Caulerpa Racemosa Var Research Articles

Seaweed flora of the St. Martin’s Reef, Bangladesh

St. Martin’s Reef (SMR) about 14 km west of the St. Martin’s Island, Teknaf, Cox’s Bazar, Bangladesh was not known during last over 50 years of seaweed researches. Recent six collections made with the assistance of Bangladesh Navy revealed 8 seaweeds species which are Pterocladiella maribagoensis Boo and Geraldo, Hypnea spinella (C. Agardh) Kützing, Peyssonnelia polymorpha (Zonars.) Schmitz, Jania pumila Lamx., Jania ungulata f. brevior (Yendo) Dawson (Rhodophyta); Caulerpa racemosa var. clavifera (Turner) Bosse, Bryopsis plumosa (Huds.) C. Ag. and Halimeda tuna (Lin.) Lamx. (Chlorophyta). Of these six seaweeds such as Pterocladiella maribagoensis Boo et Geraldino, Hypnea spinella (C. Agardh) Kützing, Jania pumila Lamx., Jania ungulata f. brevior (Yendo) Dawson, Bryopsis plumosa (Huds.) C. Ag. and Halimeda tuna (Lin.) Lamx have been newly recorded and described from the SMR in Bay of Bengal (Bangladesh territory). Presence of Peyssonnelia polymorpha and Bryopsis plumosa in the collections and physical and chemical water environments recorded indicated it as a true newly forming reef. The present illustrated account is however may be considered as base-line information on seaweed flora of the new SMR in the North-east Bangladesh coast. A total of six seaweeds have been newly recorded making the total seaweeds to 215 mostly from the SMI and nearby SMR. Bangladesh J. Plant Taxon. 30(1): 153-163, 2023 (June)

Potential of Ulva linza L. and Caulerpa racemosa var. uvifera seaweeds from Cox’s Bazar, Bangladesh as sea vegetable

The nutritional quality parameters of leafy Ulva linza L. collected from the west coast of the Naf river estuary, Teknaf and grape-like Caulerpa racemosa var. uvifera collected from St. Martin's Island, Cox's Bazar, Bangladesh, were studied. Total protein content in U. linza (22.05±1.73%) was found significantly (p<0.05) higher than C. racemosa var. uvifera (18.20±1.50%) but with low crude lipids in the former; total amino acid content was also higher in the former, both having nearly the same amount of essential and non-essential amino acids; vitamin C content (about 2.5 mg/100 g) was nearly identical but β -carotene content was higher in the later (9.04 mg/100 g dry wt.). Crude fiber in U. linza was low (4.21±0.43%) but high in C. racemosa var. uvifera (18.20±1.50%). Other micronutrients were also ascertained. The nutritional quality parameters determined suggested that the “sea-salad” and “sea- grapes” can be used as sea-vegetables and food supplements. Bangladesh J. Sci. Ind. Res.56(3), 223-230, 2021

Molecular Identification, Nutritional Profile and Heavy Metals Content of Edible Caulerpa from Binuangeun Coast, Banten

Two species of Caulerpa, locally known as “Pedesan” and “Latuh” have been traditionally consumed by coastal communities at Binuangeun, Banten. This study aimed to identify “Pedesan” and “Latuh” using the DNA barcoding method and to evaluate their nutrient and heavy metal contents. Fatty acids were determined by Gas Chromatography Flame Ionization Detector (GC FID), amino acids using Ultra Performance Liquid Chromatography (UPLC), and minerals using Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES). Based on the tufA gene sequences, the “Pedesan” was identified as Caulerpa racemosa var. macrophysa and “Latuh” as Caulerpa chemnitzia. Thirteen fatty acids were detected in C. racemosa var. macrophysa and twelve fatty acids in C. chemnitzia. Of the total fatty acid content, C. racemosa var. macrophysa contained 41.0% unsaturated fatty acids, dominated by linolenic acid and eicosapentaenoic acid. Meanwhile, C. chemnitzia contained 47.5%, dominated by oleic acid. Both seaweeds contained fatty acids with the w6/w3 ratio lower than 10, which could prevent heart disease risk based on World Health Organization (WHO) recommendation. The primary amino acids content in C. racemosa var. macrophysa were glutamic acid, alanine, serine and aspartic acid, while those in C. chemnitzia were glutamic acid, serine, aspartic acid, and glycine. The high content of glutamic acid in both samples indicated their potential use as food flavor enhancer. The Na/K ratio of C. racemosa var. macrophysa (40.31) and C. chemnitzia (27.48) were higher than those recommended by WHO. Heavy metals were not detected in either “Pedesan” nor “Latuh”, indicating that they are safe for consumption.

HPLC Detection and Antioxidant Capacity Determination of Brown, Red and Green Algal Pigments in Seaweed Extracts.

This study was carried out to determine the main pigments in some different selected seaweeds and to reveal their antioxidant potential regarding the ever-increasing demand for utilization of marine pigments in human health and nutrition. The individual amounts of algal pigments were found by reverse phase high-performance liquid chromatography (HPLC) and their total antioxidant capacities (TAC) by two spectrophotometric TAC assays, namely: CUPRAC (CUPric ion Reducing Antioxidant Capacity) and ABTS/TEAC (2,2'-azinobis [3-ethyl benzo thiazoline-6-sulfonate])/(trolox equivalent antioxidant capacity). These two tests gave the same rank order for TAC. The TAC of HPLC-quantified compounds accounted for a relatively much lower percentage of the observed CUPRAC capacities of seaweed extracts, namely ranging from 11 to 68% for brown, from 4 to 41% for red and from 3 to 100% for green species, i.e., some TAC originated from chromatographically unidentified compounds. Fucoxanthin, chlorophyll a, and pheophytin a compounds were major pigments in brown algae. The relative carotenoid contents in red marine algae were generally lower than those of chlorophylls. Overall total quantities were quite low compared with those of brown species. In general, chlorophyll a and chlorophyll b were chiefly present in green algae, but β-carotene, violaxanthin and siphonaxanthin were also detected substantially higher in some species of green algae such as Caulerpa racemosa var. cylindracea and Codium fragile.

Antioxidant and antibacterial activities and identification of bioactive compounds of various extracts of Caulerpa racemosa from Algerian coast

Objective: To evaluate the antibacterial and antioxidant activities and to identify the volatile bioactive compounds present in different crude extracts of the seaweed Caulerpa racemosa var. cylindracea. Methods: Caulerpa racemosa harvested from the intertidal zone of Mostaganem coast (N 35°54’37.94”, E 0°3’17.37”) was subjected to Soxhlet extraction using methanol, chloroform, and hexane solvents. Antioxidant properties were assessed by using 2,2’-diphenyl-1- picrylhydrazyl (DPPH), 2,2’-azino-bis(3-ethylbenzothiazoline- 6-sulfonic acid) (ABTS) and β-carotene bleaching assays. The antibacterial activity was evaluated on six standard bacterial strains using the agar disc diffusion method. The GC-MS analysis was performed using non-polar and polar capillary columns. Results: The chloroform extract of Caulerpa racemosa exhibited higher contents of polyphenols [(123.91±1.46) mg gallic acid equivalent/ g dry extract] and tannins [(59.28±5.43) mg catechin equivalent/ g dry extract] (P Conclusions: The preliminary identification of the volatile compounds reveals the presence of some new bioactive components not reported previously in Caulerpa racemosa from other geographical areas. Some of these compounds possess an interesting potential for pharmaceutical/nutraceutical applications.

The omnivorous triggerfish Melichthys niger is a functional herbivore on an isolated Atlantic oceanic island.

This study evaluated the functional role of the highly generalist omnivore Melichthys niger in the remote St. Peter and St Paul's Archipelago (SPSPA), Brazil, where grazing herbivorous fishes are very scarce. We analysed patterns of distribution from zero to 30 m deep during three time intervals during the day and sampled different aspects of their feeding behaviour, including diel feeding rate, feeding substrate and diet. The density of M. niger increased with depth (26-30 m) and decreased by the end of the day. Although M. niger did not present a typical herbivore diel feeding pattern, they targeted the epilithic algal matrix as their primary feeding substrate, ingesting predominantly algae and detritus. The characteristic Caulerpa racemosa var. peltata from SPSPA was ingested only as detached fronds. We suggest that in the isolated SPSPA, the single species M. niger may perform a unique role as a link between benthic primary production and higher levels. Further studies on the trophic ecology of omnivorous species are necessary to better understand their roles in a reef system, especially in impoverished areas where they are likely to play a crucial role.

Structural characterization and immunostimulatory activity of a novel polysaccharide from green alga Caulerpa racemosa var peltata

A novel water-soluble polysaccharide (named CRVP-1) was successfully obtained from Caulerpa racemosa var peltata by hot-water extraction, ethanol precipitation, and column chromatography. The structure of CRVP-1 was characterized by HPGPC, HPAEC-PAD, FT-IR, GC–MS and NMR. The structural analysis indicated that CRVP-1 possessed a sulfate content of 25.8%±0.7% and was a heteropolysaccharide with an average molecular weight of 29.68kDa, and composed of mannose, galactose, glucose, galacturonic acid, and glucuronic acid with rates of 92.1%, 2.9%, 1.8%, 1.7% and 1.2%, respectively, owning a backbone structure of (1→6)-linked α-D-Manp residues with (1→4)-linked α-D-Manp and (1→2)-linked α-D-Manp residues and side chain that was consisted of (1→4)-linked β-D-Galp residues. The immunostimulatory assay revealed that CRVP-1 had significant effects on the proliferation of macrophage, production of NO and secretion of cytokines (TNF-α, IL-1β and IL-6). These findings provide a scientific basis for further utilization of polysaccharides from C. racemosa var peltata.

Chemical composition and immunostimulatory properties of green alga Caulerpa racemosa var peltata

ABSTRACTThis work aimed to evaluate the nutritional composition and immunostimulatory activity of an edible green alga Caulerpa racemosa var peltata collected from South China Sea. The results indicated that this alga contained the total carbohydrates (71.67%, DW), crude protein (11.39%, DW), and crude lipid (1.03%, DW), and was rich in taurine (7.71 mg/100 g, DW), essential amino acids (40.07%), monounsaturated fatty acids (25.72%), and polyunsaturated fatty acids (26.33%). Moreover, water extraction of this alga (WEC) increased NO, ROS, TNF-α, and IL-6 in a dose-dependent manner in RAW264.7 macrophage cells. Furthermore, WEC contained the total sugar (34.19 ± 0.46 mg/g), total protein (6.76 ± 0.32 mg/g), total phenolic (1.93 ± 0.04 mg/g), and total flavonoid (4.80 ± 0.10 mg/g). In addition, the MSn analysis of WEC indicated that the presence of 19 compounds. Thus, these findings suggest that this alga may have a potential nutraceutical value.

Bioaccessibility of heavy metals in the seaweed Caulerpa racemosa var. corynephora: Human health risk from consumption

ABSTRACTThis study reports the total and bioaccessible concentrations of heavy metals (Mn, Fe, Cu, Zn, Cd and Pb) in the seaweed Caulerpa racemosa var. corynephora collected from local markets along the Andaman coast of Krabi Province, Thailand. Microwave-assisted acid digestion (EPA Method 3052) was used for sample preparation prior to total metal analysis. The in vitro Unified Bioaccessibility Method (UBM) was applied to assess the bioaccessibility of the metals in the seaweed samples. The total, gastric phase, and residual fraction concentration were determined by inductively coupled plasma-optical emission spectrometry (ICP-OES). The total amounts found in the seaweed samples, in ascending order were Cd < Pb < Cu < Zn < Mn < Fe with the mean concentrations of 0.89, 0.97, 17.4, 59.0, 63.4, and 450 mg/kg dry weight, respectively. High bioaccessibility percentages for Mn (71.8–85.3%) were observed alongside moderate bioaccessibility percentages for Cu (44.3–56.3%), Zn (37.7–47.4%), and Cd (41.8–46.7%), a low bioaccessibility percentage for Pb (22.3–32.0%), and a very low bioaccessibility percentage for Fe (11.5–16.5%). A quality control procedure was implemented which involved the analysis of a certified reference material (Seaweed NMIJ CRM 7405-a) for total metals and a mass-balance approach for the assessment of the in vitro bioaccessibility method.

In silico evaluation of bioactive peptides from the green algae Caulerpa

The genus Caulerpa consists of over than 100 members. This genus is famous because of its invasive members in the Mediterranean Sea. Although many eradication methods have been applied on these seaweeds, no validated method exists in the literature on these aliens. Research on the biotechnological utilization of these seaweeds are limited. This paper proposes an alternative in silico evaluation method for identifying possible utilization of these seaweeds. In the present study, bioactive peptides in the ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) of 28 Caulerpa species were investigated by using in silico tools. According to the results, RuBisCO in Caulerpa cylindracea, Caulerpa taxifolia, Caulerpa racemosa var. lamourouxii, and Caulerpa racemosa f. occidentalis showed the best potential for bioactive peptides. In conclusion, exotic alien Caulerpa genus members could be evaluated in the food industry as alternative sources of bioactive peptides instead of attempting eradication methods.

ALIEN MARINE SPECIES OF LIBYA: FIRST INVENTORY AND NEW RECORDS IN EL-KOUF NATIONAL PARK (CYRENAICA) AND THE NEIGHBOURING AREAS

The presence of marine alien species in El-Kouf National Park and the neighbouring areas was assessed using a compilation of available information and observations, a field survey conducted on October 2010 in the framework of the MedMPAnet project and results of further monitoring during June and September 2012. A total of 9 alien species were reported: the Rhodophyta Asparagopsis taxiformis (Delile) Trevisan de Saint-Léon, the Chlorophyta Caulerpa racemosa var. cylindracea (Sonder) Verlaque, Huisman &amp; Boudouresque, the crab Percnon gibbesi (H. Milne-Edwards, 1853) and the fishes Fistularia commersonii Rüppell, 1838, Siganus luridus (Rüppell, 1829), Siganus rivulatus Forsskål, 1775, Pempheris vanicolensis Cuvier, 1831, Lagocephalus sceleratus (Gmelin, 1789) and Sphyraena flavicauda Rüppell, 1838. Several of them were until now unknown for the National Park. The list of alien marine species of Libya is updated and discussed. Until now 63 marine aliens species were recorded along the Libyan coasts. These include 3 Foraminifera, 3 Ochrophyta, 5 Rhodophyta, 5 Chlorophyta, 1 Magnoliophyta, 11 Arthropoda, 13 Mollusca, 1 Echinodermata and 21 Chordata. Among these Non Indigenous Species, 43 are known as established along the Libyan coast including 8 invasive, 11 casual, 6 questionable, 3 cryptogenic and 1 unknown. An in-depth study of the marine organisms would substantially increase the number of alien species occurring in Libya. Monitoring of marine assemblages of MPAs is a valuable opportunity to go further into the knowledge of native and introduced species.

Do studies of functional groups give more insight to amphipod biodiversity?

Amphipod crustaceans are able to colonise different micro-habitats of coastal marine benthos due to a multiplicity of trophic and morpho-functional adaptations, and may be considered a key taxon in describing the structure of assemblages. Literature concerning amphipod feeding behaviour and way of life showed that studies on functional groups (FGs) started only in the 1980s. A short review about the state of the art of the knowledge is presented here. Aiming at investigating the functional role of amphipods and to ascertain to what extent their adaptations could be a response to different biotic and abiotic conditions, some examples of studies conducted in the Mediterranean Sea on various plant substrata (Posidonia oceanica, Cymodocea nodosa, Zostera marina, Caulerpa racemosa var. cylindracea), at different spatial and temporal scales, were given. Despite many doubts about some species, due to the lack of information and their opportunistic behaviour, the identified taxa were grouped in the main categories of suspension feeders, deposit feeders, carnivores, commensals, herbivores, plant detritus feeders, omnivores, and in the mixed categories of deposit-suspension feeders, deposit feeders-carnivores, herbivores-deposit feeders, according to the food ingested and their feeding strategies; and, according to their life-habits, in epifaunal free-living and domicolous, and infaunal free-burrowing and tube-building. FGs might be considered good descriptors of zonation patterns, mainly against gradients such as depth, where strong environmental factors play a role. FG composition was differentiated according to the structural complexity and the stability of the host plant. Changes observed on a long-term scale, due to regression phenomena in P. oceanica meadows or to the spread of the invasive species C. racemosa var. cylindracea, were well described by FGs. In the first case the trophic diversity was maintained and in the latter the lack of herbivorous forms pointed out the poor role as structuring plant of the seaweed. Although caution is suggested in studies on FGs, they can give further insight in comprehending structural and functional processes in amphipod ecology.

Can the Marine Ecosystem of a Posidonia oceanica Back-reef React and Defend Itself against the Spread of Caulerpa racemosa var. cylindracea?

A back-reef of Posidonia oceanica (Santa Liberata, Orbetello, Italy) subject to degradation lost its typical mixed meadow of Cymodocea nodosa , Nanozostera noltii and Caulerpa prolifera and was colonised by the invasive chlorophycea Caulerpa racemosa var. cylindracea ( C. racemosa ) between 2003 and 2004. When the submerged flora behind the P. oceanica barrier reef was studied between 2005 and 2006, C. racemosa constituted 25% of the macroalgal biomass and showed high cover (>50%). Residual dead patches of the mixed meadow had been colonized by Penicillus capitatus . By 2011, C. racemosa had fallen to about 3% of total algal mass and its cover had also dropped (5-25%), while other typical species predominated: P. oceanica dead mattes were covered by thin dense mats of photophile species dominated by Jania rubens and Cladophora sp. Periodically, the latter produced balls that floated freely on the bottom. We compared the lists of phytobenthic flora for 2005, 2006 and 2011 by explorative correspondence analysis. The 2011 list showed a 27% increase in autochthonous species. The results suggest that the invasion of allochthonous fast-spreading C. racemosa may occur in degraded ecosystems after events that altered the original community. The community can recover through a succession of vegetation changes.

New Mediterranean Biodiversity Records (December 2012)

This paper presents records extending or confirming the distribution of Mediterranean species. Three alien algae are included, namely Codium taylorii reported for the first time from the Aegean and Turkey (Izmir Gulf), Caulerpa racemosa var. cylindracea (Karpathos and Chalki Isl., Aegean Sea) and Ganonema farinosum (Karpathos Isl., Aegean Sea). As far as animals are concerned, Litarachna divergens (Acari: Hydrachnidia) was recorded (Side, Eastern Mediterranean) and represents a new amendment at genus level for Turkish fauna. Other invertebrates include alien species such as the crabs Dyspanopeus sayi (Lago Fusaro, SW Italy), Percnon gibbesi (Larnaca, Cyprus; Karpathos and Chalki Isl., Aegean Sea) and Callinectes sapidus (Voda estuary, NW Greece), the nudibranch Aplysia dactylomela (Boka Kotorska Bay, Montenegro), the gastropod Conomurex persicus (Karpathos and ChalkiIsl., Aegean Sea) and the bryozoan Electra tenella (Livorno harbour and Messina Straits area). The alien fish Siganus luridus, Siganus rivulatus, Fistularia commersonii, Sphyraena chrysotaenia and Sargocentron rubrum are also reported from the islands of Karpathos and Chalki, and Pteragogus pelycus from Heraklion Bay, Crete. In addition, new localities for four rare Mediterranean inhabitants are given: the cephalopod Thysanoteuthis rhombus (NW Sardinia) and the fish: Lampris guttatus (Calabria, S Italy), Petromyzon marinus (Gokova Bay) and Remora australis (Saronikos Gulf), while the opisthobranch gastropod Cerberilla bernadettae is reported for the first time from the E Mediterranean (Cyprus). Finally, three species of the Aegean ascidiofauna are recorded for the first time: Lissoclinum perforatum, Ciona roulei and Ecteinascidia turbinata. Furthermore, it was established that Phallusia nigra has extended its distributional range to the north of the Aegean Sea.

Invasive alga Caulerpa racemosa var. cylindracea makes a strong impact on the Mediterranean sponge Sarcotragus spinosulus

Here we present the first observation of the impact of the invasive Caulerpa racemosa var. cylindracea on native photophilic sponge species in the Adriatic Sea, with special focus on Sarcotragus spinosulus. Caulerpa racemosa var. cylindracea is able to completely overgrow the sponge, developing an exceptionally thick canopy with a maximum measured density of 1,887 m of stolons m−2 and 40,561 fronds m−2. Necrosis of the sponge surface was significantly correlated with the algal dry biomass, frond number and stolon length. Dense algal canopy, penetration of the algal stolon and rhizoids into the sponge oscula and covering of the ostiae probably diminishes the seawater circulation through the sponge and consequently results in its smothering and even death. We suggest that chemotropism is the reason why C. racemosa penetrates the sponge oscula and establishes such dense canopy on the sponge.

Synergism between two anthropic impacts: Caulerpa racemosa var. cylindracea invasion and seawater nutrient enrichment

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 427:59-70 (2011) - DOI: https://doi.org/10.3354/meps09053 Synergism between two anthropic impacts: Caulerpa racemosa var. cylindracea invasion and seawater nutrient enrichment Paola Gennaro1,*, Luigi Piazzi2 1Italian National Institute for Environmental Protection and Research, ISPRA ex ICRAM, 00166 Rome, Italy 2Inter-University Centre of Marine Biology and Applied Ecology G. Bacci, CIBM, 57128 Leghorn, Italy *Email: paola.gennaro@isprambiente.it ABSTRACT: Although eutrophication and biological invasions are recognized as important elements of global change, few studies have assessed how their synergism can affect structural and functional traits of marine ecosystems. The present study aimed to evaluate the effect of seawater nutrient enrichment on the spread of the introduced Chlorophyta Caulerpa racemosa var. cylindracea and the interactive effects of nutritional enrichment and C. racemosa invasion on the native macroalgal assemblages of a subtidal rocky bottom. To achieve these objectives, a manipulative field experiment was carried out at 24 m depth in the northwestern Mediterranean Sea by adding C. racemosa and supplying the water column with nutrients. The following treatments were applied: non-manipulated assemblages, nutrient enrichment, addition of C. racemosa, and both nutrient enrichment and addition of C. racemosa. Results showed that C. racemosa spread was enhanced by nutrient enrichment. Moreover, a significant interaction between nutritional increase and C. racemosa invasion was detected: the effects of C. racemosa invasion on native macroalgal assemblages were amplified by nutrient enrichment. Results suggested that synergism between effects of different anthropogenic impacts can have severe consequences on the integrity of marine ecosystems. KEY WORDS: Biological invasions · Nutrients · Rocky bottom · Macroalgal assemblages · ­Mediterranean Sea Full text in pdf format PreviousNextCite this article as: Gennaro P, Piazzi L (2011) Synergism between two anthropic impacts: Caulerpa racemosa var. cylindracea invasion and seawater nutrient enrichment. Mar Ecol Prog Ser 427:59-70. https://doi.org/10.3354/meps09053 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 427. Online publication date: April 12, 2011 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2011 Inter-Research.

Effects of Caulerpa racemosa var. cylindracea on prey availability: an experimental approach to predation of amphipods by Thalassoma pavo (Labridae)

Alien plant species, such as Caulerpa racemosa var. cylindracea, that invade Mediterranean marine vegetated habitats can affect habitat structure. In turn, changes in habitat structure may affect the associated invertebrate assemblages, either through changes in habitat selection or as a result of altered predation efficiency. In order to test for effects of changes in habitat structure resulting from colonization by C. racemosa on prey availability for predators, the importance of amphipods as a trophic resource in natural vegetated habitat was first assessed, and later experiments were undertaken to assess the effects of the alien alga on predation by Thalassoma pavo of two dominant amphipods: Elasmopus brasiliensis (Gammaridea) and Caprella dilatata (Caprellidea). Laboratory experiments were conducted in separate aquaria with five vegetation habitat types: Halopteris scoparia, Jania rubens, C. racemosa without detritus, C. racemosa with detritus, Cymodocea nodosa, together with controls. The vegetation was first defaunated, and then 30 amphipods were introduced to each aquarium and exposed to a single Thalassoma pavo individual for 1 h, after which the fish’s gut contents were examined. Consumption (per fish per hour) of caprellids (11.7 ± 1.4) was higher overall than that of gammarids (8.7 ± 1.5) and likely reflects different microhabitat use by amphipods, which affects susceptibility to predators. Consumption of amphipods also varied by habitat type. The highest predation rate was found in the C. nodosa habitat (12.7 ± 2.19) and the lowest in the C. racemosa habitats with detritus (4.1 ± 1.78) and without detritus (5.2 ± 0.55), which did not differ. The pattern of predation across habitats, however, was similar for both caprellid and gammarid amphipods, indicating a more general effect of habitat on amphipod predation. Our findings showed that invasive species such as C. racemosa can decrease feeding by predators such as T. pavo. Changes in predator–prey interactions could have consequences for food web support in the Mediterranean.

Records of alien marine species in the shallow coastal waters of Chios Island (2009)

The shallow coastline of Chios Island was surveyed for the presence of any alien marine benthic species, during August 2009. Fourteen randomly selected sites were surveyed by snorkeling during standardized one-hour transects at depths between 0 and 10 m, and the presence of all identified alien benthic species was recorded. Six alien species were identified: Asparagopsis taxiformis, Caulerpa racemosa var. cylindracea, Stypopodium schimperi, Halophila stipulacea, Percnon gibbesi, and Siganus luridus. The green alga C. racemosa var. cylindracea was found in high densities in all the surveyed sites and was characterized as invasive in the island. The brown alga S. schimperi, the crab P. gibbesi, and the fish S. luridussustain established populations in the area. For three of the recorded marine alien species (S. schimperi, P. gibbesi, and S. luridus),Chios Island seems to be the northernmost margin of their geographical range in the Aegean Sea.

Macrophyte assemblage associated with an invasive species exhibiting temporal variability in its development pattern

Many invasive species show temporal variations in abundances, such as seasonal cycles and medium to long term variations. The effects of invasive species on native assemblages have, however, mainly been investigated during the maximum abundance of the invasive species and rarely over an entire year. At the north-western limit of its distribution range in the Mediterranean Sea, the invasive marine macrophyte Caulerpa racemosa var. cylindracea shows high temporal variability in its development pattern with complete withdrawal in winter. The present study investigated the variation of the macrophyte assemblage associated with C. racemosa var. cylindracea in the bay of Marseilles (NW Mediterranean, France) over a period of one year. A comparison was made with a non-invaded assemblage at the same site. The results showed a relationship between the development of C. racemosa var. cylindracea and the structure of the macrophyte assemblage. When C. racemosa var. cylindracea was present, the associated assemblage showed significantly lower numbers of species, lower cover of native and introduced macrophytes and lower diversity (Shannon diversity index and Pielou’s evenness) compared to the non-invaded assemblage. During the temporary winter withdrawal of C. racemosa var. cylindracea, an increase in the assemblage descriptors was noted; however, this period was probably not long enough to allow the recovery of a structured macrophyte assemblage comparable to the non-invaded assemblage. Other invasive macrophytes occur in the bay of Marseilles; their cover was, however, greatly reduced in the invaded assemblage, indicating strong competitive interactions between C. racemosa var. cylindracea and the other invasive species.

Effects of the spread of the alga Caulerpa racemosa var. cylindracea on the sponge assemblage from coralligenous concretions of the Apulian coast (Ionian Sea, Italy)

AbstractThe present work investigated the modifications induced by the spread of the green macroalga Caulerpa racemosa var. cylindracea (Bryopsidales, Chlorophyta) on the sponge assemblage of Apulian coralligenous concretions (Ionian Sea – Torre Ovo, Italy). The study of qualitative and quantitative sponge composition was carried out before (2004) and after (2006) the spread of this invasive alga by means of traditional (quadrat scraping) and photographic sampling methods. Results indicate that the spread of the green alga is concomitant with a significant decrease in percentage sponge cover both on horizontal‐ and on vertical‐oriented substrates. In addition, strong modifications to the structure of the community in terms of repartition of the available substrate have been observed since the algal spread. Conversely, no major changes have affected the specific composition of the sponge assemblage, suggesting that at this stage of colonization the algal spread has not produced a loss of sponge biodiversity. However, there is a clear need to monitor closely the C. racemosa invasion to verify its long‐term impact on the sponge assemblage.