The term "seaweed" is used to refer to a huge variety of marine plants and algae that can be found in rivers, lakes, and other bodies of water in addition to the ocean. The term refers to a few more varieties of macroalgae from the Rhodophyta (red), Phaeophyta (brown), and Chlorophyta (green) families. Other species, including planktonic algae, play a crucial role in collecting carbon, creating at least 50% of Earth's oxygen. Seaweed species like kelps provide crucial nursery habitats for fisheries and other marine creatures and hence protect food sources. This article will explain to you about Seaweeds which will be helpful in preparing the Environment Syllabus for the UPSC Civil Service exam.

Seaweeds - Features

• Since seaweeds are thalloid plants, they lack real tissue differentiation, including roots, stems, and leaves. Their appendages resemble leaves.
• In the intertidal and shallow subtidal zones of the sea, seaweeds, the larger and more noticeable marine plants, are seen clinging to rocks, corals, and other submerged strata.
• Microscopic seaweeds also exist, such as the phytoplankton that support the majority of marine food chains and live floating in the water column.
• Some are massive, such as the enormous kelp that grows in numerous "forests" and rises from the sea floor like underwater redwoods.
• Most wash up everywhere at random on beaches and shorelines, are medium in size, and are shades of red, green, brown, and black.

Seaweeds - Habitat

• There are many ecological niches that seaweed occupies.
• Some species may cling to a substrate many meters beneath the surface, whereas others may only get wet by the tops of sea spray.
• Seaweed is most frequently found in the littoral zone (nearshore seas), and within that zone, on rocky coasts more so than on sand or shingle.
• Littoral seaweed colonies can spread kilometers out to sea in some places.
• Red algae species are among the deepest living seaweeds. Some individuals have evolved to survive in tidal rock pools.
• Seaweed must be able to tolerate the frequently changing salinity, temperature, and drying conditions in this ecosystem.

Seaweeds - Distribution

• Kelps and fucus are examples of brown algae (family Phaeophyceae) that are frequently found as seaweeds.
• They are not present in tropical waters but are common in cooler regions.
• The kelps are among the largest algae; in the Pacific and Antarctic, some Macrocystis and Nereocystis species can reach lengths of 33 metres (100 feet).
• Along the Pacific and Atlantic coasts, laminaria, another type of kelp, is widely distributed.
• In the Gulf Stream and the Sargasso Sea, free-floating clumps of Gulfweed (Sargassum) are prevalent.
• Seaweeds classified as red algae (division Rhodophyta) include laver, gelidium, and dulse (Palmaria palmata) (Porphyra). Along the rocky Atlantic shores, the lowest half of the zone exposed at low tide is covered in a variety of Chondrus species, including Irish moss (C. crispus).

Seaweeds - Requirements

• The ecology of seaweed is dominated by two environmental conditions.
• These are light that is strong enough to enable photosynthesis and seawater (or at least brackish water).
• An attachment point is another common requirement.
• In addition, only a few genera, including Sargassum and Gracilaria, exist free of attachment to the ocean floor.

Seaweed Farming

• Seaweed farming, often known as kelp farming, is the cultivation and harvesting of seaweed.
• In its most basic form, it entails the management of naturally occurring batches. In its most advanced version, it entails complete control of the algae's life cycle.
• Eucheuma spp., Kappaphycus alvarezii, Gracilaria spp., Saccharina japonica, Undaria pinnatifida, Pyropia spp., and Sargassum fusiforme are the top seven most cultivated seaweed taxa.
• China, Indonesia, and the Philippines are the top producers of seaweed.
• South Korea, North Korea, Japan, Malaysia, and Zanzibar are among the other prominent producers (Tanzania).
• Seaweed farming has been proposed as a means of improving economic conditions while also reducing fishing pressure and overexploitation of fisheries.
• The output volume of farmed aquatic plant production increased from 13.5 million metric tonnes (13,300,000 long tonnes; 14,900,000 short tonnes) in 1995 to just over 30 million metric tonnes (30,000,000 long tonnes; 33,000,000 short tonnes) in 2016.
• Seaweed accounted for 27% of global marine aquaculture in 2014.

Seaweeds - Significance

Beneficial to the Marine Ecosystem

• Seaweeds are important components of marine ecosystems.
• They supply nutrients and energy to animals as the first creature in marine food chains, either directly when fronds are eaten or indirectly when decomposing sections break down into tiny particles and are consumed by filter-feeding animals.
• For all or part of their lives, seaweed beds provide shelter and habitat for a variety of coastal species.
• Many commercial species such as the rock lobster, pua (abalone), and green-lipped mussel rely on them as nurseries.
• Seaweeds, for their part, get their nutrition through photosynthesis of sunlight and nutrients in seawater.
• They expel oxygen from all parts of their bodies. They also provide organic nutrients to various types of marine life.

Bioindicator for Ecological Conservation

• An organism that is used to assess the health of an environment, particularly in terms of pollution.
• That particular species gets affected due to nutrient imbalance and changes in biotic as well as abiotic factors.
• It is reflected in the presence, and processes of development of that particular species.
• When trash from agriculture, industry, aquaculture, and households is dumped in the ocean, it creates a nutrient imbalance, which leads to algal blooming, an indication of marine chemical harm.
• Seaweeds absorb excess nutrients and help to maintain the ecosystem's equilibrium.

Seaweed as an Iron Sequester

• For photosynthesis, these aquatic species require considerably more iron.
• When the amount of this mineral exceeds safe levels and poses a threat to marine life, seaweeds catch it and protect it.
• Similarly, seaweeds trap and eliminate the majority of heavy metals found in marine ecosystems.

Nutritional Medicinal Benefits for Humans

• Anti-inflammatory and anti-microbial compounds can be found in a variety of seaweeds.
• For thousands of years, their medicinal properties have been well-known.
• Researchers anticipate that potent cancer-fighting chemicals found in certain seaweeds will one day prove beneficial in the treatment of malignant tumors and leukaemia in humans.
• Seaweed is high in vitamins, minerals, and fiber, and it can also be delicious.

Seaweed Cultivation: Potential in India

• India is one of the world's 12 mega-biodiversity countries.
• India has a 2.17 million km2 Exclusive Economic Zone (EEZ).
• The numerous coastal environments around the Indian coastline enable the abundant growth of various seaweed populations, which are very significant economically.
• India has a 7,500 km coastline and has been found to be home to 844 different types of seaweed.
• Resources abound in the intertidal and subtidal zones on the West Coast, particularly in Gujarat.
• There is a lot of potential for the growth of seaweed-based industries in India due to these resources.
• Seaweed is prevalent along the coastlines of Gujarat, Lakshadweep, and the Andaman and Nicobar Islands.
• Also near Mumbai, Ratnagiri, Goa, Karwar, Varkala, Vizhinjam & Pulicat in Tamil Nadu, & Chilka in Orissa are rich seaweed beds.
• More than 240 different species of seaweed, at least 185 of which are edible, may be found in the Gulf of Mannar.

Significance of Seaweed Farming to Indian Farmers

• Seaweed farming is a carbon-negative crop with significant climate-change mitigation potential.
• As a mitigation strategy, the IPCC Special Report on the Ocean and Cryosphere in a Changing Climate advises "additional study attention."
• Seaweed farming can directly benefit Coastal fisher-families, particularly fisher-women, and their societies/ SHGs, as well as farmers and businesses.
• According to estimates, seaweed production on 10 million hectares, or 5% of India's Exclusive Economic Zone (EEZ), might provide jobs for 50 million people.
• Businesses out of Seaweed farming can contribute to the Gross Domestic Product (GDP) of the country (GDP).
• It will help in increasing the productivity of the ocean, Reduce the number of algal blooms, Millions of tonnes of CO2 is sequestered and 6.6 billion liters of bioethanol might be produced.

Challenges to Seaweed Harvesting in India

• Insufficient labor during the season of transplanting and harvesting paddy.
• Lack of security in one's livelihood because of poor pay and terrible weather.
• Insufficient technologies to enhance processed goods.
• Lack of knowledge about new and alternative raw material sources.
• Risky because seaweed must be retrieved from depths more than 25 to 30 feet.
• Market demand is lower and there is a lack of government assistance.
• Overexploitation: India has a wide variety of seaweeds, but we have solely focused on harvesting rather than farming, which has resulted in overexploitation.
• Lack of Knowledge: The population's inability to make the shift to a healthier diet is hampered by a lack of knowledge about its advantages.

Seaweed Mission

The Seaweed Mission has been established to increase the nation's economy through commercial seaweed growing and processing.

It anticipates the following actions:

• Establishing model demonstration farms larger than one hectare for the growing of seaweeds along the Indian coast is economically significant.
• Establishing seaweed nurseries to provide seed for the nation's large-scale seaweed farming of commercially significant seaweeds
• Establishing and demonstrating edible seaweed processing methods and recipes that are compatible with consumer preferences or local culinary customs.
• Development of the value and supply chains as well as the gathering of information on the social, economic, and environmental effects of seaweed projects across the nation are all included in the activity on seaweed cluster development.

Conclusion

However, seaweeds may cause health hazards. Rotting seaweed has been linked to some cases of what seems to be hydrogen sulphide poisoning because it is a significant producer of the highly poisonous gas hydrogen sulphide. Microcoleus lyngbyaceus, the so-called "stinging seaweed," is a filamentous cyanobacteria that produces lyngbyatoxin-A and debromoaplysiatoxin among other toxins. Seaweed dermatitis, which causes painful, blistering blisters that last for days, can be brought on by direct skin contact.

FAQs

Question. What are seaweeds?

Question. What are the ecological benefits of seaweeds?

Question. How are seaweeds used in human industries?

Question. What is the role of seaweeds in combating climate change?

Question. How does seaweed farming contribute to the economy?

MCQs

1. Which of the following is a type of seaweed?

A) Moss

B) Kelp

C) Fern

D) Pine Tree

2. Which of the following is a commercial use of seaweeds?

A) Production of paper

B) Biofuel production

C) Wood products

D) Textile manufacturing

3. Which of the following is a major ecological benefit of seaweed?

A) Soil erosion prevention

B) Carbon sequestration and oxygen production

C) Desertification mitigation

D) Freshwater purification

4. Seaweeds are primarily classified into which of the following categories?

A) Red, Green, and Blue

B) Red, Green, and Brown

C) Blue, Yellow, and Green

D) Green, Yellow, and White

5. Which of the following seaweed types is commonly used in Japanese cuisine for making sushi?

A) Kelp

B) Nori

C) Wakame

D) Spirulina

GS Mains Questions and Model Answers

Q1: Explain the role of seaweeds in maintaining marine biodiversity and their ecological importance.

Answer: Seaweeds are crucial to maintaining marine biodiversity and ecological balance in oceanic ecosystems. They serve as habitats for a variety of marine species, including fish, invertebrates, and other organisms. Kelp forests, for example, provide shelter and food for marine life, supporting rich biodiversity. Seaweeds also contribute to ecosystem services by:

• Carbon Sequestration: Seaweeds absorb carbon dioxide from the water, contributing to carbon sequestration and helping to mitigate climate change.
• Oxygen Production: Through photosynthesis, seaweeds generate oxygen, which is vital for marine organisms.
• Nutrient Cycling: Seaweeds help in the cycling of essential nutrients in marine ecosystems, such as nitrogen and phosphorus.
• Water Purification: Seaweed beds act as natural filters, absorbing pollutants and improving water quality. Thus, seaweeds play an essential role in the health and sustainability of marine ecosystems.

Q2: How can seaweed farming be a sustainable solution for coastal economies?

Answer: Seaweed farming offers a sustainable solution for coastal economies by providing both economic and environmental benefits:

• Revenue Generation: Seaweed farming provides income for coastal communities through the sale of seaweed products like food, cosmetics, fertilizers, and biofuels.
• Job Creation: Seaweed farming creates employment opportunities for local people, especially in rural coastal areas where other economic activities might be limited.
• Sustainable Aquaculture: Seaweeds are used as feed in aquaculture, reducing the need for fishmeal and making aquaculture more sustainable.
• Environmental Benefits: Seaweed farms help in carbon sequestration, reducing the impacts of climate change. They also help reduce coastal erosion and promote water purification, contributing to ecosystem restoration.

Q3: Discuss the potential of seaweeds as a renewable energy source and their role in addressing energy demands.

Answer: Seaweeds have significant potential as a renewable energy source due to their high carbohydrate content and fast growth rates. Seaweed-based biofuels, such as bioethanol and biogas, are gaining attention as a cleaner and more sustainable alternative to traditional fossil fuels. The potential benefits of seaweed-based biofuels include:

• Low Environmental Impact: Seaweeds do not require fresh water or arable land, making them a sustainable feedstock for biofuel production.
• High Yield: Seaweeds grow rapidly and can be harvested multiple times a year, providing a reliable source of biomass for bioenergy production.
• Carbon Neutral: The cultivation and harvesting of seaweeds for biofuel production is carbon neutral, as seaweeds absorb carbon dioxide during their growth.
• Waste Management: Seaweed farming helps utilize waste CO2 from industries and power plants, turning it into biomass for biofuels.

Seaweed biofuels could play a significant role in addressing global energy demands while also contributing to climate change mitigation.

Previous Year Questions on Seaweeds

1. UPSC CSE 2020

Question: "Explain the role of seaweeds in maintaining coastal ecosystem stability and their contribution to mitigating climate change."

Answer: Seaweeds provide critical support to coastal ecosystems by acting as natural habitats for marine organisms, promoting biodiversity, and improving water quality. They also help mitigate climate change through carbon sequestration, as seaweeds absorb CO2 from seawater. By contributing to the overall health of marine ecosystems and protecting coastal areas from erosion, seaweeds support both environmental and economic stability.