Changes In Oceans

Natural Changes

• Sea Floor Spreading along Mid Oceanic Ridge(Plate Tectonics).
• Creation of new oceans such as the Great African Rift Valley which is in the nascent stage in the process of ocean formation.

These, however, are prolonged processes that take millions of years to complete.

Climate Change Results In Changes Such As

• Ocean acidification lowering of ocean pH is a shift in ocean chemistry brought on by the ocean’s uptake of carbon compounds from the atmosphere.
• Ocean warming– According to IPCC since 1970, the world’s oceans have continued to warm, absorbing more than 90% of the extra heat in the climate system.
• Sea level rise due to temperature rise( Thermal expansion of oceans), melting of glaciers, etc. IPCC Sixth Assessment Report- Global mean sea level increased by 0.20m between 1901 and 2018.

Pollution Creates The Changes Such As

• Eutrophication occurs when the environment becomes
• enriched with nutrients, increasing the amount of plant and algae growth in estuaries and coastal waters.

Plastic pollution – Land-based activities such as urban and stormwater runoff, sewer overflows, littering, improper waste management, industrial operations, tire abrasion, building, and illegal dumping are the main sources of plastic debris detected in the ocean.

Coral Bleaching due to climate change, increased ocean temperature, and eutrophication.

Human-induced changes such as increased exploration for oil and mineral resources, ocean thermal energy extraction, fishing, transportation of goods, etc impact oceans and their ecosystem. For eg: oil spills create dead zones in oceans.

Impacts Of Such Changes

Benefits

• Natural changes help us understand the evolution of the earth and its crust such as the presence of a relatively new oceanic crust near Mid Oceanic Ridge which becomes older away from it as well as the oceanic crust being relatively new concerning continental crust.
• Oceans absorb extra heat from the atmosphere therefore these changes help regulate the Earth’s climate
• Energy security by harnessing ocean wave energy.
• Food and nutritional security through fishing, whaling, ocean ranching, etc., and alternate livelihood opportunities for the poor.

Nevertheless, the above benefits are availed at a much larger cost

Climate change – has led to the these harmful impacts on ocean 

• Changes in oceanic current patterns and the reduction difference between cold and warm currents have impacted the earth’s heat budget, fish production, the livelihood of fishers, etc
• Change in wind and weather patterns for ex: the frequency of El NINO – Southern Oscillations has increased.
• Sea level rise has become a major problem for Small Island Nations as they face submergence danger. This also impacts coastal erosion, coastal livelihood, etc.
• The increased temperature of oceans has also impacted their biodiversity due to the increased demand for oxygen.
• Pollution in oceans has threatened marine species as well as humans on a larger scale.
• For example, Eutrophication contaminates water, negatively affects seashore recreational opportunities, creates a dead water zone or hypoxia, and depleted oxygen levels impair or could kill fish in large numbers and change species composition.
• Plastic, mainly in the form of microplastic, enters the food web through bioaccumulation and biomagnification.
• Other pollutants such as disposal of harmful chemicals, industrial waste, Agri nutrients, etc also deteriorate ocean ecosystems.
• Coral bleaching also is dangerous for many reasons. Corals are an indicator of a healthy marine ecosystem and play a major role in its food chain, their destruction can impact coastal protection and biodiversity. Their destruction also impacts tourism and therefore the livelihood of people.
• Overexploitation of fish resources through unscientific practices such as trawling has impacted ocean diversity.
• Extraction of petroleum, polymetallic nodules, other metallic and non-metallic minerals, and oil spills also disrupt marine life.