Hidden Worlds Beneath the Waves

 Hidden Worlds Beneath the Waves 🌊

                                                                                    The  majority of Earth's active volcanoes are situated underwater. Submarine eruptions, which most frequently take place around tectonic spreading centers, unleash molten rock from beneath the bottom. Underwater volcanoes are fascinating geological features that lie beneath the ocean's surface. These volcanoes can have significant impacts on both the marine environment and the Earth's atmosphere. 

One notable example is the Hunga Tonga-Hunga Ha’apai eruption in January 2022. This underwater volcano in the South Pacific Ocean erupted with such force that it sent a massive plume of water vapor into the stratosphere, enough to fill more than 58,000 Olympic-size swimming pools. The eruption also caused a tsunami and a sonic boom that circled the globe twice.  

The eruption of the Krakatoa volcano in 1883 remains one of the deadliest underwater eruptions in history, highlighting the destructive power of these natural phenomena.

Over time, repeated volcanic eruptions can build up enough material to form islands. Famous examples include the Hawaiian Islands and Iceland, which were formed by underwater volcanic activity. 

Hydrothermal vents are fissures on the seabed from which geothermally heated water discharges. They form when seawater seeps into the Earth's crust, gets heated by underlying magma, and then rises back to the ocean floor, carrying dissolved minerals with it. The temperature of the water emitted from hydrothermal vents can reach up to 400°C (752°F). Despite this, the surrounding water, just a few meters away, remains near freezing due to the deep ocean's cold temperatures.

Vents that emit dark, mineral-rich water that forms chimney-like structures made of iron sulfide, giving them their black color are called black smokers, and vents that release lighter-colored minerals like barium, calcium, and silicon, resulting in white deposits, are called white smokers.

Volcanoes and vent sites, albeit they are in places too dark for sunlight to drive food production, extinct, or even moderately active, frequently harbor a variety of animal populations that have adapted to use chemical energy, a process known as chemosynthesis to make food. The base of the food web around underwater volcanoes is primarily composed of chemosynthetic bacteria and archaea. Also, hydrothermal vents release nutrient-rich fluids that support dense microbial communities. These microbes form biofilms and mats on the vent surfaces and in the surrounding sediments. Chemosynthetic bacteria use chemicals such as sulfides and methane as a source of energy to produce organic material. Chemosynthetic bacteria are then grazed on by heterotrophs, which in turn are eaten by larger predators. Some of these bacteria even live inside vent fauna (such as tube worms and Bathymodiolus mussels) or grow on specialized appendages.

Many larger organisms, such as tube worms, clams, and mussels, have symbiotic relationships with chemosynthetic bacteria. These bacteria live within the tissues of their hosts and provide them with nutrients. 

Green sulfur bacteria are unique among hydrothermal vent bacteria because they require both chemical energy (from hydrogen sulfide) and light energy to survive. Green sulfur bacteria contain chlorosomes, organelles that are so efficient at harvesting light that green sulfur bacteria can grow at much lower light intensities than other light-requiring microbes. There is no sunlight at hydrothermal vents and instead, they capture energy from the weak radioactive glow emitted from geothermally heated rock. 

Animals are present in very high abundances, but there tends to be lower diversity, with communities being dominated by only a few taxa.

The organisms living around underwater volcanoes and hydrothermal vents have developed unique adaptations to survive in high-pressure, high-temperature, and low-light conditions. For example, some species of shrimp and crabs have specialized heat-resistant enzymes. 

Underwater volcanic activity can have a significant impact on global ocean chemistry. Underwater volcanic activity releases carbon dioxide into the ocean. While some of this carbon dioxide is absorbed by seawater, contributing to ocean acidification, it also plays a role in the global carbon cycle, influencing the Earth's climate over geological timescales. The minerals and chemicals released by hydrothermal vents and underwater volcanoes can alter the chemical composition of seawater. This impact is particularly notable in the deep ocean, where these features contribute to the distribution of elements like sulfur, iron, and silica. Hydrothermal vents release a variety of minerals and gases, including iron, sulfur, and methane, into the ocean. These substances are critical for nutrient cycling in the deep sea, supporting the growth of microorganisms and, consequently, the entire ecosystem.

Many underwater volcanoes are found along mid-ocean ridges, where tectonic plates are moving apart. The volcanic activity here contributes to seafloor spreading, a process that constantly renews the ocean floor and plays a crucial role in plate tectonics. The unique organisms found in hydrothermal vent ecosystems produce novel compounds that have potential applications in medicine. For example, enzymes from these organisms have been used in biotechnology, and there is ongoing research into their potential use.

Exploring hydrothermal vents is so exciting because it teaches us about the limits of life, organisms living there have to deal with mind-boggling extremes of temperature and chemistry. 

📝Dilhari Pussawala 

3rd  year (20/21 batch)

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Congratulations

 

"The journey of a thousand miles begins with a single step." – Lao Tzu

Heartiest congratulations to our brilliant seniors who have successfully graduated at the 50th Convocation of the University of Sri Jayewardenepura! 🌊🎓

Your dedication and hard work have brought you here, and we are proud to have been part of your journey. 

May your future be filled with endless blessings, joy, and the fulfillment of all your heart's desires.

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World Tsunami awareness day

 "Preparedness today saves lives tomorrow"

On World Tsunami Awareness Day 2024, we come together to remember the devastating impacts of tsunamis and emphasize the importance of resilience. 

This day serves as a reminder to honor lives affected, recognize the power of early warning systems, and educate communities on preparedness. 

By spreading awareness and fostering global cooperation, we aim to strengthen response efforts and safeguard future generations against the threat of tsunamis. 

Let's build a safer world together, one informed step at a time.

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Sharks

 

Sharks: The Ocean's Apex Predators and Their Fight for Survival

Sharks are among the most fascinating and ancient creatures of the ocean. They have existed for over 400 million years, far longer than dinosaurs. They belong to the class _Chondrichthyes_, distinguished from other fish by their cartilaginous skeletons. Today, approximately 1,000 species of sharks inhabit a wide range of environments, from shallow coastal waters to the deep ocean. They are classified within the superorder _Selachimorpha_, which includes all true sharks. Species vary greatly in size, from the small dwarf lantern shark, which grows to just about 20 centimeters, to the massive whale shark, which can reach lengths of up to 18–20 meters.

Sharks play a crucial role in maintaining the health and balance of marine ecosystems through several important ecological functions. One of their primary roles is population control. As apex predators, sharks regulate the abundance of their prey, preventing any single species from becoming overly dominant. Additionally, sharks impact the health of various marine habitats. By controlling the numbers of certain species, such as herbivorous fish, sharks help prevent the overgrazing of critical habitats like coral reefs and seagrass beds. In coral reef ecosystems, the presence of reef sharks helps control populations of smaller fish, such as parrotfish. Without these sharks, herbivorous fish could overgraze algae, which can degrade coral reefs.

Sharks also contribute to the health of prey species. By targeting weaker and sick individuals, sharks ensure that only the fittest members of prey populations reproduce. This process of natural selection promotes stronger and more resilient species, which is vital for the overall health and stability of marine ecosystems. Sharks further support nutrient cycling in marine ecosystems. By consuming prey and excreting waste, sharks recycle nutrients back into the environment, supporting the growth of other marine organisms.

Shark populations face significant threats, many stemming from human activities. One of the primary threats is overfishing. Recent studies estimate that between 63 and 273 million sharks are killed annually, with an average of around 100 million, though this figure continues to be debated and studied. Sharks are either directly targeted for their fins, meat, and other body parts or caught unintentionally as bycatch in commercial fisheries. The demand for shark fins, particularly for use in shark fin soup, has led to a practice known as finning. In this practice, sharks are captured, their fins are removed, and the rest of the body is discarded, often while the shark is still alive. Without their fins, sharks are unable to swim properly, leading to a slow and painful death.

As demand for shark products rises, their slow reproductive rate poses a critical issue. Many shark species mature late and produce relatively few offspring, meaning that populations cannot quickly recover once depleted. As a result, even moderate levels of overfishing can have devastating long-term impacts. Another significant threat is habitat loss. Sharks rely on diverse habitats, such as coral reefs, mangroves, and open oceans, for breeding, feeding, and shelter. However, coastal urbanization, pollution, destructive fishing practices, and climate change have degraded many of these environments.

In response to these threats, numerous international and local efforts have been initiated to protect shark populations. Countries like the United States and members of the European Union have enacted laws prohibiting shark finning in their waters, aiming to reduce shark mortality and encourage sustainable use. Banning the fishing of threatened shark species is also an important conservation effort. In Sri Lanka, for example, fishing for threatened species like the whale shark ( Minimuthu mora) oceanic whitetip shark (Polkola mora), and thresher sharks (Kasa mora) is prohibited.

The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) regulates the global trade of endangered species, including shark species. As of 2022, nearly 100 species of sharks and rays are listed under CITES appendices, following significant additions at the 19th Conference of the Parties (CoP19). By controlling the trade of shark products, CITES helps reduce pressure on shark populations and encourages sustainable practices.

Sustainable fishing practices are also promoted to reduce shark bycatch, which is the unintentional capture of sharks during commercial fishing for other species. Selective fishing gear and implementing time and area closures help minimize shark bycatch. Additionally, catch limits and quotas for specific shark species vulnerable to overfishing help regulate populations and prevent extinction.

The establishment of Marine Protected Areas (MPAs) has become a crucial strategy in shark conservation. MPAs are designated regions where human activities, including fishing, are restricted providing safe havens for sharks and allowing their populations to recover. Notable examples include the Great Barrier Reef Marine Park in Australia and the Galápagos Marine Reserve in Ecuador. These protected zones help preserve shark species and the broader marine biodiversity they support.

Several countries have established shark sanctuaries, where shark fishing is prohibited. These sanctuaries, such as those in the Pacific (e.g., Palau and the Marshall Islands), offer a safe haven for shark populations to recover.

In conclusion, sharks are vital to marine ecosystems, helping regulate other species' populations and maintain ecological balance. Their role as apex predators, combined with their vulnerability to human activities, makes their conservation crucial for maintaining healthy ocean environments. Through continued international cooperation, improved fishing practices, and enhanced protection measures, we can work to ensure these ancient and remarkable creatures survive for future generations.

📝Devmika Hapuarachchi  

Second Year (21/22 batch)

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GOLDMEDAL

 With exceptional academic brilliance, Chamudi Ginige stands at the pinnacle of achievement, earning the highest GPA that reflects her unwavering commitment. Her remarkable journey in Aquatic Resources Management at the University of Sri Jayewardenapura sets a shining example for others to follow.

May your remarkable accomplishments light the path ahead, and may your dedication continue to create ripples of excellence. Heartfelt congratulations on clinching the Gold Medal! 🌟🥇👏

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