141 research outputs found
Pioneer settlement of the cold-water coral Desmophyllum dianthus (Esper, 1794) on plastic
Larval settlement is a critical step for sessile benthic species such as corals, whose ability to thrive on diverse natural and anthropogenic substrates may lead to a competitive advantage in the colonization of new environments with respect to a narrow tolerance for a specific kind of substratum. Plastic debris, widespread in marine waters, provides a large, motile, and solid substratum supporting a highly diverse biological community. Here we present the first observation of a floating plastic bottle colonized by the deep-sea coral Desmophyllum dianthus. The density pattern and co-occurring species composition suggest a pioneer behavior of this coral species, whose peculiar morphologic plasticity response when interacting with the plastic substrate (i.e., low density polyethylene) has not been observed before. The tolerance of D. dianthus for such plastic substrate may affect ecological processes in deep water environments, disrupting interspecific substrate competition in the benthic community
Sexual reproduction and biometry of the nonzooxanthellate papillose cup coral Paracyathus pulchellus
Basic information on the reproductive biology of many scleractinian corals
species is limited or entirely lacking, particularly from temperate zones, though
it is essential for a better understanding of their ecology. This study describes
the morphological aspects and the annual cycle of gametogenesis and
biometric parameters of the papillose cup coral Paracyathus pulchellus
collected at Palinuro (Italy, Southern Tyrrhenian Sea), filling a knowledge gap
about the reproductive biology of a widespread Mediterranean and Northern
Atlantic coral. Samples of P. pulchellus were collected by SCUBA diving
between 5- and 10-meters depth during 18 monthly collections from June
2010 to December 2011. Sexually active polyps displayed either oocytes or
spermaries, indicating that P. pulchellus was gonochoric. The sex ratio of
sexually active polyps was 1:1. Gametogenesis began with undifferentiated
germ cells arose in the gastrodermis that migrated towards the mesoglea of the
mesentery where they completed the development. During spermatogenesis,
spermary diameter increased from 25 to 83 µm. Oocyte diameter ranged from
9 to 146 µm and during oogenesis the nucleus/cytoplasm ratio decreased due
to the accumulation of yolk. The nucleus migrated to the periphery of the
oocyte adhering closely to the cell membrane. No embryo was observed in the
coelenteric cavity of the polyps, suggesting an external development of
planktotrophic larvae due to the small-sized mature oocytes and a possible
broadcast spawning reproductive mode. Gonadal index of both females and
males increased significantly from August until November and fertilization took
place from November to January. Only sexually inactive individuals were
observed from February to April, suggesting a quiescence period in both
males and females. Seasonal variations in water temperature and
photoperiod may have a key role in regulating gametogenesis. The analysis
of the main biometric parameters (polyp width, height, dry skeletal mass, volume, surface/volume ratio and bulk skeletal density) showed a negative
correlation between size and skeletal density, and no sexual dimorphism
Long-term effects of an informal education program on tourist environmental perception
Tourism is one of the most important economic sectors worldwide, with significant
overarching impact on the environment, including negative effects caused by tourist
inappropriate behavior while on vacation. By providing informal educational activities, tourism also has an educative role that leads to positive learning outcomes and beneficial
environmental effects. Here we present the short- and long-term outcomes of a project for environmental education (Glocal Education) carried out in three travel destinations, aimed at promoting sustainability variables (knowledge, attitude, and awareness) in participating tourists. Since psychological components can affect learning outcomes, we also considered tourist satisfaction in participating in the project and identification with its values, as well as the intention to travel with the hosting tour operator again in the future. Tourists were asked to complete evaluation questionnaires three times: before Glocal Education activities, right after activities (i.e., while still on vacation), and after at least one year from initial project participation. Short- and long-term learning outcomes were tested, and possible relations between these variables and psychological components (satisfaction, identification, and intention) of the learning experience were verified. Overall, knowledge, attitude and awareness increased in the short term, while in the
long term, knowledge and attitude decreased, and awareness remained constant. In
most cases, psychological components showed positive relation with sustainability
variables, which suggested their important role in structuring and carrying out
environmental education activities. This study suggests that informal environmental
education activities can be advantageous for tourism stakeholders in terms of customer loyalty. Such activities can contribute to enhance environment literacy, by allowing tourists to observe the environmental impact caused by human activity, and understand how their day-to-day actions, even if small, might help address some of the current concerns for environmental conservation
Low and variable pH decreases recruitment efficiency in populations of a temperate coral naturally present at a CO2 vent
Atmospheric carbon dioxide enrichment alters seawater carbonate chemistry, thus threatening calcifying
organisms such as corals. Coral populations at carbon dioxide vents are natural acidification experiments that
mimic organism responses to seawater pH values projected for 2100. Even if demographic traits are paramount
information to assess ecological relationships and habitat suitability, population dynamics studies on corals
thriving under acidified conditions are lacking. Here, we investigate the demography and reproduction of popu-
lations of the solitary, symbiotic, temperate coral Balanophyllia europaea naturally living along a pH gradient at a
Mediterranean CO2 vent. Gametogenesis and larval production were unaffected while recruitment efficiency
collapsed at low and variable pH, contributing to coral abundance decline and suggesting that life stages
between larval release and early polyp growth are hindered by acidification. Exploring these processes is crucial
to assess coral fate in the forthcoming acidified oceans, to preserve coral ecosystems and the socioeconomic ser-
vices they provide
INTEGRATED DATING OF THE CONSTRUCTION AND RESTORATION OF THE MODENA CATHEDRAL VAULTS (NORTHERN ITALY): PRELIMINARY RESULTS
After the last damaging earthquake in 2012, an anti-seismic reinforcement project of the cathedral of
Modena was designed giving us the opportunity to investigate and date the building materials. Radiocarbon (14C),
optically stimulated luminescence (OSL), and thermoluminescence (TL) dating techniques were performed on the
vaults with the aim to (1) clarify the construction timing, (2) define the history of the restorations, and (3) explore
the possible correlation of the main restoration works to the earthquake chronology deduced from the historic
catalog. Preliminary results show that medieval older bricks were reused for most of the original construction.
Only lime and non-gypsum mortar was used for the original construction in the 15th century and for later repair
of damage caused by earthquakes in the 16th and 17th centuries. Gypsum mortar was used for later repair in the
18th century. The results show much stronger damage due to earthquakes than previously thought
Decreasing pH impairs sexual reproduction in a Mediterranean coral transplanted at a CO2 vent
Ocean acidification, due to the increase of carbon dioxide (CO2) concentration in the atmosphere and its absorption by the oceans, affects many aspects of marine calcifying organisms' biology, including reproduction. Most of the available studies on low pH effects on coral reproduction have been conducted on tropical species under controlled conditions, while little information is reported for either tropical or temperate species in the field. This study describes the influence of decreasing pH on sexual reproduction of the temperate non-zooxanthellate colonial scleractinian Astroides calycularis, transplanted in four sites along a natural pH gradient at the underwater volcanic crater of Panarea Island (Tyrrhenian Sea, Italy). The average pH values of each site (range: pHTS 8.07–7.40) match different scenarios of the Intergovernmental Panel on Climate Change (IPCC) for the end of the century. After 3 months under experimental conditions, the reproductive parameters of both oocytes and spermaries (abundance, gonadal index, and diameters) seem to be unaffected by low pH. However, a delay in spermary development in the pre-fertilization period and a persistence of mature oocytes in the fertilization period were observed in the most acidic site. Furthermore, no embryos were found in colonies from the two most acidic sites, suggesting a delay or an interruption of the fertilization process due to acidified conditions. These findings suggest a negative effect of low pH on A. calycularis sexual reproduction. However, long-term experiments, including the synergistic impact of pH and temperature, are needed to predict if this species will be able to adapt to climate change over the next century
Acclimatization of a coral-dinoflagellate mutualism at a CO2 vent
Ocean acidification caused by shifts in ocean carbonate chemistry resulting from increased
atmospheric CO2 concentrations is threatening many calcifying organisms, including corals.
Here we assessed autotrophy vs heterotrophy shifts in the Mediterranean zooxanthellate
scleractinian coral Balanophyllia europaea acclimatized to low pH/high pCO2 conditions at a
CO2 vent off Panarea Island (Italy). Dinoflagellate endosymbiont densities were higher at
lowest pH Sites where changes in the distribution of distinct haplotypes of a host-specific
symbiont species, Philozoon balanophyllum, were observed. An increase in symbiont C/N
ratios was observed at low pH, likely as a result of increased C fixation by higher symbiont
cell densities. δ13C values of the symbionts and host tissue reached similar values at the
lowest pH Site, suggesting an increased influence of autotrophy with increasing acidification.
Host tissue δ15N values of 0‰ strongly suggest that diazotroph N2 fixation is occurring
within the coral tissue/mucus at the low pH Sites, likely explaining the decrease in host tissue
C/N ratios with acidification. Overall, our findings show an acclimatization of this coral dinoflagellate mutualism through trophic adjustment and symbiont haplotype differences
with increasing acidification, highlighting that some corals are capable of acclimatizing to
ocean acidification predicted under end-of-century scenarios
Gains and losses of coral skeletal porosity changes with ocean acidification acclimation
Ocean acidification is predicted to impact ecosystems reliant on calcifying organisms, potentially reducing the socioeconomic benefits these habitats provide. Here we investigate the acclimation potential of stony corals living along a pH gradient caused by a Mediterranean CO(2) vent that serves as a natural long-term experimental setting. We show that in response to reduced skeletal mineralization at lower pH, corals increase their skeletal macroporosity (features >10 μm) in order to maintain constant linear extension rate, an important criterion for reproductive output. At the nanoscale, the coral skeleton's structural features are not altered. However, higher skeletal porosity, and reduced bulk density and stiffness may contribute to reduce population density and increase damage susceptibility under low pH conditions. Based on these observations, the almost universally employed measure of coral biomineralization, the rate of linear extension, might not be a reliable metric for assessing coral health and resilience in a warming and acidifying ocean
Gains and losses of coral skeletal porosity changes with ocean acidification acclimation
Ocean acidi\ufb01cation is predicted to impact ecosystems reliant on calcifying organisms, potentially reducing the socioeconomic bene\ufb01ts these habitats provide. Here we investigate the acclimation potential of stony corals living along a pH gradient caused by a Mediterranean CO2 vent that serves as a natural long-term experimental setting. We show that in response to reduced skeletal mineralization at lower pH, corals increase their skeletal macroporosity (features >10 micrometers) in order to maintain constant linear extension rate, an important criterion for reproductive output. At the nanoscale, the coral skeleton\u2019s structural features are not
altered. However, higher skeletal porosity, and reduced bulk density and stiffness may contribute to reduce population density and increase damage susceptibility under low pH conditions. Based on these observations, the almost universally employed measure of coral biomineralization, the rate of linear extension, might not be a reliable metric for assessing coral health and resilience in a warming and acidifying ocean
Growth and Demography of the Solitary Scleractinian Coral Leptopsammia pruvoti along a Sea Surface Temperature Gradient in the Mediterranean Sea
The demographic traits of the solitary azooxanthellate scleractinian Leptopsammia pruvoti were determined in six populations on a sea surface temperature (SST) gradient along the western Italian coasts. This is the first investigation of the growth and demography characteristics of an azooxanthellate scleractinian along a natural SST gradient. Growth rate was homogeneous across all populations, which spanned 7 degrees of latitude. Population age structures differed between populations, but none of the considered demographic parameters correlated with SST, indicating possible effects of local environmental conditions. Compared to another Mediterranean solitary scleractinian, Balanophyllia europaea, zooxanthellate and whose growth, demography and calcification have been studied in the same sites, L. pruvoti seems more tolerant to temperature increase. The higher tolerance of L. pruvoti, relative to B. europaea, may rely on the absence of symbionts, and thus the lack of an inhibition of host physiological processes by the heat-stressed zooxanthellae. However, the comparison between the two species must be taken cautiously, due to the likely temperature differences between the two sampling depths. Increasing research effort on determining the effects of temperature on the poorly studied azooxanthellate scleractinians may shed light on the possible species assemblage shifts that are likely to occur during the current century as a consequence of global climatic change
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