Botanical Diversity 1: Algae

What are the general features of algae?

multicellular eukaryotes, complete body is thallus, leaf-like structures are blades, mm-m in size, stem is called stipe, some have bladders to float, part that looks like roots is a holdfast

What are some ecological seaweed adaptations?

pnematocyst, strong holdfasts, low surface/volume ratio, adaptations to low light, different life cycle traits, calcium for herbivory resistance

What are the applications of marine algae?

human and animal nutrition, high value molecules, energy products, bio-fertilizers, cosmetics, wastewater treatment, CO2 mititgation

Sea vegetable examples

Nori (Porphyra spp.), Kombu (Laminaria spp.), Wakame (Undaria spp.), Sea lettuce (Ulva spp.)

Cyanobacteria (Cyanophyta)

evolved 2.5bya, rise in atmospheric oxygen, over 6000 sp., unicellular or colonial, chlorophyll a and phycobilins, can live in extreme environments

What are the main groups of cyanobacteria?

Prochloraceae, Oscillatoriales, Nostocales, Spirulinales

General characteristics of Chlorophyta (green algae)

over 7000 sp, 90% freshwater, symbiotic associations, cells walls composed of cellulose, contains chlorophyll a and b, ancestors to all plants, phycobilins are absent

Chlorophyceae

green algae, mostly freshwater, unicells or colonial, flagellated or non-flagellated, some are terrestrial, asexual and sexual reproduction, some have eyespot to sense light direction for phototaxis

Ulvophyceae

green algae, mainly marine, 2800 sp., flagellated cells, 15 orders, multinucleated septated cells, membranous thalli, siphonous or coenocytic cells

Cladophora spp.

Ulvophyceae, dense clumps, dark green thallus, rigid texture, lower intertidal/subtidal, marine and freshwater

Codium spp.

Ulvophyceae, spongy texture with tubular thallus, main branches arising from a small basal disc, dichotomously branched, has utricle that stores nutrients and help float, coenocytic

coenocytic

no cell walls or speta, multinucleate cytoplasm

Ulva spp.

Ulvophyceae, flat and leafy thalli, thin and membranous, coenocytic, mainly marine, cryptic diversity

Caulerpa spp.

Ulvophyceae, coenocytic, rapid growth with invasive behaviour, has fronds, stolons, and rhizoids

General characteristics of Rhodophyta (red algae)

97% marine, about 7000 species, chromosome range from 2-100, evolved 900mya, contains chlorophyll a, d, and phycobilins, lack of flagella, cell wall composed of phycocolloids agar and carrageenan

Bangiales

Bangiophyceae, red algae, pit plugs rare, biphasic life history, one stellate chloroplast per cell, uninucleate

Florideophycidae

6199 sp., 90% of red algae species, multicellular, thallis are uniaxial or multiaxial, no flagella, marine and freshwater, many discoid chloroplasts, primary and secondary pit plugs, triphasic life history

Gracilariales

Florideophyceae, dark brown to purple-red colour, elongated with branched fronds, hard to identify at species level, overharvested, invasive potential

Lomentaria articulata

Florideophyceae, bright red to brown fronds, regular segments that look like a strong of beads, oval or cylindrical, soft and gelatinous branches that are hollow, slippery texture

Chondrus crispus

Florideophyceae, flat and fan-like, reddish purple sometimes green, north atlantic ocean, overharvesting concerns

Asparagopsis armata

Florideophyceae, feathery, reddish-pink, harpoon-like structures anchoring, invasive nature

Palmaria palmata

Pamariales, red and leathery fronds, North Atlantic, economic importance

Coralline algae

marine, multiaxial, calcified cells walls, reproductive structures within, conceptacles, very slow growth, pale pink, important ecosystems

General characteristics of Phaeophyta (brown algae)

2000 sp., all multicellular and mostly marine, contains chlorophyll a, c, and fucoxanthin, meristem is bas of blades, complex internal structure, higher diversity in colder oceans

Fucus spp.

Fucales, branched flat frond with distinct midrib, brown, diplontic life history, fertility specific to species

Ascophyllum nodosum

Fucales, brown to black, long and leathery branched fronds, single air bladders, North Atlantic, peak biomass in summer, natural fertilizer, animal feeds, receptacles

Colpomenia peregrina

Ectocarpales, native to Pacific Ocean, forms spherical, hollow, and bladder-like thalli, yellow-brown, gelatinous texture

Padina pavonica

Dictyotales, fan-shaped and calcified fronds, light brown to golden, white concentric bands

Anatomical features of kelp

no leaves, no stems, no true organs, large and complex thalli, has pneumatocycts, long hollow stem, life-like blades, thalli do not dry up, complex life cycle

What are the main species of kelp in the world?

Giant kelp, Bull kelp, Sugar kelp, Kombu, Winged kelp, Ecklonia radiata, Laminaria digitata

What are the main species of kelp species in Ireland?

Laminaria hyperborea, Laminaria digitata, Saccharina latissima, Saccorhiza polyschides, Alaria esculenta

Laminaria hyperborea

large blade that is split, smooth texture, only exposed at extreme low tides, stipe is inflexible, frond is a light to dark brown colour, most common in Ireland

Laminaria digitata

large holdfast, difitate or finger-like blades (5-20), plastic-like texture, exposed at low-tide, stipe is long and flexible, golden to brown, found in North Atlantic costal waters

Saccharina latissima

large kelp with short stipe, single and elongated frilly-edged frond, yellow-brown, stipe is flexible, sweet/sugary coating

Saccorhiza polyschides

annual brown kelp, finger-like blade, stipe is large and flat, yellow-brown colour and covered in smooth short spikes

Alaria esculenta

present in wave-exposed rocky shores, nutrient rich and edible, base of blade near the holdfast, perennial that lives 4-5 years in Ireland