Papers by Maurizio De Pirro
Regional Environmental Change, 2012
z to impact these systems, our predictive capacity for the extent and locations of such impacts, ... more z to impact these systems, our predictive capacity for the extent and locations of such impacts, and of any derived socioeconomic consequences, remains limited.
Heart beat rate of invasive Brachidontes pharaonis with respect to the native Mytilaster minimus within the Mediterranean Sea at varying salinites
Changes in heart beat rates (HBR) of Brachidontes pharaonis (an invasive Lessepsian species) and ... more Changes in heart beat rates (HBR) of Brachidontes pharaonis (an invasive Lessepsian species) and Mytilaster minimus (a native Mediterranean species) in response to changes in salinity values from brackish (20) to extreme hyper-saline (75) were investigated both in situ and in the laboratory. The two species displayed different responses to varying salinity, with clear differences in HBR observed between groups investigated at different salinities and between groups originating from different environments. The native species, adapted to narrow salinity changes as those observed in the superficial waters of the Mediterranean Sea, showed signs of stress at salinities slightly above 37 (in the range 37\u201345). On the other hand, the invasive species displayed clear signs of stress only at salinities over 45 and exhibited heart activity even under hyper-saline conditions (i.e. salinity = 75). These results indicate that the Lessepsian species has the potential to invade most of the transitional environments across the entire Mediterranean basin. We therefore stress the need of including Brachidontes pharaonis in all coastal monitoring programmes assessing the actual and potential spreading of alien species in the Mediterranean region
Immediate biomarker responses to benzo[a]pyrene in polluted and unpolluted populations of the blue mussel (Mytilus edulis L.) at high-latitudes
Environment International, 2008
Immediate biomarker responses of two high-latitude populations of the blue mussel Mytilus edulis ... more Immediate biomarker responses of two high-latitude populations of the blue mussel Mytilus edulis to benzo[a]pyrene (B[a]P) were evaluated. Mussels collected from a clean and a polluted site in southwest Iceland were exposed to the nominal dose of 100 microg B[a]P L(-l) for 3 h, after 4 days of acclimatization in clean seawater. To test the sensitivity to the toxicant and immediate biological responses, the following biomarkers were used: DNA single strand breaks, heart rate and feeding rate. All the biomarkers revealed differences between the study sites. Irrespective of the origin of the organisms, the short time exposure to the high B[a]P concentration did not induce DNA single strand breaks or significantly affect the feeding rate. However, the heart rate results showed significantly different responses. The mussels from the polluted site (Reykjavík harbour) increased their heart rate when exposed to B[a]P, while no difference was observed between the heart rate values of the individuals from the clean site (Hvassahraun). The mussels seem to sense the pollutant they have been previously exposed to, and their acute response indicates physiological adaptation to the polluted environment. The results indicate limited sensitivity and temporal predictivity, i.e. transient measurable changes of these biomarkers, as well as showing that the background of the organisms should be considered when evaluating short-term biomarker responses to contaminants.
Stable isotopes were used to examine the origin of organic matter in Icelandic Ascophyllum-based ... more Stable isotopes were used to examine the origin of organic matter in Icelandic Ascophyllum-based habitats, the role of different organic matters in Wlling intertidal food webs and the food preferences of the most abundant suspension feeders, grazers and predators. We selected three intertidal sites on the SW coast of Iceland where we sampled in early September 2004, organic matter sources (POM, SOM and most abundant primary producers, A. nodosum and F. vesciculosus) and the most abundant mac-rofauna species (barnacles, mussels, gastropods, sponge and crabs). Even though the primary production (Ascophyllum-based) was the same at the three study sites, the isotopic composition of commonamong-sites organisms varied due to local diVerences in the origin of available POM and SOM and in food web structures.
The transfer of peat organic matter (OM) from tidal pools of upper littoral to downstream rocky s... more The transfer of peat organic matter (OM) from tidal pools of upper littoral to downstream rocky shores and its potential incorporation into marine biota were investi-gated using the stable isotope approach. Samplings were carried out in September 2004 in two SW Icelandic sites (Osar and Hvassahraun), where we selected (1) areas with shores where grass gently declined towards rocks and, on reaching the sea line, formed small tidal peat pools and (2) areas where grass and rocky shores were not contiguous, rather the grass lower limits were several hundreds of meters back from the shore. In both grass and no grass areas, in the intertidal zone, all benthic organisms and all potential OM sources were sampled. Dominant macroalgae were Ascophyllum nodosum ([Linnaeus] Le Jolis) and Fucus vesiculosus Linnaeus. In grass sites, organisms partially reflected the isotopic composition of peat OM, while in no grass sites, peat represented only a negligible amount of available OM, or its signal was totally absent from the environment. Intertidal organisms could rely on peat both directly by suspension feeding, grazing or scavenging and indirectly by predation (crabs) on low level con-sumers (barnacles).
Stable isotopes ( 13 C and 15 N) were used to examine the origin of organic matter for the most r... more Stable isotopes ( 13 C and 15 N) were used to examine the origin of organic matter for the most representative demersal species of the SW Icelandic Wshery, accounting for over 70% of landings of those species in the North Atlantic. Samples were collected during a 2-week period in early September 2004 from landings and directly during Wshing cruises. Stable isotopes showed that particulate organic matter and sedimentary organic matter were at the base of the food web and appeared to Wll two diVerent compartments: the pelagic and the benthic. The pelagic realm was composed of only capelin and sandeel; krill and redWsh occupied an intermediate position between pelagic and benthic realms; while anglerWsh, haddock, cod and ling resulted as the true demersal species while tusk, rays and plaice were strongly linked to the benthic habitat.
J Comp Physiol B, 1999
Cardiac activity of two Mediterranean limpets was tested at dierent salinities. Patella caerulea ... more Cardiac activity of two Mediterranean limpets was tested at dierent salinities. Patella caerulea inhabits the lower midlittoral where it is exposed to variations in salinity, while P. aspera experiences more stable salinity conditions in the infralittoral fringe. When exposed to moderate hypo-and hypersalinity (23 g l )1 and 43 g l )1 ) for 24 min, P. caerulea showed no signi®cant variation in heart rate with respect to the control salinity (33 g l )1 ), while P. aspera exhibited a signi®cant increase in heart rate in both conditions. This suggests a rise in metabolic rate due to activation of behavioural responses or physiological regulation. When exposed to extremely low salinity (3 g l )1 ) for 24 min, heart contractions ceased in most specimens of P. caerulea. A smaller number of specimens also displayed cessation of heart beat when exposed to extremely high salinity (63 g l )1 ). The heart beat resumed quickly in all specimens when they were returned to control salinity conditions. In contrast, cardiac activity was not interrupted in any of the P. aspera specimens at the 3 g l )1 and 63 g l )1 salinity levels, but strong bradycardia was evident. Contractile activity of the heart ceased in all specimens of P. caerulea and P. aspera when they were exposed to prolonged hypo-osmotic stress (3 g l )1 for 24 h). This acardia was largely reversible in P. caerulea, but most specimens of P. aspera did not recover from the treatment.
Marine Biology, Nov 30, 2001
Laboratory experiments tested whether the cardiac activity of two species of limpets (Cellana spp... more Laboratory experiments tested whether the cardiac activity of two species of limpets (Cellana spp.), co-occurring on the rocky shores of Hong Kong but having dierent zonal distributions, was dierently affected by variations in physical environmental characteristics. Experiments reproduced exposure of limpets to dehydration, high water temperature and reduced salinity, all conditions that can occasionally be faced by animals during low tides. Cardiographic traces were obtained using a non-invasive method based on infrared light sensors glued onto the limpet shell in a position directly over the heart. The signals were ®ltered and ampli®ed, viewed on portable oscilloscopes and automatically transferred to computer. When tested under acclimation temperatures, the lower shore C. toreuma had faster heart rates than the upper shore C. grata, both in air and when submerged in seawater. Regular alternation of heartbeating and acardia were observed in C. grata exposed to both dry and saturated air, whilst C. toreuma showed transient acardia only during exposure to dry air. Both species showed a similar increase in heart rate with increasing temperature (Q 10 $1.8 in the range 25±34°C). When submerged in freshwater, C. grata regularly alternated acardia with beating at a rate slightly lower than in seawater, whilst C. toreuma showed strong bradycardia with reduction of beat amplitude, followed by steady acardia. Recovery of heartbeating after return to initial salinity was faster in C. grata, whilst C. toreuma, initially bradycardic, showed a consistent return to tachycardia. Overall, this study shows that the two congeneric species exhibit dierent cardiac responses to variations in environmental characteristics, which may be related to their diering vertical distribution.
Ital J Zoology, 2011
Changes in heart beat rates (HBR) of Brachidontes pharaonis (an invasive Lessepsian species) and ... more Changes in heart beat rates (HBR) of Brachidontes pharaonis (an invasive Lessepsian species) and Mytilaster minimus (a native Mediterranean species) in response to changes in salinity values from brackish (20) to extreme hyper-saline (75) were investigated both in situ and in the laboratory. The two species displayed different responses to varying salinity, with clear differences in HBR observed between groups investigated at different salinities and between groups originating from different environments. The native species, adapted to narrow salinity changes as those observed in the superficial waters of the Mediterranean Sea, showed signs of stress at salinities slightly above 37 (in the range 37-45). On the other hand, the invasive species displayed clear signs of stress only at salinities over 45 and exhibited heart activity even under hyper-saline conditions (i.e. salinity = 75). These results indicate that the Lessepsian species has the potential to invade most of the transitional environments across the entire Mediterranean basin. We therefore stress the need of including Brachidontes pharaonis in all coastal monitoring programmes assessing the actual and potential spreading of alien species in the Mediterranean region.
Journal of Experimental Marine Biology and Ecology, Jul 1, 2014
Cardiac activity (Arrhenius breakpoint temperatures and Q10 relationships) and heat shock respons... more Cardiac activity (Arrhenius breakpoint temperatures and Q10 relationships) and heat shock response (hsp70 expression) were measured in the congeneric limpets Patella rustica, P. caerulea and P. ulyssiponensis in order to test the relationship between their vertical distribution and physiological thermal tolerance. These species exhibit different vertical distributions along Mediterranean shores and despite the narrow tidal range in the Mediterranean, they experience different environmental conditions and consequently had specific thermal windows. Cardiac activity of the upper zoned P. rustica was maintained at higher temperatures than its mid-or low shore counterparts, P. caerulea and P. ulyssiponensis. P. rustica had the highest Arrhenius breakpoint temperature (37.9 ± 2.1°C, mean ± SD), followed by P. caerulea (35.9 ± 2.6°C), and finally the low-zoned P. ulyssiponensis (32.2 ± 2.3°C). The same pattern was found for Q10 relationships. Expression of hsp70 increased at 34°C and kept increasing with temperature in P. rustica. In P. caerulea, expression reached a maximum at 36°C and decreased at 38°C, suggesting that hsp70 expression in P. rustica provides a more efficient defence against thermal stress than in P. caerulea. As summer environmental temperatures in the Mediterranean regularly reach 35 to 38°C, performances of these limpets suggest that they are already living at the edges of their thermal window, and further temperature changes may have large-scale consequences for these keystone species.
Annali dell'Istituto e museo di storia della scienza di Firenze
The development of Discoglossus sardus and Bufo bufo tadpoles was investigated in 4 localities of... more The development of Discoglossus sardus and Bufo bufo tadpoles was investigated in 4 localities of Monte Argentario. When comparing development time star- ting from the same stages, Discoglossus sardus showed a shorter development time than the sintopic Bufo bufo. Moreover, Discoglossus sardus froglets seemed to remain in closer proximity to water bodies than Bufo bufo ones. For Discoglossus sardus, these fin- dings confirm observations from insular populations.
A nutrient balance was calculated in a phytotreatment system of land-based fish-farm wastewater l... more A nutrient balance was calculated in a phytotreatment system of land-based fish-farm wastewater located in Orbetello lagoon (South Tuscany, Italian West Coast). The balance considered the yearly N and P water components (as dissolved and particulate) and macroalgal and sediments contents. The expecta-tions stimulating the construction of the phytotreatment system were not completely disappointing, at least as far as the validity of the criterion adopted was concerned, nevertheless, an high nutrient quantity was still released to the lagoon environment. Introduction Nitrogen (N) and phosphorus (P) are important waste products of fish farms. In teleost fish, ammonia is excreted mainly through the gills and represents 75 to over 85% of the N loss, while P is excreted as phosphate by the kidney (Handy and Poxton, 1993). Moreover, parts of the not ingested food, together with fish faeces and dissolved excretion, are exported from the plant by outflowing water and pollute the coastal envi...
The cardiac performance clearly showed that P. rustica (ABT= 37.86 ± 2.07 °C) is able to tolerate... more The cardiac performance clearly showed that P. rustica (ABT= 37.86 ± 2.07 °C) is able to tolerate higher temperatures than P. caerulea (ABT= 35.92 ± 2.60 °C). Relatively high ABT of P. rustica indicates that individuals could maintain normal oxygen supply and cardiac function at the temperatures higher than 35°C, explaining the vertical zonation these two species have on the shore.
Physiological and Biochemical Zoology, 1999
Heart rate of the Mediterranean limpet Patella caerulea L. was investigated on the natural shore ... more Heart rate of the Mediterranean limpet Patella caerulea L. was investigated on the natural shore and in the laboratory by using a technique based on infrared phototransducers. Field recording occurred in the Gulf of Trieste (northern Adriatic) during March and June 1997. A consistent dependence of heart rate on temperature was observed in limpets both when submerged and when exposed to air in the two periods, but thermal acclimation was evident. During spontaneous activity at high tide, heart rate increased 1.5-1.7 times the values observed during resting in water at corresponding temperatures. The dependence of heart rate on temperature (10Њ, 16Њ, and 22ЊC) and size (wet weight !1.25 and 11.30 g) in submerged limpets from different populations (northern Adriatic and Tyrrhenian) was tested in the laboratory by adopting a factorial design. The results showed a marked effect of temperature, body weight, and their interaction, independent from the site of origin. Smaller limpets showed a linear increase of heart rate in the whole range of temperature tests, while in the larger ones the increase between 10Њ and 16ЊC was greater than between 16Њ and 22ЊC. Heart rate decreased with increasing body size at control (16ЊC) and high (22ЊC) temperature, while at lower temperature (10ЊC) no effect of body size was evident. When removed from their home scar, limpets increased heart rate to about 1.5 times the reference value. Finally, correlation of oxygen consumption with heart rate of submerged limpets maintained at a different temperature (10Њ-22ЊC) was statistically significant.
Marine Pollution Bulletin, 2001
The cardiac activity of three limpets (Patella rustica, P. caerulea and P. aspera), having a dier... more The cardiac activity of three limpets (Patella rustica, P. caerulea and P. aspera), having a dierent vertical zonation on the Mediterranean rocky shores, was monitored using a non-invasive technique, during 6 h exposure to copper solutions (0.1 and 0.5 ppm), and after return to copper-free conditions. At 0.1 ppm no signi®cant variation of heart rate was observed in the three species with respect to control conditions, while after 3 h at 0.5 ppm a consistent bradycardia was evident in P. caerulea and P. aspera, but not in P. rustica. After 6 h at 0.5 ppm most of the specimens of the three species were acardic but still reactive to mechanical stimulation. Tests on the resumption of cardiac activity after 6 h exposure to 0.5 ppm showed that even after a prolonged cessation of cardiac activity, limpets quickly resumed heartbeating once returned to clean seawater. However, recovery of heartbeating was faster in the mid-and high-shore species (P. caerulea and P. rustica, respectively) than in the lowershore P. aspera. Moreover, the cardiac pattern upon recovery was de®nitely bradycardic in P. aspera, while the other two species showed a signi®cant overshooting in heartbeating rate. Measurement of body burdens of copper showed that P. rustica and P. caerulea were faster in removing the excess of copper than the lower-shore P. aspera. In conclusion, this study showed that taxonomically close and syntopic species having a dierent zonal distribution exhibit dierent cardiac responses to waterborne copper and stresses the importance of comparative studies on physiological responses of organisms to metal pollution. Ó
Marine Environmental Research, 2004
The gastropod limpet, Cellana grata, is common on moderately exposed to exposed Hong Kong rocky s... more The gastropod limpet, Cellana grata, is common on moderately exposed to exposed Hong Kong rocky shores. On the basis of the existing literature on trace metal contamination in Hong Kong, four sites were identified, representative of highly polluted (Aberdeen and Lei Yue Mun) and clean (Cape d'Aguilar and Clear Water Bay) conditions. Limpets from the two polluted sites showed similar, but significantly higher body concentrations of copper than limpets from the two clean sites, which were also similar. Non-invasive measurements of cardiac activity of limpets from the four sites showed between site differences in baseline heart rates under standard seawater, irrespective of pollution level. When acutely exposed to water borne copper (2 h, 0.5 AE 0.06 SD ppm), however, limpets from clean sites showed a significantly higher increase in inter-beating time (bradycardia) than those from polluted sites. These results highlight the potential use of cardiac activity to assess the exposure of natural populations of limpets to trace metal pollution.
Marine Ecology Progress Series, 2006
In the Hong Kong rocky intertidal, the demography of the acorn barnacle Tetraclita japonica is la... more In the Hong Kong rocky intertidal, the demography of the acorn barnacle Tetraclita japonica is largely determined by regular, intense mortality events in the summer and subsequent pulses of recruitment in late summer. During 2 consecutive summers from 2000 to 2001, 34 to 52 and 98 to 99% of T. japonica were killed on the mid-and high shore, respectively, with younger cohorts suffering higher mortality in the mid-shore. Recruitment of T. japonica occurs in late summer; as a result, the population in the high shore consists of a single cohort of new recruits, while the mid-shore supports 2 cohorts (new recruits and adult survivors). To investigate how thermal stress affects acorn barnacle populations, air and rock temperatures and sub-lethal physiological measures (body temperature, sinus pulsation rate and haemolymph osmolality) of T. japonica were taken on the mid-and high shore during daytime, low spring tides in June-July 2001. Mean body temperature increased gradually after emersion, reaching a maximum of ~48°C at noon, 6 to 8°C higher than the adjacent rock surface. T. japonica entered a heat-induced coma when body temperatures reached 45°C. Osmolality of the haemolymph and sinus pulsation rate increased with body temperature as a result of water loss and possibly altered haemolymph pressure; both were greater in high than in mid-shore individuals, with barnacles on horizontal surfaces being hotter than those on vertical surfaces. Body temperature and sinus pulsation rate differed between shore levels, but were similar at spatial scales of 1 to 20 m at the same tidal height. Haemolymph osmolality, however, varied over this distance, probably due to individual variation in the amount of mantle water trapped before emersion and possible micro-habitat differences. Heat and desiccation stress, therefore, play an important role in determining the life history of T. japonica by limiting their distribution and abundance and influencing the demography of the population at different spatial scales.
Marine Ecology Progress Series, 2005
Sub-lethal responses to heat stress were investigated in the limpet Cellana grata. During summer ... more Sub-lethal responses to heat stress were investigated in the limpet Cellana grata. During summer low tides, foot temperatures were hotter than rock temperatures, but positively correlated with, heart rate, air and rock temperatures. Hotter limpets showed mushrooming behaviour, raising their shell from the rock. Over 30% of monitored limpets were not relocated during the subsequent daytime low tide. Missing animals were mostly situated on horizontal surfaces, were smaller than those recaptured, and had higher body temperatures, mushrooming heights and heart rates. A laboratory protocol was designed to resemble on-shore thermal stress conditions. Firstly, small and large limpets were held on a hot plate for 60 min and either constrained or allowed to mushroom. Secondly, unconstrained, large animals were held on the hot plate for 120 min. Unconstrained limpets were able to mushroom and had lower foot temperatures but higher heart rates than those constrained, suggesting mushrooming is an active response. Small animals had higher heart rates than large individuals. Mantle water could not be collected from most small, mushrooming limpets but was from constrained animals, and was more concentrated in small limpets. Small and constrained limpets had more concentrated haemolymph than large or mushrooming animals. Mantle and haemolymph osmolalities were positively related, except at high mantle water osmolalities. Smaller animals lost relatively more water, and constrained limpets more than those allowed to mushroom. Large limpets on the hot plate for 120 min showed similar mushrooming heights and heart rates but had hotter foot temperatures, higher haemolymph concentrations, lost all their mantle water and nearly twice as much water than those held for 60 min. Mushrooming behaviour appears to be a short-term, high-risk strategy that allows limpets temporary relief from stressful conditions and may increase their chance of survival until the next tidal immersion.
Marine Biology, 2004
The effect of cholinergic antagonists on the bradycardia induced by waterborne copper in the Medi... more The effect of cholinergic antagonists on the bradycardia induced by waterborne copper in the Mediterranean limpet Patella caerulea was investigated by using non-invasive recording of cardiac activity of whole animals. Preliminary tests were conducted to check the role of cholinergic and serotoninergic systems in the control of heart rate of P. caerulea. Superfusing the whole limpets with carbachol (cholinergic agonist) at 5·10 )5 M produced a negative inotropic and chronotropic effect (bradycardia), while superfusion with 5hydroxytryptamine produced a positive inotropic and chronotropic effect (tachycardia). Exposure of limpets to a solution of copper in artificial seawater (0.25 mg l )1 , 3 h) reduced their heart rate to about 80% the value recorded in copper-free water. This bradycardia was inhibited by injecting the limpets with atropine (cholinergic muscarinic antagonist) at 21 lg g )1 wet flesh weight and with benzoquinonium [cholinergic nicotinic antagonist blocking the K + mediated acetylcholine (ACh) response] at 10 and 100 lg g )1 prior to copper exposure. In contrast, D-tubocurarine (cholinergic nicotinic antagonist blocking Na + mediated ACh response) had no effect at 85 lg g )1 . These results agree with the involvement of the cholinergic system in the bradycardic response of limpets to copper, and support the view that gastropod ACh receptors do not fit the vertebrate nicotinic-muscarinic classification.
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Papers by Maurizio De Pirro