Improved monitoring proposed in the Indian Ocean as climatic and oceanic changes increase

Fourteen years after IndOOS, a multinational network of sustained ocean observation system was set up to better understand the impacts of human-caused climate change in the Indian Ocean region and beyond, a group of more than 60 scientists has chalked out a roadmap to upgrade the system to step up observations of the rapidly warming region.

IndOOS or the Indian Ocean Observing System is a network operated and supported by various national agencies and coordinated internationally under the Global Ocean Observing System (GOOS) which is coordinated through the World Meteorological Organisation and the Intergovernmental Oceanographic Commission of the United Nations. It was set up in 2006.

An ensemble of instruments such as floats, drifter buoys and moored buoys keep track of temperature, salinity, currents of the seawater and also the conditions like humidity, winds of the atmosphere above, in IndOOS. The group has provided recommendations to spruce up the basin-wide monitoring network following a three-year internationally coordinated review of the IndOOS. They call for “urgently” developing a more resilient and capable observing system to factor in the accelerating pace of climatic and oceanic change. 

Lisa Beal, Professor of Ocean Sciences, Rosenstiel School of Marine and Atmospheric Science at the University of Miami, who led the group of scientists, said more Indian Ocean rim nations need to participate to upgrade to IndOOS-2 (2020-2030). “And IndOOS needs not just resources and capacity from Indian Ocean rim nations, but also goal-setting and governance. Strengthening the IndOOS commitment to best practices and data sharing is also critical for the success of IndOOS,” Beal told Mongabay-India.

The goals will require new agreements and partnerships with and among Indian Ocean rim countries, creating opportunities for them to enhance their monitoring and forecasting capacity as part of IndOOS-2. But flat or declining levels of national funding pose a serious threat to sustained ocean observations in the Indian Ocean and elsewhere, they said.  At least 15 nations, from all around the world, are part of the network.

Four major improvements to the current observing system are required in IndOOS-2, including plugging gaps in scaling up biogeochemical measurements. The primary recommendations are: more chemical and biological measurements in at-risk ecosystems and fisheries; expansion into the western tropics to improve understanding of the monsoon; better-resolved upper ocean processes to improve predictions of rainfall, drought, and heatwaves; and expansion into key coastal regions and the deep ocean to better constrain the basin-wide energy budget.

“Some of the gaps in observations are along the coastal regions and exclusive economic zones. The ocean-atmospheric conditions in these regions are sometimes more important than that of the open seas. Therefore, it is important to monitor and share the hydrographic data from these regions, and that requires opening up access to these no-go zones— which is important for climate research,” India-based climate scientist Roxy Mathew Koll, at the Indian Institute of Tropical Meteorology, Pune, India, told Mongabay-India. Koll was also part of the review.

Although the smallest of the major oceans on Earth, the Indian Ocean is the fastest-warming tropical ocean. It has accounted for 30 percent of the global oceanic heat content increase over the last two decades, while it is home to 30 percent of the world’s coral reefs and 13 percent of global wild-catch fisheries. It supports one-third of the global population in 22 countries around its rim.

India-based scientist Punyasloke Bhadury, who works on unraveling the complexity of coastal (e.g. mangroves) and deep-sea environments using taxonomic and molecular tools, lauded the team for drawing attention to the need for including coastal regions and linked measurements. He was not associated with the review.

“With these measurements (IndOOS-2) we will be in a position to better understand the changes and evolving interplay of the Indian Ocean region such as the North East Indian Ocean regions (e.g. Bay of Bengal) and its link to weather and climate patterns of the region and beyond,” Bhadury, professor at Department of Biological Sciences, IISER-Kolkata, India.

As for data sharing, Bhadury points out that previous experiences from Joint Global Ocean Flux Study (JGOFS), has shown how sharing of data and resources can lead to high-quality science and most importantly how it can be truly beneficial to society. The U.S. launched the Joint Global Ocean Flux Study (JGOFS) in the late 1980s to study the ocean carbon cycle. JGOFS, which was completed in 2003, improved knowledge of the processes that control carbon exchanges between the various interfaces as well as the sensitivity of these fluxes to climate change.

The Indian Ocean and beyond

Before IndOOS there were no sustained observations of the Indian Ocean. “So while we knew about some of the features of the Indian Ocean, such as the tropical warm pool, the monsoon currents, and the zones of depleted oxygen, we knew nothing about how these features change over days, months, years, and decades,” recounts Beal.

Because the ocean is so big and because it holds so much heat energy it is necessary to keep tabs on how it is changing to understand and forecast how the climate will change. “For example, will next year’s monsoon season be wetter, or drier, than last season? Will monsoon rains get heavier in the future? To answer these questions we need sustained measurements of the Indian Ocean. This kind of information can inform policies on agriculture, fisheries, building codes etc.,” she said.

Koll adds that the proposed upgrade also aligns with shifting priorities from understanding the regional monsoon climate and forecasting it to tracking and predicting changing climatic conditions and extreme weather events that have significant impacts over the densely populated Indian Ocean rim region. One such example is supercyclone Amphan, which battered the Indian and Bangladesh coast in May 2020; it was the costliest cyclone in the north Indian Ocean, resulting in a loss of USD 14 billion in India, according to the United Nations’ State of the Global Climate 2020. A recent assessment shows that floods, droughts and cyclones have killed about 1.4 lakh (140,000) people in India during the past five decades. 

The Bay of Bengal region already witnesses more than 80 percent of global fatalities due to tropical cyclones, because of coastal flooding. The frequency of extremely severe cyclones in the Arabian Sea is also projected to increase, with 2019 already a highly unusual year. IndOOS is an integral part of India’s summer monsoon forecasts. India and her neighbours, particularly, will benefit the most from the upgrade, he believes. 

Excess freshwater input from monsoon rains and river runoff creates a shallow, low-salinity surface layer that favours warmer sea surface temperatures, which is thought to promote monsoon rainfall and more intense cyclones, reduce oceanic productivity, and lead to an oxygen minimum zone. In the Arabian Sea, oxygen-depleted waters reach the surface more frequently, causing more fish mortality events.

Impacts of the changes in the Indian Ocean are not contained within the region. Recent research by Koll and NOAA show that warming in the Indo-Pacific can impact regional rainfall patterns across the globe, which makes sense for other nations to invest in keeping tabs on the Indian Ocean observations. Warming of the Indo-Pacific Ocean is altering rainfall patterns from the tropics to the United States, “contributing to declines in rainfall on the United States west and east coasts.”

“The United States is a major funder for the IndOOS and many reports show that the funding has been stagnant for some time. At the same time, operational costs have increased. So if we need to improve the observations or even maintain existing ones, we need to invest more. This is important for monitoring, forecasting and mitigating the impacts of a changing climate in our present and future lives. India has scaled up its observational efforts recently but we need more regional partnerships so that we can efficiently utilise and share the few resources that we have,” emphasised Koll.

Getting past challenges in IndOOS-2

The IndOOS is currently composed of five in situ observing networks that need to be stepped up. These are profiling floats (Argo), a moored tropical array [Research Moored Array for African–Asian–Australian Monsoon Analysis and Prediction (RAMA)], XBT network, surface drifters, and tide gauges. Augmenting these networks are critical observations of the ocean surface from satellites, as well as a wide range of full-depth ocean sections via the Global Ocean Ship-Based Hydrographic Investigations Program (GO-SHIP).

Beal pointed out that so far progress has been made on a “fit-for-purpose” IndOOS. “A new global array of robotic floats capable of measuring biogeochemical properties of the ocean, such as nutrients and acidity, is now becoming a reality with the US-led GO-BGC (Global Ocean Biogeochemistry Array) program. Some of the Indian tropical moorings now share their data as a component of the IndOOS. And a new mooring off Northwest Australia will capture the region’s devastating marine heatwaves and their link to atmospheric variability.”

The group’s prime recommendations include the rapid intensification of coverage of the Arabian Sea and western equatorial the Indian Ocean, including biogeochemical measurements. But piracy in the western tropical Indian Ocean has put a spanner in the works for climate research in that region.

“The longstanding threat of piracy in the western tropical Indian Ocean has meant that research vessels have avoided this area for over a decade, causing a dearth of information about the ocean there. At the same time, the monsoon winds and currents in that area are exceptional in their variability and intensity and there is some evidence that the ecosystem has undergone a dramatic shift towards inedible species. In that case, the need for observations is urgent. We can achieve most of this upgrade by completing the tropical array of moored meteorological buoys (RAMA) and including physical and biogeochemical instrumentation on the mooring to measure the upper ocean,” Beal adds.

In the western Indian Ocean, strong monsoon winds interact with the ocean, resulting in blooms of phytoplankton—the microscopic plants that form the base of the food chain. But recent research by Koll shows that phytoplankton production here is declining due to ocean warming. With reduced piracy attacks, the push for IndOOS-2 agenda in the western tropical Indian Ocean presents an opportunity to obtain a clearer picture of the changing monsoons and phytoplankton.

The scientists have also sought an increase in biogeochemical measurements throughout the basin, initially targeted to regions of high variability change, such as the Arabian Sea, Bay of Bengal, and eastern equatorial Indian Ocean. Another target area is the Indonesian Throughflow, in the Indonesian seas, where a large amount of uncertainty still remains in measuring and modelling the physical and biogeochemical variability, points out the recently released World Ocean Assessment II (WOA).

The Indonesian Throughflow, the transport of Pacific Ocean water to the Indian Ocean through the Indonesian seas, is the only low-latitude connection between ocean basins. Maintaining ocean equipment here is a challenge because of the fast-moving currents in the shallow straits and also due to political interests, points out Koll.

Punyasloke Bhadury, one of the contributing authors of the WOA, stressed the need for capacity building to make the effort truly international in nature. “The capacity building could be in terms of instrumentation support, sustained training and management towards generating high-quality data such as for chemical, biological and ecosystem scales. The classic setting would be evaluating the biology, ecosystem, chemistry and physical parameters of the coastal Bay of Bengal (e.g. Sundarbans and beyond) where scientists from India, Bangladesh, Myanmar and Thailand can be roped in, trained and provided instrumentation resources for generating high-quality data that can aid IndOOS-2 and better forecasting of regional climate and weather patterns,” he said.

There are some challenges to work in some of the coastal regions such as the mangroves of the Bay of Bengal (BoB) region but the IndOOS-2 can be the benchmark for setting up long-term ecological monitoring time-series programs across coastal BoB region and rim countries which will help in gathering high-quality science data and also help improve forecasting that will support the coastal socio-economics, in particular sustainable blue economy of North East Indian Ocean. “The potential of long-term ecological time-series programs is huge and a nice example is the Sundarbans Biological Observatory Time Series (SBOTS) managed by our team which has shown the observable changes in chemistry and biology of Sundarbans mangroves and beyond is influenced by changing salinity regime. Such changes in the long-term will affect the rich coastal fisheries of the region and beyond,” added Bhadury.

In 2009, Sweden’s Stockholm Resilience Centre published the Planetary Boundaries Framework, which outlined nine key processes, influenced by humanity, that threaten the stability of the entire Earth System. These are: climate change, biodiversity integrity (functional and genetic), ocean acidification, depletion of the ozone layer, atmospheric aerosol pollution, biogeochemical flows of nitrogen and phosphorus, freshwater use, land-system change, and release of novel chemicals (including heavy metals, radioactive materials, plastics, and more).

 

Banner image: There is an urgent need to develop a more resilient and capable observing system to factor in the accelerating pace of climatic and oceanic change. Photo by Blueocean/Wikimedia Commons.