Connect with us
background

News

800 feet tall deep sea waves discovered in Pacific Ocean

Published

on

They would be the ultimate in big wave surfing. Scientists have discovered waves that rise up to be taller than some sky scrapers.

However, rather than being found on sun kissed beaches in exotic locations around the world, these waves are three miles beneath the surface of the ocean.

Researchers found the waves, which are also known as internal waves, form at the boundary between two layers of water with different densities in a deep ocean trench in the South Pacific Ocean.

These form 800 foot waves that rear up and then plunge hundreds of feet down into the dense water on the other side of the sill. However, each wave takes around an hour to break.

So while it might never be possible for surfers to ride these enormous waves, the scientists say these waves play an important role for mixing nutrients in the ocean.

Professor Matthew Alford, an oceanographer at the University of Washington who led an expedition to the channel, known as the Samoan Passage, said: “Oceanographers used to talk about the so-called ‘dark mixing’ problem, where they knew that there should be a certain amount of turbulence in the deep ocean, and yet every time they made a measurement they observed a tenth of that.

“We found there are loads and loads of turbulence in the Samoan Passage, and detailed measurements show it’s due to breaking waves.”

The findings are published in the journal Geophysical Research Letters.

The layers of water form because dense cold water in Antarctica sinks into the deep Pacific Ocean and is forced through a 25 mile gap north east of Samoa.

Around six million cubic metres of water pass through the gap every second – around the same as 35 Amazon Rivers.

Dr Alford and his team lowered specially designed “wave chaser” instruments three miles to the seabed and took measurements over thirty hour periods of the turbulence at the boundary between the cold dense water and warmer water above.

They found that as the dense bottom layer of water flows over two consecutive ridges in the Samoan Passage, it causes them to form lee waves, like air rising over a mountain.

These become unstable and break, causing the dense cold water to mix with the upper layers.

Professor Alford said this helps to explain why dense cold water does not permanently pool at the bottom of the ocean.

The waves may also play a role in stimulating global currents.

They believe waves like this form at other locations in the Samoan Passage and elsewhere in the ocean.

At their most powerful, some internal waves can sweep submarines off course or cause them to sruface.

“In addition to the primary sill, other locations along the multiple interconnected channels through the Samoan Passage also have an effect on the mixing of the dense water.

“In fact, quite different hydraulic responses and turbulence levels are observed at seafloor features separated laterally by a few kilometres, suggesting that abyssal mixing depends sensitively on bathymetric details on small scales.

“Climate models are really sensitive not only to how much turbulence there is in the deep ocean, but to where it is.

“The primary importance of understanding deep-ocean turbulence is to get the climate models right on long timescales,” Alford said.

Professor Alford, who is a surfer himself, added that these deep sea waves would make for a dull surfing experience.

He said: “It would be really boring. The waves can take an hour to break, and I think most surfers are not going to wait that long for one wave.”

 

Photo: WaveChasers APL

Marine Life & Conservation

Komodo National Park found to be Manta Hotspot

Published

on

Through a collaborative effort between citizen divers, scientists from the Marine Megafauna Foundation (MMF), and Murdoch University, a new study reports a large number of manta rays in the waters of Komodo National Park, Indonesian, a UNESCO World Heritage Site, suggesting the area may hold the key to regional recovery of the threatened species.

Reef mantas (Mobula alfredi), which grow up to 5m, tend to reside and feed in shallow, coastal habitats. They also visit ‘cleaning stations’ on coral reefs to have parasites, or dead skin picked off by small fish. Courtship ‘trains’ are also observed adjacent to cleaning stations. In Komodo National Park, manta rays are present year-round, challenging the famous Komodo dragon as the most sought-after megafauna for visitors.

Scientists teamed up with the dive operator community to source identification photographs of manta rays visiting the parks’ waters and submit them to MantaMatcher.org – a crowdsourced online database for mantas and other rays. Most of the photographs came from just four locations from over 20 commonly visited by tourism boats.

I was amazed by how receptive the local dive community was in helping collect much-needed data on these threatened animals,” said lead author Dr. Elitza Germanov. “With their support, we were able to identify over 1,000 individual manta rays from over 4,000 photographs.

People love manta rays—they are one of the most iconic animals in our oceans. The rise of the number of people engaging in SCUBA diving, snorkeling, and the advent of affordable underwater cameras meant that photos and videos taken by the public during their holidays could be used to quickly and affordably scale data collection,” said MMF co-founder and study co-author Dr. Andrea Marshall.

The photographs’ accompanying time and location data is used to construct sighting histories of individual manta rays, which can then be analyzed with statistical movement models. These models predict the likelihood that manta rays are inhabiting or traveling in between specific sites. The study’s results showed that some manta rays moved around the park and others as far as the Nusa Penida MPA (>450 km to the west), but overall, manta rays showed individual preferences for specific sites within the Park.

I found it very interesting how some manta rays appear to prefer spending their time in some sites more than others, even when sites are 5 km apart, which are short distances for manta rays,” said Dr. Elitza Germanov. “This means that manta rays which prefer sites where fishing activities continue to occur or that are more popular with tourism will endure greater impacts.”

Fishing activities have been prohibited in many coastal areas within Komodo NP since 1984, offering some protection to manta rays prior to the 2014 nationwide protection. However, due to illegal fishing activity and manta ray movements into heavily fished waters, manta rays continue to face a number of threats from fisheries. About 5% of Komodo’s manta rays have permanent injuries that are likely the result of encounters with fishing gear.

The popularity of tourism to these sites grew by 34% during the course of the study. An increase in human activity can negatively impact manta rays and their habitats. In 2019, the Komodo National Park Authority introduced limits on the number of boats and people that visit one of the most famous manta sites.

This study shows that the places where tourists commonly observe manta rays are important for the animals to feed, clean, and mate. This means that the Komodo National Park should create measures to limit the disturbance at these sites,” said Mr. Ande Kefi, an employee of the Komodo National Park involved with this study. “I hope that this study will encourage tourism operators to understand the need for the regulations already imposed and increase compliance.”

Despite Indonesia’s history with intensive manta ray fisheries, Komodo National Park still retains large manta ray aggregations that with careful ongoing management and threat reduction will benefit regional manta ray populations. The study highlights that marine protected areas that are large enough to host important manta ray habitats are a beneficial tool for manta ray conservation.

For more information about MMF visit their website here.

Continue Reading

News

Euro-Divers opens to guests at Alila Kothaifaru Maldives

Published

on

In celebration of Euro-Divers’ 50 Years of Diving with Friends in the Maldives, the team have opened a new PADI 5 Star Dive Center at Alila Kothaifaru Maldives.

Alila Kothaifaru Maldives retreat lies at the northern edge of the Maldives in the tranquil Raa Atoll, reached via a panoramic 45-minute seaplane voyage from Male. The island has 80 all-pool-villas, 36 of which are over water with a private pool for your enjoyment and 44 beachfront villas designed seamlessly to immerse guests in the natural surroundings. In support of sustainable tourism, Alila hotels adopt Earth Check operating standards, integrating their environments’ natural, physical, and cultural elements.

Raa Atoll is well-known for the excellent scuba diving it offers. The underwater landscape of Raa Atoll is characterized by a high number of thilas scattered inside the lagoons. These underwater coral mountains are magnets for marine life including huge schools of tropical reef fish, a generous splash of colour, iconic bucket-list-must-see marine creatures including sharks, mantas (appearing during the entire year), turtles, and uncrowded dive sites—a perfect diver’s heaven for beginners and experienced divers. We offer a full range of PADI courses for different levels. From November till March, the Manta cleaning station is located 15 minutes away by boat.

The team from Alila Kothaifaru Maldives look forward to welcoming you soon.

Find out more at: www.euro-divers.com/alila-kothaifaru-maldives

Continue Reading

E-Newsletter Sign up!

Competitions

A luxurious dive resort in the heart of Lembeh Strait. Enjoy refined services while exploring the rich waters of Indonesia.

The resort is nestled around an ocean front deck and swimming-pool (with pool-bar) which is the perfect place to enjoy a sundowner cocktail at the end of a busy day of critter-diving.

All accommodation is full board and includes three sumptuous meals a day. Breakfast and lunch are buffet meals and in the evening dining is a la carte.

Book and stay before the end of June and benefit from no single supplements in all room types!

Booking deadline: Subject to availability – book and stay before end of June 2022

Call Diverse Travel on 01473 852002 or email info@diversetravel.co.uk.

More Less

Instagram Feed

Popular