Search results for "Potamogeton"

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…

Osservazioni su alcuni aspetti di vegetazione lacustre nella Sicilia centrale

1977

Abstract Some aspects of lacustrine vegetation in the central Sicily.—The Authors give a short comparative survey of some hydrophytic facies observed in two small ponds near Caltanissetta, in the central Sicily. In addition to the classical zonation, typical of such water logged (or: swamp) biotopes, a Potamogeton pectinata-Chara vulgaris association is described. The presence of monospecific facies to be referred to the Lemnetum gibbae (Koch, 1954) Miyaw. et J. Tx., 1960 is ultimately reported.

Colonisation process of vegetative fragments of Posidonia oceanica (L.) Delile on rubble mounds

2005

Seagrass colonise new areas via the dispersion of seeds or vegetative fragments. Independent of the manner of colonization, habitat requirements need to be met for the successful establishment of seagrasses. Here we report on the colonization process of Posidonia oceanica in a highly disturbed area: a gas pipeline trench at Capo Feto (SW Sicily, Italy). A trench dredged through a P. oceanica bed was back-filled with rubble added from dump barges leading to the formation of a series of rubble mounds on the seabed. Over time, these mounds became colonised with P. oceanica. In order to understand the pattern of P. oceanica colonization, shoot density was quantified over 3 years (2001-2003) on …

Assessing the potential of Albufera de València Lagoon sediments for the restoration of charophyte meadows

2013

Abstract Albufera de Valencia Lagoon, the largest littoral lagoon on the Iberian Peninsula, has been affected by eutrophication processes since the 1970s due to the direct dumping of sewage waters of industrial, agricultural and urban origin. Consequently, the submerged vegetation that covered the bottom of the lagoon has been lost (charophytes and Potamogeton spp., Myriophyllum spp. and Ceratophyllum spp.). Despite efforts to improve water quality, this vegetation has not recovered. No information about the potential of the recent sediments to host charophyte development is available. In this study, we analysed several sediment cores taken from different areas of the lagoon to determine th…

Fitocenozy zespołu rdestnicy wydłużonej Potametum praelongi w starorzeczach południowo-zachodniej Polski

2018

Zespół rdestnicy wydłużonej Potametum praelongi Sauer 1937 należy do jednego z najrzadziej spotykanych zbiorowisk roślin wodnych w Polsce. Celem pracy jest przedstawienie aktualnego rozmieszczenia i charakterystyki Potametum praelongi w starorzeczach na terenie Dolnego Śląska i Śląska Opolskiego. Badania wykonano w latach 2000–2015. Stwierdzono pięć dotychczas nieznanych stanowisk tego zbiorowiska w starorzeczach Odry.

The search for reference conditions for stream vegetation in northern Europe

2008

Summary 1. The European Water Framework Directive provides a framework for improving the ecological quality of stream ecosystems, with deviation from reference used as a measure of ecological status. 2. Here we examine the possibility of using less impacted stream sites from Latvia, Lithuania and Poland to establish a Danish reference network for macrophyte assemblages, and as a guiding image for identification of possible references sites within Denmark. Both approaches were evaluated using historical Danish records. 3. Four different macrophyte assemblages were identified for mid-sized streams in the Central and Eastern Lowland ecoregions. Macrophyte assemblages could not be delineated us…

Rare and threatend pondweed communities in anthropogenic water bodies of Opole Silesia (SW Poland)

2007

Shoot age as a confounding factor on detecting the effect of human-induced disturbance on Posidonia oceanica growth performance

2007

Abstract The response of orthotropic rhizome elongation and primary production of Posidonia oceanica to anthropogenic perturbations and potential confounding effects of shoot age were assessed using a Linear Multilevel Model (LMM). This model examined the confounding effect of age by comparing the estimates of impact and variance components obtained by excluding and including Age as an explanatory variable. Age had a negative effect on rhizome elongation and primary production with an annual decrease of 0.6 mm y − 1 and 7 mg dw y − 1 respectively. According to the LMM when age effect was omitted, the differences between disturbed and control locations in rhizome elongation and primary produ…

Posidonia oceanica as a Historical Monitor Device of Lead Concentration in Marine Environment

2005

We show that Posidonia oceanica is able to reliably monitor the variability of environmental lead (Pb). We analyze lead concentration measured in the scales and rhizomes of Posidonia oceanica collected in seven sites along the coasts of the Sicily island and subsequently fractioned them according to a lepidochronological analysis. We measure lead concentration in Posidonia oceanica tissues by using the flame atomic absorption spectrophotometry technique. We compare the measured lead concentration with the estimated lead emission in air due to the gasoline sold and used for combustion in car engines in Sicily. By computation of the Pearson cross-correlation coefficient, we show that lead con…