Search results for "Seagra"
showing 10 items of 101 documents
Komunitas Gastropoda pada Padang Lamun Perairan Pantai Manokwari
2021
Penelitian ini bertujuan mengidentifikasi dan menganalisa struktur komunitas gastropoda di pesisir pantai Manokwari. Pengambilan sampel menggunakan metode transek di dua stasiun pengamatan yaitu Pantai Briosi BLK dan Pantai Rendani. Setiap stasiun diletakkan tiga garis transek ke arah laut dan setiap transek terdiri atas 10 kuadrat. Transek ini diletakkan di atas padang lamun. Analisis data dilakukan meliputi indeks keanekaragaman, indeks keseragaman, dominasi dan kepadatan gastropoda. Hasil penelitian menunjukkan ditemukan bahwa kualitas perairan di kedua lokasi sampling dapat mendukung pertumbuhan gastropoda. Komposisi spesies gastropoda yang ditemukan pada kedua lokasi sampling meliputi …
Vulnerability of algae and seagrasses to climate change
2013
Biodiversity is undergoing rapid and worrying changes, partially driven by anthropogenic activities. Human impacts and climate change (e.g. increasing temperature and ocean acidification) represent the most serious threats to biodiversity and ecosystem functioning. Aim of this study was to assess, analysing the scientific literature and published data, how climate change can affect algae and seagrasses, evaluating their vulnerability and the possibility to use these organisms as indicators. Algae and seagrasses have a central role for several important ecological processes in aquatic ecosystems, and their loss can lead repercussions for the ecological function. Climate stressors affected ac…
New Bioactive Peptides from the Mediterranean Seagrass Posidonia oceanica (L.) Delile and Their Impact on Antimicrobial Activity and Apoptosis of Hum…
2023
The demand for new molecules to counter bacterial resistance to antibiotics and tumor cell resistance is increasingly pressing. The Mediterranean seagrass Posidonia oceanica is considered a promising source of new bioactive molecules. Polypeptide-enriched fractions of rhizomes and green leaves of the seagrass were tested against Gram-positive (e.g., Staphylococcus aureus, Enterococcus faecalis) and Gram-negative bacteria (e.g., Pseudomonas aeruginosa, Escherichia coli), as well as towards the yeast Candida albicans. The aforementioned extracts showed indicative MIC values, ranging from 1.61 μg/mL to 7.5 μg/mL, against the selected pathogens. Peptide fractions were further analyzed thr…
ANTIMICROBIAL ACTIVITY FROM POLYPEPTIDE-RICH EXTRACTS OF THE SEAGRASS POSIDONIA OCEANICA
2021
The present study was carried out to assess the antibacterial, antifungal and antibiofilm properties of polypeptide-rich extracts isolated from green leaves and rhizomes of Mediterranean seagrass Posidonia oceanica (L. Delile) (Posidoniaceae). The seagrass was collected, washed with freshwater, grinded with liquid nitrogen in order to obtain fine powders that were exposed to extraction by acetic acid and antiproteases. The crude extracts isolated from leaves and rhizomes of P. oceanica were subjected to microbiological assays to evaluate the antibacterial, antifungal and antibiofilm activity of polypeptide fraction against two reference bacterial strains Staphylococcus aureus ATCC 25923 and…
The trophic structure of the pipefish community (Pisces: Syngnathidae) from a western Mediterranean seagrass meadow based on stable isotope analysis
2004
Syngnathus abaster andSyngnathus typhle (Pisces: Syngnathidae) from a dense Cymodocea nodesa meadow in the western Mediterranean Stagnone di Marsala (Italy) were studied using δ13N and δ15N analysis. Because of the presence of these two species in the same habitat and the specialized parental care by the male, the effect of species and sex on the isotopic composition was also studied to investigate the different feeding strategies between and within species.S. abaster andS. typhle exhibited enriched13C and15N values throughout the sampling period (mean ±SE, δ13C =−10.5±1.8‰ and−10.8±2.0‰, δ15N=11.9±0.7‰ and 10.6±1.0%., respectively), suggesting that these species receive their energy mainly…
The importance of dead seagrass (Posidonia oceanica)matte as a biogeochemical sink
2022
We assessed the potential of dead seagrass Posidonia oceanica matte to act as a biogeochemical sink and provide a coherent archive of environmental change in a degraded area of the Mediterranean Sea (Augusta Bay, Italy). Change in sediment properties (dry bulk density, grain size), concentration of elements (Corg, Cinorg, N, Hg) and stable isotope ratios (δ13C, δ 15N) with sediment depth were measured in dead P. oceanica matte and unvegetated (bare) sediments in the polluted area, and an adjacent P. oceanica meadow. Principal Component Analysis (PCA) revealed a clear clustering by habitat, which explained 72% of variability in our samples and was driven mainly by the accumulation of N and H…
Holothuria tubulosa Gmelin 1791 (Holothuroidea, Echinodermata) enhances organic matter recycling in Posidonia oceanica meadows
2014
Abstract The role of Holothuria tubulosa in organic matter recycling of Posidonia oceanica detritus was estimated in a laboratory feeding experiment. The individual mean ingestion rate of seagrass detritus by holothurians was evaluated and carbon and nitrogen stable isotopes, carbon and nitrogen content and C:N ratio analyzed in H. tubulosa , P. oceanica detritus and surface sediment. Results showed that H. tubulosa is capable of ingesting from 30% to 100% of the detritus produced by P. oceanica meadows, depending on the holothurian density. Stable isotope analysis provided evidence for the assimilation of seagrass detritus by H. tubulosa as their signatures were compatible with 1 trophic l…
and variability in Posidonia oceanica associated with seasonality and plant fraction
2003
Abstract The carbon and nitrogen isotopic compositions of fractions of the seagrass Posidonia oceanica (L.) Delile in a Mediterranean shallow environment (Stagnone di Marsala, western Sicily) were investigated seasonally throughout 1998. The stable isotope ratios of seagrass leaves (intermediate and adult), rhizomes, leaf litter and aegagropiles were compared over 1 year in order to distinguish between seasonal and plant part variability. Significant differences in the isotopic composition tested using ANOVA were observed as a function of both plant fraction and season. There was an overall trend towards less discrimination against 13 C in summer (average δ 13 C ∼ −10‰) than in winter (aver…
L’impiego di strumenti acustici ad alta risoluzione nella valutazione, monitoraggio e gestione delle praterie di Posidonia oceanica.
2015
High-resolution sonar system (MBS, SSS, Sub Bottom Profiler) was used to map and characterize Posidonia oceanica meadows, dead matte formations and to long-term monitor its progressive lower limit. Hydro-acoustic techniques allows to quickly acquire, at sufficiently low cost, a synoptic coverage of a large area and a high number of data by mean of non-destructive methods. Hence, they are recommended as useful tools for detecting and characterizing submerged aquatic vegetation.
The use of very high resolution images for studying Posidonia oceanica reefs
2020
Posidonia oceanica is an endemic Mediterranean seagrass that forms wide and dense meadows from the surface up to about 40 m depth. This species can develop a biogenic structure called matte, a typical terraced formation built up by itself, consisting of intertwined rhizomes, roots and sediment, which may allow shoots to reach the sea surface forming reefs (récif barrière), considered natural monuments. Posidonia oceanica reefs are particularly exposed to the ongoing increase in temperature and in storm frequency and intensity due to climate change, with negative repercussions on their conservation. Much more attention must be paid to the implementation of monitoring tools able to detect ear…