| Lobophora | |
|---|---|
 | |
| Lobophora sp. from Vietnam | |
Scientific classification  | |
| Domain: | Eukaryota |
| Clade: | Diaphoretickes |
| Clade: | SAR |
| Clade: | Stramenopiles |
| Phylum: | Gyrista |
| Subphylum: | Ochrophytina |
| Class: | Phaeophyceae |
| Order: | Dictyotales |
| Family: | Dictyotaceae |
| Genus: | Lobophora J. Agardh, 1817 [1] |
| Species | |
See text | |
| Synonyms | |
Gymnosorus J.Agardh, 1894Pocockiella Papenfuss, 1943 Contents | |
Lobophora is a genus of thalloid brown seaweed of the Phylum Ochrophyta; Class Phaeophyceae.
The genus Lobophora belongs to the Order Dictyotales; Family Dictyotaceae, and additionally to the Tribe of Zonarieae.
Currently, there are a total of seventy-one (71) taxonomically accepted species belonging to this genus:
Thalli are foliose or fan-shaped and possess different growth morphologies: decumbent, procumbent, crustose, conk-like (shelf-like), fasciculate, and stipitate, depending on species and habitat. [5] Thalli arises from matted rhizoidal holdfast with branched fronds displaying broadly flabellate to irregularly branched forms. Algal hairs are arranged in concentric lines or scattered turf. Size can reach up to 20 cm long. Coloration are commonly light brown to dark-brown.
Thalli is 7-12 cells thick, with the outermost layers composed of cortical cells overlying innermost layer of larger medullary cells. Medullary cells usually exhibit uniform sized except for the larger central cells. Discoid chloroplasts are found at the cortical layers.
The sporangial sori of Lobophora are either scattered or in concentric bands found at the surface of the thallus They are characteristically indusiated but without paraphyses. Sporangia without a basal stalk cell produce up to eight (8) spores. Oogonia are found in sori on both side of the frond surfaces.
The life history of Lobophora is currently unknown. But it may have similar stages with other members from Dictyotaceae Family.
The genus Lobophora are found throughout the pantropical and even temperate regions. They are found growing on solid substrate (rocks) at intertidal (some are wave-exposed) to subtidal areas of rocky-reef habitats. [6]
Seaweeds, such as Lobophora are naturally occurring in coral reefs. Under normal conditions, the interactions between Genus Lobophora and corals pose no threat and can co-exist in an ecosystem. This is attributed to the control of algal populations by coral chemical defense and herbivory. However, when these contributing control factors become unbalanced, Lobophora and other associated seaweeds become opportunistic in taking over reefs (i.e. increasing spatial cover) and by density-dependent negative feedback, prevents corals from settling on substrate. However, as mentioned earlier, Lobophora a species-rich group and certain individuals have different growth patterns, interactions, and habitat-preferences. Understanding and determining its taxa is utmost important. [7]
Because of capacity of seaweeds, such as Lobophora to occupy large spatial habitats, particularly in degraded reefs, they can have an impact on the chances of coral larvae to settle on a substrate. Lobophora can inhibit coral settlement, however, its effect can decrease later on life history stages because they have no effect on growing coral nubbins. Chances of coral larvae to settle in degraded reef followed by disturbance may be challenging. [8]
As mentioned, Lobophora are highly preferred by herbivores particularly fish. Growth morphological defenses have been developed by this group to become unpalatable to its herbivores. Encrust (crustose) forming Lobophora, such as L. variegata are dominant in areas with high concentration of herbivorous fish and sea urchin, compare to other seaweeds having a foliose or decumbent morphologies. This indicates that high herbivory activities in the area may influence the defense mechanisms of seaweeds, in the case of Lobophora, its specific growth morphologies. [9] [10]
Varying metabolomic concentration differs from Lobophora species when exposed to changing natural habitats and substrates. Fatty acids derivatives and polyolefins were identified as chemomarkers of these changing conditions. This indicates possible chemical plasticity of metabolites in the genus. Different Lobophora may composed varying natural products depending on bioregion. [11]
Similar to other seaweeds, Genus Lobophora has a variety of natural products. There are: Minerals: cadmium (Cd), copper (Cu), mercury (Hg), iodine (I), nickel (Ni), lead (Pb), and zinc (Zn); Pigments: carotene, chlorophyll a, chlorophyll c, fucoxanthin; Polysaccharides/ simple sugars: alginic acid, laminarin; Sugar alcohol: mannitol. [12]
In addition Lobophora may have contributions in medicinal application. Sulfated polysaccharides, fucans, from algae Lobophora variegata were shown to have anti-inflammatory activity in acute zymosan-induced arthritis in laboratory rats. It resulted in treatments by reducing cell infiltration in the synovial membrane with a decrease in TNF-α. It was also shown that heterofucans are strong antioxidants. [13] Another is Lobophora has antiprotozoal activity against parasitic protozoans such as Giardia intestinalis, Entamoeba histolytica and Trichomonas vaginalis. Extract from L. variegata shows promising result in the treatments of protozoan infection. The chloroform fraction of the extract contained a major sulfoquinovosyldiacylglycerol (SQDG), identified as 1-O-palmitoyl-2-O-myristoyl-3-O-(6´´´-sulfo-a-D-quinovopyranosyl)-glycerol, together with small amounts of 1,2-di-O-palmitoyl-3-O-(6´´´-sulfo-a-D-quinovopyranosyl)-glycerol, and a new compound identified as 1-O-palmitoyl-2-O-oleoyl-3-O-(6´´´-sulfo-a-D-quinovopyranosyl)-glycerol were identified having strong antiprotozoal attributes. [14]
The Ulvophyceae or ulvophytes are a class of green algae, distinguished mainly on the basis of ultrastructural morphology, life cycle and molecular phylogenetic data. The sea lettuce, Ulva, belongs here. Other well-known members include Caulerpa, Codium, Acetabularia, Cladophora, Trentepohlia and Monostroma.
Coralline algae are red algae in the order Corallinales. They are characterized by a thallus that is hard because of calcareous deposits contained within the cell walls. The colors of these algae are most typically pink, or some other shade of red, but some species can be purple, yellow, blue, white, or gray-green. Coralline algae play an important role in the ecology of coral reefs. Sea urchins, parrot fish, and limpets and chitons feed on coralline algae. In the temperate Mediterranean Sea, coralline algae are the main builders of a typical algal reef, the Coralligène ("coralligenous"). Many are typically encrusting and rock-like, found in marine waters all over the world. Only one species lives in freshwater. Unattached specimens may form relatively smooth compact balls to warty or fruticose thalli.
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.
Halimeda is a genus of green macroalgae. The algal body (thallus) is composed of calcified green segments. Calcium carbonate is deposited in its tissues, making it inedible to most herbivores. However one species, Halimeda tuna, was described as pleasant to eat with oil, vinegar, and salt.
Gracilaria is a genus of red algae (Rhodophyta) notable for its economic importance as an agarophyte, as well as its use as a food for humans and various species of shellfish. Various species in the genus are cultivated among Asia, South America, Africa and Oceania.
Codium is a genus of edible green macroalgae under the order Bryopsidales. The genus name is derived from a Greek word that pertains to the soft texture of its thallus. One of the foremost experts on Codium taxonomy was Paul Claude Silva at the University of California, Berkeley. P.C. Silva was able to describe 36 species for the genus and in honor of his work on Codium, the species C. silvae was named after the late professor.
Turbinaria ornata is a tropical brown algae of the order Fucales native to coral reef ecosystems of the South Pacific. Turbinaria ornata is more commonly referred to as crowded sea bells in the US and crowned sea bells worldwide. It can quickly colonize these ecosystems due in part to its method of dispersing by detaching older and more buoyant fronds that travel on surface currents, sometimes in large rafts of many individual thalli, or fronds. Some scientists are investigating whether the increase in density of seaweeds, and a decrease in living coral density, on coral reef ecosystems indicates a change in the health of the reef, focusing studies on this particular species of brown alga.
Dictyotales is a large order in the brown algae. Members of this order generally prefer warmer waters than other brown algae. One genus in this order is calcareous, Padina, the only calcareous member of this phylum.
Bryopsis is a genus of marine green algae in the family Bryopsidaceae. It is frequently a pest in aquariums, where it is commonly referred to as hair algae.
Valonia is a genus of green algae in the Valoniaceae family. The genus Ventricaria is now regarded as a synonym of Valonia.
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.
Halymenia a genus of a macroscopic red algae that grows in oceans worldwide.
Hydroclathrus is a genus of perforate brown alga, of the phylum Ochrophyta and the class Phaeophyceae.
Lobophora variegata is a species of small thalloid brown alga which grows intertidally or in shallow water in tropical and warm temperate seas. It has three basic forms, being sometimes ruffled, sometimes reclining and sometimes encrusting, and each form is typically found in a different habitat. This seaweed occurs worldwide. It is the type species of the genus Lobophora, the type locality being the Antilles in the West Indies.
Hypnea is a genus of red algae, and a well known carrageenophyte.
Dictyota is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals (diterpenes) which have potential medicinal value. As at the end of 2017, some 237 different diterpenes had been identified from across the genus.
Padina is a genus of brown macroalgae in the family Dictyotaceae.
Titanophora is a genus of seaweeds belonging to family Schizymeniaceae of the order Nemastomatales.
Halymeniales is an order of red algae belonging to the class Florideophyceae and the subclass Rhodymeniophycidae.