supports numerous economic sectors, including fishing, maritime transportation, biotechnology, and tourism (Barbier, 2017). In its 2015 report “Reviving the Ocean Economy: The Case for Action”, the WWF estimated the ocean’s total value at $24 trillion, although this wealth is rapidly declining (Hoegh-Guldberg et al., 2015). Overfishing, climate change, and pollution remain the primary threats, undermining not only the ocean’s economic potential but also its environmental integrity (UNCTAD, 2023).

Ocean pollution, in particular, involves the release, discharge, or disposal of contaminants into the environment, including chemical compounds, trash, and other debris (NOAA, 2023). These pollutants disrupt marine ecosystems by contributing to the formation of garbage patches, toxic algal blooms, coral bleaching, and the bioaccumulation of heavy metals and microplastics (Marcharla et al., 2024; Aziz et al., 2023; Lebreton et al., 2018).

Marine faunas are especially vulnerable to the detrimental effects of these pollutants, exhibiting health problems via debris ingestion, impairing reproduction and development, and altering behavior (Thushari et al., 2020; Oehlmann et al., 2009). Such environmental threats have been depicted in various forms of media, serving as both artistic inspiration and tools for raising awareness.

Another Crab’s Treasure is an action-platformer video game developed by Aggro Crab that follows the story of Kril, a hermit crab on a journey to recover his confiscated shell. Along the way, Kril encounters numerous locations afflicted by pollution, including coral reef cities buried in trash, poisonous sludge lakes, sandy sea floors littered with microplastics, bleached coral areas, and algae forests damaged by eutrophication. Furthermore, a blight known as the Gunk has spread throughout the ocean due to the accumulation of trash, rendering afflicted fauna irreversibly violent and erratic. As a hermit crab, Kril can use trash to replace his shell, defend himself against Gunk-infected enemies, aid in traversal, and even serve as clothing.

Despite the clear inspiration and representation of human impact in the game, little is explained about the biological processes affecting these organisms and their environments. In this work, we examine the biological mechanisms underlying the effects of marine debris and overall pollution, as portrayed in the game, and place these fictional depictions in the context of real-world oceanic conditions.

Another Crab’s Treasure showcases a diverse array of marine life, including fish, mollusks, worms, and arthropods such as shrimps, isopods, lobsters, and, of course, crabs. However, this fauna is shown struggling against persistent pollution. In the following sections, we will contextualize how different contaminants present affect both the ecosystem and its inhabitants.

THE GUNK

The Gunk is a purplish, iridescent substance that spreads across the seafloor, corrupting not only the marine environment but also the very conscience of its inhabitants (Fig. 1). For the player, contact with Gunk pools inflicts a poison-like status effect, gradually depleting health points (HP). For non-playable characters (NPCs), however, prolonged exposure results in drastic behavioral changes. Once afflicted, these characters fall into nihilism and hostility, attacking Kril on sight.

Figure 1. Environment and fauna afflicted by the Gunk. a) River of “Gunk” running through the Expired Grove’s seabed. b) Magista, Tyrant of Slacktide, a crab, spewing “Gunk” during her boss battle. Kril is shown for scale. Game screenshots were captured on a PC.

The Gunk shares several similarities with real-world contamination sources such as leachates from landfills, agricultural runoff entering the sea, and oil spills.

On the one hand, leachate forms when water percolates through solid waste, dissolving and transporting hazardous substances (Shaari et al., 2021). Once in the ocean, it introduces heavy metals, organic chemicals, and pathogens, creating toxic conditions for marine organisms (Shaari et al., 2021). Runoff, on the other hand, refers to surface water flow that carries contaminants into rivers, lakes, or coastal systems (Müller et al., 2020).

One of the principal consequences of both leachates and runoff is eutrophication, the excessive enrichment of aquatic systems with nutrients, particularly nitrogen and phosphorus. Landfill leachate wastewater is typically characterized by high values of chemical oxygen demand (COD), acidity, ammonia, heavy metals, and organic materials (Shaari et al., 2021). Such chemical imbalances promote harmful algal blooms (HABs) that degrade water quality and threaten the survival of marine fauna (Akinnawo, 2023). Indeed, HABs secrete bioactive extracellular compounds with paralytic effects on shellfish and other ichthyotoxic effects on fish (Rolton et al., 2022). This phenomenon is reflected in the Expired Grove, a region overrun by algal blooms to the extent that algae even grow on the shells of crabs and on the skin of fish. Figure 2 shows the Diseased Lichenthrope, a fish similar to the frogfish with a watering can on its head and algae growing on its skin.

Figure 2. Algae overgrowth on fish in the Expired Grove. a) The Diseased Lichenthrope resembles b) a frogfish with algae growing on its skin and a watering can placed on its head. Kril is shown for scale. Game screenshots were captured on a PC. The frogfish image was obtained from Wikimedia Commons (Stephen Childs – Flickr, CC BY-SA 2.0).

Similarly, oil spills involve the release of hydrocarbon-derived compounds into aquatic systems (Zhang et al., 2019). Common sources of oil contamination include shipwrecks, fuel leaks, offshore platforms, and drilling rigs (Zhang et al., 2019). Oil pollution primarily affects the marine environment in two ways: oiling and toxicity (NOAA, 2024). Oiling physically coats aquatic organisms with oil, often leading to suffocation and death. Toxicity*,* on the other hand, arises from the release of harmful compounds such as mono- and polycyclic aromatic hydrocarbons, with effects ranging from cellular damage to shifts in population and community dynamics (NOAA, 2024; National Research Council, 2003). Indeed, oil can enter the food chain via plankton and cause impaired development, deformities, and death in fish, bivalves, and crustaceans (Vignier et al., 2015; Mitra et al., 2012; Kasymov et al., 1987). The impact of hydrocarbon pollution is evident in the Flotsam Vale area, where debris from a shipwreck, including shipping containers and propane tanks, is observed. This contamination gives the water a brownish appearance and leads to the formation of viscous pools of Gunk on the seabed (Fig. 3a).

Figure 3. Hydrocarbon and chemical contamination in Flotsam Vale. a) Pool of “Gunk” on the seabed, derived from shipwreck debris and oil spills. b) Car batteries acting as a source of cadmium contamination. Kril is shown for scale. Game screenshots were captured on a PC.

Flotsam Vale also illustrates another form of chemical contamination: heavy metal pollution from discarded car batteries (Fig. 3b). Batteries are classified as hazardous materials because they contain ecotoxicological components, such as cadmium, lead, lithium, nickel, and other emerging contaminants, including metal and carbon nanomaterials, as well as ionic liquids (Melchor-Martínez et al., 2021). These compounds induce toxicity manifested through bioaccumulation in tissues, embryonic malformations, organ damage, elevated oxidative stress, and interference with DNA synthesis, ultimately contributing to carcinogenic processes (Melchor-Martínez et al., 2021).

Together, these contaminants create inhospitable conditions across the microenvironments of Another Crab’s Treasure, symbolized by the Gunk itself. Yet the ocean floor is poisoned not only by invisible chemicals, but also physically smothered by discarded trash.

THE GARBAGE PATCH

Every area in Another Crab’s Treasure shows some degree of trash pollution. The seafloor is often covered in multicolored plastic particles, similar to those seen in The Sands Between, and even coral reef cities, such as New Carcinia, are found buried in debris (Fig. 4a,b). Pollution extends even into the abyssal depths of The Unfathom, where trash can still be observed (Fig. 4c).

Figure 4. Presence of trash in different oceanic regions. a) Microplastics and glass debris in the neritic zone of The Sands Between. b) Piles of trash burying the coral reef city of New Carcinia. c) Polystyrene packing peanuts and glow sticks in the abyssal region of The Unfathom. d) Buoyant pieces of trash in the floating garbage patch. Kril is shown for scale. Game screenshots were captured on a PC.

Unlike chemical contamination, which has multiple sources, trash pollution in Another Crab’s Treasure can be traced to a more specific origin: garbage patches (Fig. 4d). Garbage patches, also known as garbage islands, are large accumulations of debris formed by oceanic gyres, circular currents that trap and concentrate floating waste and organic material (Leal Filho et al., 2021). The Great Pacific Garbage Patch, for example, is the largest in the world, covering an estimated 1.6 million km² and containing ~80,000 metric tons of plastic waste, including fishing gear, bottles, and other small rigid objects (Lebreton et al., 2018).

However, garbage patches are not restricted to the open ocean; they can also form in coastal areas. These coastal garbage patches (CGPs) develop at oceanic fronts, regions where two water masses converge, and typically accumulate buoyant plastics such as films (Hajbane et al., 2021). Since Another Crab’s Treasure takes place in tidepools and coral reef systems, the garbage patch depicted in the game can be inferred as a CGP. In this context, the trash that rains down onto the seabed and reefs can be traced directly to its accumulation above.

The presence of this debris has multiple ecological effects, both in the game and real-life ecosystems. First and foremost, the trash is scattered throughout the environment, covering ecosystems such as coral reefs and algae forests, and forcing the fauna to adapt. One way the fauna adapts is by using the trash as shelter, makeshift clothing, or protection (e.g., Fig. 5).

Figure 5. Another Crab’s Treasure and real-world hermit crab adaptation to debris. a) Kril and b) a Coenobita purpureus hermit crab carrying a plastic cap as “trash shells”. Game screenshots were captured on a PC. Coenobita purpureus photo by Shawn Miller (2015), retrieved from Burgess (2016).

In real ecosystems, marine debris provides new artificial habitats for pelagic and coastal species (Haram et al., 2021). However, this same debris can also damage sedentary organisms through breakage and abrasion (Aguilar et al., 2022). Colonization of human-made litter not only affects benthic organisms but also disrupts other ecosystems. For instance, the colonization of buoyant debris creates a “raft effect” that transports fauna and threatens foreign ecosystems (De-la-Torre et al., 2023).

One of the most recognizable examples of trash being used as shelter comes from our hermit crab protagonist, Kril (Fig. 5a). Due to their evolutionary history, hermit crabs depend on empty gastropod shells for survival, as their soft, asymmetrical, coiled abdomens are adapted to fit inside them. These shells provide not only protection and shelter but also influence the crustacean’s development (da Silva et al., 2020). Hermit crabs, however, have had to adapt to the presence of litter, exchanging their shells for trash (Fig. 5b). In Kril’s case, these “trash shells” not only grant him protection but also special abilities he can use against enemies. Nonetheless, it has been suggested that real-life hermit crabs carrying “trash shells” would experience reduced reproductive success, higher metabolic costs, and an impaired anti-predatory effectiveness (Jagiello et al., 2024).

Although trash provides certain advantages for Kril, it remains a pervasive and insidious component of ocean pollution, with detrimental effects on marine environments that will persist for years to come.

MICROPLASTICS

Regarding trash pollution, one of its most prominent components is microplastics. These consist of plastic particles less than 5 mm in size, originating from the fragmentation or degradation of larger plastic waste (Marcharla et al., 2024). Such fragments have become ubiquitous hazardous materials, accumulating across virtually every ecosystem.

Another Crab’s Treasure, however, peculiarly depicts microplastics: they function as a form of currency used to purchase items or costumes. Fittingly (though unfortunately), microplastics are obtained through the sale of plastic trash, such as hair claws or staple removers, as well as by defeating enemies. This latter gameplay mechanic implies that marine fauna carries microplastics on their bodies (Fig. 6). Indeed, ingestion of microplastics leads to their bioaccumulation in the tissues of the marine fauna, causing toxic effects on the host (Yang et al., 2021). These effects can be further exacerbated when microplastics interact with other chemical pollutants (Yang et al., 2021). Altogether, this combination of chemical and plastic pollutants could serve as a biological explanation for the heightened aggression of the fauna encountered in Another Crab’s Treasure.

Figure 6. Defeated enemies bear microplastics within them. A sardine enemy releasing microplastics (black arrows) after being defeated by Kril’s fork attack. Game screenshots were captured on a PC.

CONCLUSION

Behind the action and adventure of Another Crab’s Treasure lies an ecological warning about the damage that contamination inflicts on marine ecosystems. The representation of trash and the indifference of the game’s inhabitants toward it serve as a metaphor for our own lack of awareness of the catastrophic consequences our waste may bring. Scientific evidence already demonstrates the harm trash causes to marine fauna, and whilst video games can help translate that knowledge into narratives that raise public awareness, awareness alone is not enough. If we truly want (and urgently need) to prevent these outcomes, further action must be taken. Trash should never be anyone’s treasure.

REFERENCES

**Aguilar, R.; Álvarez, H.; Sánchez, N.; Marín, P. **(2022) Underwater Dumps: The plastic siege on biodiversity. Oceana, Madrid.

Akinnawo, S.O. (2023) Eutrophication: causes, consequences, physical, chemical and biological techniques for mitigation strategies. Environmental Challenges 12: 100733.

**Aziz, K.H.H.; Mustafa, F.S.; et al. **(2023) Heavy metal pollution in the aquatic environment: efficient and low-cost removal approaches to eliminate their toxicity: a review. RSC advances 13: 17595–17610.

Barbier, E.B. (2017) Marine ecosystem services. Current Biology 27: R507–R510.

Burgess, A. (2016) Incredible photos of the hermit crabs who live in trash. Atlas Obscura. Available from: https://www.atlasobscura.com/articles/the-trash-homes-of-hermit-crabs (Date of access: 24/Oct/2025).

da Silva, A.R.; Rodrigues, G.F.; Lima, D.; et al. (2020) The hermit crab–shell relationship through the lens of interaction networks: the use of network metrics and species role across communities. Austral Ecology 45: 896–908.

**De-la-Torre, G.E.; Romero Arribasplata, M.B.; Lucas Roman, V.A.; et al. **(2023) Marine litter colonization: methodological challenges and recommendations. Frontiers in Marine Science 10: 1070575.

**Hajbane, S.; Calmanovici, B.; Reisser, J.; et al. **(2021) Coastal garbage patches: fronts accumulate plastic films at Ashmore Reef marine park (Pulau Pasir), Australia. Frontiers in Marine Science 8: 613399.

Haram, L.E.; Carlton, J.T.; Centurioni, L.; et al. (2021) Emergence of a neopelagic community through the establishment of coastal species on the high seas. Nature Communications 12: 6885.

Hoegh-Guldberg, O.; et al. (2015) Reviving the Oceans Economy: The case for action, — 2015. WWF International, Geneva.

Jagiello, Z.; Dylewski, Ł.; Szulkin, M. (2024) The plastic homes of hermit crabs in the Anthropocene. Science of The Total Environment 913: 168959.

Kasymov, A.G. & Gasanov, V.M. (1987) Effect of oils and oil-products on crustaceans. Water, Air, and Soil Pollution 36: 9–22.

Leal Filho, W.; Hunt, J.; Kovaleva, M. (2021) Garbage patches and their environmental implications in a plastisphere. Journal of Marine Science and Engineering 9: 1289.

Lebreton, L.; Slat, B.; Ferrari, F.; et al. (2018) Evidence that the Great Pacific Garbage Patch is rapidly accumulating plastic. Scientific Reports 8: 4666.

Marcharla, E.; Vinayagam, S.; Gnanasekaran, L.; et al. (2024) Microplastics in marine ecosystems: a comprehensive review of biological and ecological implications and its mitigation approach using nanotechnology for the sustainable environment. Environmental Research 256: 119181.

Melchor-Martínez, E.M.; Macias-Garbett, R.; Malacara-Becerra, A.; et al. (2021) Environmental impact of emerging contaminants from battery waste: a mini review. Case Studies in Chemical and Environmental Engineering 3: 100104.

Mitra, S.; Kimmel, D.G.; Snyder, J.; et al. (2012) Macondo‐1 well oil‐derived polycyclic aromatic hydrocarbons in mesozooplankton from the northern Gulf of Mexico. Geophysical Research Letters 39: L01605.

Müller, A.; Österlund, H.; Marsalek, J.; Viklander, M. (2020) The pollution conveyed by urban runoff: a review of sources. Science of the Total Environment 709: 136125.

National Research Council. (2003) Oil in the Sea III: Inputs, fates, and effects. National Academies Press, Washington, D.C.

NOOA (National Oceanic and Atmospheric Administration). (2023) Ocean pollution and marine debris. NOAA. Available from: https://www.noaa.gov/education/resource-collections/ocean-coasts/ocean-pollution (Date of access: 28/Aug/2025).

NOOA (National Oceanic and Atmospheric Administration). (2024) Oil spills. NOAA. Available from: https://www.noaa.gov/education/resource-collections/ocean-coasts/oil-spills (Date of access: 28/Aug/2025).

**Oehlmann, J.; Schulte-Oehlmann, U.; Kloas, W.; et al. **(2009) A critical analysis of the biological impacts of plasticizers on wildlife. Philosophical Transactions of the Royal Society B 364: 2047–2062.

Rolton, A.; Rhodes, L.; Hutson, K.S.; et al. (2022) Effects of harmful algal blooms on fish and shellfish species: a case study of New Zealand in a changing environment. Toxins 14: 341.

Shaari, A.L.; Sa, S.N.C.; Surif, M.; et al. (2021) Growth of marine microalgae in landfill leachate and their ability as pollutants removal. Tropical Life Sciences Research 32: 133.

Thushari, G.G.N. & Senevirathna, J.D.M. (2020) Plastic pollution in the marine environment. Heliyon 6: e04709.

UNCTAD (United Nations Conference on Trade and Development). (2023) Fast-growing trillion-dollar ocean economy goes beyond fishing and shipping. UNCTAD. Available from: https://unctad.org/news/fast-growing-trillion-dollar-ocean-economy-goes-beyond-fishing-and-shipping (Date of access: 28/Aug/2025).

Vignier, J.; Donaghy, L.; Soudant, P.; et al. (2015) Impacts of Deepwater Horizon oil and associated dispersant on early development of the eastern oyster Crassostrea virginica. Marine Pollution Bulletin 100: 426–437.

Yang, H.; Chen, G.; Wang, J. (2021) Microplastics in the marine environment: sources, fates, impacts and microbial degradation. Toxics 9: 41.

**Zhang, B.; Matchinski, E.J.; Chen, B.; et al. **(2019) Marine oil spills—oil pollution, sources and effects. In: Sheppard, C. (Ed.) World Seas: An environmental evaluation. Academic Press, Cambridge. Pp. 391–406.

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Acknowledgments

This work was partly supported by using Grammarly for grammar and style suggestions. The author reviewed, edited, and revised the texts and suggestions to his liking and takes ultimate responsibility for the content of this publication.

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About the author

MSc. Abraham U. Morales-Primo is a Mexican biologist and science communicator specializing in the role of NETs in leishmaniasis. A proud geek, he explores the biological mechanisms of video game-related phenomena (and sometimes real-world ones). When he’s not theorizing about carcinization, he’s dreaming up new ways to blend science with video game culture; all in the company of his wife and their beloved puppy.