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Ocean acidification a murky phenomenon with little research done, say scientists
View(s):By Tharushi Weerasinghe
Ocean acidification—a critical yet understudied issue in Sri Lanka—results from increased atmospheric CO2 levels dissolving into the ocean, altering its chemistry. This phenomenon poses significant threats to marine biodiversity and ecosystems, yet research efforts remain constrained by limited data, coordination, and resources.
“Four years ago, NARA established two permanent stations to measure and monitor pH levels—one off the western coast of Sri Lanka, covering the Arabian Sea, and the other off Trincomalee, for the Bay of Bengal,” says Dr K. Arulananthan, Director General of the National Aquatic Resources Research and Development Agency (NARA). These stations aim to collect long-term data to understand oceanic changes better.
“The Sri Lankan government has funded these initiatives through the Treasury. While we’ve observed strong seasonal variations in pH levels, such fluctuations—lower during the rainy season and higher during dry periods—are natural and normal,” he explains. However, Dr. Arulananthan notes that four years of data is insufficient to establish definitive trends.
In addition to pH monitoring, NARA also tracks ocean temperatures at these locations. “We are recording a tendency for increasing temperatures. Prolonged periods of consistently high temperatures during summer have been observed, but four years is not enough time to establish a long-term trend in pH changes,” he adds.
The agency has also been monitoring coral reefs in areas such as Kalpitiya, Bar Reef, and Pigeon Island. “The tendency for coral bleaching is increasing, and this is closely linked to high summer temperatures. If heat surges last for more than a month, corals bleach, which we’ve documented over the past two years,” he says. Coral bleaching serves as a direct indicator of environmental stress, particularly linked to rising temperatures.
Dr. Arulananthan emphasised the interconnectedness of pH levels and carbon dioxide. “Acidification is directly related to CO2. While Sri Lanka’s emissions are negligible, making us not a major contributor, the responsibility lies with big emitters. However, we do have significant ecosystems, such as mangroves, that help absorb CO2. Replanting mangroves is a major step forward,” he notes.
Sea-level rise is another pressing concern. “We have over a decade of temperature data showing a rising trend, and our measurements indicate sea levels are increasing by 3-4 millimetres per year,” Dr. Arulananthan explains.
To mitigate human impacts, NARA is working to protect coral reefs and other critical ecosystems. “We’re monitoring the health of reefs in protected areas like Bar Reef and Pigeon Island, as well as sea bass reefs along the southeastern coast. Establishing these protected zones helps reduce anthropogenic impacts,” he concludes.
Dr. Arulananthan also stressed the need for long-term observations to effectively study phenomena like ocean acidification. “We just started, but we hope to continue so that we will have reliable information as soon as possible,” he said.
“Measuring pH and observing its changes is a very basic analysis that alone cannot reflect acidification. To establish a trend and study the impact, we need data from multiple locations over a long period,” says Prof. Terney Pradeep Kumara, Professor of Oceanography at the University of Ruhuna, Sri Lanka.
According to Prof. Terney, the lack of proper coordination in data collection and processing is a major obstacle to understanding ocean acidification trends in Sri Lanka. “Data collection happens, but the information is not collated well enough, and we don’t have sufficient trend records to quantify acidification. However, there is evidence to suggest that changes are occurring,” he notes.
The professor highlighted the absence of state-of-the-art technology as another critical challenge. “We need more advanced tools, such as data loggers on reefs and rocks, to analyse long-term trends. Right now, no reliable data is being created,” he says.
While global scenarios of ocean acidification have been studied extensively, Prof. Terney pointed out the gap in localised research. “We don’t have our own data, so we can’t conclusively say what the impact is. Theoretically, we can assume coral growth rates are changing, but we haven’t connected those changes to acidification. We haven’t calculated calcification rates,” he explains.
Globally, scientists have not observed clear trends linking acidification to coral growth rates, but Prof. Terney emphasised the importance of monitoring Sri Lanka’s unique conditions. “Different parts of the ocean around Sri Lanka exhibit varying pH levels due to local factors such as river discharges. For example, Trincomalee’s deep channel is influenced by the Mahaweli River, so it cannot serve as the focal point for data extraction,” he says.
The professor highlighted the complexity of the issue, citing numerous variables affecting ocean pH, including river inputs and human activities. “What we do to our rivers impacts the ocean in different ways, but we don’t yet have the systems to analyse these connections effectively,” he observes.
Currently, simulations and IT-driven models are being used to predict scenarios, but Prof. Terney argues that real-time monitoring is essential. “Simulations give us models, but they’re not a substitute for real data. We need a consistent pH study that monitors trends over a few decades to provide actionable insights,” he says.
With the rise in global CO2 levels accelerating, the urgency for better data collection is clear. “Global warming is over; it’s global boiling now,” Prof. Terney warns. He calls for a unified effort to establish a comprehensive water monitoring program. “We need one well-planned, regulated system for measuring environmental conditions, with collaboration and shared data to address this issue effectively,” he concludes.
“The root cause of acidification is climate change because the increase of CO2 in our atmosphere leads to ocean acidification,” says Dr. Sivakumaran Sivaramanan, Environmental Assessor at the Central Environmental Authority (CEA). According to Dr Sivaramanan, addressing climate change is essential to mitigating ocean acidification. “Global and local attempts to tackle global warming will naturally reduce acidification. But any meaningful climate effort—whether in research, mitigation, or adaptation—usually takes about a decade of consistent work to yield results,” he explains.
Dr. Sivaramanan highlights the challenges in advancing research locally. “Research in this area is moving slowly because it demands significant time and funding. You need to measure everything consistently to gain actionable insights,” he says. While awareness programs are being conducted, mitigation strategies require robust data and consistent action. “The only permanent solution is to resolve the climate crisis,” he emphasises.
“Corals are excellent indicators of multiple environmental issues, but attributing changes accurately requires further study. Prolonged heatwaves, for example, have a direct impact, leading to bleaching events when high temperatures persist for over a month,” Dr. Sivaramanan explains.
The initial impacts of acidification, he notes, will primarily affect marine biodiversity. “Fish migration patterns will change as the Indian Ocean, particularly around Sri Lanka, is a biodiversity hotspot. Large marine animals like whales will also feel the effects. It’s a chain reaction—corals are affected first, followed by species dependent on them, and the impacts ripple through the ecosystem,” he says.
Dr. Sivaramanan also addresses misconceptions about acidification. “Some assume that eutrophication leads to acidification because nutrient-induced algal blooms block sunlight, slowing photosynthesis and creating anoxic conditions. While this must be mitigated, it does not cause acidification directly,” he clarifies. “The root cause is climate change.”
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