My Science School

In the centre of the North Atlantic Ocean, amidst the vast blue expanse, is a huge floating mat of brown seaweed called sargassum. These mats are quite common in the Sargasso Sea, a region around Bermuda. The region has been named after the seaweed. These floating mats of seaweed were first reported by Christopher Columbus in the 15th Century. But since 2011, the Atlantic Ocean has been witnessing massive sargassum blooms every year. It stretches nearly 9000 km from West Africa to the Gulf of Mexico. Scientists call this the Great Atlantic Sargassum Belt. The seaweed band has been getting bigger every year, posing a serious threat to marine life, coastal ecosystem and the fishing communities dependent on it.

Sargassum is a genus of large brown seaweed (a type of algae) that floats in island-like masses. The seaweed species found in the Great Atlantic Sargassum Belt include Sargassum natans and Sargassum fluitans. They have many leafy appendages, branches, and round, berry-like structures called pneumatocysts, which keep them buoyant and close to the surface. The seaweed band attracts fish, shrimp, crabs, birds, and turtles, providing essential habitats. The seaweed is in turn nourished by the excrement of these organisms. Even larger creatures find plenty to eat amid the sargassum.

While the seaweed can be a boon for marine wildlife under normal circumstances, too much of it can pose a huge problem. As sargassum decays it consumes the oxygen, creating low oxygen conditions that affect marine life. Coral reefs and seagrass ecosystems can suffer when high levels of sargassum change water chemistry and block organisms from moving freely. Thick mats can also block sunlight from reaching the ocean depths. The seaweeds often wash up ashore en masse and choke coastal ecosystems. As the seaweed rots, it releases foul-smelling hydrogen sulphide gas, causing respiratory illness in local populations. They also affect coastal tourism.

Recurrent blooms

Scientists are concerned over the recurrent blooms having become the new normal. They attribute it to various factors such as warming of the ocean due to climate change, discharge of nutrients (nitrogen and phosphorus) from agricultural run-off and wastewater originating from major river basins such as the Congo and the Amazon and the deposition of iron and nutrient-rich Saharan dust on the ocean. Scientists say that multidisciplinary research and international efforts are required to address this issue.

 

Picture Credit : Google

You must have read about NGT banning firecrackers in areas where air quality is "poor". But do you know what NGT is and what its functions are?

NGT is the National Green Tribunal established in October 2010 under the National Green Tribunal Act 2010. A specialised judicial body, it has over the years emerged as a significant player in environmental regulation in the country, passing strict orders on issues ranging from pollution and deforestation to waste management. People can approach the tribunal against projects that affect the environment or seek compensation for damages caused due to violation of environmental laws.

Civil cases heard The NGT deals with all civil cases under the seven laws related to the environment which are the Water (Prevention and Control of Pollution) Act, 1974; the Water (Prevention and Control of Pollution) Cess Act, 1977; the Forest (Conservation) Act, 1980; the Air (Prevention and Control of Pollution) Act, 1981; the Environment (Protection) Act, 1986; the Public Liability Insurance Act, 1991; and the Biological Diversity Act, 2002. Any violation pertaining to these laws or any decision taken by the Government under these laws can be challenged before the NGT. From individuals and conservation groups to the community at large, anyone can file a case against everyone - from the State pollution control board to the Union government- at the NGT by paying a fee. The cases are to be disposed of within six months from the date of filing. The proceedings of the tribunal are conducted only in English. The NGT has as much power to grant relief as it has to impose a penalty for non-compliance of its orders

How does the NGT function?

The main bench of the NGT is in New Delhi, with regional benches in Pune, Bhopal, Kolkata and Chennai having jurisdiction over specific geographical areas.

The NGT has a chairperson, who is a retired Judge of the Supreme Court appointed by the Central Government and judicial and expert members. Besides, expert members are required to have a minimum of 15 years experience in the field of environment, forest conservation and related subjects. Though the NGT is supposed to function with a minimum of 10 members and a maximum of 20 members who will serve a five-year term, the number has been changing over the years. According to latest reports, it has only six members and a chairperson, retired justice Adarsh Kumar Goel.

Quick facts

• Over 400 cases were heard by the NGT via video conferencing till June-end during the lockdown period.


• The tribunal on its own passed several directives on COVID-19 waste management, as its improper handling poses a grave threat to the health of the environment and the people.


• It also dealt with matters relating to solid waste management and rejuvenation of water bodies such as the Ganga and the Yamuna.

Migration pattern

The impact of climate change on birds’ migration patterns has been noticed in the last few decades. Scientists have documented that fewer birds show up in breeding and wintering grounds and they attribute it to the increasing temperatures changing vegetation and extreme weather conditions.

Birds synchronise their migratory movements with seasonal changes. The start of their journey and their speed must match the life cycle (before caterpillars pupate) of food sources at the stopover and destination sites. But these environmental cues go for a toss with changing climate.

Lack of food

A number of birds has adjusted breeding times to match early Spring. They arrive at the breeding site earlier than before. Meanwhile, increasing temperatures also make the vegetation bloom and insects hatch earlier at the site. But sometimes these shifts are not in line with each other. As a result, the chicks hatch way after the caterpillars are gone. And so, they starve. (On average the window of time when birds lay their eggs has gotten earlier by almost two weeks over half a century. Since many small songbirds can raise their young in roughly one month, two weeks is a big shift in their timing.)

Habitat loss

One of the major effects of climate change is the loss of habitats. While some species face shrinking ranges, others face habitat destruction. For migrating birds, flooding or desertification could spell doom. Flocks might fly thousands of kilometres only to find their destination submerged or barren. Many goose species use the Siberian tundra's rocky bedrock to raise their offspring. But increasing temperatures make the permafrost soil to thaw and change the habitat completely, making it impossible for the geese to breed.

Sea-level rise

Sea-level rise and erosion alter coastal wetlands. Many birds, such as piping plovers, that inhabit coastal areas lay their eggs directly on the sand of the beach in a shallow depression. The erosion of beaches and storm surges can cause nests to be lost to the ocean.

Lack of sea ice

Climate change affect penguins in two ways - non-availability of food and nesting habitats. The Adelie penguins nest on land during the summer, and migrate during the winter to the edge of the sea ice, where they feed at sea. As icebergs break off in warming Antarctica, Adelie penguins are forced to take longer routes to find food in the ocean.

Antarctica's climate is generally cold and dry but warming could cause unprecedented rain or melting of ice, creating puddles on the ground. This is bad news for penguins that lay their eggs on the ground. Their eggs cannot survive when they are lying in a pool of water.

Chinstrap penguins, which also breed in Antarctica, are affected by melting ice. Lack of sea ice affects the abundance of krill their main source of food.

Smaller body, larger wings

A study published in December 2019 found that global warming was causing birds to shrink and their wingspans to grow in size. Scientists explained that it could be more adaptation of birds as smaller birds are better at cooling off, losing body heat more quickly due to their larger surface area to volume ratios. But smaller body size means less energy available for the birds to complete long journeys. Scientists say that birds would have evolved to grow long wings to compensate for their smaller bodies as it helps them survive migration.

Will birds be able to adapt to climate change?

In the past, species and ecosystems were able to respond to global temperature shifts because average global temperatures changed slowly. Now, the change is simply too fast for many species to adapt. As we saw earlier, birds are adapting ways such as starting their migration early to match earlier Springs, but scientists are not sure if they will be able to keep up with the speed of climate change.

 

Picture Credit : Google