An Introduction to the Seaweeds of British Columbia by Colin Bates, Dept of Botany, University of British Columbia

An Introduction to the Seaweeds of British Columbia by Colin Bates, Dept of Botany, University of British Columbia. Adapted from an account originally published on E-Flora BC website. All photos by Colin Bates. any people are unaware can be large or small, helpful or endosymbiotic events gave rise to that British Columbia is a harmful, and believe it or not, red and green algae (e.g., Moreira et Mveritable hot spot of sea- stunningly beautiful and head- al. 2000). It is generally accepted weed biodiversity. At last count, scratchingly interesting. that there were multiple secondary there were approximately 650 endosymbiotic events. With the Unlike plants and animals, the algae macroalgal species found in waters advent of molecular tools, algal do not arise from a single common of the Pacific Northwest (Scagel et systematics is in the midst of a ancestor (a condition referred to as al. 1989, Gabrielson et al. 2000). Of substantial reworking of these and monophyly). Instead, they are a these, 530 are known to occur in other questions. group composed of many lineages BC. (group composed of many lineages; Molecular tools have also provided Why are so many people unaware of i.e. polyphyletic (Graham & Wilcox the opportunity to examine relation- the diversity of seaweeds that in- 2000). Throughout the history of ships between algae and land plants habit British Columbia’s waters and algal taxonomy, various characters (Bhattacharya & Medlin 1998). shores? Many initial encounters with have been invoked to describe this Mounting evidence suggests that seaweeds can be unpleasant, disparate group: simple bodied land plants are derived from an especially if you are wading into the organisms, reproductive propagules ancestor of the green algal order ocean for a swim, or trying to main- lacking well-developed structures as Charales (Mishler & Churchill 1985, tain your footing while scrambling in flowers or cones, mostly aquatic, Surek et al. 1994). Land plants are on the rocks. As well, detached and generally photosynthetic. Yet, excluded from algae because they do seaweeds end up washing ashore because the algae are polyphyletic, not conform to the character set and amassing into smelly decom- arising from various ancient described above; these plants have posing piles. Seaweeds generally get ancestors, there are myriad complex bodies, typically with a bad reputation in the press (if any exceptions to these characters as flowers or cones, and are normally at all). Books like “Killer Algae” well as many non-algal taxa that terrestrial. (Meinesz, 1999), which describes possess them. The study of algae is called phy- the invasive nature of a green The tie that binds all algae together cology, from the Greek root phykos seaweed species called Caulerpa is a concept known as the ‘serial meaning algae. Algae are a vast taxifolia, and talk of ‘Harmful Algal endosymbiosis hypothesis’ group including many classes of Blooms” (a microalgal phenom- (Bermudes & Margulis 1985, unicellular and multicellular enon) do not help. All of these Bhattacharya 2000), which suggests organisms. Below, I focus on the factors contribute to the idea that that the commonality among all multicellular macrophytes, and in seaweeds are a nuisance. Yet, it is algae is that, at one or more points in particular, the benthic marine macro- my experience that seaweeds are their lineage, they acquired photo- phytes that most refer to as the most certainly not a nuisance, and synthetic abilities through either the seaweeds. instead are beautiful organisms with uptake of a photoautotrophic bac- fascinating natural history, diverse Seaweeds are a macroscopic subset terium (known as a primary endo- economic uses, and essential of marine algae (as opposed to the symbiotic event), or through the ecological roles. microscopic subset known as phyto- uptake of a heterotroph that had plankton). The west coast of British Seaweeds are a subset of a larger previously taken up a photoauto- Columbia has a diverse flora and group known as the algae. When trophic bacterium (a secondary arguably is home to the widest most people think of algae, they endosymbiotic event). A current hot variety of kelp (Order Laminariales) picture a green scum on the side of a topic in algal phylogenetics is in the world. pond or fish tank, but in reality algae determining if one or two primary 4 • menziesia The seaweeds are split into three Cladophora is a genus represented major groups, originally delineated by up to eight species in the Pacific by their pigment complement (and Northwest. Cladophora is hence color): the green algae superficially similar to Acrosiphonia (Division Chlorophyta), the brown but is usually shorter and lacks algae (Class Phaeophyceae, hooked branches. Patches of Division Ochrophyta), and the red Cladophora look instead like tufts of algae (Division Rhodophyta). I will moss on exposed rocks or spreadout refer to them henceforth as the filaments in tidepools. greens, browns and reds. Codium is locally represented by Codium setchellii three species, but only two are Green seaweeds Ulva is represented by eleven species common: C. setchellii and C. fragile. The greens are often a brilliant in British Columbia. Traditionally, The cells of Codium are grassy green, although a few such Ulva was recognized as a thin ‘coenocytic,’ meaning that they lack as Codium setchellii are so dark that distromatic (two-cell layer) green cross-walls in their cells. As a result, they appear almost black. The blade, which is fast growing and a an individual of C. fragile meas- bright green stems from a lack of weedy. You may confuse Ulva with uring up to 25 cm can be composed accessory pigments to mask the numerous other less-common green of a single multi-nucleate cell! chlorophyll a pigments used in blades, such as Ulvaria, photosynthesis. There are many Economically, kelps and rockweeds Monostroma, or Kornmannia. These are harvested and used in their raw freshwater green algae, but some three genera are monostromatic (one- classes of greens are almost form for food products, cosmetic cell layer) blades. Recent molecular and luxury spa items, and fertilizers. exclusively marine (e.g. evidence (Hayden et al. 2003) Ulvophyceae, which contains the In addition, through processing, their demonstrated that Ulva also cell wall components (alginic acids genera Ulva and Acrosiphonia). encompasses the genus previously Green seaweeds come in a wide and other polysaccharides) can be called Enteromorpha. Traditionally, it removed and used as emulsifiers, variety of morphologies, ranging was separated from Ulva because of from unicells and filaments to anticoagulants, and in the production its tubular growth form. As a result, of textiles and rubbers. blades and fleshy forms. species previously known as In general, the greens are Enteromorpha are now known as Ecologically, kelps and rockweeds encountered in the intertidal zone. Ulva, (e.g. Enteromorpha intestinalis are major habitat providers and The diversity of greens in the = Ulva intestinalis). nursery environments for fish, Pacific Northwest includes 117 taxa invertebrates, and for other algae. Acrosiphonia is a branched Their extensive biomass provides a in 51 genera (Gabrielson et al. filamentous green. The locally 2000). Common genera of green large amount of primary produc- abundant species Acrosiphonia tivity, carbon and oxygen to near- algae in British Columbia include: coalita grows in clumps resembling Ulva (including Enteromorpha), shore food webs. Further, nearshore green dreadlocks due to the presence kelp beds protect shorelines from Acrosiphonia, Cladophora, of tiny hooked branches. Codium, and Prasiola. erosion by decreasing the impacts of Consequently, its common name is water motion. “Witches Hair.” Interestingly, for part of The fucoids are represented in its life history, British Columbia by four genera: Acrosiphonia is endo- Fucus, Sargassum, Cystoseira, and phytic inside certain red Pelvetiopsis. Fucus is likely the algal species (Sussmann most conspicuous seaweed in British & DeWreede 2001), Columbia, represented by two such as Mazzaella species: Fucus distichus subsp. splendens and the evanescens (also known as Fucus ‘Petrocelis’ phase of gardneri) and Fucus spiralis. Mastocarpus (see the Sargassum is represented by one Ulva sp. section about red introduced species, S. muticum, seaweeds below). which is suspected of entering autumn 2004 • 5 British Columbia prior to 1940 as a sulfuric acid (pH approximates 2; byproduct of oyster spat importation the same as your stomach!) when from Japan (Scagel 1956). To keep disturbed or exposed to air for too oyster spat moist and cool during long. You may see it digesting transport, S. muticum was used as itself after being swept ashore after wrap, and presumably was dumped a storm. If collecting, make sure into British Columbian waters. this one goes into its own bag with Cystoseira is a less common alga that plenty of seawater. resembles Sargassum, and Red algae are economically Pelvetiopsis limitata, which looks important. Directly or indirectly much like juvenile Fucus but lacks a (through extraction), red algae are midrib, is common in the upper part of daily life for many North intertidal zone of wave-exposed Americans as food, for compounds British Columbian shores. made with their cell wall compon- The diversity of kelp in British ents, and for their potential as Columbia is nearly unparalleled. Over sources of natural chemicals. 30 species of these beautiful brown Food: Many red algae are eaten.

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