Marine Phanerogams Research Articles

Native and Non-Indigenous Biota Associated with the Cymodocea nodosa (Tracheophyta, Alismatales) Meadow in the Seas of Taranto (Southern Italy, Mediterranean Sea)

The collection of photos during the systematic monitoring activities is useful to witness the ecological role of marine phanerogams as hosts for a rich variety of organisms in coastal and transitional waters. Cymodocea nodosa is present in the Taranto seas. In Mar Piccolo, it reached high coverage in a short amount of time, up to 100%, due to the improvement in environmental conditions. The most recent observations showed that it offers a welcoming habitat for several vertebrates and invertebrates, native and non-indigenous, as well as to micro- and macroalgae. The NPPR-funded activities will make these observations more robust and structural.

Response of the toxic dinoflagellate Alexandrium minutum to exudates of the eelgrass Zostera marina

Biotic interactions are a key factor in the development of harmful algal blooms. Recently, a lower abundance of planktonic dinoflagellates has been reported in areas dominated by seagrass beds, suggesting a negative interaction between both groups of organisms. The interaction between planktonic dinoflagellates and marine phanerogams, as well as the way in which bacteria can affect this interaction, was studied in two experiments using a non-axenic culture of the toxic dinoflagellate Alexandrium minutum exposed to increasing additions of eelgrass (Zostera marina) exudates from old and young leaves and to the presence or absence of antibiotics. In these experiments, A. minutum abundance, growth rate and photosynthetic efficiency (Fv/Fm), as well as bacterial abundance, were measured every 48 h. Toxin concentration per cell was determined at the end of both experiments. Our results demonstrated that Z. marina exudates reduced A. minutum growth rate and, in one of the experiments, also the photosynthetic efficiency. These results are not an indirect effect mediated by the bacteria in the culture, although their growth modify the magnitude of the negative impact on the dinoflagellate growth rate. No clear pattern was observed in the variation of toxin production with the treatments.

C and N stable isotopes enlighten the trophic behaviour of the dugong (Dugong dugon)

The dugong (Dugong dugon), a large marine mammal herbivore of the Indo-Pacific, is vulnerable to extinction at a global scale due to a combination of human-related threats including habitat degradation. The species forages on seagrass habitats (marine phanerogams) and plays a key role in the functioning and sensitivity of these declining coastal ecosystems. The trophic behaviour and plasticity of dugong populations in response to extrinsic and intrinsic factors are therefore crucial features to both dugong and seagrass conservation. Yet, this knowledge remains limited to few visual observations and analyses of mouth, stomach or faecal contents of stranded individuals. We take advantage of a long-term monitoring of stranded individuals from the endangered New Caledonian population to depict features of dugongs’ trophic ecology from Carbon and Nitrogen stable isotopes. A total of 59 dugong skin samples were used to portrait the stable isotope niche of dugongs according to their sex and maturity. In light of previous work conducted in New Caledonia, a subset of these samples was used to model the trophic mix of dugong males and females. Our stable isotope mixing models used C and N isotope values of 10 taxa bbelonging to five divisions of metazoans, plants, and chromists. Our results represent the first estimate of the species dietary niche in the isotopic space. They suggest that the diet of dugong calves overlaps more with that of adult females (δ13C: − 6.38 ± 1.13 ‰; δ15N: 2.49 ± 1.10 ‰) than males (δ13C: − 5.92 ± 1.10 ‰; δ15N: 3.69 ± 1.28 ‰). Further, we highlight differences in the expected trophic mix of dugong adult males and females. From these, we formulate a sex-specific foraging behaviour hypothesis in dugongs, whereby lactating females could forage over smaller spatial ranges but more diverse food sources thanmales. The study emphasizes the importance of long-term stranding monitoring programs to study the ecology of marine mammals.. Finally, it depicts an ecological feature that may contribute to the sensitivity of vulnerable dugongs to ongoing changes on tropical coastal ecosystems.

Material revalorization of beach wrack comprising seaweed and marine phanerogams: Optimization of hydrothermal treatments

Tidal waste causes accumulation of seaweed and marine plants on coasts, resulting in an.eutrophication process and proliferation of insects, nematodes, and bacteria that negatively affect the beach ecosystem and local human economic activities. This work highlights the potential of beach wrack from the Andalusian Mediterranean coastline as cellulosic materials, in the frame of concepts such as waste management, revalorization, and reduction of hazardous chemicals. With this purpose, beach waste was harvested, washed with water, characterized, and subjected to chemical-free hydrothermal treatments. A central composite design was defined in order to relate the hydrothermal treatment conditions to the composition of the liquid and solid fractions. It was concluded that polynomial models encompassing linear, quadratic, and binary effect parameters reproduce the experimental results satisfactorily (e.g., R2 = 0.97–0.98 for saccharides released). As expected, severe conditions resulted in higher removal of hemicellulose, and of small amounts of lignin along with it, but at the expense of the yield. Results allowed us to choose high temperature (150 °C), short time (30 min) and low liquid/solid ratio (8) as a compromise solution, by which the yield and the outlet concentrations of glucose, xylose, and arabinose approached their optimal values. Although longer times grant further removal of non-fibrous materials, this small difference is compensated by energy savings and reduction on water consumption.

Molluscs from Tidal Channels of the Gulf of Gabès (Tunisia): Quantitative Data and Comparison with Other Lagoons and Coastal Waters of the Mediterranean Sea

The present study analyses the spatio-temporal structuration of the molluscan fauna from four tidal channels of the Gulf of Gabès. A total of 26 stations were sampled at four seasons from March 2016 to January 2017, leading to the identification of 2695 individuals and 57 species. The species richness and abundances are higher in autumn than in other seasons. The fauna is dominated by seven species, three gastropods [Cerithium scabridum Philippi, 1848, Bittium reticulatum (da Costa, 1778) and Tricolia speciosa (Megerle von Mühfleld, 1824)] and four bivalves [Abra alba (W. Wood, 1802), Loripes orbiculatus Poli, 1791, Varicorbula gibba (Olivi, 1792) and Peronaea planata (Linnaeus, 1758)], which are characteristic of habitats with detritus accumulation and seagrass meadows. These dominant species are commonly recorded in lagoons and coastal shallow waters of the Mediterranean Sea. The structure of the molluscan fauna is linked to the location of tidal channels in the Gulf of Gabès. Abundances are lower in the Mimoun channel than in the other channels, especially the Maltine channel which shows a great accumulation of organic matter and high abundances of molluscs. Low abundances are found in high-energy hydrodynamic zones with gravel sediment; conversely, the presence of macrophytes (mainly in seagrass meadows) increases molluscan diversity. Comparisons with other sites in the shallow waters of the Tunisian coast and lagoons show that the taxonomic diversity of molluscs of the tidal channels of the Gulf of Gabès is equivalent to that reported elsewhere, but the abundance per m2 is among the lowest levels recorded here. Moreover, most of the dominant species found in the Gulf of Gabès tidal channel are reported as dominant in other studies covering the Mediterranean Sea. A distance-based redundancy analysis shows that depth, sediment type and the presence of marine phanerogams and filter-feeder bivalves on fine sands and gravels account for the structure of mollusc assemblages associated with each channel.

Benthic foraminifera as proxy for fossil seagrass from the Lower Pleistocene deposits of the Stirone River (Emilia-Romagna, Italy)

This paper analyses and describes the benthic foraminiferal associations within the Pleistocene deposits of the Stirone River (Emilia-Romagna, Italy), with the purpose of testing foraminifera as Indirect Palaeo-Seagrass Indicators (IPSIs). Our analyses focused on two different biofacies: a Thalassinoides biofacies, characterised by an oligotypic biotic assemblage and a Pinna biofacies representing an infralittoral soft bottom colonised by marine phanerogams and characterized by high biodiversity. To strengthen the analyses, we have compared the Stirone foraminiferal association with the one of Fauglia (Tuscany, Italy), in which a well-preserved, early Pleistocene, fossil Posidonia meadow, is present. The aim of this work is to provide qualitative and quantitative parameters that can be used to recognize past vegetated environments, where fossil seagrass are no longer present. Considering the influence of ecological constraints and diagenetic processes on the foraminiferal assemblages, several indexes such as the IndexEP, the modified FORAM index (FI’), the “long vs. short life-span index” (ILS), and the K/REXT (keeled/rounded morphotypes) have been calculated and a morphotype-based analysis has been provided. Among the tested indexes, the latter proved to be the most reliable IPSI, in association with the presence of morphotype A*, permanently attached, encrusting foraminifera and the abundance of Rosalinidae.

Evaluating Seagrass Meadow Dynamics by Integrating Field-Based and Remote Sensing Techniques.

Marine phanerogams are considered biological sentinels or indicators since any modification in seagrass meadow distribution and coverage signals negative changes in the marine environment. In recent decades, seagrass meadows have undergone global losses at accelerating rates, and almost one-third of their coverage has disappeared globally. This study focused on the dynamics of seagrass meadows in the northern Adriatic Sea, which is one of the most anthropogenically affected areas in the Mediterranean Sea. Seagrass distribution data and remote sensing products were utilized to identify the stable and dynamic parts of the seagrass ecosystem. Different seagrass species could not be distinguished with the Sentinel-2 (BOA) satellite image. However, results revealed a generally stable seagrass meadow (283.5 Ha) but, on the other hand, a stochastic behavior in seagrass meadow retraction (90.8 Ha) linked to local environmental processes associated with anthropogenic activities or climate change. If systemized, this proposed approach to monitoring seagrass meadow dynamics could be developed as a spatial decision support system for the entire Mediterranean basin. Such a tool could serve as a key element for decision makers in marine protected areas and would potentially support more effective conservation and management actions in these highly productive and important environments.

Biorefinery of Coastal Wastes Comprising Seaweed and Marine Phanerogams: Optimisation of Hydrothermal Treatments

Biorefinery of Coastal Wastes Comprising Seaweed and Marine Phanerogams: Optimisation of Hydrothermal Treatments

National blue carbon assessment in Spain using InVEST: Current state and future perspectives

Coastal and marine ecosystems supply multiple services in which human well-being is highly dependent. However, high-resolution spatial distribution studies of marine ecosystem services are scarce, even if it is known that this information is needed to better manage and conserve these ecosystems. With the aim of filling this gap, in this study we have: (1) mapped and assessed the current capacity of marine phanerogams (Posidonia oceanica, Cymodocea nodosa, Zostera noltii, Zostera marina, and Halophila decipiens) to store and sequester blue carbon in Spain; (2) mapped and assessed the future capacity of marine phanerogams to store and sequester blue carbon under three plausible futures; and (3) assess the economic implications of these scenarios. Our results are based on the InVEST Blue Carbon model and exhibit high spatial resolution (100 m/pixel) of carbon stored in marine phanerogams. We found that 82% of carbon storage and sequestration by marine phanerogams is currently managed within Natura 2000 areas. However, results from the modeled future scenarios indicate a constant decrease in the amount of carbon stored in these ecosystems by 2050 (24% lost in the business-as-usual scenario). The economic impact of these losses is equivalent to 17,974 million € (around 1.6% of the Spanish GDP). Finally, we consider that a transformative management change is needed to conserve marine phanerogams in Spain, and we discuss the importance of the Natura 2000 Network in managing marine ecosystems and their services in the near future.

Aneusomaty and polysomaty in Cymodocea nodosa (Ucria) Ascherson from Mediterranean Sea (Sicily, Italy)

Basic cytogenetic knowledge and genome size data on marine phanerogams are essentially limited, although they are indispensable to plan correct experimental designs and for the right interpretation of genetic data, particularly those requiring detailed analyses of genome structure and evolution. Observations on mitotic divisions and chromosomal behaviours as well as DNA measurements have been carried out on five Cymodocea nodosa populations from Sicilian coasts. Standard chromosome counting and Image Cytometric analyses were used to determine the chromosome number and the ploidy of each population. High chromosome number variation was detected in individuals from all the studied populations, even in a single root (aneusomaty). The numbers varied according to the cell position. Near the apical meristem, it was lower, while far from the apex the majority of dividing cells showed higher chromosome numbers. Mitotic anomalies were also detected. The relative DNA value of nuclei confirmed that all of the studied populations presented polysomaty. Cytological and cytometric data clearly indicated that the combined action of endopolyploidy and mitotic anomalies were involved in this uncommon cytogenetic behavior. The data reported represent the first contribution to understanding the basic cytogenetics in this genus.

Karyomorphology and DNA quantification in the marine angiosperm Halophila stipulacea (Forsskål) Ascherson from Mediterranean and Red Seas

Cytogenetic studies for systematic and evolutionary purposes are lacking on marine phanerogams. Halophila stipulacea is a tropical seagrass that invaded the Mediterranean from the Red Sea through the Suez Canal. In this study, we report, for the first time, the karyotype features and genome size of H. stipulacea populations from different localities. Also, an attempt to compare our data with those reported in literature on other Halophila species is discussed. To determine the karyological relationships among taxa, we used basic karyotypic features such as chromosome number, size and symmetry, and position of chromosomal landmarks. To estimate karyotype asymmetry, the Coefficient of Variation of Chromosome Length (CVCL) and the Mean Centromeric Asymmetry (MCA) values were calculated. The estimations of DNA amounts were carried out by Image Cytometry (IC) using the interphase-peak method. All the taxa, including those reported in literature, present a uniform and slightly bimodal karyotype, but significant differences are found in nuclear DNA content among species. Each taxa had a karyotype formula 2n = 18 = 10m + 2sm + 6st. Aneuploidy and polyploidy seemed to not be involved in the speciation of this genus. The conserved karyotype in these taxa suggests the presence of mechanisms selecting for constancy, or against changes, in karyotype number and morphology.

Evolution Temporelle Et Spatiale De La Macroflore Benthique De L’ecosysteme Lagunaire De Nador

The objective of the present study undertaken in 2011is to evaluate the status of the benthic macroflora of the Nador lagoon after the management works carried out in 2009 to improve the lagoon environmental quality. Relying on a previous study carried out in 1987, the results of analysis in 2011 showed that the lagoon seabed macroflora recorded a marked decline and an overall change in its distribution and specific composition. The marine Phanerogams, represented by Cymodocea and Zostera, in association with Caulerpa, which were the main vegetationin 1987, were replaced by a macroflora highly dominated by macroalgae (64.3% of the total area), essentially represented by Rhodophyceae (58% of total area).In 2011, the genus Alsidiumwas the main representative in the macroflora(55% of total area),while the genus Caulerpa, and Phanerogamssaw their area of occurrence regress to 25.6% and 18% respectively.

Levels of heavy metals in wetland and marine vascular plants and their biomonitoring potential: A comparative assessment

The present study investigated the levels of As, Cd, Cr, Cu, Hg, Mn, Ni, Pb and Zn in the seagrasses Posidonia oceanica and Cymodocea nodosa, and in the wetland macrophytes Phragmites australis, Arundo donax, Typha domingensis, Apium nodiflorum, and Nasturtium officinale. Results showed that the bioaccumulation capacity from sediments, translocation, total levels in plant tissues, and bioindication of metals in sediments, are generally species-specific. In particular, the patterns of metals in the aquatic plants studied were overall independent of ecology (coasts vs wetlands), biomass, anatomy (rhizomatous vs non rhizomatous plants), and life form (hemicrytophytes vs hydrophytes). However, marine phanerogams and wetland macrophytes shared some characteristics such as high levels of heavy metals in their below-ground organs, similar capacity of element translocation in the rhizosphere, compartmentalization of metals in the different plant organs, and potential as bioindicators of Cu, Mn and Zn levels in the substratum. In particular, the present findings indicate that, despite ecological and morphological similarities, different plant species tend to respond differently to exposure to heavy metals. Furthermore, this seems to result from the species individual ability to accumulate and detoxify the various metals rather than being attributed to differences in their ecological and morpho-anatomical characteristics.

Hábitos alimentarios de los peces del género Acanthurus (Perciformes: Acanthuridae) en la región de Santa Marta (Caribe colombiano)

A total of 29 genera of algae, 15 rhodophytes, 7 phaeophytes and 7 chlorophytes, as well as marine phanerogams, were found in the stomach contents of the reef fishes Acanthurus bahianus Castelnau, A. chirurgus (Bloch) and A. coeruleus Bloch and Schneider. The plants included genera which develop morphological or chemical defenses, and carne from adult fishes, whose simpatric coexistence is examined.

Level of contamination by metallic trace elements and organic molecules in the seagrass beds of Guadeloupe Island

Seagrass bed ecosystems occupy the most important part of coastal shelf in the French West Indies. They also constitute nurseries for many invertebrates and fishes harvested by local fisheries. In Guadeloupe, coastal fish stocks are declining meanwhile several agroecosystems revealed to be heavily contaminated by pollutants (agricultural lands, rivers, mangroves, seagrass beds, and coral reefs). Considering these facts, a study of the contamination of seagrass beds (8000ha) of the Grand Cul-de-Sac Marin (GCSM) bay was conducted on their sediments and marine phanerogams. The analyses concerned six metals (Cd, Cu, Hg, Pb, V, Zn), tributyltin, 18 polycyclic aromatic hydrocarbons (PAHs), eight polybrominated diphenyl ethers (PBDEs), 38 polychlorobiphenyls (PCBs), dithiocarbamates (CS2 residues), and 225 pesticide molecules.Overall, the level of contamination of the seagrass beds was low for both sediments and phanerogams. Metallic trace elements were the main pollutants but with higher concentrations recorded in coastal sites, and their distribution can be explained by the proximity of river mouths and current patterns. The level of contamination was lower in plants than in sediments. However, the level of contamination between these two compartments was significantly correlated. The conclusion of this study is that, unlike other coastal ecosystems of Guadeloupe such as mangroves, the seagrass beds in the GCSM present a low degree of pollution. The observed level of contaminants does not seem to threaten the role of nursery played by the seagrass beds and does not likely present a risk for the reintroduction of manatees.

Limited Consequences of Seagrass Decline on Benthic Macrofauna and Associated Biotic Indicators

Marine phanerogams are ecosystem engineers, as their presence induces major environmental changes that impact on the benthic fauna. Consequently, modifications to the structure of benthic communities would be expected to be associated with seagrass decline. Since 2005, Zostera noltii seagrass beds in Arcachon Bay (France), the largest in Europe, have undergone a severe decline. Twelve stations distributed throughout the lagoon were sampled in 2002, and all were found to be densely planted at that time. Subsequently, the same stations were revisited in 2010 and seagrass cover had drastically decreased by that time. Based on benthic macrofauna, multidimensional scaling (MDS) analysis identified four groups. Years were separated. In 2002, two groups were distinct in relation to the water body, since in 2010 separation between the two other groups was related to seagrass occurrence. When looking at community structure and dominant species there were moderate differences within and between years, independent of seagrass decline. Seagrass loss did not drastically modify the species composition as they were preserved in the remaining seagrass patches. However, there was a drop in macrofauna abundance in unvegetated muddy compared with abundance in the remaining seagrass areas. Epifauna was particularly affected by seagrass decline. Among biotic indicators based on macrofauna, multivariate indicator MISS (Macrobenthic Index in Sheltered Systems) was in agreement with the similarity of macrofauna structure among groups, while other tested indicators performed badly in relation to seagrass occurrence. However, no index detected seagrass loss, highlighting the necessity of maintaining a separate survey on seagrass cover.

Chemical analysis of flavonoid constituents of the seagrass Halophila stipulacea: First finding of malonylated derivatives in marine phanerogams

The flavonoid fraction from the butanol extract of a Mediterranean sample of the seagrass Halophila stipulacea was chemically analyzed. A new malonylated flavone glucoside, genkwanin-4′- O-(6“-malonyl-glucopyranoside) ( 3), was isolated together with known flavone glucosides 4- 9, previously reported only from terrestrial sources. The structure of 3 was established by means of spectroscopic techniques, mainly NMR methods.

Biologia e Ecologia das Fanerógamas marinhas do Brasil

Normal 0 21 false false false MicrosoftInternetExplorer4 st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabela normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} Marine phanerogams (also known as seagrasses) constitute an important and diverse habitat of coastal zones. In the present study, the state of knowledge about the biology and ecology of Brazilian seagrasses is analyzed. Despite there being relatively few studies carried out in Brazil, we critically discussed the following themes: richness and distribution of seagrass species along the coast; morphology and environmental conditions within the seagrass beds; reproductive biology and phenology; productivity, growth, the biomass and density of the plants; the seagrass habitat itself and its flora and fauna; trophic relationships and connectivity with other habitats (reefs, mangroves, estuaries etc.); and the degradation and impacts due to man activities. Moreover, areas for future study are pointed out.

Marine Organisms As Biomonitors

Biomonitors are organisms mostly used for the quantitative determination of contaminants in the environment (see Chapter 1). The present chapter discusses mainly the employment of seaweeds, sea phanerogams and molluscs as bioindicators of heavy metal contamination, since they are the organisms of choice in most of the programmes of biological monitoring of coastal marine waters (see Water Framework Directive 2000/60 EC (WFD) [1]). Bioindicators provide an integrated view of the presence of micropollutants, and in the aquatic environment they respond only to the fraction presenting a clear ecotoxicological relevance (see Chapter 1). Among the different methodological approaches of biological monitoring of a marine ecosystem, the approach based on the bioaccumulation capacity of some chemical species, as for instance trace metals, is among the most important. This capacity is particularly present among macroalgae, sea phanerogams, molluscs, oysters, etc. These organisms can be proposed as possible bioindicators when the presence of a direct correlation between internal and environmental levels of the various metals has been verified [2]. Therefore, the chemical analysis of the tissues of such organisms represents a method for measuring the integrated bioavailability of trace metals in the marine environment over time, given their remarkable bioconcentration capacity [3–5]. Comparing the levels of metals in the organisms collected at different sites is a very useful way to gather information on the biologically available levels of inorganic contaminants in the areas under study. In general, micro and macroalgae, marine phanerogams, mussels, oysters, tellinid bivalves, polychaets and crustaceans are some of the organisms used as bioindicators of marine ecosystems [4]. Marine organisms can accumulate contaminants present in solution and in the particulate material, thus determining a variation in the level of bioaccumulation depending on the trophic level occupied. Some marine invertebrates can take contaminants from the particulate material of the sediment, especially when their physico-chemical conditions are being altered. Algae and phanerogams take contaminants in solutions and many herbivorous crustaceans reflect their concentrations. Therefore, in order to have a full picture of the bioavailability of the various pollutants of water ecosystems, it is necessary to use several kinds of WITPress_BMTA_ch004.qxd 11/26/2007 17:00 Page 81

Indirect estimation of benthic secondary production in the Lagoon of Venice (Italy)

Five published indirect methods to estimate benthic secondary production of intertidal mudflats and a new proposed formulation based on quarter-power allometric scaling and the “Universal Temperature Dependence” of biological processes (UTD) were compared. For this purpose, a dataset consisting of an annual series of samples, taken from the Lagoon of Venice from March 1996 to March 1997, at sites characterised by different seagrass coverage was used. All methods resulted in that biomass and secondary production decreased progressively when moving from the seagrass meadow toward areas of unvegetated substrate, suggesting an influence of the available marine phanerogams on the neighbouring sites. The equation proposed in this paper gives results comparable with those obtained using empirical regression models from literature. The main conclusion from this study is that general equations proposed by the “metabolic theory of ecology” can be applied for indirect estimations of secondary production of benthic communities.