Skating on thin ice…?
Science, like a cat on a hot tin roof, doesn’t stand still. Should it ever stand still it will wither and die. To avoid this fate, it needs to keep moving. Moving for science means advancing knowledge by continuing to ask questions and building upon what has gone before. In that way it helps to define and refine our view of the world. Although this is not the place for a long essay about the Scientific Method[1,2] and how science works[3,4], insight into the gradual, bit-by-bit, progress of science can be illustrated by a look back into the Cuttings’ archives. Almost five and a half years ago we reported on an oceanic algal bloom[5] that occurred not in the open sea – where it might be expected – but beneath Arctic sea ice[6]. That was a bizarre phenomenon since the commonly held view was that light conditions under the ice would be too low to support such an event. Nevertheless, happen it did. Although the reasons for this bloom were uncertain, Kevin Arrago et al.[7] did suggest that it may partly be due to thinner ice in the region (which would let through more light than thicker ice) and the presence of so-called melt ponds – puddles of melted ice[8,9] – on top of the ice that permitted the ice beneath them to transmit four times more light than snow-free ice. Subsequent modelling of the process predicted that those ice and melt conditions could increase growth of shade-adapted Arctic phytoplankton and increase NPP (net primary productivity[10,11]) of the area in the way observed in nature[12]. Now, Christopher Horvat et al.[13] have taken that modelling approach further and confirmed the contribution of melt ponds to a more bloom-favourable light environment beneath the ice. But they also point out that the contribution of thinner ice to the phenomenon is more important than melt ponds. And noting the prevalence of thinner ice in the Arctic [I wonder what might have caused that…?] over the past 30 years – and therefore the possibility of more extensive sub-ice blooms – they raise a note of caution about our ideas of the ecology of this area because the ‘foundation of the Arctic food web is now growing at a different time and in places that are less accessible to animals that need oxygen’ (presumably they here have in mind air-breathing mammals such as whales and seals that would find it harder to get oxygen beneath ice rather than in open water)[14]. They also remind us that light isn’t the only abiotic factor needed for a bloom to develop, as the role of nutrients also needs to be taken account of in more comprehensive models*. So, corroboration for the original work of Arrigo et al., but there remain more questions to answer, more investigations to be undertaken, more science to do. Like money (apparently[15]), science never sleeps.
* They also point out the difficulties in detecting and monitoring sub-ice blooms because satellite-based approaches – used to monitor chlorophyll levels on land, in freshwaters and the oceans to give an estimate of photosynthesis[16,17], hence NPP – can’t detect chlorophyll through the ice. This probably partly explains why sub-ice blooms are likely to have been under-reported and their contribution to ocean ecology under-appreciated.
Image from: Wikimedia Commons
References
[1] https://plato.stanford.edu/entries/scientific-method/
[2] http://teacher.nsrl.rochester.edu/phy_labs/AppendixE/AppendixE.html
[3] http://undsci.berkeley.edu/article/howscienceworks_01
[4] https://www.newscientist.com/blogs/thesword/2009/12/how-science-works-isnt-working.html
[5] http://www.waterencyclopedia.com/A-Bi/Algal-Blooms-in-the-Ocean.html
[6] https://aobblog.com/2012/10/rejoice-tis-the-real-blooms-day-to-be-sure-2/
[7] Science336: 1408, 2012; doi: 10.1126/science.1215065
[8] http://nsidc.org/cryosphere/glossary/term/melt-ponds
[9] http://neven1.typepad.com/blog/melt-ponds/
[10] https://earthobservatory.nasa.gov/GlobalMaps/view.php?d1=MOD17A2_M_PSN
[11] https://indicators.ucdavis.edu/waf/model/indicator/net-primary-production
[12] Molly Palmer et al., Deep-Sea Research II105: 85–104, 2014; doi: http://dx.doi.org/10.1016/j.dsr2.2014.03.016
[13] Sci. Adv. 2017; 3: e1601191; doi: https://doi.org/10.1126/sciadv.1601191
[14] https://www.sciencedaily.com/releases/2017/03/170329150201.htm?utm_source=feedburner&utm_me
[15] http://www.imdb.com/title/tt1027718/quotes
[16] https://science.nasa.gov/earth-science/oceanography/living-ocean/remote-sensing
[17] http://www.iaglr.org/jglr/release/39/2012.12.007_lesht3.php.
New Plant Resources
At Cuttings HQ we like few things more than sharing knowledge about plants and plant-related items – especially if they’re free! In that regard Mr Cuttings is pleased to share the following information about a trio of plant resources with the wider plant community.
Plant Image Bank
The power of images to convey information – especially in science communication which can often-times be quite complicated[1] – is surely not in doubt. And that is why many of us have spent time wrestling with graphics programs to create bespoke diagrams, etc. to illustrate our text-based efforts. As therapeutic as that creative activity can be – especially the colouring-in – it’s extremely time-consuming. So, wouldn’t it be useful to have access to a source of ready-made images (especially if they only need to be ‘tweaked’ for your particular purpose)? Yes (!). In an attempt to satisfy that need, plant scientists Erin Sparks, Guillaume Lobet, Larry York and Frédéric Bouché have created the Plant Illustrations repository[2,3]. Although intended primarily for ‘vector graphic’[4] images (a format that allows the images to be modified in a range of graphics packages to suit the user’s particular purpose, and any amendments are permitted by the repository’s terms of use*), the site also hosts a folder of more conventional images (plant pictures – or, as us old ’uns call them – ‘photographs’). At present (early May 2017) the great majority of the images are contributed by the site’s founding quartet, but it is hoped that others will upload and share images to make this a much-expanded, shareable resource for the plant science community. Each contribution has a doi (digital object identifier[5,6]) and is citable, so the originator can be credited for his/her original contribution. Illustration categories at present include roots, shoots, inflorescences, and cell biology. If interested in sharing your own artwork, check out the guidance on this[7]. The repository uses the FigShare (a ‘permanent, open-access database for non-peer-reviewed scientific documents’[8]) internet facility, which also hosts many other plant, and more general biology, collections[9]. We encourage you to explore this resource, and look forward to seeing appropriate Plant Illustration images appearing in your papers, conference presentations, etc. in future.
*Although what is permitted in each case will depend upon the image’s specific licence requirements.
Image from: Figshare
References
[2] https://figshare.com/authors/Plant_Illustrations/3773596
[3] https://i1.wp.com/aobblog.com/wp-content/uploads/2017/03/plantgraphics.png?ssl=1
[4] https://techterms.com/definition/vectorgraphic
[6] http://www.apastyle.org/learn/faqs/what-is-doi.aspx
[7] https://figshare.com/articles/Plant_illustrations_repository/4685599
[8] https://figshare.com/about
[9] https://figshare.com/categories/Biological_Sciences/48.
All the world’s plants (at Kew!)
Well, not quite all. The Royal Botanic Gardens at Kew[1] is home to many living specimens of the world’s flora, and its collections of ‘dead stuff’ – principally from the Plant[2] and Fungus[3] Kingdoms – represent 95% of known angiosperm (i.e. flowering plants[4]) genera[5] and 60% of the known fungal[6] genera[7]. Which, by any metric, is pretty impressive. But, of its estimated 8.5 million specimens (!!), only a fifth is available on-line. So, that tremendous repository of plant information is largely out of sight. That’s a cause for concern to all of us who believe that shared knowledge is empowering. It’s also a cause for concern of the good people at Kew, which is why they’re doing their best to plug that knowledge vacuum. One of their responses is the launch of the Plants of the World Online portal (POWO[7]). Its aim is simple: To put information on all the world’s known seed-bearing plants (presumably angiosperms and gymnosperms[8]) online by 2020*. POWO’s goal is to disseminate Kew’s wealth of scientific knowledge of plants and fungi ‘to maximize its impact in science, education, conservation policy and management’. This ambitious plan started with POWO’s launch in March 2017 with its main focus on the key tropical African Floras – Flora Zambesiaca[9], Flora of West Tropical Africa[10], and Flora of Tropical East Africa[11]. But, POWO currently also includes data from Kew’s Grassbase[12] and PalmWeb[13] databases along with species level data for some orchids. As you might expect from Kew the information is primarily taxonomic, but the portal allows users to browse – for free! – 336,000 global plant names, 34,900 detailed descriptions, and 19,700 images (which can be copied and used to illustrate one’s own work…).
*So, it looks like the mycophilous amongst us will have to wait a while longer for an equivalent resource. Unless the fun guys and gals of Kew create a parallel portal – SOWOT (‘Shrooms of the World Online Together)…?
Image from: Wikimedia Commons
References
[2] https://www.infoplease.com/science-health/life-science/plant-kingdom
[3] http://www.zephyrus.co.uk/funguskingdom.html
[5] http://www.dictionary.com/browse/genera
[6] http://biology.tutorvista.com/organism/kingdom-fungi.html
[7] http://powo.science.kew.org/
[8] http://www.botany.wisc.edu/courses/botany_401/lecture/03Lecture.html
[9] https://plants.jstor.org/collection/FLOZAM
[10] https://archive.org/details/FloraOfWestTropi00hutc
[11] https://plants.jstor.org/collection/FTEA
[12] http://www.kew.org/data/grasses-db.html
All the world’s trees in one place
If the POWO (see news item above) is not enough plant database for you, there is also a new database specifically for the world’s trees*. Called GlobalTreeSearch[1,2], it is hosted by Botanic Gardens Conservation International (BGCI[3]), and proudly claims to be the ‘first complete global database of tree species and country distributions’[4]. The resource lists 60,065 tree species – the number of tree species currently known to science **, ‘based on comprehensive analysis of published data sources and expert input’ (this figure represents 20% of the entirety of all angiosperm[5] and gymnosperm[6] species). Although the information databased for each species is not as comprehensive as that held for plants by POWO[7], GlobalTreeSearch allows users to search the 60,000+ entries by species names and country distributions, to find out the geographical distribution of a tree species, and discover all tree species found in a country[8]. The intention is that GlobalTreeSearch will be a tool for monitoring and managing tree species diversity, forests, and carbon stocks on a global, regional, and/or national level, the better to conserve these precious natural resources. GlobalTreeSearch will also serve as the basis of the Global Tree Assessment[9,10,11], which aims to assess the conservation status of all of the world’s tree species by 2020. It will be interesting to see whether Plants of the World Online or GlobalTreeSearch achieve their ambitious goals first, and if both can do so by 2020… No pressure, then.
* I know you’re curious. For this database a tree is defined as ‘a woody plant with usually a single stem growing to a height of at least two metres, or if multi-stemmed, then at least one vertical stem five centimetres in diameter at breast height’[12].
** Of an estimated 80,000 tree species[13].
[Ed. – one of the nicest aspects of the Beech et al. paper (and what a great first author’s name[14] for a tree database article!) is the Results section. At a mere 286 words it is a model of succinctness, and something to which we all can aspire in our own papers. After all, the Results section of a scientific paper should be one of the shortest sections of all.]
Image from: Wikimedia Commons
References
[1] http://www.bgci.org/global_tree_search.php
[2] http://www.bgci.org/global_tree_search.php?action=about
[3] http://www.bgci.org/about-us/index
[4] Emily Beech et al. (2017), Journal of Sustainable Forestry, doi: 10.1080/10549811.2017.1310049
[6] http://www.theplantlist.org/1.1/browse/G/
[7] http://powo.science.kew.org/
[8] http://www.bgci.org/global_tree_search.php
[9] http://globaltrees.org/iucn-ssc-global-tree-specialist-group/
[10] http://globaltrees.org/wp-content/uploads/2013/08/GTALeaflet-FINAL.pdf
[11] Adrian Newton et al., Oryx49(3): 410-415 (2015); doi: 10.1017/S0030605315000137
[12] http://www.bgci.org/global_tree_search.php?action=about
[13] http://globaltrees.org/wp-content/uploads/2013/08/GTALeaflet-FINAL.pdf
Snails living the high life
We all know – or should know! – how important and impressive trees are as a life form[1,2,3]. But all living things can’t aspire to be a tree. In which case the next best thing in life is to associate yourself with one. This ploy has been discovered and exploited by numerous plant species that cling precariously to branches of trees as they perch high above the forest floor. Such a lifestyle is termed epiphytic[4] and is derived from the Greek words ‘epi’ meaning upon[5], and ‘phyte’ which means plant[6]. By definition, the term epiphyte says nothing about the organism that has adopted this lifestyle; it merely specifies the surface/substrate that is occupied. However, common usage appears to have reserved this term for plants that live on the outside of other plants[7,8]. But – and unusually for him – Mr Cuttings is keen to promote an animal dimension to the tree-dwelling epiphytic phenomenon, specifically that of the land-snail Euhadra brandtii sapporo[9]. As a land snail one might assume this mollusc’s normal habitat to be the land[10], such as the forest floor, not up a tree. Yet, these vertically-aspirational individuals appear to prefer to occupy the bark of trees, and not terra firma[11]. Intrigued by this lignophilic behaviour, Ikuyo Saeki et al. duly investigated this snail’s behaviour further[12]. What did they find? First, tree-dwelling is not this snail’s lifestyle throughout the entire year; E. b. sapporo hibernates in winter in the ground litter, climbs into the canopy – to heights of 10 metres above the ground – in early spring, and returns to the ground in late autumn. This seasonal migration appears to be an effective means of escaping predation by ground-dwelling carabine beetles (which are known to eat the snails[13]), and whose activity was high during the summer. But, stuck up a tree for such a long time, the snails need a food source to survive. Chemical analyses suggest that the snails use epiphytic lichens and mosses as food resources. Understandably, the researchers conclude that for E. b. sapporo arboreality has a marked advantage in reducing mortality, and that their tree-climbing behaviour is probably supported by food availability as well. Admittedly, the snails aren’t fixed to the tree’s surface like botanical epiphytes such as mosses, orchids and bromeliads[14]. Which is why this animal behaviour is termed arboreality, and not (zoo) epiphytism. And one suspects it’s the ability to move about that means animals are probably excluded from the term epiphytes, so we don’t need to specify phytoepiphytes for plants that live in this way. There are, however, many animals that are fixed to their substrate (e.g. benthic organisms in the oceans[15]), so the searching question for you all this month is can you name a true tree-dwelling animal epiphyte? Answers (though – let’s be honest – they’re probably more likely to be wildly overly-optimistic suggestions…) to the usual address, please.
[Ed. – and in some attempt to sate your whetted appetite for other arboreal invertebrates[16], a new species (and a new genus) of tree-dwelling crab has been described by Appukuttannair Biju Kumar et al.[17]. Kani maranjandu[18] is wholly arboreal – living in tree-hollows or the canopy – in the Western Ghats biodiversity hotspot[19] in Kerala (southern India). The crabs have been observed to feed on leaves, seeds, slugs, worms, and insects on the trees; anecdotally, the crabs are in their turn preyed upon by mongooses and owls. In the interests of some sort of botanical balance, one of the tree species frequented by this newly described life-form is Terminalia paniculata, a useful tropical plant[20,21]. Presumably, usefully guarded by crabs.]
Image from: Wikimedia Commons
References
[1] https://www.treepeople.org/resources/tree-benefits
[3] http://www.savatree.com/whytrees.html
[4] https://www.collinsdictionary.com/dictionary/english/epiphyte
[5] https://www.collinsdictionary.com/dictionary/english/epi
[6] https://www.collinsdictionary.com/dictionary/english/phyte
[7] https://en.wikipedia.org/wiki/Epiphyte
[8] https://en.oxforddictionaries.com/definition/epiphyte
[9] http://www.conchology.be/?t=66&family=BRADYBAENIDAE&species=Euhadra%20brandtii%20sapporo
[10] http://www.snail-world.com/where-do-snails-live/
[11] http://www.dictionary.com/browse/terra-firma
[12] Animal Behaviour (2017). doi: 10.1016/j.anbehav.2017.02.022
[13] https://www.tsukuba.ac.jp/en/research-list/p201703311445
[14] https://www.lifestyle.com.au/plant-guide/epiphytes.aspx
[15] http://www.fisheries.is/ecosystem/marine-life/benthic-animals/
[16] http://www.encyclopedia.com/social-sciences/applied-and-social-sciences-magazines/invertebrates
[17] Journal of Crustacean Biology (2017) 1–11. doi:10.1093/jcbiol/rux012
[18] https://phys.org/news/2017-04-species-tree-crab-western-ghats.html
[19] http://whc.unesco.org/en/list/1342
[20] http://tropical.theferns.info/viewtropical.php?id=Terminalia+paniculata
[21] https://www.flowersofindia.net/catalog/slides/Kindal%20Tree.html.
Nigel Chaffey
E-mail: [email protected]
Chaffey N. 2017. Plant Cuttings, July, Annals of Botany120(1): iv–vii.
