Cargo ships create deep water distress

Cargo ships create deep water distress
30/04/2019 https://www.hellenicshippingnews.com/cargo-ships-create-deep-water-distr...

Nature has a beautiful mechanism of maintaining balance through food chains, resulting in a stable ecosystem. A foreign organism, which does not have a well defined position in the food chain, disrupts the existing ecosystem. Marine life is facing such a crisis due to invasion of non-native organisms through ballast water.

Large tanks in a ship are filled and emptied with sea water when a ship is loaded or unloaded to maintain its structural integrity, balance, and stability. The water in tanks then transports thousand of specimens of local marine organisms. While majority don’t survive the extensive journey, those left alive are introduced to new environments.

Untreated ballast water releases species from one ecosystem to another. If the new ecosystems conditions are suitable, the species can thrive and become an invasive aquatic life form.

Billions of tonnes of ballast water gets shipped over thousands of miles every year. Since ships are the main source of cargo transportation and global trade has been increasing over the years, the need for ballast water treatment systems (BWTS) has arisen.

These systems disinfect the water from invasive organisms before it is discharged into the sea. Multiple types of BWTS exist which involve amongst others electrolysing process, deoxygenation, thermal treatment, UV treatment and chemical treatment. While there are many types of BWTS technologies available, not every technology works with every type of vessel.

It is estimated that almost 10 billion tonnes of ballast water gets transported around the world every year, contributing to an average transfer of 7,000 species per day. By one estimates, this causes an aquatic life form invasion once every nine weeks on average, becoming a major threat to the environment, public health and economy.

An invasive species is a non-indigenous organism in the ecosystem, whose introduction causes environmental or economic harm. They create loss of biodiversity and impact on economic enterprises like agriculture, forestry and fisheries. Zebra mussel, green crab and goby are examples of aquatic invasions through ballast water.

A study by US Congress in 1993 “Harmful Non-Indigenous Species in the United States”, estimated a $97bn loss due to 79 invasive life forms, from 1906 to 1901. The worst case scenario estimate was $134bn in future economic losses for selected non-indigenous species.

While the US Coast Guard’s (USCG) regulations for treating ballast water came into effect in 2012, the International Maritime Organisation’s (IMO) Ballast Water Management Convention came into force in 2017. USCG requires all ships to have a BWTS by 2021 and the latter offers a window till 2024.

However, many ships are delaying installation of BTWS because of looming restrictions on sulphur emissions that will be implemented from 2020. Ships may face penalties if a certified BTWS is not installed by 2024.

As per IMO, there are two standards for ballast water management, D1 and D2. D1 standards require ships to exchange ballast water in open seas, away from coastal waters. This means ships must discharge water at least 200 nautical miles away from the port to minimise threat of invasive aquatic organisms.

It also specifies the volume of water that must be replaced. By taking these measures, fewer organisms will survive so ships are less likely to introduce potentially harmful species when they release ballast water.

D2 standards are more stringent, requiring the use of an approved BWTS. They rule that there should be less than 10 viable organisms, greater or equal to 50 micrometres, in the water released. Existing ships must comply with D1 standards, and new ships with D2 standards, by September 2017. All ships must comply with D2 standards by 2024.

Effective implementation of the convention requires enforcement by all contributing countries, availability of inspectors, and an administrative set up for proper adherence to convention. At least 59 states, representing more than 60pc of the global merchant shipping tonnage, have agreed to this convention.

Due to the rapidly increasing inter-country and intercontinental transport, the protection of marine and coastal ecology has become a crucial issue. It is estimated that about 20pc of the total ocean pollution is caused by marine transport.

The introduction of invasive life forms in ecosystems creates ecological imbalance, carrying the possibility of inflicting irreversible damage. Hence serious consideration needs to be given to the importance of protecting marine ecology for sustainable development around the globe.
Source: Dawn