Anchors Cause “extensive, persistent” Damage to Seafloor

[grantmc]

A High-resolution mapping study by New Zealand's NIWA (National Institute of Water and Atmospheric Research) has produced the first ever global estimates of coastal habitat damage caused by anchoring.

The COVID-19 pandemic resulted in port congestion around the world, leading to unprecedented bottlenecks in maritime traffic and intensive anchoring of high-tonnage ships.

Researchers from NIWA, University of Auckland, and Auckland University of Technology wanted to characterise the footprint and extent of anchoring on the seafloor, which has never been quantified before. Using sonars and ship tracking data, they documented the morphology of anchoring outside Picton’s marine port on New Zealand’s South Island, revealing an extensive and persistent physical impact.

They discovered that every time a high-tonnage ship anchors, it can excavate the seafloor up to 80cm, displacing enough sediment to fill an Olympic-sized swimming pool. Comparison data shows that the damage remains for at least 4 years.

Scaled-up globally, this equates to at least 6,000km2 of impacted seabed. However, this is probably a “substantial underestimate,” says the study’s lead author Dr Sally Watson, a marine geophysicist at NIWA and lecturer in marine science at the University of Auckland.

“Picton is a low congestion port but in higher congestion ports, such as Wellington or Long Beach, USA, the footprint extends over a much wider region. In fact, the number could be as high as 20,000km2 of damaged seabed worldwide,” Dr Watson said.

The numbers are comparable to that of trawling because even though trawling occurs over a greater area, anchoring is done much more frequently, for longer, and penetrates more deeply.

“The anchor digs into the seabed and is moved around as the ship drifts on the surface, dragging the chain and causing ‘broomstick-like’ abrasions, killing off marine species and releasing carbon stores from the sediment. This has far-reaching implications for already stressed ecosystems and carbon cycling.

“It seems that this problem is ‘out of sight, out of mind’ because the environmental footprint of anchoring is not yet considered in official reporting of global human impacts on the marine ecosystem,” Dr Watson said.

Dr Marta Ribó is a lecturer in marine geology at Auckland University of Technology and is the study’s co-author. She said that new solutions are needed to reduce the destruction of anchorage on the seafloor.

“The impact of regular anchoring worldwide likely represents a major driver of shallow marine habitat degradation. This brings up questions about how anchor sites are chosen - do we know what kind of habitat anchors are being dropped onto or is it done without regard to what’s below the surface?

“We also don’t yet have a snapshot of cruise ships because our analysis was done during the height of the pandemic when most had ceased operating. Cruise ships are large and numerous, and they often drop anchor in pristine areas. Now knowing what we do, we must ask ourselves whether we want to encourage this kind of tourism,” Dr Ribó said.

Dr Watson said that their research has unearthed the ‘hidden cost’ of ship anchoring.

“To meet the climate goals outlined in COP26, countries have agreed to work towards a net-zero goal for global maritime shipping. As seaborne trade is projected to quadruple by 2050 and cruise ships begin to sail once more, new solutions are needed to avoid irreversible damage to marine habitats caused by this unreported problem,” she said.

The study was published in Nature Scientific Reports.

[Uncle Bob]

Originally Posted by grantmc

A High-resolution mapping study by New Zealand's NIWA (National Institute of Water and Atmospheric Research) has produced the first ever global estimates of coastal habitat damage caused by anchoring.

The COVID-19 pandemic resulted in port congestion around the world, leading to unprecedented bottlenecks in maritime traffic and intensive anchoring of high-tonnage ships.

Researchers from NIWA, University of Auckland, and Auckland University of Technology wanted to characterise the footprint and extent of anchoring on the seafloor, which has never been quantified before. Using sonars and ship tracking data, they documented the morphology of anchoring outside Picton’s marine port on New Zealand’s South Island, revealing an extensive and persistent physical impact.

They discovered that every time a high-tonnage ship anchors, it can excavate the seafloor up to 80cm, displacing enough sediment to fill an Olympic-sized swimming pool. Comparison data shows that the damage remains for at least 4 years.

Scaled-up globally, this equates to at least 6,000km2 of impacted seabed. However, this is probably a “substantial underestimate,” says the study’s lead author Dr Sally Watson, a marine geophysicist at NIWA and lecturer in marine science at the University of Auckland.

“Picton is a low congestion port but in higher congestion ports, such as Wellington or Long Beach, USA, the footprint extends over a much wider region. In fact, the number could be as high as 20,000km2 of damaged seabed worldwide,” Dr Watson said.

The numbers are comparable to that of trawling because even though trawling occurs over a greater area, anchoring is done much more frequently, for longer, and penetrates more deeply.

“The anchor digs into the seabed and is moved around as the ship drifts on the surface, dragging the chain and causing ‘broomstick-like’ abrasions, killing off marine species and releasing carbon stores from the sediment. This has far-reaching implications for already stressed ecosystems and carbon cycling.

“It seems that this problem is ‘out of sight, out of mind’ because the environmental footprint of anchoring is not yet considered in official reporting of global human impacts on the marine ecosystem,” Dr Watson said.

Dr Marta Ribó is a lecturer in marine geology at Auckland University of Technology and is the study’s co-author. She said that new solutions are needed to reduce the destruction of anchorage on the seafloor.

“The impact of regular anchoring worldwide likely represents a major driver of shallow marine habitat degradation. This brings up questions about how anchor sites are chosen - do we know what kind of habitat anchors are being dropped onto or is it done without regard to what’s below the surface?

“We also don’t yet have a snapshot of cruise ships because our analysis was done during the height of the pandemic when most had ceased operating. Cruise ships are large and numerous, and they often drop anchor in pristine areas. Now knowing what we do, we must ask ourselves whether we want to encourage this kind of tourism,” Dr Ribó said.

Dr Watson said that their research has unearthed the ‘hidden cost’ of ship anchoring.

“To meet the climate goals outlined in COP26, countries have agreed to work towards a net-zero goal for global maritime shipping. As seaborne trade is projected to quadruple by 2050 and cruise ships begin to sail once more, new solutions are needed to avoid irreversible damage to marine habitats caused by this unreported problem,” she said.

The study was published in Nature Scientific Reports.

Yep, no more anchoring or shipping trade to be done by us anchoring bandits, the natural world will be saved.

[HankOnthewater]

Boats without anchors, and CF without threads on anchors?
Nearly unthinkable.

[CaptTom]

I see a lot of these "unseen impact" articles. And I think it's very true that we (humans) have an impact on the environment with everything we do.

Taken together, these reports of ecological damage lead me to an inevitable conclusion as to the root of the problem: Humans.

Clearly something needs to be done to eliminate this threat to our environment. Who's willing to do their part to reduce this invasive population? (No fair volunteering someone else!)

[Simi 60]

Yep, no more anchoring for us
Instead we'll drift onto the beach and have a big fuel spill plus wreck cleanup
Winning.

[sailorboy1]

I believe it, but so what?

[Chotu]

Proudly brought to you by your local marina cartel... Er... trade association.

Stop on by your local marina today to save the environment.

Note: we require a survey, to be listed as a loss payee on your insurance, a safety inspection, a sea trial, $2000/mo plus electric and water; and you must volunteer to scrub bathrooms and fix docks one weekend a month. You may not stay on your boat other than one weekend a month and may not leave a vehicle anywhere on the premises. That includes bicycles. If you take your boat out for a weekend, we reserve the right to fill your slip and charge $280 a night to the visitor, plus electric. If you complain, there is the channel. Keep the red to your left and don’t let the door hit you on the way out of the office.

[GreenWave]

Sure anchors of all sorts put holes in the sea floor and stir up sediment. However, way too soon in this research to truly state that is a problem that will cause more problems. And is this stirring worse than storms and their effects? Is it different in a bad way?

Surely we have something else to study. Sad that someone is actually sponsoring this research.

[GordMay]

Originally Posted by GreenWave

... is this stirring worse than storms and their effects? Is it different in a bad way? ...

One occurs despite mankind’s efforts, and the other because of our activities.

“Grant me the serenity to accept the things I cannot change, The courage to change the things I can, And the wisdom to know the difference.” ~ AA Serenity Prayer

[Cwens]

When we discovered that leaded motor fuel was poisoning us, the alternative wasn't to stop driving, it was to develop improved fuels and engine technology. And it was a huge success: lead levels are way down.


When we discovered that CFC refrigerants and propellants were trashing the ozone layer, we didn't stop having air conditioners or products in aerosol containers; we developed superior alternatives. And the result was a reversal of the environmental damage that was nothing short of spectacular: one of the true success stories for environmental protection



So why are people cynically ridiculing this article that points out seafloor damage from anchoring and saying, sarcastically, "Well, then we'll all have to stop shipping and commerce, or let our ships run aground on beaches?"

What has happened to people's ingenuity and willingness to look for solutions to problems?

[ItDepends]

Now we just need to wait for the ultimate solar powered static position system (AKA anchor) that holds your boat in place without contact with the sea bed. It should come as a mandatory feature of all those solar only cruising yachts plying the world’s oceans.

Because it is the internet, I have point out the above is sarcasm…

[dfelsent]

There are areas in the northeast where anchoring is limited due to eelgrass damage that was occurring.
This is not a new story.

[fstbttms]

Originally Posted by sailorboy1

I believe it, but so what?

This is what:

"The anchor digs into the seabed and is moved around as the ship drifts on the surface, dragging the chain and causing ‘broomstick-like’ abrasions, killing off marine species and releasing carbon stores from the sediment. This has far-reaching implications for already stressed ecosystems and carbon cycling."

[Bowdrie]

I wonder if any correlation was established in which the nationality of the offending ships was noted, (what flag do they fly).
I have strong suspicions that a majority are what might be referred to as 2nd/3rd world countries.
Send them the bill for assumed damages to the seabed and released carbon.
Perhaps the countries in which most of the anchoring takes place could take steps to produce more of what they need "in house/in country" thereby reducing, (to a degree,) their import needs and reliance on foreign labor/products.

How can I get some grants of several million dollars to design an anchor/rode system that will neither dig into the seabed nor allow a rode to drag upon the seabed for a 150,000 ton vessel?
If I'm unsuccessful it just means I wasn't given enough money, right?

[Greatest Lakes]

The only prevention for such an issue would be special mooring fields. How big would a mooring have to be for a super container ship? Who is going to maintain and pay for such a thing? It would be another chunk of logistics needed near every port to maintain, and assist ships with their temporary hookups. Maybe another job for pilot boats? Would all these mooring fields be hazards to navigation? Would they affect fishing operations? How much would it effect the cost of shipping?

They are not complaining about cruisers. Yet. For a change.