The greatest threat to biodiversity in the oceans

-Josefin Johansson

This week we’ve been learning about the environmental consequences of shipping. One part included ballast water transported in cargo vessels. The ballast water is stabilizing vessels when cargo isn’t loaded on or in it since the ships often isn’t built to travel empty. It’s also needed in order to compensate for different salinity levels in the oceans which affects the buoyancy of the .

This subject is an important one since the ballast water going long distances contain species from other ecosystems which can be problematic and sometimes even disastrous. According to the Swedish project Advantage Environment, driven and owned by the Confederation of Swedish Enterprise, tens of thousands m3 of water can be with one vessel alone. I’ve experienced a lot of problems with the invasive Spanish snail in my garden and seen what it is capable of doing in terms of eating loads, having tremendous survival skills and an efficient reproduction. Thus it never occurred to me that species such as my horrible garden guest could be introduced in to a distant area in a completely new environment in such an expansive (for invasive species that is).

An article in “Svenska dagbladet” from 2006 described the pace of changing ecosystems in the Baltic Sea and Skagerrak with its surroundings as a “McDonaldsification” of the maritime biosphere. New species introduced in an ocean can be a great danger to the ecosystems and might at its worst exterminate entire species. The main reason for this rapid introduction of new, sometimes invasive, species is said to be from ballast water from cargo vessels. According to the article the situation has worsened due to warmer climate but also regulations imposing the use of double-hull cargo vessels. This means that the water temperature remain stable and thus more of the algae and plankton survive the journey across the oceans. As we’ve learned in the course and what is also told in the article the Baltic Sea is especially endangered since it lacks in biodiversity, it’s already unbalanced and have relatively young ecosystems and on top of that low amounts of predatory fish due to over fishing.

In September 2016 IMO, the International Maritime Organisation, could finally enforce the Ballast Management Convention. It took them many years to get enough countries signing the convention, equivalent to 35 percent of the total tonnage transport. This convention demand ship owners to handle the organisms and pathogens in their ballast water meaning a cleaning system for the ballast water needs to be installed. This is for international trade with the start in September 2017 (Wärtsilä, 2016). According to a Wärtsilä, a technical maritime engineering company, more than 29.000 active vessels are without these cleaning systems and will need an approved cleaning solution installed when dry-docking the next time after the date mentioned above.

Miljönytta present the following techniques that can be used in order to clean the ballast water: chemicals, ultrasound, heating and ozone. Engineers also try to develop and construct ships that don’t need ballast water at all or just small amounts of it.

I feel this post is showing that change is happening and that in a positive way. The fact that more than 29.000 vessels will need to be equipped with cleaning system for the ballast water made me reflect on how much water that is

Me, as a soon to be traffic engineer, with some knowledge about efficient truck logistics, couldn’t help reflecting on the possibilities of improving and implementing solutions so that the cargo vessels get loaded in both directions. Filling the ships with goods rather than water. By this I mostly think of container vessels. Oil tankers is of course harder to fill in both ways but there are such examples as well such as OBO-ships (Ore Bulk Oil Carrier). However, I understand this demands both highly developed logistic solutions and that the import and export from the docks are pretty much the same and are going in the opposite direction which probably isn’t the case. But when this is the case – it might be a future improvement to aim for, both for economy as for the environment. I believe container cargo vessels have the best prerequisites for this, obviously it’s hard to implement for oil tankers.

/Josefin Johansson



  • Advantage Environment. 2013. ”Problem för ovälkomna fripassagerare”. 20130515.

  • Rådelius, Maja-Lena. 2006.Främmande arter intar Östersjön”. Svd. 20061124.

  • Wärtsilä. 2016. “Ny utveckling inom ballastvatten”.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s