Brown algae are a large group of multicellular algae comprising the class Phaeophyceae. They include many seaweeds located in colder waters of the Northern Hemisphere. Brown algae are the major seaweeds of the temperate and polar regions. Many brown algae, such as members of the order Fucales, commonly grow along rocky seashores. Most brown algae live in marine environments, where they play an important role both as food and as a potential habitat. For instance, Macrocystis, a kelp of the order Laminariales, may reach 60 m (200 ft) in length and forms prominent underwater kelp forests that contain a high level of biodiversity. Another example is Sargassum, which creates unique floating mats of seaweed in the tropical waters of the Sargasso Sea that serve as the habitats for many species. Some members of the class, such as kelps, are used by humans as food.
Nereocystis is a monotypic genus of subtidal kelp containing the species Nereocystis luetkeana. Some English names include edible kelp, bull kelp, bullwhip kelp, ribbon kelp, bladder wrack, and variations of these names. Due to the English name, bull kelp can be confused with southern bull kelps, which are found in the Southern Hemisphere. Nereocystis luetkeana forms thick beds on subtidal rocks, and is an important part of kelp forests.
Caulerpa taxifolia is a species of green seaweed, an alga of the genus Caulerpa, native to tropical waters of the Pacific Ocean, Indian Ocean, and Caribbean Sea. The species name taxifolia arises from the resemblance of its leaf-like fronds to those of the yew (Taxus).
Caulerpa is a genus of seaweeds in the family Caulerpaceae. They are unusual because they consist of only one cell with many nuclei, making them among the biggest single cells in the world.
Palmaria palmata, also called dulse, dillisk or dilsk, red dulse, sea lettuce flakes, or creathnach, is a red alga (Rhodophyta) previously referred to as Rhodymenia palmata. It grows on the northern coasts of the Atlantic and Pacific Oceans. It is a well-known snack food. In Iceland, where it is known as söl, it has been an important source of dietary fiber throughout the centuries.
Mastocarpus stellatus, commonly known as carrageenan moss or false Irish moss, is a species in the Rhodophyceae division, a red algae seaweed division, and the Phyllophoracea family. M. stellatus is closely related to Irish Moss. It grows in the intertidal zone. It is most collected in North Atlantic regions such as Ireland and Scotland, together with Irish moss, dried, and sold for cooking and as the basis for a drink reputed to ward off colds and flu. Marine biologists have completed studies on the medicinal reputation of M. stellatus to discover the full potential of its pharmaceutical benefits. Additionally, marine biologists have conducted research on its potential to serve as an alternative to plastic. The application of M. stellatus in these different industries is correlated with the seaweed's adaptations which developed in response to the environmental stressors present around its location on the rocky intertidal.
Postelsia palmaeformis, also known as the sea palm or palm seaweed, is a species of kelp and classified within brown algae. It is the only known species in the genus Postelsia. The sea palm is found along the western coast of North America, on rocky shores with constant waves. It is one of the few algae that can survive and remain erect out of the water; in fact, it spends most of its life cycle exposed to the air. It is an annual, and edible, though harvesting of the alga is discouraged due to the species' sensitivity to overharvesting.
Polysiphonia is a genus of filamentous red algae with about 19 species on the coasts of the British Isles and about 200 species worldwide, including Crete in Greece, Antarctica and Greenland. Its members are known by a number of common names. It is in the order Ceramiales and family Rhodomelaceae.
Conceptacles are specialized cavities of marine and freshwater algae that contain the reproductive organs. They are situated in the receptacle and open by a small ostiole. Conceptacles are present in Corallinaceae, and Hildenbrandiales, as well as the brown Fucales. In the Fucales there is no haploid phase in the reproductive cycle and therefore no alternation of generations. The thallus is a sporophyte. The diploid plants produce male (antheridia) and female (oogonia) gametangia by meiosis. The gametes are released into the surrounding water; after fusion, the zygote settles and begins growth.
Gelidium is a genus of thalloid red algae comprising 134 species. Its members are known by a number of common names.
Kappaphycus alvarezii, the elkhorn sea moss, is a species of red algae. The elkhorn sea moss varies in size, weight, and age. It is a dark greenish-brown hue and can sometimes be deep purple. The moss is cylindrical in shape throughout the seaweed. Its diameter averages 1.526 mm when dried. Near the base of the seaweed, its average length is from 1 mm to 17 mm and 1 mm to 2 mm in diameter. Firm algae are around 2 m tall, with axes and branches around 1–2 cm in diameter. It used to be believed they reproduced through vegetative fermentation, but recent studies show that they reproduce sexually. They reproduce through vegetative propagation and reproduce sexually. Cross sections of the Elkhorn sea moss have a medulla composed of small thick-walled cells interspaced among large parenchyma cells. This moss is used for various types of foods that humans consume and can also be used to make a jelly-like dessert. This moss is a very good source of minerals and of high commercial interest. It is one of the most important commercial sources of carrageenans, a family of gel-forming, viscosifying polysaccharides. Farming methods affect the character of the carrageenan that can be extracted from the seaweed. It is very fast-growing, known to double its biomass in 15 days.
In algal anatomy, a pit connection is a hole in the septum between two algal cells, and is found only in multicellular red algae − specifically in the subphylum Eurhodophytina, except haploid Bangiales. They are often stoppered with proteinaceous "pit plugs". By contrast, many fungi contain septal pores − an unrelated phenomenon.
Red algae, or Rhodophyta, make up one of the oldest groups of eukaryotic algae. The Rhodophyta comprises one of the largest phyla of algae, containing over 7,000 recognized species amidst ongoing taxonomic revisions. The majority of species (6,793) are Florideophyceae, and mostly consist of multicellular, marine algae, including many notable seaweeds. Red algae are abundant in marine habitats. Approximately 5% of red algae species occur in freshwater environments, with greater concentrations in warmer areas. Except for two coastal cave dwelling species in the asexual class Cyanidiophyceae, no terrestrial species exist, which may be due to an evolutionary bottleneck in which the last common ancestor lost about 25% of its core genes and much of its evolutionary plasticity.
Hildenbrandia is a genus of thalloid red alga comprising about 26 species. The slow-growing, non-mineralized thalli take a crustose form. Hildenbrandia reproduces by means of conceptacles and produces tetraspores.
Ulva linza is a green alga in the family Ulvaceae that can be found in British Isles.
Christine Adair Maggs is a British phycologist. Formerly Executive Dean of the Faculty of Science & Technology at Bournemouth University, she was the first Chief Scientist of the Joint Nature Conservation Committee, retiring in 2022. She is now an independent non-executive Director of Ocean Harvest Technology https://oceanharvesttechnology.com/corporate-governance/board-of-directors/
Phyllophora crispa is a medium-sized fleshy, marine red alga. This alga forms dense mats of up to 15 cm thickness, which influence environmental factors, thus creating habitat for several associated organisms.
Padina sanctae-crucis is a species of brown macroalgae in the family Dictyotaceae. It is a tropical brown algae species native to the south pacific that belongs to the Padina genus. this alga includes sexual reproduction and spore-producing asexual reproduction which is moved with the tide until spores plants itself on a hard rocky substrate. Other habitats include rocks and shell fragments in the shallow sublittoral, seagrass meadows, mangrove roots and coral reefs on tidal flats.
Halymeniales is an order of red algae belonging to the class Florideophyceae and the subclass Rhodymeniophycidae.
Kathleen "Kay" Margaret Cole was a Canadian phycologist, known as one of the world's leading experts in the cytology of marine algae. In 1998 the Canadian Botanical Society awarded her the George Lawson Medal for lifetime achievement.
