Tag Archives: Ships

There’s a newly found responsible for ocean plastic waste — merchant ships

Despite initially thought to come from land, most plastic debris in the sea can be linked to merchant ships, according to a new study which analyzed plastic bottles and containers from the past three decades.

Credit: Wikipedia Commons

Researchers looked at the waste that arrived at the coast of Inaccessible Island – an isolated, uninhabited island in the central South Atlantic Ocean – and found that plastic drink bottles were the fastest-growing source of debris.

While tides could be blamed for the South American bottles that washed up there, they didn’t explain why most of the bottles there now are from Asia. Their recent manufacturing dates suggest that ships are the main culprits.

This means that the vast garbage patches floating in the middle of oceans, which have sparked much consumer handwringing in recent years, are less the product of people dumping single-use plastics in waterways or on land than initially thought.

The island examined by the researchers is located roughly midway between Argentina and South Africa in the South Atlantic gyre, a vast whirlpool of currents that has created what has come to be known as an oceanic garbage patch.

Despite an initial inspection of the trash showed labels indicating it had come from South America (some 2,000 miles / 3,000 kilometers to the west), by 2018 three-quarters of the garbage appeared to originate from Asia, mostly China. Many of the plastic bottles had been crushed with their tops screwed on tight, as is customary on-board ships to save space.

Around 90 percent of the bottles found had been produced in the previous two years, ruling out the possibility that they had been carried by ocean currents over the vast distance from Asia, which would normally take three to five years.

Since the number of Asian fishing vessels has remained stable since the 1990s, while the number of Asian—and in particular, Chinese—cargo vessels has vastly increased in the Atlantic, the researchers concluded that the bottles must come from merchant vessels, which toss them overboard rather than dumping them as trash at ports.

“It’s inescapable that it’s from ships, and it’s not coming from land,” Peter Ryan, director of the FitzPatrick Institute of African Ornithology at the University of Cape Town in South Africa. “A certain sector of the merchant fleet seems to be doing that, and it seems to be largely an Asian one.”

Our ships carry invasive species, not just trade — and it is rapidly getting worse

More maritime traffic means a higher standard of living — but also more invasive species.

Paper ship.

Image via Pixabay.

The rise in global maritime traffic could lead to dramatic increases in the number of invasive species globally over the next 30 years, a new study from McGill University researchers reports. The authors also say that this increase in shipping will come to far outweigh climate change in the spread of non-indigenous pests to new environments in the coming decades.

“My passion is traveling”

“Biological invasions are believed to be a major driver of biodiversity change, and cause billions of dollars in economic damages annually,” says senior author Brian Leung, an associate professor in McGill’s Department of Biology and School of Environment. “Our models show that the emerging global shipping network could yield a three-fold to twenty-fold increase in global marine invasion risk between now and 2050.”

Some 80% of world trade gets ferried around on boats, as do between 60% and 90% of marine invasive species. The latter get onto ships either in ballast water — which is pumped in to help balance the vessels — or attach to their hulls as stowaways. So, the team says that to understand how invasive species will evolve over time, we need to look at how shipping patterns could change.

To that end, the team used socioeconomic-growth scenarios (developed as part of the United Nations’ Intergovernmental Panel on Climate Change, the IPCC) to build several computer models that estimated future rates of global shipping traffic growth. As population and wealth increase in different areas of the globe, the demand for goods and services that aren’t available locally also spikes — leading to more shipping. The models estimated a pretty wide range of increases in bio-invasion risk — from three- to twenty- fold — which the team says comes down to uncertainty in the socioeconomic paths different areas will take in the future.

“Our study suggests that, unless appropriate action is taken, we could anticipate an exponential increase in such invasions, with potentially huge economic and ecological consequences,” says Anthony Sardain, a graduate student in Leung’s lab at McGill and the study’s lead author.

“Despite this large range, all scenarios point to an increase in both shipping and invasions. That should alert us to the gravity of the situation, and the importance of measures to curtail biological invasions.”

Some progress is being made into limiting the spread of invasive species, the team writes, citing major policy initiatives such as the International Ballast Water Management Convention. The Convention entered into force in 2017 and represents the latest global effort to control bio-invasions through measures such as ballast exchange. Leung explains that it’s still too early to gauge the efficacy of this measure globally, but that their work suggests it’s a step “in the right direction.”

The paper “Global forecasts of shipping traffic and biological invasions to 2050” has been published in the journal Nature Sustainability.

Light pollution from research ship makes Artic zooplankton return to the deep

Zooplankton.
Image credits: Wikipedia.

Scientists discovered that zooplankton from the Arctic is very sensitive to light pollution. Even light coming from research ships can make these small organisms sink back into darkness. Sure, it was previously known that the light of a full moon or the northern lights would make these creatures retreat to deeper waters, but the possibility that ship-borne lights bothered them was still debatable.

“We did have a suspicion that this was the case,” said Martin Ludvigsen, a professor in NTNU’s Department of Marine Technology and at the university’s Centre of Autonomous Marine Operations and Systems. “We were able to demonstrate this, and show the significance of the lights from the ship” he added.

Run for the depths!

Zooplankton is the most widespread vertical migratory biomass on Earth (and armed to the teeth). Around the globe, these tiny animals rise to the surface during the night to feed and descend into deeper waters to avoid predators during the day. Research over the last decade shows that the weak moonlight or the northern lights cause zooplankton to retreat to darker waters.

Because of its photosensitivity, scientists have a hard time actually studying zooplankton: if light from their ships shines through to the small animals, any accurate recording of their population in an area becomes highly improbable.

To better understand the effects of light and light pollution on zooplankton, a team of researchers from NTNU, UiT (The Arctic University of Norway), the University of Delaware, and the Scottish Association for Marine Science modified a kayak, equipped it with sensors, a petrol engine, strapped it to a ship, and set it all out to sea. Once in open waters the kayak, dubbed Jetyak, was sent away from the research vessel and used to measure the depth reached by artificial light, as well as to record plankton thickness via sonar.

The “Jetyak” and a part of the research team.
Photo: Geir Johnsen, NTNU/UNIS

The acoustic data collected by the autonomous Jetyak showed that the layer of zooplankton was far thicker and started from closer to the surface near itself compared to that near the research boat (where the plankton was hiding from light). This effect reached depths of up to 80 meters.

“We were sort of surprised how pronounced this avoidance behavior was,” Ludvigsen said. “It was so clear and so fast. Even when we tried to reproduce this in a small boat and a headlamp, it was really easy to see in the echosounder.”

Photo from the board of the research ship.
Photo: Benjamin Hell

“These findings tell us that zooplankton populations and behavior can be under- or overestimated because these marine organisms respond to light, either by swimming away from it, or sometimes towards it,” said Geir Johnsen, co-author and a marine biologist at NTNU.

The biologist believes that scientists have to undertake their studies under natural conditions if they want to discover what zooplankton is truly up to. This means developing autonomous vehicles equipped to sample the vast seas.

Arctic fauna — ranging from bowhead whales to marine birds, to cod — feeds on zooplankton, particularly those in the genus Calanus. Their high content of fatty acids is what makes them such a filling meal.

Calanus glacialis
Photo: Malin Daase, UiT — The Arctic University of Norway

“Light pollution may disturb zooplankton behavior with respect to feeding, predator-prey relationships and diurnal migration, in addition to their development from juveniles to adults,” Johnsen said.

Global warming also poses a serious threat to the Arctic’s tiny inhabitants — as sea ice cover is growing thinner, or outright melting completely in large areas, zooplankton is rapidly running out of the dark areas they like, Johnsen remarked. Considering how central zooplankton is on the local menus, the Arctic ecosystem may have a lot to suffer.

The paper was published in the journal Science Advances.

The Greek Navy’s wooden wall — Olympias, last trireme on duty in the world

The HS Olympias is a ship of a kind. Build in 1987, the craft conforms to ancient standards and is currently commissioned by the Hellenic Navy of Greece.

‘Pretty as a trireme’ should definitely be an idiom.
Image credits Templar52 / Wikimedia.

The next time grandpa says ‘they don’t do X like they used to’, feel free to reply with ‘but they do boats’. Then you can thank the Hellenic Navy of Greece for your epic comeback because three decades ago they commissioned a breathtaking reconstruction of a trireme — a variant of the galley with three oar-decks, commonly used by Mediterranean civilizations. The ship was built in 1987 in Piraeus. It currently serves with the Navy, and it’s the only ship of its kind in the world on duty.

Work on the vessel began in 1985 based on blueprints made by naval architect John F Coates with help from historian J.S Morrison. Classics teacher Charles Willink was also brought on board to make sure the ship followed ancient standards by picking up clues from history, art, literature, and shipwrecks.

Greece has a long and proud naval tradition. They were a collection of city states that colonized the Mediterranean and united the known world on the decks of their galleys. Their ships explored, fought wars, and traded in goods and science. Faced with invasion from a hugely superior force (yep it was the Persians), Greek oracles said that ‘Zeus, the all-seeing, grants that the wooden wall only shall not fail’ — and through a long and bloody war, it was the only one that didn’t.

The navy is a central cultural pin for Greece — and nothing screams Greek-navy louder than the bronze-headed, painted-eyes trireme. So they set about to create this awesome piece of experimental archaeology at work.

Old tricks

One thing that’s stood the test of time is that triremes are not cheap to build. The project was funded mainly by the Hellenic Navy, with individual donors such as Frank Welsh, a banker and trireme enthusiast, also pitching in. Olympias was built from Virginia Oak, Oregon pine, and an Iroko hull. Her bow is adorned with a hefty, 200 kg bronze ram, copied after one currently held by the Piraeus archaeology museum. This was the main anti-ship weapon of triremes, and in ancient battles was supplemented with the spears and bows carried by her crew.

Some things, unfortunately, could not be perfectly recreated. Triremes were designed to be fast, aggressive attack ships with low displacement, so they were built to be as light as possible. They were also really long, to house a lot of oars. Combined, these factors meant that the ships were particularly susceptible to bending on the waves — like a bow being pulled. To sustain the hull, a hypozomata (bracing rope) was mounted beneath the deck, tying the two ends of the ship (bow and stern) together. It kept the hull from breaking in two without adding weight — win-win. After every trip, the ships were pulled ashore in slides and the hypozomata was re-tightened.

Originally made out of hemp, the hypozomata had to be replaced with steel cables. Unlike the natural fiber ropes which kept a constant pull, the tension in these cables varied as the hull bent on the waves. Protective measures were taken to prevent crew injury in case they snapped.

The result

So what can this baby do? The Olympias underwent trials at sea in 1987, 1990, 1992, and 1994. In the first one, 170 volunteer men and women took to the oars to power the trireme. She reached 9 knots and could turn 180 degrees in one minute, setting an arc of just two and a half ship-lengths.

These results were achieved with an amateur crew of volunteers, not a seasoned crew. Olympias was also considerably overloaded compared to the triremes of old, due to the addition of the steel hypozomata and protective measures. Still, the ship proves that the ancient Greek historians didn’t embellish the capabilities of their triremes.

Olympias isn’t just a revived sliver of history — the ship is making history today, too. In 1993, she went to Britan for the celebration of two and a half millennia since the birth of democracy. In 2004, she carried the Olympic Flame from Keratsini to the main port of Piraeus, for the Summer Olympic Games.

Today, Olympias is put to dry dock in the Naval Tradition Park, Palaio Faliro, Athens.

All image credits to Wikimedia user Templar52.