Marine Life & Conservation
Narwhal’s tusk is super sensitive
Narwhals’ distinctive long tusks are super sensitive, research has found.
The whales are known for their tusks which can reach 2.6m (9ft) in length, earning them comparisons with mythological unicorns.
The tusk is an exaggerated front tooth and scientists have discovered that it helps the animals sense changes in their environment.
Experts suggest males could use the tusks to seek out mates or food.
The results are published in the journal The Anatomical Record.
Dr Martin Nweeia from the Harvard School of Dental Medicine, US, undertook the study alongside an international team of colleagues.
Through the years, many theories have tried to explain the function of the narwhal’s impressive tusk.
“People have said it’s everything from an ice pick to an acoustic probe, but this is the first time that someone has discovered sensory function and has the science to show it,” said Dr Nweeia.
More recently, experts have agreed that the tusk is a sexual characteristic because it is more often exhibited by males and they appear to use them during fights to assert their social hierarchy.
But because the animals are rarely seen, the exact function of the tusk has remained a mystery.
Previous studies have revealed that the animals have no enamel on their tusk – the external layer of the tooth that provides a barrier in most mammal teeth.
Dr Nweeia and the team’s analysis revealed that the outer cementum layer of the tusk is porous and the inner dentin layer has microscopic tubes that channel in towards the centre.
In the middle of the tusk lies the pulp, where nerve endings which connect to the narwhal’s brain are found.
“Although it’s a rigid tooth, it has a very permeable membrane,” said Dr Nweeia.
He explained that because of this structure, the tusk is sensitive to temperature and chemical differences in the external environment.
The researchers proved the link when the tusk was exposed to different salt levels in the water and there was a corresponding change in the narwhal’s heart rate.
He described the tusk as “unique” in the animal kingdom because its porous outer layer is usually only found below the gum line in mammals, where it is only exposed by damage or disease.
“The narwhal is the only example documented where teeth are shown to have the ability to constantly sense environmental stimuli that would not necessarily be considered a threat,” he said.
“If you were looking for an ideal and fascinating tooth to study there’s no question this would be it.”
The tusk grows in a counter-clockwise spiral so it does not curve in the same way as an elephant’s tusk but protrudes straight out.
Dr Nweeia is fascinated by the fact that narwhals put all their tooth-growing energy into a single tusk rather than having a set of teeth to help them eat their diet of large fish, such as halibut.
His previous studies of narwhal skulls and tusks held in museums revealed that the distinctive tusk is the left canine tooth that erupts through the upper lip of males.
Their right canine tooth remains embedded in their skull and in females neither of these teeth usually erupt; though in some rare cases they have a pair of tusks reaching up to 30cm long.
It remains unclear whether the animals have evolved the tusk’s sense functions or whether it is an evolutionary throw back.
“We’re just looking at one time frame in evolutionary history,” said Dr Nweeia.
“We don’t know if this is a sensory organ that is gaining more function, or is this a sensory function that is losing some of its ability?”
He added: “It’s an incomplete puzzle and basically we’ve added a few important pieces.”
The dentist suggests the sensory ability of the tusk might have advantages for males as they could use it to detect where females are, whether they are ready to mate, or how to find food for newborn calves.
His research is now focusing on traditional knowledge, asking hunters in the high Arctic for their observations in the hope that more information on the secretive animals’ behaviour can unravel the mystery of the narwhal’s tusk.
Source: www.bbc.co.uk/nature
Marine Life & Conservation
Reef-World launch new toolkit in response to the current global coral bleaching event
The Reef-World Foundation – international coordinator of the UN Environment Programme’s Green Fins initiative – has launched a new coral bleaching toolkit in response to the 4th global coral bleaching event confirmed by the National Oceanic & Atmospheric Administration (NOAA) and International Coral Reef Initiative (ICRI) in April 2024.
The Green Fins Global Coral Bleaching Response Toolkit provides guidance to the marine tourism industry on how they can help manage and monitor the impacts of coral bleaching and get involved in recovery efforts. It features information about coral bleaching, including the causes, impacts and response strategies. The toolkit is compiled from a variety of readily available resources from multiple organizations and initiatives, such as ICRI, Coral Reef Alliance, Reef Check and NOAA, along with Green Fins materials, to ensure it is accessible to everyone. These resources cover methods for reducing local impacts, monitoring the reefs and engaging tourists and local communities.
The El Niño phenomenon has been present since February 2023, which has led to persistently warmer temperatures being experienced around the world and has affected the sea surface temperatures. Coral bleaching has been recorded in all ocean regions ever since. While this event is widespread and serious, there is still hope as bleached corals are not dead corals. Corals can survive bleaching events and thrive if they are given the time to adapt to the changing climate.
“Coral reefs are under a huge amount of stress every day and that reduces their chance of recovery from bleaching events,” said Chloe Harvey, Executive Director at The Reef-World Foundation. “However, this time around the scientists have been watching the data closely, so we’re prepared. We understand what it means and we know what we need to do to respond to it. This global event calls for global action to protect these vital ecosystems for generations to come.”
By equipping the industry with the necessary knowledge and tools, Reef-World hopes to empower these key stakeholders to play a crucial role in preserving the health and resilience of our precious coral reef ecosystems. Reef-World believes that with the right resources, the marine tourism industry can be a driving force in the fight against coral bleaching and contribute significantly to the long-term sustainability of marine environments.
With this momentum, other key players in the industry, such as PADI AWARE Foundation and NOAA, have gotten on board the campaign for more citizen scientists to help out in monitoring coral bleaching. With the toolkit available to all, The Reef-World Foundation is looking forward to more collaborative actions in the industry.
Explore the toolkit on Green Fins’ website: greenfins.net/coral-bleaching
A real solution for an environmental catastrophe is in reach
Six years after setting sail for the Great Pacific Garbage Patch (GPGP), we have developed the cleanup technology to relegate the patch to the history books.
On 6 September 2024, The Ocean Cleanup will return to San Francisco, where founder and CEO Boyan Slat will provide an update in which he will announce what is needed in terms of time, money and efforts to eradicate the GPGP.
To confirm your presence, please RSVP to press@theoceancleanup.com
PROGRAM
- Press conference: CEO and founder Boyan Slat will announce the next phase of the cleanup of the Great Pacific Garbage Patch
- Interviews: opportunities to interview Boyan Slat (CEO & founder), Joël Jansen (Director of Oceans), Arjen Tjallema (Director of Technology) and Matthias Egger (Director of Environmental and Social Affairs)
- Vessels & technology: visit our two iconic ships, take a look at extraction System 03 and see the extracted plastic up-close and personal*
*Limited availability; RSVP soon to press@theoceancleanup.com
PRACTICALITIES
Date: September 6, 2024
Press conference: 12 pm (noon) / doors open 11.30 am
Location: The Exploratorium (Google Maps)
Pier 15 (Embarcadero at Green Street), San Francisco, CA
Parking: Visit The Exploratorium’s website for details
RSVP: press@theoceancleanup.com
Press kit: a press kit will be shared afterwards
To find out more about the Ocean Cleanup, visit www.theoceancleanup.com.
-
News2 months agoMurex Bangka Announce New Oceanfront Cottages & Beachfront Dining
-
Blogs3 months agoA new idea in freediving from RAID
-
Blogs3 weeks agoGozo: An Underwater Treasure Trove in the Heart of the Mediterranean
-
Gear Reviews2 months agoGear Review: Scubapro Luna 2 AI Dive Computer
-
Marine Life & Conservation2 months agoIceland issue millionaire whale hunter a licence to murder 128 vulnerable fin whales
-
Blogs2 months agoMamma Mia! Diving Skopelos (Part 1)
-
Marine Life & Conservation2 months agoSHARK MONTH ARRIVES AT ROYAL WILLIAM YARD, PLYMOUTH
-
Blogs2 months agoAlonissos: The complete diving destination (Part 1)