Search results for "Alismatales"
showing 10 items of 23 documents
Letter to the editor regarding the article “Taking advantage of seagrass recovery potential to develop novel and effective meadow rehabilitation meth…
2020
Alagna et al. (2019) suggest new transplantation methods for Posidonia oceanica (Linnaeus) Delile, inspired by its natural recovery process after disturbance due to dredging operations for gas-pipelines. They observe that P. oceanica vegetative fragments naturally settled only on loose calcareous stones deployed to fill the trenches of the gas-pipeline. No recovery was noted on dead matte, sand and large calcarenitic boulders. Following a new pilot restoration project currently ongoing in the same area, we demonstrate that natural recovery also occurs on dead matte. After examining other alternative transplantation methods for P. oceanica, the Authors suggest using their "habitat enhancemen…
Ocean Acidification and the Loss of Phenolic Substances in Marine Plants
2012
Rising atmospheric CO(2) often triggers the production of plant phenolics, including many that serve as herbivore deterrents, digestion reducers, antimicrobials, or ultraviolet sunscreens. Such responses are predicted by popular models of plant defense, especially resource availability models which link carbon availability to phenolic biosynthesis. CO(2) availability is also increasing in the oceans, where anthropogenic emissions cause ocean acidification, decreasing seawater pH and shifting the carbonate system towards further CO(2) enrichment. Such conditions tend to increase seagrass productivity but may also increase rates of grazing on these marine plants. Here we show that high CO(2) …
Short-term response of the slow growing seagrass Posidonia oceanica to simulated anchor impact
2007
Experimental evaluations about the impact of anchors of small vessels have previously shown that each anchoring can on average damage up to six shoots of Posidonia oceanica, removing small amount of biomass and, at the same time, interrupting continuity among shoots. The aim of the paper was to investigate the response of P. oceanica to different damage intensity at two levels of substrata compactness. Three treatments were considered: control (no damage); low damage (simulated anchor damage by three strokes of a hoe); and high damage (six strokes). Disturbance was higher where the substratum was highly penetrable and after one year significant variation was observed among treatments for bo…
Long-term effects of elevated CO2 on the population dynamics of the seagrass Cymodocea nodosa: Evidence from volcanic seeps
2021
Population reconstruction techniques was used to assess for the first time the population dynamics of a seagrass, Cymodocea nodosa, exposed to long-term elevated CO2 near three volcanic seeps and compared them with reference sites away from the seeps. Under high CO2, the density of shoots and of individuals (apical shoots), and the vertical and horizontal elongation and production rates, were higher than at the reference sites. Nitrogen limitation effects on rhizome elongation and production rates and on biomass were more evident than CO2 as these were highest at the location where the limitation of nitrogen was highest. At the seep where the availability of CO2 was highest and nitrogen low…
Resistance of seagrass habitats to ocean acidification via altered interactions in a tri-trophic chain
2020
Despite the wide knowledge about prevalent effects of ocean acidification on single species, the consequences on species interactions that may promote or prevent habitat shifts are still poorly understood. Using natural CO2 vents, we investigated changes in a key tri-trophic chain embedded within all its natural complexity in seagrass systems. We found that seagrass habitats remain stable at vents despite the changes in their tri-trophic components. Under high pCO2, the feeding of a key herbivore (sea urchin) on a less palatable seagrass and its associated epiphytes decreased, whereas the feeding on higher-palatable green algae increased. We also observed a doubled density of a predatory wr…
Resilience of the seagrass Posidonia oceanica following pulse-type disturbance.
2020
Understanding the response of species to disturbance and the ability to recover is crucial for preventing their potential collapse and ecosystem phase shifts. Explosive submarine activity, occurring in shallow volcanic vents, can be considered as a natural pulse disturbance, due to its suddenness and high intensity, potentially affecting nearby species and ecosystems. Here, we present the response of Posidonia oceanica, a long-lived seagrass, to an exceptional submarine volcanic explosion, which occurred in the Aeolian Archipelago (Italy, Mediterranean Sea) in 2002, and evaluate its resilience in terms of time required to recover after such a pulse event. The study was carried out in 2011 i…
Collating evidence on the restoration efforts of the seagrass Posidonia oceanica: current knowledge and gaps
2022
Seagrass meadows are important shallow coastal ecosystems due to their contribution to enhancing biodiversity, nu-trient cycling, carbon burial, and sediment stabilisation, but the maintenance of their integrity has been threatened by several anthropogenic disturbances. Active restoration is considered a reliable strategy to enhance recovery of seagrass ecosystems, and decision making for correct seagrass restoration management requires relying on valuable informa-tion regarding the effectiveness of past restoration actions and experimental efforts.Previous experimental efforts and human-mediated active restoration actions of the slow growing seagrass Posidonia oceanica have been collated h…
Modeling of copper fixed-bed biosorption from wastewater by Posidonia oceanica
2009
Biosorption of copper from aqueous solutions by Posidonia oceanica was investigated in batch and fixed-bed experiments. Batch experiments were conducted to evaluate the removal equilibrium at pH 5.0 and 6.0; experimental data were fitted to Langmuir model with maximum uptake capacities of 56.92 and 85.78 mg g(-1), respectively. Five column experiments were carried out at different feed concentrations. Breakthrough times and continuous sorption isotherm were obtained from breakthrough curves. Differences among batch and continuous isotherms were observed; the maximum uptake capacity in dynamic conditions was found in 56.70 mg g(-1) for final pH between 5.0 and 5.5. The biosorbent was regener…
Morphology ofMaundiasupports its isolated phylogenetic position in the early-divergent monocot order Alismatales
2013
According to recent molecular phylogenetic data, the rare Australian endemic Maundia triglochinoides does not form a clade with taxa traditionally classified as members of Juncaginaceae. Therefore, views on the morphological evolution and taxonomy of Alismatales require re-assessment. As the morphology of Maundia is poorly known and some key features have been controversially described in the literature, the flowers, fruits, inflorescence axes and peduncles were studied using light and scanning electron microscopy. Inflorescences are bractless spikes with flowers arranged in trimerous whorls. Except in the inflorescence tip (where the flower groundplan is variable), flowers possess two tepa…
The effects of anthropogenic organic matter inputs on stable carbon and nitrogen isotopes in organisms from different trophic levels in a southern Me…
2005
Stable isotope ratios were used to determine the impact of anthropogenically derived organic matter from onshore and offshore fish farming and a sewage outfall on organisms at different trophic levels (primary producers and consumers) on the south-east coast of Sicily (Italy, Mediterranean). Representative macroalgae and consumers were collected in three sampling locations: "Impact" and two putative "Controls" sited to the north of the impacted location. While delta(13)C values of both organic matter sources and consumers varied little between locations, delta(15)N spatial variability was higher and delta(15)N was shown to be a good descriptor of organic enrichment and uptake of anthropogen…