Distribution of Toxigenic Halomicronema spp. in Adjacent Environments on the Island of Ischia: Comparison of Strains from Thermal Waters and Free Living in Posidonia Oceanica Meadows

Organisms adaptable to extreme conditions share the ability to establish protective biofilms or secrete defence toxins. The extracellular substances that are secreted may contain monosaccharides and other toxic compounds, but environmental conditions influence biofilm characteristics. Microorganisms that are present in the same environment achieve similar compositions, regardless of their phylogenetic relationships. Alternatively, cyanobacteria phylogenetically related may live in different environments, but we ignore if their physiological answers may be similar. To test this hypothesis, two strains of cyanobacteria that were both ascribed to the genus Halomicronema were isolated. H. metazoicum was isolated in marine waters off the island of Ischia (Bay of Naples, Italy), free living on leaves of Posidonia oceanica. Halomicronema sp. was isolated in adjacent thermal waters. Thus, two congeneric species adapted to different environments but diffused in the same area were polyphasically characterized by microscopy, molecular, and toxicity analyses. A variable pattern of toxicity was exhibited, in accordance with the constraints imposed by the host environments. Cyanobacteria adapted to extreme environments of thermal waters face a few competitors and exhibit a low toxicity; in contrast, congeneric strains that have adapted to stable and complex environments as seagrass meadows compete with several organisms for space and resources, and they produce toxic compounds that are constitutively secreted in the surrounding waters.

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AMEBAS PATÓGENAS DE VIDA LIBRE DEL GÉNERO ACANTHAMOEBA EN AGUAS RECREATIVAS EN LA HUASTECA POTOSINA, MÉXICO

BIOCYT Biología Ciencia y Tecnología ◽

10.22201/fesi.20072082.2014.7.76134 ◽

2014 ◽

Vol 7 ◽

Author(s):

Ricardo Ortiz Ortega ◽

Alonso Vilches Flores ◽

Marco Aurelio Rodríguez Monroy ◽

Patricia Bonilla Lemus

Keyword(s):

High Temperature ◽

Water Body ◽

Tropical Climate ◽

Dry Season ◽

Thermal Waters ◽

Free Living ◽

Severe Infections ◽

Amebic Encephalitis ◽

Animal Tests

Studies accomplished in freshwater demonstrate the importance of identify the presence of protozoa like free living amoebae (FLA). In particular, the genera Acanthamoeba is associated with severe infections in man, as the Granulomatous Amebic Encephalitis (GAE). The most important factor for the development of these organisms is the high temperature of the water body. The region of the Huasteca Potosina in Mexico, with a tropical climate and great aquatic resorts, like rivers, waterfalls and pools of thermal waters, that allows the development of amoebae. In this study we evaluated the presence of amoebas in the most visited places on the Huasteca Potosina. Samples of a liter were taken in nine sites during the rainy and dry season. 54 strains of amoebas were identify, 46 belong to the genera Acanthamoeba, resulting 30 of them pathogenic in the animal tests. The pathogenic isolated amoebas were present in the most attended resorts by the people in the waterfalls or pools of the places sampling. Temperature turned out to be the most important factor for the presence of amoebae.

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Epiphytic hydroids on Posidonia oceanica seagrass meadows are winner organisms under future ocean acidification conditions: evidence from a CO2 vent system (Ischia Island, Italy)

The European Zoological Journal ◽

10.1080/24750263.2021.1899317 ◽

2021 ◽

Vol 88 (1) ◽

pp. 472-486

Author(s):

C. Gravili ◽

F. Cozzoli ◽

M. C. Gambi

Keyword(s):

Ocean Acidification ◽

Posidonia Oceanica ◽

Seagrass Meadows ◽

Ischia Island

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Posidonia oceanica as a Source of Chromophoric Dissolved Organic Matter for the Oligotrophic NW Mediterranean Coast

Journal of Marine Science and Engineering ◽

10.3390/jmse8110911 ◽

2020 ◽

Vol 8 (11) ◽

pp. 911

Author(s):

Francesca Iuculano ◽

Carlos M. Duarte ◽

Jaime Otero ◽

Xosé Antón Álvarez-Salgado ◽

Susana Agustí

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Rocky Shore ◽

Posidonia Oceanica ◽

Mediterranean Coast ◽

Balearic Islands ◽

Chromophoric Dissolved Organic Matter ◽

Absorption Increase ◽

Seagrass Meadows ◽

Nw Mediterranean

Posidonia oceanica is a well-recognized source of dissolved organic matter (DOM) derived from exudation and leaching of seagrass leaves, but little is known about its impact on the chromophoric fraction of DOM (CDOM). In this study, we monitored for two years the optical properties of CDOM in two contrasting sites in the Mallorca Coast (Balearic Islands). One site was a rocky shore free of seagrass meadows, and the second site was characterized by the accumulation of non-living seagrass material in the form of banquettes. On average, the integrated color over the 250–600 nm range was almost 6-fold higher in the beach compared with the rocky shore. Furthermore, the shapes of the CDOM spectra in the two sites were also different. A short incubation experiment suggested that the spectral differences were due to leaching from P. oceanica leaf decomposition. Furthermore, occasionally the spectra of P. oceanica was distorted by a marked absorption increase at wavelength < 265 nm, presumably related to the release of hydrogen sulfide (HS−) associated with the anaerobic decomposition of seagrass leaves within the banquettes. Our results provide the first evidence that P. oceanica is a source of CDOM to the surrounding waters.

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Free-living freshwater nematodes from Brazil: checklist of genera and regional patterns of diversity

Nematology ◽

10.1163/15685411-bja10100 ◽

2021 ◽

pp. 1-14

Author(s):

Taciana Kramer de Oliveira Pinto ◽

Sérgio A. Netto ◽

André Morgado Esteves ◽

Francisco José Victor de Castro ◽

Patricia Fernandes Neres ◽

...

Keyword(s):

Benthic Communities ◽

Extreme Environments ◽

Freshwater Ecosystems ◽

Freshwater Biodiversity ◽

High Turnover ◽

Free Living ◽

Regional Patterns ◽

Freshwater Nematodes ◽

Spatial Coverage ◽

Freshwater Habitats

Summary Brazil has one of the largest varieties of aquatic ecosystems and rich freshwater biodiversity, but these components have constantly been damaged by the expansion of unsustainable activities. Free-living nematodes are an abundant and ubiquitous component of continental benthic communities, occurring in all freshwater habitats, including extreme environments. Despite this, hardly any studies have examined the generic composition of nematodes in different latitudes and the geographic overlap of assemblages. We provide data on nematode genera from six regions in Brazil, over a north-south gradient spanning about 4000 km, encompassing rivers, coastal lakes, and reservoirs with different levels of human impact. Interpolation/extrapolation curves were generated and the zeta diversity was used to assess the overlap of nematode assemblages. Freshwater nematode assemblages comprised 54 families and 132 genera. Mononchidae, Monhysteridae, Chromadoridae, Tobrilidae and Dorylaimidae were the most diverse families. Differences in diversity and high turnover of genera were found among regions, probably related to stochastic processes. Mononchus was the only widely distributed genus. Our results revealed a high biodiversity of free-living freshwater nematodes among the regions. The limited spatial coverage of the data reveals an enormous knowledge gap in a country with 12% of the world’s freshwater resources. The lack of spatial patterns, e.g., latitudinal variation, suggests that freshwater nematode assemblages are primarily structured by the intrinsic properties of habitats. This reinforces the uniqueness of freshwater ecosystems and suggests that the nematode assemblages may be sensitive to environmental disturbances, since the limited distributions of taxa may lead to lower resilience.

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Toxicity of Corymbia citriodora essential oil compounds against Ascia monuste (Linnaeus, 1764) (Lepidoptera: Pieridae) and Plutella xylostella (Linnaeus, 1758) (Lepidoptera: Plutellidae)

Entomological Communications ◽

10.37486/2675-1305.ec02013 ◽

2020 ◽

Vol 2 ◽

pp. ec02013

Author(s):

Renata C. Santos ◽

Jhersyka S. Paes ◽

Arthur V. Ribeiro ◽

Abraão A. Santos ◽

Marcelo C. Picanço

Keyword(s):

Plutella Xylostella ◽

The Other ◽

Biotic Factors ◽

Safe Alternative ◽

Toxic Compounds ◽

Low Toxicity ◽

Abiotic And Biotic Factors ◽

The Individual ◽

Corymbia Citriodora ◽

Essential Oil Compounds

Essential oils (EO’s) have been investigated as a safe alternative to pest management. The toxicity of an EO can vary due to abiotic and biotic factors. The individual compounds of different EO’s have shown promise to insect control and they may present toxicity similar to or greater than the EO’s. In this study, we determined the toxicity of Corymbia citriodora EO compounds against Ascia monuste (Linnaeus, 1764) and Plutella xylostella (Linnaeus, 1758). Citronellal, trans-caryophyllene, and citronellol (LD50 = 23.24, 24.17 and 27.84 μg/mg, respectively) were the most toxic compounds to A. monuste. On the other hand, α-pinene and β-pinene presented low toxicity to this pest. For P. xylostella, citronellol and citronellal were the most toxic compounds (LD50 = 22.36 and 25.53 μg/mg, respectively). The other compounds presented lower toxicity with similar doses. Thus, the individual compounds of C. citriodora EO can be an alternative for A. monuste and P. xylostella control.

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Trait gradients inform predictions of seagrass meadows changes to future warming

Scientific Reports ◽

10.1038/s41598-021-97611-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Arianna Pansini ◽

Gabriella La Manna ◽

Federico Pinna ◽

Patrizia Stipcich ◽

Giulia Ceccherelli

Keyword(s):

Global Warming ◽

Posidonia Oceanica ◽

Shoot Density ◽

Western Mediterranean ◽

Seagrass Meadows ◽

Western Mediterranean Sea ◽

Seagrass Ecosystem ◽

Rhizome Biomass ◽

And Function ◽

Time Substitution

AbstractComparing populations across temperature gradients can inform how global warming will impact the structure and function of ecosystems. Shoot density, morphometry and productivity of the seagrass Posidonia oceanica to temperature variation was quantified at eight locations in Sardinia (western Mediterranean Sea) along a natural sea surface temperature (SST) gradient. The locations are spanned for a narrow range of latitude (1.5°), allowing the minimization of the effect of eventual photoperiod variability. Mean SST predicted P. oceanica meadow structure, with increased temperature correlated with higher shoot density, but lower leaf and rhizome width, and rhizome biomass. Chlorophyll a (Chl-a) strongly impacted seagrass traits independent of SST. Disentangling the effects of SST and Chl-a on seagrass meadow shoot density revealed that they work independently, but in the same direction with potential synergism. Space-for-time substitution predicts that global warming will trigger denser seagrass meadows with slender shoots, fewer leaves, and strongly impact seagrass ecosystem. Future investigations should evaluate if global warming will erode the ecosystem services provided by seagrass meadows.

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Feeding preferences of amphipod crustaceans Ampithoe ramondi and Gammarella fucicola for Posidonia oceanica seeds and leaves

Scientia Marina ◽

10.3989/scimar.04892.06b ◽

2019 ◽

Vol 83 (4) ◽

pp. 349

Author(s):

Inés Castejón-Silvo ◽

Damià Jaume ◽

Jorge Terrados

Keyword(s):

Direct Evidence ◽

Paracentrotus Lividus ◽

Posidonia Oceanica ◽

Feeding Preferences ◽

Research Attention ◽

Seagrass Meadows ◽

Idotea Baltica ◽

Published Evidence ◽

Sarpa Salpa

The functional importance of herbivory in seagrass beds is highly variable among systems. In Mediterranean seagrass meadows, macroherbivores, such as the fish Sarpa salpa and the sea urchin Paracentrotus lividus, have received most research attention, so published evidence highlights their importance in seagrass consumption. The role of small crustaceans in seagrass consumption remains less studied in the region. Herbivory on Posidonia oceanica seeds has not previously been reported. In turn, crustacean herbivory on P. oceanica leaves is broadly recognized, although the species feeding on the seagrass are mostly unknown (except for Idotea baltica). This work evaluates P. oceanica consumption by two species of amphipod crustaceans commonly found in seagrass meadows. Ampithoe ramondi and Gammarella fucicola actively feed on P. oceanica leaves and seeds. Both species preferred seeds to leaves only when the seed coat was damaged. This study provides the first direct evidence of consumption of P. oceanica seeds by the two named amphipod crustaceans, and confirms that they also consume leaves of this seagrass species.

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