Skip to main content

Marine heatwaves - an ever growing threat?

Hi everyone,

So today we're talking about marine heatwaves. We all know about normal heatwaves, they come almost every summer and are either a blessing or a curse depending on where you live. But today we're talking about marine heatwaves. They are increasing rapidly and have become a commonly mentioned topic.
There are multiple definitions of marine heatwaves. Generally, they are considered a period of time with unusually high temperatures. Exactly how high and for how long changes depending on which definition you choose. The most common one definition is when the temperature is over the 90th percentile of the area's average seasonal temperature for at least 5 days in a row. For anyone who doesn't know what a percentile is, if you take a test and are at the 90th percentile then it means you are better than 90% of the people who took that test. So in our context, the temperature has to be higher than 90% of the seasonal temperatures measured in that area (normally over a 30 year period) for at least 5 days.

So what are the impacts of such an increase in temperature? Surprise surprise: marine heatwaves aren't exactly good for the environment. It is worth mentioning here, that marine heatwaves are natural occurances in the ocean temperature and have always been around. But the frequency and intensity of them is not natural. Both of these parameters have been rising rapidly in the last 100 years. Marine heatwaves can cause waters to reach temperature of 30°C, which is about the temperature of a warm bath. El Niño, a weather cycle that repeats about every 7 years, is shown to cause stronger heatwaves.
In the late 1990s, a marine heatwave intensified by El Niño lead to a reproductive failure and mass mortality in Galápagos sea lions and king penguins. Then, in 2011, the western coast of Australia was hit by a marine heatwave that caused the mass dieback of kelp forests and impacted ecosystems hundreds of kilometers further along the coast. An interesting phenomen was seen here, when several fish species changed their habitat and spread further towards the poles. This has been seen a couple time since in multiple species, sometimes the fish return once the waters have cooled, sometimes they stay in their new home and sometimes they die, either from new predators or a lack of food.
In 2014-2016, the northeastern Pacific saw mass mortality in seabirds as they failed to adapt to soaring temperatures. In 2017, there are reports of mass mortality affecting 40 coral reef fish species correlated with an increased risk of bacterial infection and harmful algal blooms, which produce toxins. And finally, in August 2020, a marine heatwave in the East China Sea caused a major typhoon in that area. The East China Sea rarely experiences typhoons and normally those that come in from the Pacific tend to die down, but this time the high surface temperatures caused a typhoon of Category 3.
There are some postives, mussels have been found to be able to change their heart rate so as to better deal with higher temperatures. This is just one example of how amazing and resilient nature can be.
So marine heatwaves are clearly a massive problem. As you can imagine, typhoons and collapsing fish populations are also a bit of a disaster for us. These marine heatwaves will only continue to become more frequent and more devastating as climate change warms up our oceans. We couldn't cover all of the aspects in this post so let us know what we missed in the comments. We hope this was a good introduction in this complex topic. Have a nice weekend!

Your Green World Blog Team💚




Title image: This image is owned by a blog editor.
"Galapagos sea lion", owned by Darek Keats (on flickr.com), is licensed under CC BY 2.0.
"Baltic blooms", owned by European Space Agency (on flickr.com), is licensed under CC BY-SA 2.0.

Comments

Popular posts from this blog

Ozone layer

Hi everyone, What even is ozone? And the ozone layer? Where does the hole in the ozone layer come from and what does it mean? Is it dangerous? What can be done? Often the ozone-talk can be complicated and confusing, keeping an overview is hard and understanding all the problems always difficult. Let us break it down a bit for you: What is the ozone layer? We'll start with the basics: The ozone layer is part of the stratosphere, which is the second layer of the Earth's atmosphere, between 10 and 50 km above the Earth's surface and made up of protective gases. One of these protective gases is ozone. There is not much ozone in the atmosphere, only 0.3 molecule of ozone per 1 million molecules of air. This is because ozone is chemically unstable and only forms when ultra violet radiation (UV light) hits oxygen and breaks the bonds between the atoms. It fact it is so unstable that even when it has formed, it breaks down again relatively quickly. This leads to ozone turning back ...

02.08.2020 Animal of the week: Owl

Hi everyone, This week's blog post is all about owls. Habitat There are many different types of owl: barn owls, long-eared owls, snowy owls and lots more. Different species live in different places. Here are a few examples. Snowy owls live in the Arctic . Great grey owls live in pine forests. Elf owls live in deserts. There are about 130 different species of owl. Owls can be found everywhere in the world apart from Antarctica . Owls live in trees, holes in the ground, barns and caves. Most owls do not migrate in winter. Diet Owls eat insects, spiders, fish, reptiles, amphibians, birds and small mammals. What they eat the most depends on the type of owl and where it lives. Screech owls feed mostly on insects. Barn owls mainly eat mice, shrews and voles. Eagle owls eat hares and young foxes. Some owls can even fish like the Asian Fish Owl. Even though some species prefer a certain type of food, most owls will eat whatever they can find...

Ecosia

We all need to do something to save our planet: it is no use just leaving it to Greta Thunberg! She is very inspirational, yes, but she can only do so much. She isn't superhuman! The climate crisis is up to us; up to you. We all have to get stuck in. Research, learn, discover and most importantly: never give up! The world's animals need us. The world's trees need us and a simple way to do this is to switch to Ecosia. Ecosia is a search engine but it plants trees while you search the web. Okay, it doesn't have as many websites as google so you may want to have google as a backup but it plants trees: this is your opportunity to make a simple change. Just google Ecosia and search to plant trees. Make a difference. Image: This image  is owned by  Binyamin Mellish on  pexels.com .

How much do you know about extinction? | quiz

Hi Everyone! Welcome back to the blog! This week is our last monthly quiz! We'd love to hear which one was your favourite in the comments! We also have a quick online survey for what our monthly post should be next year. We really appreciate any feedback and this is the best way for you to tell us what you want to see us post about and share! From a monthly challenge to an environmental book of the month - we just want to know what you think! 🍂 click here to vote! So, how much do you know about extinction? You may know some from our " animals you don't know are on the edge of extinction " series, or from the news as extinction is such a buzzword. All of these facts are from reliable sources such as National Geographic, as well as the statistics being cross checked with other websites. 1. How many years ago was the most recent mass extinction? a) 44 million b) 55 million c) 66 million 2. How many species could be threatened ...

16.08.2020 Animal of the week: Elephant

Hello. On the 12th of August it was International Elephant Day, so we decided that this week's post should be about elephants. Elephants are the largest living land mammals. There are three types of elephant; the African bush elephant; the African forest elephant and the Asian elephant. African elephants have larger ears, whereas Asian elephants have smaller ears. Elephants use their trunks to breath, bring food and drink to their mouths and to grasp objects. Elephants' legs are like pillars. They carry the Elephant's massive weight. African bush elephants weigh 6000kg, Asian elephants weigh 4000kg and African forest elephants weigh 2700kg. Basically, they are very heavy.Elephants eat grasses, small plants, bushes, fruit, twigs, tree bark, and roots. Elephants can live up to 70 years old in the wild. They communicate by sight, touch and smell. Sadly, these wonderful mammals are in danger. African elephants are listed as vulne...

The life of ... an alcon blue butterfly

Hi everyone, Today we are going to be looking into the life of an alcon blue butterfly (Phengaris alcon). After mating, the females lay their eggs on marsh gentian, a blue-coloured wildflower. The eggs can only be laid on these flowers, as this is what the newly hatched caterpillars will eat. Although in some alp regions, they can also be found on willow gentians, a close relative of the marsh gentian. Once the caterpillars have hatched from the eggs, their main predator and danger are the ants that swarm below. But high on their plant homes, the caterpillars are safe. However, this isn't where the alcon blue caterpillars are going to stay forever. Eventually, they drop down to the ground using silk strings. With no protection, they are soon dragged off by the ants. The most amazing part is, the alcon blue caterpillars give off the same scent and chemicals as the ant larvae. So the ants take the caterpillars back to their brood chamber, wher...

Sustainable food choices challenge

Hi everyone, Welcome back to our second challenge! Today we're talking about sustainable food choices.  1. No meat on Mondays challenge The production of meat, especially beef, is resource-intensive and contributes significantly to deforestation, greenhouse gas emissions, and water pollution. By dedicating one day a week to plant-based meals, you can decrease your carbon footprint and help to reduce the strain on natural resources. This challenge encourages a more sustainable and ethical approach to food consumption, gaining a better understanding of the environmental impact of meat production. Reducing meat intake is also associated with health benefits, including lower risks of heart disease and certain cancers, making it a win-win for both your personal well-being and the planet. 2. Local / seasonal eating challenge Choosing local and seasonal foods is important in helping to reduce the environmental impact of food production and transporta...

Animals 36-40 in our '50 incredible animals' series

Hi, As you probably noticed, we took a break from this series, mostly due to having just too much to do. But we're back now with the last three posts. 36. The Pinocchio frog The Pinocchio frog can be found in the Foja Mountains in Indonesia. They mainly eat insects, although little is known about them. They are named because the males have a spike on their noses. They were only discovered in 2008, and this was completely by accident! It remained unnamed scientifically until over ten years later when it was given the name " Litoria pinocchio " . There is very little information about them but Wikipedia states that "the male Pinocchio frog inflates its nose when calling, and the nose decreases in size when the frog is calm and quiet," which I think is hilarious and so interesting! 37. Snub-nosed monkey Especially noticeable due to their curious looks, the snub-nosed monkeys can be found in the forests of central China and northern...

15.11.2020 Animal Of The Week: Red Squirrels

Hello Everyone, This week's animal of the week is the red squirrel. There are lots of different types of squirrel (about 200 as this includes marmots and prairie dogs). I have some grey squirrels in my garden and you might too. We often see them so hopefully you can learn about red squirrels today. Habitat As you might know, squirrels live mainly in woodland areas. The red squirrel can live in all types of woodland, even if it is quite small. See the maps below for more information on where they live. Diet They feed on mainly nuts, fruit, fungi and other plants. They need to chew as their teeth grow continuously and so can grow so long that they can't eat if they don't chew often. When food is scarce they can eat some insects and small vertebrates. What is thought of them Squirrels are sometimes seen as pests, but not usually as much as many other rodents. They can raid bird feeders (they manage to get in to mine even if ...

Factfile-November 2021

Hello, Welcome to the November Factfile! Finally, it is December, and Christmas is just around the corner! Settle in, and read all the hot info from November. Here's a quick reminder to vote about the fact file's future. It closes in a month! Thanks, and enjoy! News COP26 Quickly for everyone who does not know: COP stands for "Conference of the Parties" and is a conference hosted by the UN, which brings together the members of the UN to discuss climate issues and come up with agreements regarding these issues. This year, COP was held for the 26th time-hence COP26-in Glasgow from October 31st to November 13th. These are the main outcomes from this conference: The nations agreed on four main topics to take action on Mitigation, Adaption, Finance and collaboration. Apart from that, they agreed on keeping the 1.5 degrees limit but also stated that action must be taken immediately to make it. Mitigation is about reducing carbon emis...