Wereldwijde koraalverbleking, oorzaak en gevolg

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Foto’s van voor (december 2014, links) en na (februari 2015) koraalverbleking in een rif in Amerikaans-Samoa. Gemaakt door de XL Catlin Seaview Survey (www.globalcoralbleaching.org).  

De afgelopen week kwamen van allerlei media berichten dat het noordelijke deel van het Groot Barrièrerif bij Australië zwaar verbleekt is (meer dan 90%). Verschrikte koraalrifbiologen gaven interviews over de schade die mogelijk is aangericht aan dit UNESCO werelderfgoed. Koraalverbleking kan leiden tot het afsterven van de koralen die het rif met al zijn biodiversiteit in stand houden. Het koraalrif kan zich herstellen, maar dan praten we over een proces van tientallen jaren. De media probeerden kort uit te leggen wat koraalverbleking is, maar het bleef voornamelijk bij alleen het melden dat de verbleking gaande was. Er werd niet ingegaan op de oorzaken en verstrekkende gevolgen van de koraalverbleking die op dit moment niet alleen in Australië, maar door de hele Stille en Indische Oceanen en het Caribische gebied plaatsvindt . Maar wat is koraalverbleking en hoe wordt dit veroorzaakt? En wat zijn de gevolgen van verbleekte riffen?

Oorzaken

Koraalriffen zijn hotspots van biologische activiteit wat mogelijk gemaakt wordt door de harde koralen die de complexe driedimensionale rifstructuur bouwen als skelet. Het bouwen van dit skelet is topsport voor de koralen, maar ze kunnen dit volhouden doordat ze samenleven met algen in hun weefsels die de tropische zonneschijn gebruiken voor de productie van suikers door fotosynthese. Deze voedingsstoffen delen de algen met hun koraalgastheer die daardoor voldoende energie heeft om hard aan zijn skelet te bouwen. Net als bij topsport zitten de koralen en hun algen aan de toppen van hun kunnen. Als het water waar ze in leven nu te lang te warm is, dan beginnen de algen schadelijke stoffen te maken die het koraal stresseren. Op dat moment gooit het koraal de kleurrijke algen eruit en blijft het verbleekt achter zonder zijn primaire energiebron. Als het water op tijd afkoelt, dan kan het koraal nieuwe algen opnemen en verder leven. Het komt echter steeds vaker voor dat het te lang te warm blijft. Dan verzwakken de koralen en sterven ze in groten getale af, iets waar de volledige koraalrifgemeenschap zwaar onder lijdt.

De afgelopen jaren zijn de oceanen langzaam aan het opwarmen door klimaatverandering. Koralen wonen in de warme topische delen van de oceanen en een kleine opwarming van de maximale temperaturen in de heetste maanden van het jaar kan deze topsporters al overbelasten. De afgelopen decennia zien we steeds vaker koraalverblekingen gebeuren met de grootste wereldwijde verblekingen in 1998 en 2010. Op dit moment vindt de derde wereldwijde verbleking plaats. Alle drie de keren hingen deze wereldwijde gebeurtenissen samen met het El Niño verschijnsel. Dit verschijnsel komt eens in de drie tot zeven jaar voor en kan wereldwijd tot grote gevolgen leiden doordat lokale klimaten tijdelijk veranderen. De wateren rond veel koraalriffen worden dan gedurende de heetste maanden van het jaar nog een paar graden warmer waardoor de verblekingen veel erger zijn dan in de omliggende jaren. Dit geeft ons nu al zicht op wat er waarschijnlijk jaarlijks met koraalriffen gaat gebeuren als de opwarming van het klimaat niet afgeremd wordt.

Gevolgen

Zelfs als veel koralen op een koraalrif afsterven, dan kan het zich in de volgende jaren herstellen door het groeien van de overgebleven koralen en de instroom van koraallarven die zich op de vrijgekomen ruimte wortelen. Als echter in de nabije toekomst verblekingen vaker gaan gebeuren doordat de zeeën verder opwarmen, dan krijgen de koraalriffen niet meer de kans om zich te herstellen. Dit leidt dan tot afbraak van het koraalrif met zijn driedimensionale structuur met grote gevolgen. Het veelvuldig onderzochte Groot Barrièrerif met zijn beschermde status  staat nu in de spotlight, maar koraalriffen wereldwijd lopen op dit moment grote schade op. Hoe erg dit zal zijn moeten we in de komende tijd gaan bepalen, maar het is zeker dat wat nu gebeurt een groot effect zal hebben in de komende jaren.

Als wij in Noordwest-Europa de beelden vanuit Australië voorbij zien komen, dan vinden veel mensen dat natuurlijk erg. Koraalriffen zijn kleurrijke gebieden vol leuke Nemo’s en andere visjes en heerlijk om op vakantie naar te snorkelen en te duiken. Voor veel mensen ter wereld gaat het belang van koraalriffen echter veel verder. Koraalriffen komen veel voor in tropische zones met een arme bevolking (bijvoorbeeld Zuidoost-Azië, Oost-Afrika, Oceanië). Miljoenen mensen wonen aan deze kusten en deze mensen zijn zwaar afhankelijk van koraalriffen voor hun inkomen en voedselvoorziening. Koraalriffen kunnen in deze behoefte voorzien doordat ze zo’n hotspot van leven zijn. Als de hoge activiteit instort doordat de basis van koralen weg is, dan valt er voor de mensen niet meer te vissen voor hun inkomen, of nog erger, voor de eiwitten uit vis of schaaldieren die ze dagelijks nodig hebben en niet ergens anders vandaan kunnen halen. Koraalrifwetenschappers zijn op zoek naar beschermings- en herstelmaatregelen door bijvoorbeeld koralen met algen die beter tegen langdurige hitte kunnen uit te zetten op koraalriffen, maar de huidige opties zijn niet in staat om de wereldwijde schade door verbleking te voorkomen of te verminderen.

Op deze manier zien we dus hoe klimaatverandering ervoor kan zorgen dat het levensonderhoud en zelfs de voedselvoorziening van miljoenen mensen bedreigd worden. De topsportkoralen die essentieel zijn om de koraalriffen in stand te houden zijn de spreekwoordelijke kanarie in de koolmijn voor de gevolgen die ecosystemen wereldwijd gaan ondervinden als de opwarming door klimaatverandering niet afgeremd wordt. De klimaatafspraken van vorig jaar in Parijs waar al die regeringsleiders zo vol van waren leiden ons al naar een absolute bovengrens van wat de koralen van de wereld gemiddeld aankunnen qua opwarming in de komende decennia. Als deze afspraken in de komende jaren afgezwakt worden door compromissen, dan is het goed mogelijk dat de koraalriffen wereldwijd verdwenen zijn in 2040 met alle gevolgen van dien voor de lokale bevolking die van de riffen afhankelijk is.

Food for thought Pt. 2 The vegan life

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www.veganosity.com

“Being vegan is like being in food prison”

Russell Brand

After our adventures living plastic free for a month, my fiancée Rosa and I decided to up the ante. She’s already a fulltime vegetarian and I’m sort of a veggie leaning flexitarian who doesn’t eat fish (if that makes sense). The goal was to be vegan for the whole of October; so no dairy, no eggs, and of course no meat or fish. Going vegan is something that many people find “a little extreme”. Quite some people we talked to could see themselves going vegetarian, but vegan? No way! As we did some reading, we found this to be a strange attitude. There are many reasons why you could go vegetarian or vegan, the main ones I think are:

  • the massive environmental impact of raising and catching loads of animals for our food requirements (deforestation, climate change, pollution, depleting natural populations, and diseases)
  • the welfare of those animals (stress, injuries, minimal living space, extensive transports, again diseases and the overuse of antibiotics, maiming animals (without anesthetics) to maintain them in very high densities, and not allowing the animals to perform natural behavior)
  • your personal health (obesity, cancer, cardiovascular diseases, zoonotic diseases, exposure to antibiotics and hormones)
  • the inefficiency of animal based foods and their effect on food availability to the entire human population now and as that population will increase towards 2050

If you decide that those reasons are enough to make you go vegetarian, then why not vegan? Vegetarians in general consume dairy and eggs. Both these industries have many of the downsides of the meat industry; the only concrete difference is that an animal did not directly die for your food. However, to produce your eggs and milk, male chicks and calves need to be born. While male chicks are for the majority immediately discarded (i.e. killed), male calves are destined to be raised for veal (go check out that industry). Female calves have the chance to follow in their mother’s footsteps and produce milk for a couple of years before a drop in milk productivity causes them to be written off and discarded. On top of that, the production of dairy and eggs costs an enormous amount of energy, crops, and water; far more than would be needed to produce the same amount of food from plant-based sources (soy, beans, nuts, etc.).

I am sure many people know the above mentioned reasons, so why are they still hesitant? When I started to read up on vegan options, I kind of felt like Russell Brand at the top there: a vegan diet must only contain vegetables and beans, how dreary. I was convinced that tofu has a negative flavor, it even sucks tastiness out of the rest of your ingredients. Feeling like this was a challenge which needed some solid prep work, Rosa ordered some vegan cookbooks online to give us some inspiration. These had titles like the “Oh she glows” cookbook and mainly consisted of overly perky American housewives showing off their kale and pine nut casseroles. I was also not really convinced by their tone indicating that some of those recipes would even convince their beastly men and kids to skip meat for a day. However, ignoring those issues, we did find some cool recipes to work with (tofu scramble is an awesome breakfast egg substitute, and many of our guests over the month were more than happy with our apple pie oatmeal and applesauce pancakes).

As we progressed through the month, it started to dawn on me that we all have a mental framework of habits that is hardwired into us and which needs substantial effort to be shifted. If we are capable of getting all our dietary requirements from plant based sources (vitamin B12 excluded, but that can be remedied with a twice a week supplement), then why do we maintain a highly inefficient and enormously costly livestock/dairy industry? This is normally the point where somebody trots out that we’ve always eaten animal products, evolution has made us omnivores, and so on. Now the argument from tradition is always the weakest argument people can have. A history of doing something is, by itself, no reason to continue doing it. Deciding to change your habits due to new insights is called progress which is generally considered a good thing. On top of that, consumption of animal products in the western world has exploded over the last 65 years. The average Dutch person now consumes 85 kg of meat per year where this was 36 kg in 1950. People from the US top the charts at an average of 118 kg per year. While animal food products cost more energy and lead to more environmental damage, we have made them the default setting for our daily consumption pattern. A clear example of this was the one big difficulty during our vegan month, eating out. It didn’t matter if it was just a sandwich, or going to a fancy restaurant, animal products are everywhere. Often, there is an abundance of meat/fish options with one or two vegetarian alternatives which in the Netherlands and Belgium generally means cheese. Eating a vegan alternative in a normal restaurant means calling ahead and then you are left with the vegetarian option with the cheese removed.

Over the month, we experimented with lots of Middle Eastern and Asian options like humus, baba ganoush, marinated tofu, tempeh, seitan, as well as more local options like the Dutch Weed Burger (the weed stands for seaweed, not the other kind, go try it!), and alternatives to meat from the Vegetarische Slager (vegetarian butcher). I started noticing that there are very few animal based things for which there is not a decent plant based alternative. Making soy milk mayonnaise is super easy and fast; add garlic and you’re good to go with falafel sandwiches for a quick snack. Vegan pestos are awesome with sundried tomatoes or basil, cashew nuts, and nutritional yeast. Combine with pasta, some rocket, and cherry tomatoes and pasta night is saved as well. There was however one problem which all our efforts over the month could not fix. Cappuccinos need milk. Many attempts were made, but the right frothy foam and taste could not be produced. Unsweetened soymilk was the worst of the bunch and Rosa still refers to it as smelling like musty rodent bedding. Overall that is not a bad score and the quest for the vegan cappuccino continues. Having completed the month, we seem to have moved ourselves into a new mental framework. Meat and eggs no longer seem like an essential diet component. Dairy in general is off the books as well, while I’m making an exception for the 1.5 kg of Parmesan we still have left from our Italian road trip in September. Will I go full vegan after that bunch is finished? At home for sure, but I think I will make exceptions when eating at friend’s places or in restaurants.

At the end of this experience, all I can say is try it for yourselves, make it a new year’s resolution! You don’t need to go a full month, maybe make it two days a week, but do some experimenting with your daily food, you may find out you also love tofu for breakfast (seriously, the recipe is below, it’s awesome!)

Scrambled tofu

Take your tofu block the night before you want to eat it and place it between 4 layers of paper towels between plates with something heavy on top. Place this stack in a stable place and leave overnight to squeeze the moisture out of the tofu.

The next morning, shred the tofu and slice some onions and mushrooms/chilies and whatever else you like. Fry the other ingredients for a few minutes in oil and then add the tofu. Add paprika powder, curry powder, ginger powder, and ground cumin. Stir fry this for a few minutes and then add a splash of sweet soy sauce (ketjap manis for the Dutchies and Indos). A few more minutes and your scramble is done.

Eat on your favorite bread with mashed avocado!

Food for thought Pt. 1 Plastic Free

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http://www.wehatetowaste.com/plastic-free-july/

Over the last couple of months, my fiancée Rosa and I have been doing monthly food challenges. So far, we’ve done Plastic Free July and Vegan October. Full disclosure: there was an Italian-All-You-Can-Eat-September trip in between. As I am sitting here drinking my kale, peanut butter, banana, chia seed smoothie, I got to thinking on what those months were like and how I ended up drinking hipster-foodie smoothies. Let me start off with encouraging you to give it a try. I know we are all exceedingly busy, but it really gives you a new perspective on the food we eat everyday and where it comes from. Many people say they can’t cook, or are just not interested. Some even have a weekly schedule, pretty much eating the same seven things each week. As a cooking enthusiast, this blows my mind. Food is something we take in three times a day, every day. It most likely has the biggest influence on how we feel and how healthy we are and many people treat it as a chore to get through.

Changing your daily routine is something which takes a little effort. We are all creatures of habit, and there have been times were I was frustrated by the lack of plastic-free options in the supermarket (cheese and meat especially are almost always off limits). But if you invest that little bit of effort, you will learn so many new recipes, ingredients, and new food options which will enrich your daily meals that you will wonder why you always stuck to your pasta bolognese, fried rice/noodles, and especially potatoes, veggies and meat for you Dutch people out there. To keep this post within a reasonable length, I will focus on our plastic-free experiences here. Our month of plant-based diet will be the subject of the next post.

Plastic is pretty much the foundation on which our modern civilization is built. It is cheap, light-weight, durable, and there are so many types used in clothing, packaging, appliances, etc. The sheer number of ways in which we are currently using these oil-derived materials is astounding. There is however a down side to this abundance of uses for plastics. Many plastic products are for single use only, often being discarded immediately after getting home from the store. In western countries, a percentage of this plastic waste is now being recycled (26% EU average) and another part (also 36% for the EU) is being burned as fuel for power plants and other factories. Its energy is being ‘recovered’ as it is euphemistically phrased. This burning of course contributes to carbon dioxide levels in the atmosphere and thereby to climate change. These levels of recycling and burning for energy are currently some of the most positive scenarios of plastic waste treatment. In many places, disposable plastics ends up in landfills (the remaining 38% in the EU), or the environment (there is not a big difference between these two). As a coral reef biologist, I have seen the effect of plastic pollution on the marine environment. Endless amounts of single use bags and bottles end up on the shore and underwater where they slowly fall apart and enter the food web, poisoning and physically harming wildlife. During a research cruise on the Atlantic Ocean, we  brought up plastic trash from over 4000 meters deep.

Because of this, we decided to spend July living single use plastic-free (medicinal package plastics excluded). The first thing you notice as you walk into your favorite supermarket is how limited your options have now become. A rough estimate would be that more than 90% of the products comes in plastic packaging. Almost all meat, fish, prefab food, and dairy come in plastic. Of non-cooled foods, your only options are glass, cardboard/paper, and tins if you gloss over their lining. Vegetables and fruits leave you about a third of the options. No boxes of mushrooms, cherry tomatoes, salad, or berries. No bags of apples, oranges, onions, garlic, carrots, or bell peppers. Many things are available in bulk, but you soon notice that these always cost more than the prepackaged versions. Why do bag-less bananas cost substantially more than bagged bananas? Another thing is the packaging per item. why do all eggplants have to be shrink-wrapped? A Dutch government agency claimed (link in Dutch) that this was to lower damage during transport which would lead to levels of food waste which would outweigh the cost of the plastic wrapping, but there must be other ways to solve this. Veggies on the market are hardly ever wrapped and they seem just fine. Part of this problem is the customer’s aversion to any blemish on fruits and veggies. All produce must now be picture perfect, or people will assume there is something wrong with it. Supermarkets provide those flimsy single use bags for the things they offer in bulk. There may still be some which offer paper bags but those are getting more and more rare. To solve this, we got some mesh drawstring bags online as a replacement. These work great for pretty much everything and I wonder why supermarkets don’t have a stand for them in the veg department. As you wander around the vegetables, most of which are now off limits, you notice that the majority of what you can still buy is more ‘old fashioned’: turnips, leeks, cauliflowers and the like. You are pretty much left with only whole vegetables most of which require a bit more prep time than a short stir fry. We had a great time coming up with recipes for stews, soups, casseroles, and other ways to use these.

Package-free stores seem to be popping up all over the place. These bring-your-own-container shops are offering more and more of your daily needs in vegetables, grains, drinks, cleaning products, etc. Sadly enough, we did not have one nearby and making a 40km roundtrip to do the shopping would kind of defy the point. However there was just an announcement that the major Belgian biological supermarket is starting with minimal packaging/bring your own container, so there is definitely some movement in the major supermarkets.  Another option was the Saturday morning market on a square near where we live. Of course this required some meticulous planning shopping list-wise as I generally just pop over to the supermarket everyday for dinner shopping, but there is something fun about coming home with a bounty of produce which you hunted down at your local market. The people manning the stalls were happy to oblige us with our funny bags and were more than willing to put things like goat’s cheese in the re-usable containers we brought. After our plastic-free month, the only real failures were finding coffee and toilet paper in a non-plastic package. Both of these are sadly enough essential, so we did make some allowances.

There are of course no official rules to this kind of experiment. Plastic-free July did have some organization behind it, Facebook groups and the like, but you are free to set up your own month-long experiment. Do some pre-research so you have alternatives for your standard daily wants and set up some rules: just skipping those plastic veggie bags at the supermarket, or avoid the supermarket altogether and just buy local. Make the rules which you think you can manage for a month.

For us, the big thing was the realization that single-use plastics have become omni-present in the food industry. Is it really necessary to display the cherry tomatoes/apricots/apples in a plastic box? Why are there no more sustainable alternatives available at the supermarket for packing your food? It is amazing how empty your trash can is after a few weeks of not buying pre-packaged food. It will take some adjustment on your part, but there is something fulfilling about getting your weekly food without all the accompanying plastic. So give it a try and do not be discouraged by a weird non-packaged vegetable which you may never have heard of (topinambur, scorsonere, or even the epically named cardoon) . Googling its name will give you more recipes for it than you could ever use!

The rainforests are not the lungs of the Earth, we are actually making them the opposite

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WWF France (2008) TWBA\Paris – print

Everyone has heard the cliché of the rainforests being the “lungs of the Earth”, its all over the news with the ongoing climate summit in Paris. As an ecologist, this has bugged me for a while now. I never gave it much thought until now, but it just felt off. The statement infers that the rainforests produce the oxygen in the atmosphere which helps us and all other aerobic organisms live. This seems to make sense since plants produce oxygen through photosynthesis and we use that oxygen in our respiration. However, it glosses over the other product of photosynthesis. Plants do not photosynthesize to make our oxygen, they do so to produce carbon compounds which they use to respire themselves and grow. On top of that; the multitude of animals in rainforests together with the abundance of (still mostly unknown) micro-organisms live off the plant material and each other while respiring as well. All this respiration is also boosted by the year round high temperatures since increased temperature leads to increased metabolism in coldblooded organisms. If we tally all this up, it turns out that a rainforest is a balanced system with hardly any oxygen surplus. Another thing is the carbon production during photosynthesis. If rainforests produced excess oxygen for us to breath, there should also be excess carbon produced. This carbon should then build up as litter on the forest floor, not being eaten by anything and if the forests would contribute substantially to the world’s oxygen reserves, this build up should be pretty massive. We in fact find the opposite with high decomposition rates quickly removing litter from the forest floor all the while consuming oxygen in the process. The only way there could be a net excess of oxygen is when the plant material was sealed off from the air in, for example, peat swamp forests where a layer of peat builds up over time.

These peat swamp forests are currently at the center of a major environmental disaster happening in Indonesia. Massive forest fires along Indonesia’s 5000 km length are releasing as much carbon dioxide in three weeks as Germany releases per year. This of course besides the danger to human health and massive destruction of key rainforest habitats for innumerable animals for which the orangutans are the poster boys/girls as long as they are still around.

Sadly enough, rain forests in other parts of the world are facing similar threats, a key example being the Amazon which is being burned to clear land for cattle pastures. The burning of our rainforests is actually doing the opposite of lungs: using oxygen for the transformation of plants to carbon dioxide. But don’t worry, there is far more oxygen in the atmosphere (21%)  than we can consume by burning all our forests. The problem comes from the carbon dioxide being released. Since there is far less carbon dioxide in the atmosphere (0.04%), all this burning does have a major effect on its atmospheric levels. It is estimated that the carbon dioxide released by deforestation through burning exceeds that of all cars and trucks in the world, leading to increased global warming.

So, although it paints a pretty image, the tropical rainforests are not the lungs of the earth. We are, however, destroying them at an unprecedented rate, leading to death and habitat loss for vast numbers of plants and wildlife, serious health issues for local people, and an increase in climate change, something we could really do without right now.