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SlideShare utilise les cookies pour améliorer les fonctionnalités et les performances, et également pour vous montrer des publicités pertinentes. Si vous continuez à naviguer sur ce site, vous acceptez l’utilisation de cookies. Consultez notre Politique de confidentialité et nos Conditions d’utilisation pour en savoir plus.
Sharing with you today why I think seaweeds are way cool. By way cool, I mean important to understand, appreciate and ultimately conserve, and I hope by the end of this presentation you agree with me. Thought I’d start with a glimpse into how seaweeds have influenced and enriched my life... Photo: Ecklonia (algaebase.org) FEEDBACK FROM TALK: – had this slide up as people taking seats. Asked “How many different kinds of seaweed can you find in this picture?”, and they wanted a definitive answer at the end. Not sure if this really worked. – overall, talk went well. Took ~40 minutes, and I didn’t feel rushed – took lots of little detours to explain pictures, tell small stories, etc. Clicker questions each took 2-3 minutes total. Kids really liked clickers. - 55 people attended, ~ 12 kids, rest adults of varying backgrounds. Some clearly not at all strong biology background, others knew quite a bit about seaweeds. I felt, at times while speaking, that I didn’t really know this audience. My first general public audience. – how to craft a talk for both adults and kids? Needs many layers, like a PIxar movie, but how do you write that? – think the gimmick of challenging people with “when was the last time you ate seaweed” doesn’t have the same “wow” factor here in Vancouver. When I asked that question, lots of people said they eat seaweeds directly, others knew it was in chocolate milk, etc. – feedback from audience – I was enthusiastic, slides beautiful, and had lots of questions: “how old can seaweeds live to be”, “why is Pyropia yezoensis (nori) green after processing but not when pressed”, “does seaweed aquaculture damage the ecosystem if you’re artificially adding organisms to a habitat where they weren’t before”, “how can you catalogue the total number of species in the world”, “how do you come up with a predicted number of species in the world”.
– I’m a biologist and for most of the last 7 years I studied a group of seaweeds and specifically tried to find out how many species there are, how to tell them apart, and how they are related to one another. – This project took me to all kinds of different and wonderful places... Photos: Katy Hind
Like California... Photos: Katy Hind
...even the sub-Arctic – this is up in Churchill, Manitoba – places we don’t typically associate with seaweeds... So today I’m here to talk with you about seaweeds. And I thought we could start with a little game, using your clickers. Photos: Kathryn Roy, Bridgette Clarkston
Ok, look at these four pictures and try to decide for yourself what the answer to the question is. Nod your head when you’ve decided. Ok, now using your clicker... Photos: Top right, Champia (algaebase.org), Zostera (algaebase.org), Mazzaella and Nereocystis (Bridgette Clarkston)
...vote for the number of seaweed types you think there are. Take home message: seaweeds come in all shapes and sizes and many other things look and act like seaweeds, but are not. FEEDBACK: clicker votes – A) 0%, B) 8%, C) 38%, D) 35%, E) 19% (26 total)
When I ask people what they think about seaweeds, what words jump into their minds, I often hear “green”, “slimy”, “stinky” and other negative-sounding words. I think this is because most people I know mostly see seaweeds in this state – dead and rotting, washed up on the beach. FEEDBACK: Need better picture here; a picture with more perspective, of the beach perhaps. – Need more powerful analogy here to convey that many people only encounter seaweeds when they’re dead. A “living-dead” comparison, perhaps with a whale – everyone has mental image of living whale, can then show pic of whale washed up on beach. Then draw parallel to seaweeds – dead on beach, rotting, smelly (same as dead whale), but beautiful when alive and in their natural habitat, just like a whale.
We don’t often think of or see seaweeds like this and we certainly don’t see them this way in popular culture or media, if at all, with the exception of kelp forests. – this is a picture of the intertidal – the zone of the shore that is exposed to air at low tide and covered by water at high tide. I took this picture in California, but you can find sites just like this all over B.C. coast with this kind of diverse number of different seaweeds. Photo source: Bridgette Clarkston
I’ll be talking about the biodiversity of seaweeds, a word I often see in media and popular culture associated with places like this...
Tropical, coral reefs with lots of different fish, or maybe the Amazon rain forest. The word biodiversity has several different meanings to the people that study it, which I won’t get into; today I’ll stick to talking about biodiversity as the number of different species, the number of different types of organisms. When I hear about biodiversity, it’s often about the loss... Image source: http://oceanservice.noaa.gov/facts/threecorals.html
The destruction of habitat – like the bleaching of coral reefs –, and the loss or even extinction of species. Naturally, we are very concerned with understanding and reducing the loss of biodiversity when it’s due to human activities. Photo source: http://phylas.blogspot.ca/2011/05/coral-bleaching.html
However, it’s hard to measure what’s been lost if you don’t know how many species were there in the first place. That’s where we are with most types of organisms – we simply don’t know with much accuracy or precision, how many species there are, where they live or how to tell them apart.
And that includes the seaweeds. Most people aren’t aware of the impact seaweeds and their diversity has on us, on humanity. My goal today is to share with you my awe for the weird and wonderful types of seaweeds there are and their importance to coastal ecosystems, and my appreciation for the extent to which seaweeds impact the everyday lives of humans. I hope by the end that you agree with me! *– for example, many people are unaware that BC is a hotspot of seaweed diversity* biodiversity of forms, diversity of functions and uses.
So as we saw with the clicker question earlier, seaweeds come in all shapes, sizes and colours. – there are some characteristics that almost all seaweeds have. Though, as with almost everything in nature, there are exceptions to these. Seaweeds tend to be...
Photo source: Bridgette Clarkston
To something. Usually the ground or other attached organisms.
Some are even mobile, though they are attached. Can anyone see what the red seaweeds are attached to here? A decorator crab (Oregonia gracilis). I’ve been startled many times while scuba diving around B.C. when I’d reach out to pick a seaweed and it either started running away or trying to pinch me! Image credit: http://www.robots4farms.com /
There are some cool exception to this, e.g., some seaweeds are parasites that infect other seaweeds.
So how many species of seaweeds are there? Photo source: Bridgette Clarkston
This graph shows the approximate number of species living in the world today for these different groups of organisms. I want you to tell me which number represents the number of species of seaweeds, using your clickers. Think about it to yourself for a moment and nod when you’re ready. Source: Chapman, 2009 (for all taxa except seaweeds); Guiry, 2012 & seaweeds.ie (for seaweeds)
FEEDBACK: clicker votes – A) 36%, B) 28%, C) 12%, D) 12%, E) 12% (25 total) – went over well, I think, except that most guessed the top number! Does this then make the actual diversity seem less impressive??
So there are lots of different kinds of seaweeds and also many found in Canada. Most Canadian species – about 600 or so – are found here along the B.C. coast. Source: http://canadianbiodiversity.mcgill.ca
But how are seaweeds related to one another and to other groups of life? Well, without getting to far into it...
...seaweeds are a bit like the mafia. You know how in mafia movies, what they call a family isn’t necessarily made up of people who are blood relatives (i.e., closely-related by descent)? Some might be, but this kind of “family” isn’t defined by ancestry, it’s defined in a more functional way – the members work together and have similar roles in society. Well, the term “seaweed” is a lot like that, it describes three major groups... FEEDBACK: Think the mafia analogy went over well, but didn’t ask anyone afterwards if they got it. Would be interesting to know... image: http://newspaper.li/goodfellas/
The “greens”, “reds” and “browns”. The species within each group, and there are many... Photos: algaebase.org (Ulva, Callophyllis, Alaria)
...are relatively closely-related and we can trace their history back to a single common ancestor. However, the three groups have been evolving separately from each other for a very long time, millions and millions of years and are not each other’s closest relatives. In fact, the brown seaweeds are more closely-related to a group of phytoplankton called diatoms than they are to either reds or greens. – Incidentally, originally grouped by pigments they contain and hence colour they are, however, not all are these colours. Reds in particular can be anything from red... FEEDBACK: Stephan noted that I mentioned the oldest fossil of a red algae as ~1.2 billion years old (had not planned to talk about that), but I didn’t put that number into perspective. Suggested that, with kids in the audience, that I draw a comparison to age of dinosaurs or their extinction – something they immediately identify with happening a very long time ago.
...to green... Data source: www.algaebase.org, www.seaweeds.ie , Guiry, 2012 (see references) Photo: algaebase.org (John Huisman) of Asteromenia
...to almost black. Can anyone think of a well-known example of brown seaweed? Of green? What about red? FEEDBACK: Didn’t ask the above question as planned, but should have. Photo: Polyides (Colin Bates, algaebase.org)
During my PhD I worked on a big group of red seaweeds (including one that’s black); my favourite species came from these three smaller groups – the genus Euthora, the genus Pugetia and the genus Callophyllis. All of the images here are from seaweeds collected in B.C. I was lucky enough to get to describe four brand new species of seaweed, all found here in B.C., including my favourite... FEEDBACK: Noticed that at this point I started using the word “genera” without explaining it. Need to explain if going to use! Photos: Gary Saunders
...the first species I discovered and decided to name in honour of one of my artistic inspirations, the filmmaker Tim Burton. New species of seaweeds are discovered all the time, however, this particular discovery got a bit of attention in the media – CBC, Discovery Channel – because of its name. FEEDBACK: From Stephan – I didn’t talk at all about WHY I named this after Tim Burton. S pointed out that people generally excited, interested to hear about what goes into naming a species. Add more for next time.
Bottom line: still many species yet to discover.
What seaweeds do INTERACTIVE: what do seaweeds do in nature? How many people have seen seaweed underwater (video, SCUBA, snorkelling) Global --> local Photo: istockphoto.com (purchased)
provide habitat – from the commonly known kelp forests, to lesser known reds/browns as understory, tidepools, intertidal prevent desiccation, floating oceanic mats for fish shelter, structure for coral reefs, etc. FEEDBACK: kinda rushed through this section (and cut out other slides prior to talk) because I thought I would be short on time. In retrospect, could and should have spent more time here exploring habitats little known to most people.
SLIDE provide habitat (kelp forest, reds/browns as understory, tidepools, intertidal prevent desiccation, floating oceanic mats for fish shelter, structure for coral reefs VIDEO SLIDE where are these habitats? deep-water kelp refugia?? Photo: crab on Macrocystis (algaebase.org)
When think of habitat, usually image of kelp forest jumps to mind. But other important seaweed habitats as well. Organisms living in the intertidal are exposed to the air regularly, exposing them to stressful and even fatal levels of desiccation, high temperatures, and low salinity. However, if you stay tucked under a robust species such as Fucus, etc., you can avoid these stressors and survive. FEEDBACK: audience seemed interested in this slide, but I could have gone into greater depth, e.g., showed more organisms that benefit from protection provided during low tide. Photos: algaebase.org (Fucus vesiculosus in Ireland)
Are consumed by many different organisms directly “ Their [kelp and rockweed beds] extensive biomass provides a large amount of primary productivity oxygen to nearshore food webs.” Bates paper FEEDBACK: kind of butchered this part, went through it very superficially. Could have shown more info, explained more. TOO SHALLOW. Photos: algaebase.org (Macrocystis, Osmudea)
Still have a long way to go before we understand all the different roles that seaweeds play in our coastal marine ecosystems. Not known what will happen with changing climate, human disturbances.
Even though we still don’t fully understand seaweed biodiversity, we sure do make use of it! (though we could be using seaweeds much more than we currently do) This man here is my friend and mentor, Dr. Louis Druehl. He’s a world-expert on kelps and other browns and worked for many years at Simon Fraser University. He now lives in Bamfield, west coast of Vancouver Island, and with his wife, Rae, runs a successful seaweed farm there. Here he is pulling up a crop of kelp. Probably the most obvious use of seaweed by humans is as food. So let’s find out if you guys eat seaweed... Photo source: (Not sure, a fellow student at Bamfield in 2003. Maybe Hana Kucera or Rodney Withall)
Even if you have a very traditionally-Western diet – which does not make much direct use of seaweed as food – you’ve probably consumed something that contains at least an extract of seaweed in it recently. FEEDBACK: clicker votes – A) 59%, B) 37%, C) 0%, D) 4%, E) 0% (27 total)
– Many modern and ancient human populations with access to the seashore has used seaweeds in one way or another. Over 500 different species used in human history. – 2000 years, China; 400 years ago in Scotland – First Nations groups like the Coast Salish are well-documented as using seaweeds for many purposes. – – for three main purposes: fodder, chemicals and food. – Source: Graham & Wilcox Photos: Top left, Chondrus harvest in PEI ( http://www.tourismpei.com/photo-contest-2010 ), lower left, Ecklonia harvest in South Africa (algaebase.org), right, Eucheuma harvest in Zimbabwe (algaebase.org)
Reds, browns and greens each have compounds in their cell walls that protect their cells and help the seaweed stay upright in and out of the water. Globally, by far the main industrial use of seaweeds is in extracting these compounds from just a few different species of reds and browns. Used for commercial use as gelling agents to stiffen solutions and also as preservatives. Agar from a few different types of red algae, like Gelidium. Info source for chemical extracts: seaweeds.ie, Graham, Graham & Wilcox. 2009. The Algae. 2nd Edition. Pearson. Photo source: Gelidium (algaebase.org). Agar plate: http://upload.wikimedia.org/wikipedia/commons/0/02/Salmonella_sp._on_DC-agar_from_Flickr_69017875.jpg
From red algae the compounds extracted called carrageenans come from relatively few types of red seaweeds, like Chondrus crispus (important historically in Canada, but today other genera used more for carrageenans, like Kappaphycus). Photos: Chondrus (algaebase.org), powder ( http://zailingtech.en.made-in-china.com )
alginates from browns used in all kinds of things, also as thickener. Salad dressings, cream cheese, etc. photo: salad dressing ( http://www.steveklotz.com/blog/?p=700 )
Compounds extracted from seaweeds – alginates, carrageenans, agars – too complex to synthesize. – since we only make use of a few dozen species for chemical extracts, huge potential of chemical uses yet to be discovered.
What’s a really common food around Vancouver that has seaweed in it? Are about a dozen or so seaweeds of global importance as food for humans, only going to mention a couple today that many of you are probably familiar with.
What’s a really common food around Vancouver that has seaweed in it? Photo: istockphoto.com (purchased)
*Note: Is not true actually Pyropia yezoensis in top right. Cheated and used a collection from B.C. (No P. yezoensis in B.C.) FEEDBACK: had people volunteer what they thought. Had votes for the Ulva, Pyropia and Mazzaella. Photos: Ulva (algaebase.org), Pyropia (Dan McDevit), Mazzaella, Nereocystis (Bridgette Clarkston)
Nori has been farmed in Japan for over 300 years. Since the 1940’s – when a seaweed biologist named Kathleen Drew Baker made a crucial discovery about the life history of Pyropia – nori farming has scaled up to become the biggest seaweed aquaculture industry in the world. The annual Pyropia harvest is estimated to be worth $2.5 billion dollars – Pyropia is a good source of digestible protein – 25–35% dry weight of the plant is protein, most of which is digestible by humans. – The economic success of crop seaweeds depends on detailed knowledge of the seaweeds themselves. Photos: Pyropia specimen (Dan McDevit), nori farm ( http://www.edenfoods.com/articles/view.php?articles_id=159 ), nori sheets ( http://huntgatherlove.com/content/super-super-bowl-snack-ajitsuke-nori )
The last human use I want to touch on is one that’s quite personal to me – the aesthetic of seaweeds, the sheer pleasure I get from the beauty of their form and how that beauty inspires me. They may look simple And I’m not the only one... Photo: Macrocystis (algaebase.org)
Example of seaweeds inspiring art, and seaweed used to make art. stamps: http://www.alga-net.com / designer sushi: http://www.designboom.com/weblog/cat/8/view/20710/lasercut-nori-for-designer-sushi.html
I think that when you’re inspired by something – the way I’m inspired and invigorated by the beauty of seaweeds – that inspiration can ripple out and affect those around you in positive ways. As an example, the species I was so excited to describe, E. timburtonii, inspired my sister Meghan Clarkston to make this painting, and my friend Kathryn Roy to make these beautiful cupcakes (and, by coincidence, the fruit roll-up used on top likely contains seaweed!)
To conclude, I want to come back to the question of why, why do I care so much about seaweeds, why I think they’re way cool and why I hope that you do to. For me, it all boils down to their diversity...
They may look simple or uninteresting from far away or when they’re rotting, but take a look up close and in their element and I think you’ll be inspired too. Photo: Phycodrys (algaebase.org)
Showed this and next slide – advertised algaebase and seaweeds.ie as places for people to go if they’d like to learn more about seaweeds. Also pointed out that vast majority of seaweed images used in talk came from algaebase.
MAIN GRID USED FOR BUILDING SLIDES for one box: 204.8x153.6 for two x one box (long): 204.8x307.2 for four boxes (square): 409.6x307.2 for two boxes x one wide: 409.6x307.2 for 4 x 4 boxes: 820 x 612
B.Clarkston seaweed biodiversity Nov.4 2012
Seaweeds are way cool because... Bridgette Clarkston Beaty Biodiversity Museum Photo: algaebase.org
Literature cited:•Graham, Graham, and Wilcox. 2009. The Algae. 2nd edition. Pearson.•Bates, C. An Introduction to the Seaweeds of British Columbia(http://www.geog.ubc.ca/biodiversity/eflora/Seaweeds_in_British_Columbia_by_Colin_Bates.pdf)•Guiry, M. 2012 HOW MANY SPECIES OF ALGAE ARE THERE?. Guiry, M. D. (2012). HOW MANY SPECIES OF ALGAE ARE THERE? Journal OfPhycology, 48(5), 1057–1063. doi:10.1111/j.1529-8817.2012.01222.x•Turner, N. C., & Bell, M. A. M. (1971). The ethnobotany of the coast Salish Indians of Vancouver Island. Economic Botany, 25(1), 63–99.•Harley, C. D. G., Anderson, K. M., Demes, K. W., Jorve, J. P., Kordas, R. L., Coyle, T. A., & Graham, M. H. (2012). EFFECTS OF CLIMATECHANGE ON GLOBAL SEAWEED COMMUNITIES. Journal Of Phycology, 48(5), 1064–1078. doi:10.1111/j.1529-8817.2012.01224.x•MacArtain, P., Gill, C. I. R., Brooks, M., Campbell, R., & Rowland, I. R. (2007). Nutritional value of edible seaweeds. Nutrition reviews, 65(12),535–543. doi:10.1301/nr.2007.dec.535–543•Kenicer, G., Bridgewater, S., & Milliken, W. (2000). The Ebb and Flow of Scottish Seaweed Use. Botanical Journal of Scotland, 52(2), 119–148.doi:10.1080/13594860009441750•Smit, A. J. (2004). Medicinal and pharmaceutical uses of seaweed natural products: A review. Journal of Applied Phycology, 16(4), 245–262.