Ice-ice is a disease condition of seaweed. Ice-ice is caused when changes in salinity, ocean temperature and light intensity cause stress to seaweeds, making them produce a "moist organic substance" that attracts bacteria in the water and induces the characteristic "whitening" and hardening of the seaweed's tissues. [1] Bacteria involved include those in the Vibrio-Aeromonas and Cytophaga-Flavobacteria complexes. [2] The bacteria lyse epidermal cells and chloroplasts, turning the seaweed tissue white. [2] The disease is known from seaweeds including Kappaphycus alvarezii and Eucheuma denticulatum , economically important sources of carrageenan. [2] [3] In countries where seaweed is harvested as a crop, ice-ice can wreak havoc on yields. Zamboanga, Philippines, had an outbreak of ice-ice in 2004, [1] and Bali, Indonesia, experienced an outbreak in 2009. [4] A rise in surface sea temperatures of 2–3 degrees Celsius can trigger ice-ice outbreaks. [4]
Analysis has been performed to determine the pathogens affecting the Gracilaria verrucosa and Kappaphycus alvarezii seaweeds. Morphologic and phenotypic characteristics (16s RNA analysis) showed that the isolates from diseased Gracilaria belong to various genera: Vibrio, Chromobacterium, Flavobacterium, Pseudomonas , and Achromobacter . [5] They belong for the most part to the group of Gammaproteobacteria, already well known from disease-related study on seaweeds. For the seaweeds K. alvarezii a leading candidate bacterium has been identified: Stenotrophomonas maltophilia . [6] In most cases it seems these microorganisms are opportunistic pathogens. Some treatments have been investigated to cure these ice-ice infections, the green algae Caulerpa racemosa seems to inhibit the action of the most part of these pathogens. [5]
The disease seems to affect the formation of micropropagule of the algae. The protoplasm content is higher in a healthy micropropagule than in the infected ones. Protoplasm indicates occurrence of severe chronic infections of the micropropagules (algae disease are characterized by reduced number of cell protoplasm [7] ).
Agar, or agar-agar, is a jelly-like substance consisting of polysaccharides obtained from the cell walls of some species of red algae, primarily from "ogonori" (Gracilaria) and "tengusa" (Gelidiaceae). As found in nature, agar is a mixture of two components, the linear polysaccharide agarose and a heterogeneous mixture of smaller molecules called agaropectin. It forms the supporting structure in the cell walls of certain species of algae and is released on boiling. These algae are known as agarophytes, belonging to the Rhodophyta phylum. The processing of food-grade agar removes the agaropectin, and the commercial product is essentially pure agarose.
Chondrus crispus—commonly called Irish moss or carrageenan moss —is a species of red algae which grows abundantly along the rocky parts of the Atlantic coasts of Europe and North America. In its fresh condition this protist is soft and cartilaginous, varying in color from a greenish-yellow, through red, to a dark purple or purplish-brown. The principal constituent is a mucilaginous body, made of the polysaccharide carrageenan, which constitutes 55% of its dry weight. The organism also consists of nearly 10% dry weight protein and about 15% dry weight mineral matter, and is rich in iodine and sulfur. When softened in water it has a sea-like odour. Because of the abundant cell wall polysaccharides, it will form a jelly when boiled, containing from 20 to 100 times its weight of water.
Carrageenans or carrageenins are a family of natural linear sulfated polysaccharides that are extracted from red edible seaweeds. Carrageenans are widely used in the food industry, for their gelling, thickening, and stabilizing properties. Their main application is in dairy and meat products, due to their strong binding to food proteins. In recent years, carrageenans have emerged as a promising candidate in tissue engineering and regenerative medicine applications as they resemble native glycosaminoglycans (GAGs). They have been mainly used for tissue engineering, wound coverage, and drug delivery.
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.
Algaculture is a form of aquaculture involving the farming of species of algae.
Monostroma is a genus of marine green algae (seaweed) in the family Monostromataceae. As the name suggests, algae of this genus are monostromatic. Monostroma kuroshiense, an algae of this genus, is commercially cultivated in East Asia and South America for the edible product "hitoegusa-nori" or "hirohano-hitoegusa nori", popular sushi wraps. Monostroma oligosaccharides with degree of polymerization 6 prepared by agarase digestion from Monostroma nitidum polysaccharides have been shown to be an effective prophylactic agent during in vitro and in vivo tests against Japanese encephalitis viral infection. The sulfated oligosaccharides from Monostroma seem to be promising candidates for further development as antiviral agents. The genus Monostroma is the most widely cultivated genus among green seaweeds.
Turbinaria is a genus of brown algae (Phaeophyceae) found primarily in tropical marine waters. It generally grows on rocky substrates. In tropical Turbinaria species that are often preferentially consumed by herbivorous fishes and echinoids, there is a relatively low level of phenolics and tannins.
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.
Limu, otherwise known as rimu, remu or ʻimu is a general Polynesian term for edible plants living underwater, such as seaweed, or plants living near water, like algae. In Hawaii, there are approximately one hundred names for kinds of limu, sixty of which can be matched with scientific names. Hundreds of species of marine algae were once found in Hawaii. Many limu are edible, and used in the cuisine throughout most of Polynesia.
Caulerpa lentillifera is a species of ulvophyte green algae from coastal regions in the Asia-Pacific. This seaweed is one of the favored species of edible Caulerpa due to its soft and succulent texture. It is traditionally eaten in the cuisines of Southeast Asia, Oceania, and East Asia. It was first commercially cultivated in the Philippines in the 1950s, followed by Japan in 1968. Both countries remain the top consumers of C. lentillifera. Its cultivation has since spread to other countries, including Vietnam, Taiwan, and China. C. lentillifera, along with C. racemosa, are also known as sea grapes or green caviar in English.
Gulaman, in Filipino cuisine, is a bar, or powdered form, of dried agar or carrageenan used to make jelly-like desserts. In common usage, it also usually refers to the refreshment sago't gulaman, sometimes referred to as samalamig, sold at roadside stalls and vendors.
Seaweed, or macroalgae, refers to thousands of species of macroscopic, multicellular, marine algae. The term includes some types of Rhodophyta (red), Phaeophyta (brown) and Chlorophyta (green) macroalgae. Seaweed species such as kelps provide essential nursery habitat for fisheries and other marine species and thus protect food sources; other species, such as planktonic algae, play a vital role in capturing carbon, producing at least 50% of Earth's oxygen.
Edible seaweed, or sea vegetables, are seaweeds that can be eaten and used for culinary purposes. They typically contain high amounts of fiber. They may belong to one of several groups of multicellular algae: the red algae, green algae, and brown algae. Seaweeds are also harvested or cultivated for the extraction of polysaccharides such as alginate, agar and carrageenan, gelatinous substances collectively known as hydrocolloids or phycocolloids. Hydrocolloids have attained commercial significance, especially in food production as food additives. The food industry exploits the gelling, water-retention, emulsifying and other physical properties of these hydrocolloids.
Seaweed farming or kelp farming is the practice of cultivating and harvesting seaweed. In its simplest form farmers gather from natural beds, while at the other extreme farmers fully control the crop's life cycle.
Kappaphycus is a genus of red algae. Species are distributed in the waters of East Africa, Indonesia, Malaysia, Hainan Island, the Philippines, and Micronesia.
Eucheuma, commonly known as sea moss or gusô, is a rhodophyte seaweed that may vary in color. Eucheuma species are used in the production of carrageenan, an ingredient for cosmetics, food processing, and industrial manufacturing, as well as a food source for people in the Philippines, Caribbean and parts of Indonesia and Malaysia. Eucheuma cottonii – which grows in the Caribbean and cultivated in the Philippines – is the particular species known as gusô. Other species include Betaphycus gelatinae, Eucheuma denticulatum, and several species of the genus Kappaphycus, including K. alvarezii. Since the mid-1970s, Kappaphycus and Eucheuma have been a major source for the expansion of the carrageenan industry.
Gavino Trono Jr. is a Filipino marine biologist dubbed as the "Father of Kappaphycus farming". He was conferred the rank of National Scientist of the Philippines for contributions to the study of tropical marine phycology, focusing on seaweed biodiversity. He is currently a professor emeritus of the University of the Philippines Marine Science Institute.
Hypnea is a genus of red algae, and a well known carrageenophyte.
Seaweed fertiliser is organic fertilizer made from seaweed that is used in agriculture to increase soil fertility and plant growth. The use of seaweed fertilizer dates back to antiquity and has a broad array of benefits for soils. Seaweed fertilizer can be applied in a number of different forms, including refined liquid extracts and dried, pulverized organic material. Through its composition of various bioactive molecules, seaweed functions as a strong soil conditioner, bio-remediator, and biological pest control, with each seaweed phylum offering various benefits to soil and crop health. These benefits can include increased tolerance to abiotic stressors, improved soil texture and water retention, and reduced occurrence of diseases.