rocky shore
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2023 ◽  
Vol 83 ◽  
Author(s):  
P. De Los Ríos-Escalante ◽  
C. Esse ◽  
C. Stella ◽  
P. Adikesavan ◽  
O. Zúñiga

Abstract The intertidal rocky shores in continental Chile have high species diversity mainly in northern Chile (18-27° S), and one of the most widespread species is the gastropod Echinolittorina peruviana (Lamarck, 1822). The aim of the present study is do a first characterization of spatial distribution of E. peruviana in along rocky shore in Antofagasta town in northern Chile. Individuals were counted in nine different sites that also were determined their spectral properties using remote sensing techniques (LANDSAT ETM+). The results revealed that sites without marked human intervention have more abundant in comparison to sites located in the town, also in all studied sites was found an aggregated pattern, and in six of these sites were found a negative binomial distribution. The low density related to sites with human intervention is supported when spectral properties for sites were included. These results would agree with other similar results for rocky shore in northern and southern Chile.


Author(s):  
Carlos Sanz-Lazaro ◽  
Nuria Casado-Coy ◽  
Aitor Navarro-Ortín ◽  
Marc Terradas-Fernández

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12550
Author(s):  
Romina Vanessa Barbosa ◽  
Cédric Bacher ◽  
Fred Jean ◽  
Yoann Thomas

Individual traits and population parameters can be used as proxies of processes taking place within a range of scales, thus improving the way we can evaluate species response to environmental variability. In intertidal rocky shores, patterns at the within-site scale, i.e., between centimeters to hundreds of meters, are important for understanding the population response into these highly variable environments. Here, we studied a rocky-shore mussel population at the within-site spatial scale (1) to test how intertidal height and orientation of the shore affect individual traits and population parameters, (2) to infer the link between individual and population level features, and (3) to explore the upscaling mechanisms driving population structure and processes. We analyzed the patterns of six population parameters: density, biomass, crowding, median individual size, recruitment and mortality rate, and four individual traits: growth rate, spawning phenology, size and condition index. Crowding was defined as the degree of overlapping of individuals within a given area, for which we created a “crowding index”. Mussels were studied along the intertidal height gradient in two rocky shores with contrasted orientation at one site over a full year. Our results showed a significant effect of intertidal height and shore orientation on most of individual traits and population parameters studied. In contrast, biomass contained in a full covered surface did not vary in space nor in time. This pattern likely results from relatively constant crowding and a trade-off between median individuals’ size and density. We hypothesize that growth, mortality and recruitment rates may all play roles in the stability of the crowding structure of mussel aggregations. Variation in spawning phenology between the two shores in the study site was also observed, suggesting different temporal dynamics of microclimate conditions. Interestingly, despite the different population size distribution between the two shores, our estimates indicate similar potential reproductive output. We hypothesize that the structure of the patches would tend to maintain or carry a maximum of biomass due to trade-offs between density and size while maintaining and maximizing the reproductive output. The patterns of spatial variability of individual traits and population parameters in our study site suggest that heterogeneous within-site conditions influence variation in individual performance and population processes. These results provide insights about the relationship between individual traits and how these relationships make patterns at the population level emerge. They provide baseline information necessary to improve models of metapopulation with spatially explicit processes.


2021 ◽  
Author(s):  
◽  
Jennifer N. Howe

<p>Photosynthetic dinoflagellates of the genus Symbiodinium form symbiotic relationships with many marine hosts, including cnidarian corals and sea anemones. This partnership is extremely successful in tropical waters leading to a great diversity of coral species and Symbiodinium types. Environmental condition in the tropics are stable, changes to which can lead to destabilization of the symbiotic interactions between the host and symbiont, which in turn can lead to total breakdown of the partnership and expulsion of the symbiont. Temperate symbiotic cnidarian species, especially sea anemones, are less common but locally abundant. Environmental conditions are highly variable with extreme differences in light and temperature. Adaptation to these conditions has led to the success of resilient partnerships, but also to less diversity of Symbiodinium types. This study looked at the relationship between the endemic New Zealand anemone, Anthopleura aureoradiata, and its symbiotic relationship with the Symbiodinium cells it harbours. The aim was to determine why and how this symbiotic relationship is so resilient to the temperate conditions by 1) determining the molecular identity of the Symbiodinium spp. within the anemone, throughout its latitudinal range and through the seasons, and whether any seasonal changes differed between two habitats, the rocky shore and mudflats; 2) comparing the identity of the Symbiodinium spp. in New Zealand with those from four species of anemones from Europe (Cereus pedunculatus, Anthopleura ballii and Anemonia viridis from the south-west of England and Aiptasia mutabilis from Brittany (France)) to establish any differences or similarities between the northern and southern hemispheres; 3) determining whether resilience to environmental conditions is attributed to the Symbiodinium photoprotective mechanisms. A. aureoradiata were collected in early autumn in five sites from the top (Parengarenga Harbour) to the bottom (Stewart Island) of New Zealand for the latitudinal study. Seasonal anemones were collected from a rocky shore in Wellington Harbour (Point Halswell, Kau Bay) and a mudflat at Pauatahanui Inlet. Symbiodinium types were identified to subcladal level using ITS2 sequencing. A low diversity of types was found, with all anemones harbouring algal cells identified as being similar, or identical to, Symbiodinium sp. Mediterranean clade A (Med clade A) and Symbiodinium sp. Amed (Amed). 96.55% of the anemones from the latitudinal study, all the winter anemones, 87.50% of the summer anemones and almost 78% of the autumn anemones harboured Symbiodinium cells most similar or identical to Med clade A. All Symbiodinium sequences from the European anemones also were identified as being similar or identical to Med clade A or Amed, suggesting that the Symbiodinium in A. aureoradiata are likely not endemic. It is not known whether anemones harbour both types simultaneously and whether a change in dominant symbiont type occurs with seasons within anemones by “shuffling”.  The photophysiology of the Symbiodinium cells isolated from the anemones was studied using an Imaging-PAM fluorometer whilst being maintained in six light and temperature treatments. The photosynthetic rate of PSII, energy quenching by NPQ, and photosystem recovery were measured to determine whether the Symbiodinium cells had a strong capacity for photoprotection and were able to down-regulate quickly to reduce photodamage to the chloroplast. The main outcome of this study is that the Symbiodinium cells within A. aureoradiata are very effective in protecting themselves against photo-damage by activating an efficient NPQ system. Down-regulation of the quantum efficiency of PSII under high light conditions appeared to cease altogether. Whether this was a true measurement of down-regulation to stop photodamage, or whether these clade A types use an alternative electron transport that bypasses PSII, and can therefore not be measured with the I-PAM fluorometer technique used, needs to be addressed in future studies.</p>


2021 ◽  
Author(s):  
◽  
Jennifer N. Howe

<p>Photosynthetic dinoflagellates of the genus Symbiodinium form symbiotic relationships with many marine hosts, including cnidarian corals and sea anemones. This partnership is extremely successful in tropical waters leading to a great diversity of coral species and Symbiodinium types. Environmental condition in the tropics are stable, changes to which can lead to destabilization of the symbiotic interactions between the host and symbiont, which in turn can lead to total breakdown of the partnership and expulsion of the symbiont. Temperate symbiotic cnidarian species, especially sea anemones, are less common but locally abundant. Environmental conditions are highly variable with extreme differences in light and temperature. Adaptation to these conditions has led to the success of resilient partnerships, but also to less diversity of Symbiodinium types. This study looked at the relationship between the endemic New Zealand anemone, Anthopleura aureoradiata, and its symbiotic relationship with the Symbiodinium cells it harbours. The aim was to determine why and how this symbiotic relationship is so resilient to the temperate conditions by 1) determining the molecular identity of the Symbiodinium spp. within the anemone, throughout its latitudinal range and through the seasons, and whether any seasonal changes differed between two habitats, the rocky shore and mudflats; 2) comparing the identity of the Symbiodinium spp. in New Zealand with those from four species of anemones from Europe (Cereus pedunculatus, Anthopleura ballii and Anemonia viridis from the south-west of England and Aiptasia mutabilis from Brittany (France)) to establish any differences or similarities between the northern and southern hemispheres; 3) determining whether resilience to environmental conditions is attributed to the Symbiodinium photoprotective mechanisms. A. aureoradiata were collected in early autumn in five sites from the top (Parengarenga Harbour) to the bottom (Stewart Island) of New Zealand for the latitudinal study. Seasonal anemones were collected from a rocky shore in Wellington Harbour (Point Halswell, Kau Bay) and a mudflat at Pauatahanui Inlet. Symbiodinium types were identified to subcladal level using ITS2 sequencing. A low diversity of types was found, with all anemones harbouring algal cells identified as being similar, or identical to, Symbiodinium sp. Mediterranean clade A (Med clade A) and Symbiodinium sp. Amed (Amed). 96.55% of the anemones from the latitudinal study, all the winter anemones, 87.50% of the summer anemones and almost 78% of the autumn anemones harboured Symbiodinium cells most similar or identical to Med clade A. All Symbiodinium sequences from the European anemones also were identified as being similar or identical to Med clade A or Amed, suggesting that the Symbiodinium in A. aureoradiata are likely not endemic. It is not known whether anemones harbour both types simultaneously and whether a change in dominant symbiont type occurs with seasons within anemones by “shuffling”.  The photophysiology of the Symbiodinium cells isolated from the anemones was studied using an Imaging-PAM fluorometer whilst being maintained in six light and temperature treatments. The photosynthetic rate of PSII, energy quenching by NPQ, and photosystem recovery were measured to determine whether the Symbiodinium cells had a strong capacity for photoprotection and were able to down-regulate quickly to reduce photodamage to the chloroplast. The main outcome of this study is that the Symbiodinium cells within A. aureoradiata are very effective in protecting themselves against photo-damage by activating an efficient NPQ system. Down-regulation of the quantum efficiency of PSII under high light conditions appeared to cease altogether. Whether this was a true measurement of down-regulation to stop photodamage, or whether these clade A types use an alternative electron transport that bypasses PSII, and can therefore not be measured with the I-PAM fluorometer technique used, needs to be addressed in future studies.</p>


2021 ◽  
Author(s):  
◽  
Christopher Lynton Gibbons

<p>This study investigated the algal density and growth, photophysiology and contribution of algae to animal respiration requirements (CZAR), in the symbiosis between the sea anemone Anthopleura aureoradiata and its dinoflagellate symbionts (zooxanthellae) under field and laboratory conditions. A. aureoradiata was collected during summer and winter on sunny and cloudy days from a rocky shore and mudflat environment. Algal densities displayed a trend of being 2.6 and 1.7 times greater during summer than winter on the mudflat on a sunny and cloudy day respectively. Algal division was asynchronous under field conditions over a daily period, and was 2.1 and 1.3 times greater on the rocky shore and mudflat respectively, during winter than summer on sunny days. Under field conditions, the efficiency and maximum rate of photosynthesis (per cell and per association) as well as respiration rate, were all greater during summer than winter. Cloud cover resulted in a difference in a higher maximum rate of photosynthesis per cell on a sunny day than a cloudy day within summer at Kau Bay. Additionally, these photosynthetic parameters and respiration rate were all greater on the rocky shore than mudflat while the photosynthetic compensation irradiance was greater on the mudflat. The CZAR was greatest on the rocky shore during summer on a sunny day (151%) and was also > 100% on a cloudy day in summer at this same site (129%); on the mudflat the CZAR was greatest during summer on a sunny day (89%). The CZAR was measured to be zero during winter at both sites during winter on cloudy days. Additionally, under laboratory conditions A. aureoradiata was exposed to gradual (GTC) and rapid (RTC) temperature changes. While under GTC and RTC, the algal density did not vary, though higher temperatures led to an increase in algal division. Under both GTC and RTC, the photosynthetic efficiency, maximum photosynthetic rate (per cell and per association) and respiration rate all increased with temperature, however under GTC these parameters all decreased between 32.5 [degrees]C and 35 [degrees] C. Photosynthetic compensation irradiance increased with temperature under both GTC and RTC until 30 [degrees] C, after which respiration exceeded maximum photosynthesis, meaning that photosynthetic compensation did not occur. Furthermore, photosynthetic saturation irradiance increased with temperature and peaked at 15 [degrees] C before declining with temperature under both GTC and RTC. The CZAR under GTC increased with temperature until it peaked at 15 [degrees] C (128%), before decreasing to zero at 30 [degrees] C - 35 [degrees] C. Under RTC, the CZAR was zero for all temperatures except at 10 [degrees] C where it was 25.1%. A CZAR < 100% may suggest that the symbiosis between A. aureoradiata and its zooxanthellae is parasitic under most conditions and at most times of the year. Alternatively, there may be some benefit to the symbiosis due to a competitive advantage over other macro-invertebrate species as a result of carbon translocation from the symbiont providing extra support for reproduction and growth. This study also showed A. aureoradiata to have a wide temperature tolerance reflecting the fluctuating conditions of a variable temperate environment. The wide temperature tolerance of this species suggests that it will tolerate short term (50 - 100 years) increases in ocean temperatures however, the threat beyond this time frame with other factors such as ocean acidification remains to be determined.</p>


2021 ◽  
Author(s):  
◽  
Christopher Lynton Gibbons

<p>This study investigated the algal density and growth, photophysiology and contribution of algae to animal respiration requirements (CZAR), in the symbiosis between the sea anemone Anthopleura aureoradiata and its dinoflagellate symbionts (zooxanthellae) under field and laboratory conditions. A. aureoradiata was collected during summer and winter on sunny and cloudy days from a rocky shore and mudflat environment. Algal densities displayed a trend of being 2.6 and 1.7 times greater during summer than winter on the mudflat on a sunny and cloudy day respectively. Algal division was asynchronous under field conditions over a daily period, and was 2.1 and 1.3 times greater on the rocky shore and mudflat respectively, during winter than summer on sunny days. Under field conditions, the efficiency and maximum rate of photosynthesis (per cell and per association) as well as respiration rate, were all greater during summer than winter. Cloud cover resulted in a difference in a higher maximum rate of photosynthesis per cell on a sunny day than a cloudy day within summer at Kau Bay. Additionally, these photosynthetic parameters and respiration rate were all greater on the rocky shore than mudflat while the photosynthetic compensation irradiance was greater on the mudflat. The CZAR was greatest on the rocky shore during summer on a sunny day (151%) and was also > 100% on a cloudy day in summer at this same site (129%); on the mudflat the CZAR was greatest during summer on a sunny day (89%). The CZAR was measured to be zero during winter at both sites during winter on cloudy days. Additionally, under laboratory conditions A. aureoradiata was exposed to gradual (GTC) and rapid (RTC) temperature changes. While under GTC and RTC, the algal density did not vary, though higher temperatures led to an increase in algal division. Under both GTC and RTC, the photosynthetic efficiency, maximum photosynthetic rate (per cell and per association) and respiration rate all increased with temperature, however under GTC these parameters all decreased between 32.5 [degrees]C and 35 [degrees] C. Photosynthetic compensation irradiance increased with temperature under both GTC and RTC until 30 [degrees] C, after which respiration exceeded maximum photosynthesis, meaning that photosynthetic compensation did not occur. Furthermore, photosynthetic saturation irradiance increased with temperature and peaked at 15 [degrees] C before declining with temperature under both GTC and RTC. The CZAR under GTC increased with temperature until it peaked at 15 [degrees] C (128%), before decreasing to zero at 30 [degrees] C - 35 [degrees] C. Under RTC, the CZAR was zero for all temperatures except at 10 [degrees] C where it was 25.1%. A CZAR < 100% may suggest that the symbiosis between A. aureoradiata and its zooxanthellae is parasitic under most conditions and at most times of the year. Alternatively, there may be some benefit to the symbiosis due to a competitive advantage over other macro-invertebrate species as a result of carbon translocation from the symbiont providing extra support for reproduction and growth. This study also showed A. aureoradiata to have a wide temperature tolerance reflecting the fluctuating conditions of a variable temperate environment. The wide temperature tolerance of this species suggests that it will tolerate short term (50 - 100 years) increases in ocean temperatures however, the threat beyond this time frame with other factors such as ocean acidification remains to be determined.</p>


2021 ◽  
Vol 8 ◽  
Author(s):  
Diana Boaventura ◽  
Ana Teresa Neves ◽  
Jaime Santos ◽  
Paula Colares Pereira ◽  
Cristina Luís ◽  
...  

To enable the process of energy transition towards carbon neutrality, it is important to educate the community on the need for social, economic, environmental and institutional transformation, and to educate and inform citizens to participate proactively in this change. This study evaluated the effectiveness of participation by elementary school students in educational activities and citizen science actions in enhancing their scientific knowledge and skills related to Ocean Literacy in the context of climate change. The activities were directed to children (aged 9–11) and involved pre-service teachers, in-service teachers and researchers, in formal and non-formal contexts. A total of 329 elementary school students participated in interdisciplinary science activities, focusing on the cause &amp; effect of climate change in the ocean. They learned to identify rocky shore marine species used to monitor climate change and acquired ICT skills by inserting species observations in a biodiversity mapping platform. Finally, students worked collaboratively to communicate to the community what they have learned through an exhibition at the Museum João de Deus. To assess the impact of the activities on acquisition of scientific knowledge and skills by the students, a mixed methodology was applied using pre and post-tests, analysis of the data inserted by students in the platform, and content analysis of the students’ work for the museum exhibition. The results of pre and post-tests revealed a significant increase in knowledge of the effects of climate change on the rocky shore species distribution, as well as of the importance of monitoring these species distribution. The data from the online biodiversity platform showed that 42% of the species identifications made by the students were correct. The ability of the students to communicate their learning to the wider community was evaluated by the scientific content, structure, presentation and creativity and of posters, models, videos and games produced. Most of students focused their communications and creations on the greenhouse effect, cause &amp; effect of climate change in the ocean and biodiversity. This study reinforces the importance of addressing Ocean Literacy and climate change through formal and non-formal educational activities with an investigative nature.


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