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Lakes: How they form and their vital role in the environment

By: Elizabeth Ann McNulty

Millions of lakes can be found around the world! Lakes are bodies of water surrounded by land, and they vary greatly in size, depth, location, and origin, and there is a story behind how each lake forms. Additionally, lakes also play a key role in ecosystems, providing us with water, food, plants, and sustaining diverse species that depend on these lakes for their survival. They are mainly affected by temperature, wind, and light, which all vary based on the location of the lake. Since lakes form in many different ways, such as through glacier activity, tectonic movement, volcanic activity, river systems, and human engineering, understanding these processes is essential for recognizing the important roles lakes have in maintaining a healthy environment (Lake, 2023).

Glacial Lakes: Above is an image of a glacial lake (Aerial, 2017).

Glaciers are massive bodies of snow and ice that have accumulated over thousands of years and move slowly across land. During the last Ice Age, many lakes formed when these glaciers moved across the land, carving out deep basins.  When the climate started to warm up around 10,000-15,000 years ago, the glaciers began to melt, and the water from the glaciers dripped and flowed down to fill these spaces, creating lakes. This process is one of the most common processes of lake formation, and it mainly occurred in regions such as Europe and North America (Knibb, 2023).

Tectonic Movement : Above is an image of a tectonic lake, called the Caspian Sea, which is the world’s largest lake, located between Asia and Europe. (Schmalz, 2010)

Seven major tectonic plates make up the crust of the Earth and have been moving throughout history. This movement causes volcanic eruptions, earthquakes, formation of mountains, but it can also lead to the creation of lakes. Tectonic lakes are created as a result of the deformation of the Earth’s crust. When the crust fractures or folds along the fault lines, basins or depressions are developed, which gradually fill with precipitation, groundwater, or inflowing streams to become lakes. They are essential because they act as water storage, provide unique habitats for species, as well as recreation (Tectonic, n.d.).

Volcanic Activity : Above is Crater Lake located in the caldera of Mount Mazama, Oregon. It is one of the deepest and clearest lakes in the world.

Some lakes form when the crater (also known as the caldera) of inactive volcanoes fill up with rain or snow once a volcano becomes inactive, creating what are known as crater lakes. Volcanic lakes are produced by volcanic activity and are often referred to as volcanogenic lakes because they originate from volcanoes, with crater lakes being the most common type. Lava lakes are rare, and temporary types of lakes found in active volcanoes occur when molten lava collects in a depression and partially fills it (Volcanic, n.d.).

Fluvial Lakes: Above is an image that shows a fluvial lake in the Great Lakes Coastal Wetlands (An example, 2021),

Fluvial lakes are bodies of water formed by the movement of running water from rivers changing their course and developing into unique basins. These lakes are shaped by geomorphological processes such as erosion, channel migration, and deposition. When the rivers shift, they leave behind cutoffs or depressions that create fluvial lakes. They are open lakes, meaning that they connect to rivers, and differ from closed lakes: lakes that do not connect to any rivers. They have a key component in floodplain ecosystems, where they act as natural storage areas and provide habitats for fish, and other wildlife, supporting biodiversity. Fluvial lakes contribute to resources we use in daily life, such as improving water quality and running nutrient dynamics (Fiveable, 2024).

Artificial Lakes: Above is an image of Lake Kariba in Central Africa, which is the largest man-made lake in the world (The Editors, 2025).

In addition to all these lakes formed by natural processes, humans create lakes for purposes such as water storage, flood control, wildlife habitat, and hydroelectric power. Engineers carefully plan the shape, location and design of the lakes to make sure it is sustainable and beneficial to the surrounding environment. First, experts decide which depression, basin, or valley to use by conducting geographic surveys and environmental studies. Builders then construct a dam from materials like concrete, rock, or earth to block the natural flow from running water of rivers. The reservoir fills with precipitation, river inflow, and groundwater, and water management systems are installed to help regulate the levels of the water in the lake and aid in producing electricity. These new lakes transform ecosystems by supporting habitats for fish, birds, and plants, as well as helps provide us with clean water, power, recreation and drinking water. (How are, n.d.)

From natural processes like the movement of glaciers, tectonic plates, or rivers, to human-made reservoirs, every type of lake helps contribute to biodiversity and maintains a healthy ecosystem by regulating water systems and providing unique habitats for wildlife.

Bibliography:

Aerial view of body of water : lake in the mountains [Photograph]. (2017, August 22). Unsplash. https://www.sciencealert.com/study-says-glacier-lakes-are-accelerating-disappearance-of-permanent-ice

An example of a riverine Great Lakes coastal wetland [Photograph]. (2021, January 19). United States Environmental Protection Agency. https://19january2021snapshot.epa.gov/great-lakes-monitoring/summary-great-lakes-coastal-wetland-monitoring-program-cwmp_.html  

Fiveable. (2024, August 20). 1.3 Fluvial lake formation – Limnology. https://library.fiveable.me/limnology/unit-1/fluvial-lake-formation/study-guide/1NC17gh2C0HPgTbw  

Gautier, A. (2022, February 15). What are glacial lakes? National Snow and Ice Data Center. Retrieved September 3, 2025, from https://nsidc.org/learn/ask-scientist/what-are-glacial-lakes  

How are man made lakes made. (n.d.). Western Liner. Retrieved September 7, 2025, from https://westernliner.com/blog/how-are-man-made-lakes-made/  

Knibb, F. (2023, September 27). How are lakes made? Deep Sea World. Retrieved September 3, 2025, from https://www.deepseaworld.com/water/how-are-lakes-made/  

Lake. (2023, October 19). National Geographic. Retrieved September 1, 2025, from https://education.nationalgeographic.org/resource/lake/

Schmaltz, J. (2010, June 4). NASA Caspian Sea [Photograph]. https://earthobservatory.nasa.gov/images/44253/caspian-sea

Tectonic lakes. (n.d.). Prepp. Retrieved September 6, 2025, from https://prepp.in/news/e-492-tectonic-lakes-types-of-lakes-geography-notes 

The Editors of Encyclopaedia Britannica (2025, January 31). Lake Kariba. Encyclopedia Britannica. https://www.britannica.com/place/Lake-Kariba

Volcanic lakes. (n.d.). Prepp. Retrieved September 6, 2025, from https://prepp.in/news/e-492-volcanic-lakes-types-of-lakes-geography-notes

The Golden Ratio: Superstition or Science?

By Alondra Caba

Whether it is Pi (π) day, the pursuit of many to memorize thousands upon thousands of digits, or eating celebratory pies in its honor, this irrational number is never short of fame every year. Phi, however, does not fall too far behind. It is best known as the “golden” ratio, and appreciated for its “natural” presence in nature, art, and society. However, is it really as mystical as people believe? The Pythagoreans were horrified at the thought of any irrational numbers, but were their fears reasonable? Though the mathematics behind the golden ratio are relatively simple, its irrationality, so to speak, is something that can be appreciated regardless of any superstitious value or otherwise.

Fibonacci Numbers, Phi, and the Golden Ratio

To understand phi (Φ) and the golden ratio, it is important to first understand the Fibonacci sequence. The Fibonacci sequence is an example, specifically the most popular, of a recursive sequence. A recursive sequence is a series of numbers defined by at least one of its preceding values (Morris., n.d.) Thus, the Fibonacci sequence is a type of recursive sequence where each number in the sequence is a sum of the two values that precede it. Algebraically, it is expressed as F_{N =}F_(N-1)+ F_(N-2). It is important that, though the Fibonacci sequence is standardized by its two starting numbers 0 and 1, the sequence can be achieved with any two starting values. The reason why is because any series of Fibonacci sequences share a vital characteristic: the ratio between sequential values will get closer and closer to the golden ratio, Φ. For example, in the following standard sample of the Fibonacci sequence, the later ratios are closer to 1.618 (the rounded value of phi) than the previous ones:

Although the Fibonacci sequence was found to have a relationship with the golden ratio, the history of the golden ratio actually precedes Fibonacci’s numbers. The golden ratio was identified as far back as 300 B.C.E, though not by name. Euclid’s Elements repeatedly highlights the idea of a straight line divided into “extreme and mean ratio” (Heiberg, 2008). His book, which provides proofs and definitions for elementary geometry, provides a geometric visualization of the golden ratio. Euclid claims that a straight line is in extreme and mean ratio when “as the whole is to the greater segment so the greater (segment is) to the lesser” (2008). In other words, given a straight line ABC segmented at point B where AC represents the whole, AB is the longer part, and BC is the shorter part; the ratio of AC to AB is equal to the ratio of AB to BC. Phi is, essentially, the relationship between the line segments when split into this special “extreme and mean ratio.”

Basic Formula of Phi

Euclid’s Elements provides an accurate geometric representation of the golden ratio, but it can be expressed algebraically as well. Assuming that the greater and lesser segments are instead defined as values x and y, x and y are in the golden ratio when the following equation is true:

Thus, the ratio is algebraically defined as the following equation:

However, this equation does not give an exact value of Φ. Rather, it just shows the conditions that must be met to fulfill the ratio. A solution to this is to set y equal to 1, creating a unit ratio that is still equivalent to the original equation. This way, y = 1, and we can say that x = Φ (Choi et al. 2023). The new equation is now

Solving for can be done with algebra and creating the quadratic equation Φ² – Φ – 1 = 0. With the quadratic formula, we can find the following solutions:

Of the two solutions, the golden ratio, , is the positive root. Keeping in mind Euclid’s geometric representations, it is impossible to have a “negative” line segment. Thus, it’s vital that the equation is the positive solution. Therefore:

Is it Superstition or Science?

Visually, the golden ratio is so special because the sequence creates a spiral image. The best example of this is the “golden rectangle” in which the side lengths of the rectangle are in the golden ratio. This is done by splitting the rectangle into a square and another smaller rectangle. Within this smaller rectangle, another square can be placed, and the cycle continues to make similar rectangles all in the golden ratio. Then, arcs can be drawn through each square to create the spiral.

(Marples & Williams, 2022).

However, though spirals are common patterns in nature, this does not grant a “mystical” power to the golden ratio. Rather, the mathematical value of the golden ratio is something that can be utilized and applied in different disciplines. For example, petal and seed growth on different species of flowers can be found to follow closely in relation to Fibonacci numbers. Specifically, the seeds in the center of sunflowers are shown to follow spiral patterns in two opposing directions. Counting these seeds in each direction shows a relationship approximate to the golden ratio between the opposing spirals (Choi et al., 2023). Visually, the golden ratio is pleasing and oddly satisfying, but human appreciation for spirals does not exactly mean there is true “power” behind the ratio. Thus, it is more likely that the golden ratio may not have any metaphysical value other than what society attributes to it.

However, it is acceptable if the ratio does not have any mysterious power in nature. What makes the golden ratio special is not the myths surrounding it. Rather, it is the ability to find beauty in a number, one that was feared by the Pythagoreans centuries ago. To make sense of the irrational is something unique, both aesthetically and also theoretically. Its naturally occurring presence in nature gives scientists a value to reference when finding similar patterns.

Bibliography:

Choi, J. , Atena, A. and Tekalign, W. (2023) The Most Irrational Number that Shows up Everywhere: The Golden Ratio. Journal of Applied Mathematics and Physics, 11, 1185-1193

Heiberg, J. L. (2008). Euclid’s Elements of Geometry (R. Fitzpatrick, Ed. & Trans.). https://farside.ph.utexas.edu/Books/Euclid/Elements.pdf (Original work published 1883-1885).

Mann, A. (2019, November 25). Phi: The Golden Ratio. Live Science. https://www.livescience.com/37704-phi-golden-ratio.html

Marples, C. R. & Williams, P. M. (2022). The Golden Ratio in Nature: A Tour Across Length Scales. Symmetry, 14(10), 2059. https://doi.org/10.3390/sym14102059

Meisner, G. (2012, May 13). History of The Golden Ratio. GoldenNumber. https://www.goldennumber.net/golden-ratio-history/

Morris, J. (n.d.) Recursively Defined Sequences. LibreTexts Mathematics, https://math.libretexts.org/Bookshelves/Combinatorics_and_Discrete_Mathematics/Combinatorics_(Morris)/02%3A_Enumeration/06%3A_Induction_and_Recursion/6.01%3A_Recursively-Defined_Sequences

Naini, F. B. (2024). The Golden Ratio–Dispelling The Myth. Maxillofacial Plastic and Reconstructive Surgery, 46(2), https://doi.org/10.1186/s40902-024-00411-2

Yearsley E. S. (2022). Nature and Math: The Fibonacci Sequence in Nature. Johnson Museum of Art, https://museum.cornell.edu/nature-and-math-the-fibonacci-sequence/

Surviving the Sea: Challenges and Adaptations of Ocean Animals

By Elizabeth Ann McNulty

Introduction

About 22% of all marine animals are currently at risk of extinction. Yet, throughout the history of the Earth, marine species have evolved to possess extraordinary adaptations, such as bioluminescence, camouflage, and specialized body structures, which help them adapt to their changing environments and the threat of human activities. The unique adaptations reveal the resilience of life in the ocean, as countless aquatic species have thrived because of the adaptations they have evolved. Although many aquatic organisms have evolved remarkable traits for survival, modern challenges such as climate change, overfishing, and pollution continue to put them at risk.

Main Threats to Ocean Life

Marine animals face natural challenges and human-caused challenges on a daily basis. Charges such as predation on the species at the bottom of the food chain have always been a natural aspect of life in the ocean. However, there have been threats from human activity, including overfishing, pollution, and most significantly, climate change.

The oceans have been becoming increasingly warmer and more acidic over the years, and since water expands as it gets warmer, sea levels rise, which has a significant impact on marine habitats. Another threat to ocean life is overfishing, which happens when fishing disrupts the health of the ecosystem by changing the predator-prey balance, reducing biodiversity. It can also harm the sea floor of the ocean animals’ habitats. (Threats, n.d.).

More than 80% of marine pollution comes from land-based activities. A common example of this is when sea turtles accidentally eat pieces of plastic, thinking that they are jellyfish, which can cause fatal intestinal blockages and digestive problems. Around 80% of all marine debris is from plastic. The National Ocean and Atmospheric Administration (NOAA) estimates that anywhere from around 20 million to 1.8 billion pieces of plastic would be found around the coastlines of the United States (Marine debris, n.d.).

Natural Selection

Natural selection is the primary mechanism of evolution through which populations adapt and evolve traits that allow them to survive and reproduce in their environment. This process occurs over the course of many generations within the same species,

Individuals who have traits better suited for their environment are more likely to pass on those traits to their offspring. Over time, the helpful trait that was selected for gradually becomes more common in that population. The process of natural selection is essential for ocean animals to develop adaptations that will help them survive changes to their environment (Marine organisms, n.d.). 

Ocean animals can adapt to some changes in their environment due to pollution, but they can’t adapt to vast changes that destroy their natural habitat. Unfortunately, ocean pollution moves through populations much faster than ocean life can adapt to its environment.

Marine Animal Adaptation Examples

Ocean wildlife display a diverse range of adaptations to survive in their environments, including bioluminescence, locating prey with specialized senses, and streamlined bodies.

Bioluminescence is the ability of some living organisms, such as jellyfish, to produce light through chemical reactions. Marine animals that are deeper than 200 meters are unable to rely on photosynthesis or vision, where sunlight no longer penetrates the water. Since many sea animals can’t see in deep ocean waters, bioluminescence helps them find food and spot potential danger. (How far, n.d.).

Another example of an ocean animal adaptation is camouflage, which helps to hide from predators. Sting rays camouflage themselves by staying near and burying themselves in the ocean floor as a behavioral adaptation to help them hide from predators. In addition, many jellyfish are transparent, allowing them to hide from their predators more easily. However, some sea animals have evolved with a strategy opposite to camouflage. For example, sharks have evolved the unique ability to sense faint electric fields of other sea creatures to help them find prey. This is because of their Ampullae of Lorenzini, which are sensory organs on sharks.

(Amazing Adaptations, 2024). 

The image above shows the Ampullae of Lorenzini (Shark, n.d.)

Cetaceans like whales and dolphins evolved specialized vertebrae that move their tails up and down. This unique movement supports their large size and makes it more efficient for long-distance travel, and contrasts with the side-to-side tail movement that can be found in most fish (Heywood, 2024). All these adaptations allow these marine creatures to be well-suited to their environments. Above is an image displaying the up and down tail movement of dolphins (How does, n.d.).

Conservation Efforts

Currently, conservationists are working to make expansive marine reserves for the future health of our oceans by protecting biodiversity. Maintaining biodiversity in the ocean is essential because it plays a key role in our ecosystem and helps regulate our climate. Oceans absorb lots of carbon dioxide every year to help the climate of our planet remain moderate. In addition, biochemists have studied the natural defense mechanisms of marine species, and their compounds have made a significant contribution to the discovery of new medicines. Marine parks and other protective areas for marine species help sea creatures live longer, and help endangered animals recover. Anyone can help the ocean by reducing materials that aren’t good for the environment: helping clean up litter on the beach and raising awareness of the challenges these ocean species face. Together, an impact can be made to protect marine life and save those 22% of marine animals from extinction.

Bibliography:

Amazing Adaptations of Ocean Animals. (2024, October 23). SeaWorld San Diego Blog. https://seaworld.com/san-diego/blog/ocean-animal-adaptations/ 

Heywood, W. (2024, October 15). How whales and dolphins are adapted for life on the water. The Harvard Gazette. Retrieved August 24, 2025, from https://news.harvard.edu/gazette/story/2024/10/how-whales-and-dolphins-adapted-for-life-on-the-water/ 

How does a dolphin move? [Photograph]. (n.d.). Young Ocean Explorers. https://www.youngoceanexplorers.com/yoe/video/235268530371 

How far does light travel through the ocean? (n.d.). National Ocean Service. Retrieved August 18, 2025, from https://oceanservice.noaa.gov/facts/light_travel.html#:~:text=Light%20may%20be%20detected%20as,photosynthesis%20is%20no%20longer%20possible. 

Marine debris impacts. (n.d.). U.S. Department of the Interior. Retrieved August 22, 2025, from https://www.doi.gov/ocl/marine-debris-impacts#:~:text=It%20is%20believed%20that%20at%20least%208,debris%20from%20surface%20waters%20to%20deep%2Dsea%20sediments. 

Marine organisms and adaptations. (n.d.). Science Learning Hub. Retrieved August 24, 2025, from https://www.sciencelearn.org.nz/resources/142-marine-organisms-and-adaptations 

Shark-anatomy-ampullae-of-lorenzini-1 [Photograph]. (n.d.). Ocean Treasures Memorial Library. https://otlibrary.com/shark-anatomy-ampullae-of-lorenzini-1/ 

Structures and adaptations to marine living. (n.d.). Marine Bio. https://www.marinebio.org/conservation/marine-ecology/structures-adaptations/ 

Threats facing our oceans. (n.d.). The Kwanatanga O Aotearoa Department of Conservation. Retrieved August 22, 2025, from https://www.doc.govt.nz/nature/habitats/marine/threats-facing-our-oceans/ 