Lobophora is a genus of thalloid brown seaweed of the Phylum Ochrophyta; Class Phaeophyceae.
Taxonomy and nomenclature Source:
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:
Lobophora abaculusa C.W.Vieira, Payri & De Clerck Lobophora abscondita C.W.Vieira, Payri & De Clerck Lobophora adpressa O.Camacho & C.Fernández-García Lobophora africana C.W.Vieira & M.Zubia Lobophora agardhii Payri & C.W.Vieira Lobophora antsirananaensis Viera & Rasoamanendrika Lobophora asiatica Z.Sun, Ji.Tanaka & H.Kawai Lobophora astrolabeae C.W.Vieira & Payri Lobophora bandeirae C.W.Vieira, DeClerk & F.Leliaert Lobophora boudeuseae C.W.Vieira & Payri Lobophora boussoleae C.W.Vieira & Payri Lobophora brooksii D.L.Ballantine & J.N.Norris Lobophora caboverdeana C.W.Vieira & C.H.Almada Lobophora canariensis (Sauvageau) C.W.Vieira, De Clerck & Payri Lobophora ceylanica (Harvey ex E.S.Barton) C.W.Vieira, De Clerck & Payri Lobophora challengeriae C.W.Vieira Lobophora colombiana O.Comacho & Fredericq Lobophora coquilleae C.W.Vieira Lobophora crispata O.Camacho & Fredericq Lobophora dagamae C.W.Viera Lobophora delicata Camacho & Fredericq Lobophora dichotoma (R.H.Simons) P.C.Silva Lobophora dickiei Payri & C.W.Vieira Lobophora dimorpha C.W.Vieira, Payri & De Clerck Lobophora dispersa Camacho, Freshwater & Fredericq Lobophora endeavouriae C.W.Vieira Lobophora erythraea C.W.Vieira Lobophora esperanceae C.W.Vieira Lobophora etoileae C.W.Vieira Lobophora evanii C.W.Vieira & Rasoamanendrika Lobophora flabellata C.W.Vieira, De Clerck, R.J.Anderson & J.J.Bolton Lobophora garyi C.W.Vieira & Rasoamanendrika Lobophora gibbera C.W.Vieira, Payri & De Clerck Lobophora gloriosa C.W.Vieira & M.Zubia Lobophora hederacea C.W.Vieira, Payri & De Clerck Lobophora henae C.W.Vieira & Rasoamanendrika Lobophora indica V.Krishnamurthy & M.Baluswami Lobophora variegata var. indica Umamaheswara Rao Lobophora isselii (Piccone & Grunow) C.W.Vieira, De Clerck & Payri Lobophora kimiae C.W.Vieira & Rasoamanendrika Lobophora lamourouxii Payri & C.W.Vieira Lobophora lessepsiana C.W.Vieira Lobophora lubaoreniana Luan Rixiao & Ding Lanping Lobophora madagascariensis C.W.Vieira & Rasoamanendrika Lobophora maldivensis C.W.Vieira & C.Payri Lobophora minima V.Krishnamurthy & M.Baluswami Lobophora variegata var. minima Umamaheswara Rao Lobophora monticola C.W.Vieira, Payri & De Clerck Lobophora nigrescens J.Agardh Lobophora novae C.W.Vieira & M.Zubia Lobophora obscura (Dickie) C.W.Vieira, De Clerck & Payri Lobophora pachyventera Z.Sun, P.-E.Lim, Ji.Tanaka & H.Kawai Lobophora pacifica (Setchell) C.W.Vieira, De Clerck & Payri Lobophora panamensis O.Camacho, C.Fernández-García & Fredericq Lobophora papenfussii (W.R.Taylor) Farghaly Lobophora petila C.W.Vieira, Payri & De Clerck Lobophora providenceae C.W.Vieira Lobophora rechercheae C.W.Vieira Lobophora richardii C.W.Vieira & Payri Lobophora rickeri Kraft Lobophora rosacea C.W.Vieira, Payri & De Clerck Lobophora schneideri C.W.Vieira Lobophora setchellii C.W.Vieira & Payri Lobophora soaresii CW.Vieira & F.A.Rasoamanendrika Lobophora sonderi C.W.Vieira, De Clerck & Payri Lobophora tortugensis O.Camancho & Fredericq Lobophora tsengii D.Tien & Z.Sun Lobophora undulata C.W.Vieira, Payri & De Clerck Lobophora variegata (J.V.Lamouroux) Womersley ex E.C.Oliveira Lobophora zmaragdina C.W.Vieira & C.Payri
General morphological characteristics Sources:
Thalli 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. 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.
Cellular structure (internal morphology) 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.
Reproductive structures 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.
Life history The life history of Lobophora is currently unknown. But it may have similar stages with other members from Dictyotaceae Family.
Distribution and habitat 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.
Ecology and impacts 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.
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.
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.
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.
Economic importance/ natural products 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.
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. 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 sulfoquinovosyl diacylglycerol (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.
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