Approach to the answer 

Understanding and structuring the answer: 

The question has 2 main parts – 1) Potential Uses of seaweed and 2) Challenges in seaweed cultivation. 

Introduction:  

Type 1: Give a brief description about seaweed. 

Body: 

Heading 1: Potential uses of seaweeds 

Heading 2: Challenges in seaweed cultivation 

Conclusion: Write a way forward as your conclusion. 

Answer: Seaweeds are macroscopic algae growing in marine and shallow coastal waters and on rocky shores. Seaweeds are wonder plants of the sea as they are the new renewable source of food, energy, chemicals and medicines with manifold nutritional, industrial, biomedical, agriculture and personal care applications. The worldwide seaweed industry provides a wide variety of products for direct or indirect human uses that have an estimated total value of US$10 billion per year.
 

SEAWEED- THE WEALTH OF THE OCEAN  

1. Bio-indicator: When waste from agriculture, industries, aquaculture and households are 

let into the ocean, it causes nutrient imbalance leading to blooming of seaweed species, 

which is a sign of marine chemical damage. 

1. Carbon sequestration: Seaweed absorbs CO2 more effectively than trees. By afforesting 

9 per cent of the ocean with seaweed, it is possible to sequester 53 billion tons of carbon dioxide annually. 

1. Iron Sequestrator: Seaweeds heavily rely on iron for photosynthesis. When the quantity 

of this mineral exceeds healthy levels and becomes dangerous to marine life, seaweeds 

trap it and prevent damage. Similarly, most heavy metals found in marine ecosystems are 

trapped and removed by seaweeds. 

1. Climate change adaptation: Seaweed aquaculture contributes to climate change 

adaptation by damping wave energy and protecting shorelines.

Potential Uses of Seaweeds 

• Food: Seaweeds are used as important source of nutrition since ancient times.  

• For example, Chinese people were consuming seaweeds in 2500 B.C. 

• Medicinal Utility: Seaweeds can be used as raw material in pharmaceutical industry.  

• For example, Seaweeds possess anti-cancer, anti-diabetic and anti-inflammatory properties. 

• Industrial Utility: Agar is produced from seaweed. Agar is used in the manufacture of photographic film, paint, batteries, graphite, glue etc. 
• Renewable Energy: Seaweed is a rich source of biomass which can be used for producing biogas. 

• For example, According to United Nations University, Baltic Sea contains large quantity of Sugar kelp (type of seaweed) which can be used to produce biogas. 

• Organic Farming: Seaweeds are a rich source of organic material which makes them suitable for use as manure and biofertilizers. 

• For example, the Ministry of Earth Sciences and the Council of Scientific and Industrial Research (CSIR) are involved in research and development activities related to the use of seaweed as organic manure. 

• Sewage treatment: Seaweeds can remove most of the nutrients efficiently from the waste waters.  

• For example, seaweed can remove nutrients like nitrogen and phosphorus from domestic sewage.  

Although seaweed can have several potential uses, there are many challenges associated with seaweed cultivation. 

Challenges in Seaweed Cultivation 

• Water use conflicts between fish landing centre and commercial fishing activities is a major constraint in expanding seaweed cultivation ground. 
• Eutrophication due to human sewage rich in phosphate and nitrate from major municipalities and small towns has negative impacts on seaweed growth. 
• Run-off from land-based agriculture, thermal power plants and chemical factories contributes to commercial cultivation challenges as seaweed is highly sensitive to water pollution. 
• Rising sea surface temperatures (SST) due to climate change inhibits the growth of seaweed species. 
• Cyclones and high sea water turbulence is witnessed during Monsoonal periods. Cultivation during this period is restricted to seed bank preservation. 
• Shortage of labour and technology: Other challenges include labour shortages during the paddy harvesting & transplanting season, and lack of technology to improve processed products.  
• Over-exploitation: India has rich source of seaweed varieties, but we have only focused on harvesting and not cultivation, thus leading to over-exploitation. 

Keeping in mind the benefits of seaweed cultivation, Government of India has earmarked 640 Cr Rupees exclusively to promote seaweed cultivation with a targeted production of more than 11.2 lakh tonnes by 2025, in the Pradhan Mantri Matsya Sampada Yojana (PMMSY).