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 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 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.

Participating in a Citizen Science Monitoring Program: Implications for Environmental Education.

Tourism is of growing economical importance to many nations, in particular for developing countries. Although tourism is an important economic vehicle for the host country, its continued growth has led to on-going concerns about its environmental sustainability. Coastal and marine tourism can directly affect the environment through direct and indirect tourist activities. For these reasons tourism sector needs practical actions of sustainability. Several studies have shown how education minimizes the impact on and is proactive for, preserving the natural resources. This paper evaluates the effectiveness of a citizen science program to improve the environmental education of the volunteers, by means of questionnaires provided to participants to a volunteer-based Red Sea coral reef monitoring program (STEproject). Fifteen multiple-choice questions evaluated the level of knowledge on the basic coral reef biology and ecology and the awareness on the impact of human behaviour on the environment. Volunteers filled in questionnaires twice, once at the beginning, before being involved in the project and again at the end of their stay, after several days participation in the program. We found that the participation in STEproject significantly increased both the knowledge of coral reef biology and ecology and the awareness of human behavioural impacts on the environment, but was more effective on the former. We also detected that tourists with a higher education level have a higher initial level of environmental education than less educated people and that the project was more effective on divers than snorkelers. This study has emphasized that citizen science projects have an important and effective educational value and has suggested that tourism and diving stakeholders should increase their commitment and efforts to these programs.

Redox-Based Flagging of the Global Network of Oxidative Stress Greatly Promotes Longevity.

Despite more than 50 years of investigations into the free radical theory, the direct role of oxidative stress (OS) in aging and age-related diseases remains unproven. Little progress in identifying antioxidant drugs promoting longevity has been made, likely due to selectivity toward one or few radical species, variable efficacy in vivo, inherent pro-oxidant behavior of such drugs, or lack of synergism with metabolic redox homeostasis. Silencing the wide range of reactive free radicals has a great impact on OS-linked outcomes and age-related disorders. Here we show that an innovative, redox-active, multi-radical-scavenger catalytic drug delays the age-associated decline in physiological processes and markedly prolongs the mean lifespan of the adult freshwater annelids Aeolosoma viride by 170%. This unprecedented extension is associated with a decreased OS status. Consistently, treatment of annelids increases their natural resistance to oxygen-derived damage without affecting mitochondrial respiration or reproductive activity. Conversely, the superoxide dismutase (SOD)-mimetic EUK 134 that we selected as a positive control led to an increase in lifespan of ~50%, the same increase previously observed in nematodes. Our results show that reduction of the global network of OS has a profound impact on aging, prompting the development of a possible redox-based therapeutic intervention to counteract the progression of aging.

Biomineralization control related to population density under ocean acidification.

Anthropogenic CO2 is a major driver of current environmental change in most ecosystems1, and the related ocean acidification (OA) is threatening marine biota2. With increasing pCO2, calcification rates of several species decrease3, although cases of up-regulation are observed4. Here, we show that biological control over mineralization relates to species abundance along a natural pH gradient. As pCO2 increased, the mineralogy of a scleractinian coral (Balanophyllia europaea) and a mollusc (Vermetus triqueter) did not change. In contrast, two calcifying algae (Padina pavonica and Acetabularia acetabulum) reduced and changed mineralization with increasing pCO2, from aragonite to the less soluble calcium sulphates and whewellite, respectively. As pCO2 increased, the coral and mollusc abundance was severely reduced, with both species disappearing at pH < 7.8. Conversely, the two calcifying and a non-calcifying algae (Lobophora variegata) showed less severe or no reductions with increasing pCO2, and were all found at the lowest pH site. The mineralization response to decreasing pH suggests a link with the degree of control over the biomineralization process by the organism, as only species with lower control managed to thrive in the lowest pH.

How the Reorganization Free Energy Affects the Reduction Potential of Structurally Homologous Cytochromes.

Differences in the reduction potential E(0) among structurally similar metalloproteins cannot always be fully explained on the basis of their 3-D structures. We investigate the molecular determinants to E(0) using the mixed quantum mechanics/molecular mechanics approach named perturbed matrix method (PMM); after comparison with experimental values to assess the reliability of our calculations, we investigate the relationship between the change in free energy upon reduction ΔA(0) and the reorganization energy. We find that the reduction potential of cytochromes can be regarded as the result of the sum of two terms, one being mostly dependent on the energy fluctuations within a limited range around the mean transition energy and the second being mostly dependent linearly on the difference Δλ = λred - λox of the reorganization free energies for the ox → red (λred) and for the red → ox (λox) relaxations.

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.

Unusual pattern of embryogenesis of Caryophyllia inornata (Scleractinia, Caryophylliidae) in the Mediterranean sea: maybe agamic reproduction?

While knowledge of the reproductive biology of tropical scleractinian corals is extensive, information from temperate zones is limited. The aim of this study is to describe the reproductive biology of Caryophyllia inornata, a temperate species, and to increase the understanding of the reproductive strategies of Mediterranean corals. Samples of C. inornata were collected during SCUBA surveys at Elba island. Sexually active individuals displayed either male or female germ cells, showing a gonochoric sexuality. C. inornata exhibited an unusual pattern of embryogenesis. Embryos appeared throughout the whole year in males and in sexually inactive individuals, and they did not show a seasonal pattern of development, as usually expected for sexual reproduction. This observation suggests the possibility of asexual origin. These embryogenetic sexually inactive individuals were larger in size than the embryogenetic sexually active ones, and they might be senile polyps that preserve the ability to produce embryos only by agamic reproduction.

Environmental implications of skeletal micro-density and porosity variation in two scleractinian corals.

The correlations between skeletal parameters (bulk density, micro-density and porosity), coral age and sea surface temperature were assessed along a latitudinal gradient in the zooxanthellate coral Balanophyllia europaea and in the azooxanthellate coral Leptopsammia pruvoti. In both coral species, the variation of bulk density was more influenced by the variation of porosity than of micro-density. With increasing polyp age, B. europaea formed denser and less porous skeletons while L. pruvoti showed the opposite trend, becoming less dense and more porous. B. europaea skeletons were generally less porous (more dense) than those of L. pruvoti, probably as a consequence of the different habitats colonized by the two species. Increasing temperature had a negative impact on the zooxanthellate species, leading to an increase of porosity. In contrast, micro-density increased with temperature in the azooxanthellate species. It is hypothesized that the increase in porosity with increasing temperatures observed in B. europaea could depend on an attenuation of calcification due to an inhibition of the photosynthetic process at elevated temperatures, while the azooxanthellate species appears more resistant to variations of temperature, highlighting possible differences in the sensitivity/tolerance of these two coral species to temperature changes in face of global climate change.

Unite research with what citizens do for fun: "recreational monitoring" of marine biodiversity.

Institutes often lack funds and manpower to perform large-scale biodiversity monitoring. Citizens can be involved, contributing to the collection of data, thus decreasing costs. Underwater research requires specialist skills and SCUBA certification, and it can be difficult to involve volunteers. The aim of this study was to involve large numbers of recreational divers in marine biodiversity monitoring for increasing the environmental education of the public and collecting data on the status of marine biodiversity. Here we show that thousands of recreational divers can be enrolled in a short time. Using specially formulated questionnaires, nonspecialist volunteers reported the presence of 61 marine taxa encountered during recreational dives, performed as regular sport dives. Validation trials were carried out to assess the accuracy and consistency of volunteer-recorded data, and these were compared to reference data collected by an experienced researcher. In the majority of trials (76%) volunteers performed with an accuracy and consistency of 50-80%, comparable to the performance of conservation volunteer divers on precise transects in other projects. The recruitment of recreational divers involved the main diving and tour operators in Italy, a popular scientific magazine, and mass media. During the four-year study, 3825 divers completed 18757 questionnaires, corresponding to 13539 diving hours. The volunteer-sightings-based index showed that in the monitored area the biodiversity status did not change significantly within the project time scale, but there was a significant negative correlation with latitude, suggesting improved quality in the southernmost areas. This trend could be related to the presence of stressors in the northern areas and has been supported by investigations performed by the Italian Ministry of the Environment. The greatest limitation with using volunteers to collect data was the uneven spatial distribution of samples. The benefits were the considerable amounts of data collected over short time periods and at low costs. The successful development of citizen-based monitoring programs requires open-mindedness in the academic community; advantages of citizen involvement in research are not only adding large data sets to the ecological knowledge base but also aiding in the environmental education of the public.

Morphological aspects of gonadal morphogenesis in Bufo bufo (Amphibia Anura): Bidder's organ differentiation.

We have described the architecture of Bidder's organ, defined its compartmented structure, and affirmed the presence of basal laminae. We did not find morphological differences between sexes in Bidder's organ. All specimens initially developed gonads with a peripheral fertile layer surrounding a thin primary cavity. The first oogenetic wave was observed early, showing all phases of meiosis, including leptotene, zygotene, and pachytene, which had been previously thought to be lacking. The peculiar presence of an asynchronous germ cell nest was discussed. Diplotene oocytes issued from the peripheral layer and migrated inside the primary cavity. They were surrounded by a single layer of follicular cells, which originated from the peripheral layer somatic cells and were delimited by a basal lamina. There were few medulla or central layer cells. At the end of metamorphosis, while the oocytes of the first oogenetic wave came into close contact with blood vessels, a second oogenetic wave took place just as the first, except for the presence of synchronous germ cell nests. The central layer was not visible and we did not observe the formation of an ovarian pocket. Stocks of stem germ cells remained in the peripheral layer during both the first and second oogenetic waves. The asymmetric model, in which there is a tendency toward a primary female differentiation, was confirmed. The female differentiation becomes stable in the Bidder's organ because of the absence of further interaction between germ and medullary somatic cells, which would have led toward a male differentiation.

Tsunami survey expedition: preliminary investigation of Maldivian coral reefs two weeks after the event.

On December 26th 2004, a earthquake west of Sumatra generated a devastating tsunami. Hundreds of thousands of people fell victim. Economic losses were greatest in those countries dependant on tourism. The impact in the Maldives on persons and things was modest. Immediately following the event and notwithstanding the lack of scientific data, the mass media gave catastrophic reports on the state of coral reefs in the area. This paper reports on the first survey on coral reefs in the Maldives after the Tsunami. Ocean walls, passes, inner reefs, and shoals in the North and South Malé atolls, were surveyed two weeks after the event. Significant damage was recorded in the passes in the South Malé atoll. Our observations showed that the damage was more or less extensive depending on latitude and topography. Sri Lanka may have broken the wave's rush, reducing the extent of the impact on northern atolls. The water's acceleration inside the passes was so intense as to cause reef collapses. The observed damage represents a minimum fraction of the entire coral reef system. Tourist perception of the area seems unchanged. These data may be used to disseminate correct information about the state of Maldives coral reefs, which would be useful in relaunching local economy.

Ultrastructural aspects of gonadal morphogenesis in Bufo bufo (Amphibia Anura) 1. Sex differentiation.

The morphogenesis of gonads in Bufo bufo tadpoles was studied, and ultrastructural differences between sexes were identified. All specimens analyzed initially developed gonads made up of a peripheral fertile layer (cortex) surrounding a small primary cavity. Subsequently a central layer of somatic cells (medulla) developed. Both layers were separated by two uninterrupted basal laminae between which a vestige of the primary cavity persisted. During female differentiation, the peripheral layer continued to be the fertile layer. In males, the central layer blended into the peripheral layer and the basal laminae disappeared. The somatic cells of the central layer came into direct contact with the germ cells; this did not occur in females. Testicular differentiation continued with the migration of germ cells towards the center of the gonad. The somatic elements surrounding the germ cells appeared to play an active role in their transfer to the center of the gonad. The peripheral layer shrank and became sterile. Two basal laminae then re-formed to separate the fertile central layer from the peripheral sterile one. Germ cells have always been thought to perform a passive role in sex differentiation in amphibians. Following the generally accepted "symmetric model", the mechanism of gonad development is symmetrical, with cortical somatic cells determining ovarian differentiation and medullary somatic cells determining testicular differentiation. In contrast, we found that sex differentiation follows an "asymmetric" pattern in which germ cells tend primarily toward a female differentiation and male differentiation depends on a secondary interaction between germ cells and medullary somatic cells.