Search results for "LCA"
showing 10 items of 1995 documents
Temporal fluctuations in seawater pCO2 may be as important as mean differences when determining physiological sensitivity in natural systems
2015
AbstractMost studies assessing the impacts of ocean acidification (OA) on benthic marine invertebrates have used stable mean pH/pCO2 levels to highlight variation in the physiological sensitivities in a range of taxa. However, many marine environments experience natural fluctuations in carbonate chemistry, and to date little attempt has been made to understand the effect of naturally fluctuating seawater pCO2 (pCO2sw) on the physiological capacity of organisms to maintain acid–base homeostasis. Here, for the first time, we exposed two species of sea urchin with different acid–base tolerances, Paracentrotus lividus and Arbacia lixula, to naturally fluctuating pCO2sw conditions at shallow wat…
Volcanic CO2 seep geochemistry and use in understanding ocean acidification
2020
AbstractOcean acidification is one of the most dramatic effects of the massive atmospheric release of anthropogenic carbon dioxide (CO2) that has occurred since the Industrial Revolution, although its effects on marine ecosystems are not well understood. Submarine volcanic hydrothermal fields have geochemical conditions that provide opportunities to characterise the effects of elevated levels of seawater CO2 on marine life in the field. Here, we review the geochemical aspects of shallow marine CO2-rich seeps worldwide, focusing on both gas composition and water chemistry. We then describe the geochemical effects of volcanic CO2 seepage on the overlying seawater column. We also present new g…
Seaweed fails to prevent ocean acidification impact on foraminifera along a shallow-water CO2 gradient
2014
Ocean acidification causes biodiversity loss, alters ecosystems, and may impact food security, as shells of small organisms dissolve easily in corrosive waters. There is a suggestion that photosynthetic organisms could mitigate ocean acidification on a local scale, through seagrass protection or seaweed cultivation, as net ecosystem organic production raises the saturation state of calcium carbonate making seawater less corrosive. Here, we used a natural gradient in calcium carbonate saturation, caused by shallow-water CO2 seeps in the Mediterranean Sea, to assess whether seaweed that is resistant to acidification (Padina pavonica) could prevent adverse effects of acidification on epiphytic…
Geochemical survey of Levante Bay, Vulcano Island (Italy), a natural laboratory for the study of ocean acidification
2013
Abstract Shallow submarine gas vents in Levante Bay, Vulcano Island (Italy), emit around 3.6t CO2 per day providing a natural laboratory for the study of biogeochemical processes related to seabed CO2 leaks and ocean acidification. The main physico-chemical parameters (T, pH and Eh) were measured at more than 70 stations with 40 seawater samples were collected for chemical analyses. The main gas vent area had high concentrations of dissolved hydrothermal gases, low pH and negative redox values all of which returned to normal seawater values at distances of about 400 m from the main vents. Much of the bay around the vents is corrosive to calcium carbonate; the north shore has a gradient in s…
Distribution of sea urchins living near shallow water CO2 vents is dependent upon species acid-base and ion-regulatory abilities.
2013
To reduce the negative effect of climate change on Biodiversity, the use of geological CO2 sequestration has been proposed; however leakage from underwater storages may represent a risk to marine life. As extracellular homeostasis is important in determining species' ability to cope with elevated CO2, we investigated the acid-base and ion regulatory responses, as well as the density, of sea urchins living around CO2 vents at Vulcano, Italy. We conducted in situ transplantation and field-based laboratory exposures to different pCO2/pH regimes. Our results confirm that sea urchins have some ability to regulate their extracellular fluid under elevated pCO2. Furthermore, we show that even in cl…
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…
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…
Notes on the bryophyte flora and vegetation of the central and south-western Balkans.
2013
Pugl isi, M., Campisi, P., lakus ic , D., surina, B., Di Pietro, R., Privitera, M. Notes on the bryophyte flora and vegetation of the central and south-western Balkans. Lazaroa 34: 107-116 (2013). A study on the bryophyte fl ora and vegetation was carried out in the mountains at the boundary between Al bania, Ma - cedonia and Montenegro. The study area incl uded Maja and jezerces massif (Prokl etije mts., sE Dinaric Al ps) and Mt korab (S ar-Pindos Range) in Macedonia. several records for the bryol ogical fl ora of Macedonia and Al bania are reported. In particul ar Scapania cuspiduligera and Distichium inclinatum are new records for the Al banian fl ora. In addition some bryophytic and bry…
Fen and spring vegetation in western Pamir-Alai Mountains in Tajikistan (Middle Asia)
2016
The paper presents the results of phytosociological research on spring and fen vegetation of the western Pamir-Alai Mountains in Tajikistan. In total, 211 relevés were sampled during field studies conducted in 2008–2013 and 2015 with application of the Braun-Blanquet method. Plant communities of spring heads and peat-accumulated fens inhabiting the high montane and alpine zones in the Zeravshan, Hissar, Hazratishoh, Darvaz, Turkestan and Peter the 1st Mountains are described. A hierarchical syntaxonomic synopsis of spring and fen plant communities in the western Pamir-Alai Mountains is provided. As a result of field investigations and numerical analyses, three fen associations: Caricetum ps…
Severe effects of long-term drought on calcareous grassland seed banks
2018
Climate change models project shifts in precipitation patterns at regional and global scales. Increases in dry areas and the occurrence of drought predicted in future scenarios are likely to threaten grassland ecosystems. Calcareous grassland seed banks have proven to be resistant to short-term drought, but their responses to long-term drought are unknown. Here we show that 14 years of summer drought changed calcareous grassland seed bank composition, reducing its size and richness, and that these responses do not simply reflect patterns in the above-ground vegetation. Moreover, the effect of drought was larger on seed banks than on vegetation, and above-ground responses mediated by soil de…