Ar-Rehman

The largest accumulation of ocean plastic in the world, Great Pacific Garbage Patch

The Great Pacific Garbage Patch is the largest accumulation of ocean plastic in the world and is located between Hawaii and California. Scientists of The Ocean Cleanup have conducted the most extensive analysis ever of this area. Every minute, more than 3,300* kilograms of plastic enter the ocean. It is the largest of the five offshore plastic accumulation zones in the world’s oceans and located halfway between Hawaii and California in the Pacific Ocean. When we picture the open Pacific, it is supposed to be only blue water. Marine researchers, however, are now seeing something very different: places like the Great Pacific Garbage Patch where plastic waste has built a kind of artificial shoreline far from any land. In the North Pacific Subtropical Gyre, the huge rotating current system between California and Hawaii, floating objects tend to get trapped instead of drifting away. That’s where you find what people commonly call the Great Pacific Garbage Patch, a region which now holds tens of thousands of tons of plastic pieces sturdy enough to move around the ocean for years at a time. It is estimated that 1.15 to 2.41 million tonnes of plastic are entering the ocean each year from rivers. More than half of this plastic is less dense than the water, meaning that it will not sink once it encounters the sea. The stronger, more buoyant plastics show resiliency in the marine environment, allowing them to be transported over extended distances. They persist at the sea surface as they make their way offshore, transported by converging currents and finally accumulating in the patch. Once these plastics enter the gyre, they are unlikely to leave the area until they degrade into smaller microplastics under the effects of sun, waves and marine life. As more and more plastics are discarded into the environment, microplastic concentration in the Great Pacific Garbage Patch will only continue to increase.

For a long time, biologists treated coastal waters and the open ocean as two separate neighborhoods. Coastal species were expected to stay on rocks, piers and shorelines, while pelagic species were the ones that belonged offshore. People knew that a storm could knock a log or a raft of seaweed loose and carry coastal organisms away from land, but the usual assumption was that those passengers would eventually die because conditions in the open ocean are too harsh. A big clue that this view was incomplete came after the Great East Japan Tsunami. The huge waves ripped loose docks, boats and many plastic objects and sent them drifting into the Pacific. For years afterward, pieces of that debris landed on beaches in North America and Hawaii. When scientists checked those objects, they found that many Japanese coastal species had stayed alive on them for at least six years as they crossed the ocean. This led to a new question: were these coastal species only passing through the open ocean, or were they beginning to form more permanent communities there? The GPGP covers an estimated surface area of 1.6 million square km's, an area twice the size of Texas or three times the size of France. Due to seasonal and interannual variabilities of winds and currents, the GPGP’s location and shape are constantly changing. Only floating objects which are predominantly influenced by currents and less by winds were likely to remain within the patch. By simulating concentration levels in the North Pacific, the researchers were able to follow the location of the patch, demonstrating significant seasonal and interannual variations. On average the patch orbits around 32°N and 145°W. However, the team observed seasonal shifts from west to east and substantial variations in latitude (North to South) depending on the year.

To explore, scientists joined research cruises to the eastern side of the gyre. Standing on deck, crew members watched the sea surface and picked out plastic items at least 6 inches (15 cm's) long. In the end they brought on board 105 pieces of floating plastic, including bottles, buoys, crates, nets, ropes and buckets, along with a “wildcard” group of especially life‑covered objects. Every item was labeled, photographed and tagged with its position before being set aside for careful study back in the lab. Back in the laboratory, taxonomists went through each piece of plastic and looked for invertebrates, animals without backbones. They found a wide variety of creatures, such as barnacles, crabs, amphipods, bryozoans, hydroids and sea anemones. Altogether they identified 46 different kinds of invertebrates from six major animal groups. Of those 46, 37 were coastal species and 9 were pelagic, which means roughly 80% of the diversity on the debris came from coastal organisms. At the time of sampling, there were more than 1.8 trillion pieces of plastic in the patch that weigh an estimated 100,000 tonnes. These figures are 4-16 times more than previous calculations. This weight is also equivalent to more than 740 Boeing 777s. The center of the GPGP has the highest density and the further boundaries are the least dense. A plastic count that is equivalent to 250 pieces of debris for every human in the world. Using a similar approach as they did when figuring the mass, the team chose to employ conservative estimations of the plastic count. While 1.8 trillion is a mid-range value for the total count, their calculations estimated that it may be range from 1.1 to up to 3.6 trillion pieces. Using data from multiple reconnaissance missions, a mass concentration model was produced to visualize the plastic distribution in the patch. The mass concentration model shows that the center concentration levels contain the highest density, reaching 100s of kg/km² while decreasing down to 10 kg/km² in the outermost region.

Interestingly, pelagic communities were strongly linked to the type of plastic object, while coastal communities were more tied to when the debris was collected during the cruises. The researchers then compared these gyre communities with earlier work on debris from the 2011 tsunami. Many of the coastal species found on plastics in the gyre had also been seen on Japanese tsunami debris. However, the groups that were most diverse were not exactly the same, and some coastal groups, such as mollusks, were much less common in the gyre. Overall, the gyre debris supported fewer species than the tsunami debris, and the researchers’ analyses suggested that there are probably still coastal species living on plastics in the gyre which scientists have not yet recorded. Results of these expeditions proved that the buoyant plastic mass is distributed within the top few meters of the ocean. Factors such as wind speed, sea state and plastic buoyancy will influence vertical mixing. However, buoyant plastic will eventually float back to the surface in calmer seas. Larger pieces were observed to resurface much more rapidly than smaller pieces. Characteristics of the debris in the Great Pacific Garbage Patch, such as plastic type and age, prove that plastic has the capacity to persist in this region. Plastic in the patch has also been measured since the 1970’s and the calculations from subsequent years show that microplastic mass concentration is increasing exponentially, proving that the input of plastic in the patch is greater than the output. Unless sources are mitigated, this number will continue to rise.

One of the biggest questions was whether coastal organisms were just temporary passengers on the plastic or whether they could live out their whole life cycles there. The team looked for evidence of reproduction and growth. They searched for brooding females, as they carrying eggs or young, in several crustacean groups such as amphipods and crabs, and they did find them. They also saw reproductive structures on hydroids. The scientists also measured individual animals and noted the range of sizes on each piece of debris. On some species of sea anemones and amphipods they saw tiny juveniles, medium‑sized individuals and full‑grown adults all living together on the same plastic surface. The pattern suggests that new generations were growing up on these rafts instead of all arriving at the same time from the coast. When the team checked the plastic, almost every piece they had picked up was carrying life, mostly invertebrates. Invertebrates were present on 98% of the objects. Pelagic species showed up on more than 94% of the pieces, and coastal species on a bit over 70%. Many items hosted both coastal and pelagic species at the same time, so these very different organisms were sharing the same floating “islands” in the middle of the ocean. On average, each plastic item carried about four to five kinds of organisms, and coastal species were slightly more common than pelagic ones. Nets and ropes tended to have especially dense communities, probably because their many strands and small spaces offered plenty of places to hang on and hide. The vast majority of plastics retrieved were made of rigid or hard polyethylene (PE) or polypropylene (PP), or derelict fishing gear. Ranging in size from small fragments to larger objects and meter-sized fishing nets. When accounting for the total mass, 92% of the debris found in the patch consists of objects larger than 0.5 cm, and three-quarters of the total mass is made of macro- and mega plastic. However, in terms of object count, 94% of the total is represented by microplastics. Once the plastics were collected, classified the plastic into:

Hard plastic, plastic sheet or film

Plastic lines, ropes, and fishing nets

Pre-production plastics (cylinders, spheres or disks)

Fragments made of foamed materials

These plastic types were then screened for clues on age and origin. This was performed by examining each object for dates, languages, trademarks, symbols or ‘made in’ statements.

Because the plastics have been shown to persist in this region, they will likely break down into smaller plastics while floating in the GPGP. This deterioration into microplastics is usually the result of sun exposure, waves, marine life and temperature changes. Microplastics have been discovered floating within the water surface layers, but also in the water column or as far down as the ocean floor. Once they become this small, microplastics are very difficult to remove and are often mistaken for food by marine animals. To understand why some species handle this lifestyle better than others, the researchers looked at traits which might be useful on a plastic raft. They noted whether adults stayed fixed in place (sessile) or could move around, and they recorded how each species fed, for example, by filtering particles from the water, grazing on surfaces, hunting prey or using more than one of these methods. Many of the coastal species living on the plastic were able to reproduce asexually, essentially cloning themselves. Their larvae also did not need to spend much time drifting freely in the water. Young animals could grow right on the same surface as the adults. This kind of life cycle fits well with a small, isolated raft of plastic that slowly circles within the gyre. Taken together, these results point to the rise of a “neopelagic” community in the open ocean, where “neo” means new and “pelagic” refers to life in the open sea. This neopelagic community includes both the usual pelagic rafters and coastal species which can now survive far from land because plastic items act as durable homes.

In the past, one big reason coastal species stayed near shore was the lack of long‑lasting, floating hard surfaces in the open ocean. Human‑made plastics have changed that by adding countless new floating “islands” for coastal life in waters that used to be almost entirely pelagic. Plastic pollution is, therefore, not only an eyesore or a trash problem; it also shifts where marine life can live and allows coastal organisms to survive, reproduce and spread across huge distances. This discovery may reshape marine ecosystems and species ranges around the world. The finding confirms that stopping plastic inflow from land and river will not be enough to stop the GPGP to grow, we need to work with policy makers to find a binding agreement on the use of plastic in the industry. Not only does plastic pollution in the Great Pacific Garbage Patch pose risks for the safety and health of marine animals, but there are health and economic implications for humans as well. Studies have shown that about 900 species have encountered marine debris, and 92% of these interactions are with plastic. 17% of the species affected by plastic are on the IUCN (International Union for Conservation of Nature) Red List of Threatened Species.

A peer-reviewed study assessed the environmental impact of removing plastic from the Great Pacific Garbage Patch. The findings from this collaborative research between our in-house experts and independent scientists highlighted that the benefits of cleaning the GPGP outweighed potential environmental costs, including greenhouse gas emissions and ecosystem disruptions from carrying out the cleanup. The study states that the findings show that marine life is more vulnerable to plastic pollution than to our offshore cleanup efforts. Not only is the size and count of the plastic in the GPGP important to calculate, but the way in which the plastic interacts in the water helps the team learn more about the buoyancy and depths of the plastic. It is commonly known that harmful PBT (Persistent Bio-accumulative Toxic) chemicals are found in ocean plastics, so researchers at The Ocean Cleanup tested plastic samples from the expeditions for their chemical levels. Their results helped them to realize what chemicals are present in the patch and what that means for animals feeding there. Plastics ranging from various type and size were analyzed by placing them in mixtures which would allow the various chemicals to be identified. A process known as Chromatography. They found through various tests that 84% of the plastics in the GPGP contain at least one type of PBT chemical. More research will be required in order to discover if this also applies to the other garbage patches around the world.

Perovskite-CIGS tandem solar cell achieve record 25.14% efficiency at Tokyo City University Japan

Researchers at Tokyo City University in Japan have reportedly achieved a new world record power conversion efficiency for a tandem solar cell which combines a perovskite top cell with a copper-indium-gallium-selenide (CIGS) bottom cell. The two-terminal device has an active area of 1 cm² and reached a certified efficiency of 25.14%. The result was certified by Japan’s National Institute of Advanced Industrial Science and Technology (AIST). Researchers in Japan claim to have achieved a world record power conversion efficiency for a tandem solar cell based on a top perovskite device and a bottom cell based on copper, indium, gallium and selenium (CIGS). They said further efficiency improvements can be expected by optimizing the cell configuration to improve the short-circuit current. In addition, they aim to accelerate research and development toward practical application through improvements in additives and passivation technology, with no further technical details of the new cell design being revealed.

This surpasses the previous record of 24.6% for a perovskite-CIGS tandem, which was set by Germany’s Helmholtz-Zentrum Berlin (HZB) in February 2025, after which groups worldwide had been trying to push the technology beyond the 25% threshold. The Japanese team notes that, until now, this 25% mark had remained out of reach despite intensive international research efforts. The tandem device has a two-terminal (2T) configuration, an active area of 1 cm2, and an certified efficiency of 25.14%. “Since then, improvement research has been conducted around the world, but the 25% barrier had not been broken,” the Japanese team stated. The layer promotes better crystallinity of the perovskite film by providing a more suitable growth surface. At the same time, it reduces interfacial recombination losses which would otherwise lower device efficiency. It also prevents unwanted chemical reactions between the CIGS layer and perovskite precursors.

The new record cell is built on a CIGS bottom device originally developed at AIST, paired with a perovskite top cell which uses an improved absorber layer with higher crystallinity. This enhancement is enabled by a newly introduced interfacial barrier layer between the two subcells, which provides a more favorable surface for perovskite growth, suppresses interfacial recombination losses, and blocks undesirable chemical reactions between the CIGS absorber and the perovskite precursor materials. The top cell was built with a substrate made of indium tin oxide (ITO), a self-assembled monolayer (SAM) known as MeO-2PACz, the perovskite absorber, an electron transport layer (ETL) relying on buckminsterfullerene (C60) and tin dioxide layer deposited via atomic layer deposition (ALD-SnO2), another ITO layer, an antireflective coating made of magnesium fluoride (MgF2), and silver metal contact.

The scientists explained that the cell is based on bottom CIGS device developed by AIST itself and top perovskite cell with an improved perovskite absorber with higher cristallinity, which was achieved via a new barrier layer placed between the two cells. In the top perovskite cell, the researchers employed an indium tin oxide (ITO) substrate, a MeO-2PACz self-assembled monolayer (SAM), the perovskite absorber, and an electron transport stack consisting of buckminsterfullerene (C60) and an atomic-layer-deposited tin dioxide (ALD-SnO₂) layer, followed by an additional ITO layer, a magnesium fluoride (MgF₂) antireflection coating, and a silver contact. The CIGS bottom cell uses soda-lime glass (SLG) as the substrate, a molybdenum (Mo) back contact, the CIGS absorber layer, a cadmium sulfide (CdS) buffer, and a zinc oxide (ZnO) window layer. Tested under standard illumination conditions, the tandem cell achieved an efficiency of 25.14%.

Under standard test conditions, the tandem device delivered not only 25.14% efficiency but also an open-circuit voltage of 1.845 V, a short-circuit current density of 16.25 mA/cm², and a fill factor of 83.5%. The team expects that further gains are possible by refining the device architecture to increase the short-circuit current, and they plan to speed up development toward practical applications through improved additives and passivation strategies, although detailed information on these aspects has not yet been disclosed. We have to wait for final outcome in near future.