Coral reefs have largely declined across multiple spatial scales due to a combination of local-scale anthropogenic impacts, and due to regional-global climate change. This has resulted in a significant loss of entire coral functional groups, including western Atlantic Staghorn coral (Acropora cervicornis) biotopes, and in a net decline of coral reef ecosystem resilience, ecological functions, services and benefits. Low-tech coral farming has become one of the most important tools to help restore depleted coral reefs across the Wider Caribbean Region. We tested a community-based, low-tech coral farming approach in Culebra Island, Puerto Rico, aimed at adapting to climate change-related impacts through a two-year project to propagate A. cervicornis under two contrasting fishing management conditions, in coastal areas experimenting significant land use changes. Extreme rainfall events and recurrent tropical storms and hurricanes had major site-and method-specific impacts on project outcome, particularly in areas adjacent to deforested lands and subjected to recurrent impacts from land-based source pollution (LBSP) and runoff. Overall, coral survival rate in "A frame" units improved from 73% during 2011-2012 to 81% during 2012-2013. Coral survival rate improved to 97% in horizontal line nurseries (HLN) incorporated
During development of the otic anlage, a certain proportion of epithelial cells migrate toward the mesenchymal compartment to form part of the acoustic-vestibular ganglion. The migrating cells are observed only in the zone of the otic anlage that will make contact with the acoustic-vestibular ganglion (so-called ganglion zone). In Hamburger and Hamilton's stages 13 to 16, the number of epithelial cells that migrate is relatively low, but it becomes steadily higher from stage 17 on. In the otic anlage of chick embryos, between developmental stages 9 and 21 (48 to 94 hours of incubation), mitotic index, apical or basal localization within the epithelium of dividing cells, and orientation of the mitotic spindles were analyzed. These features in the ganglion zone were compared with observations in the rest of the otic epithelium, where migratory processes do not take place. In stages 13 to 15, when few epithelial cells are migrating, the mitotic index (MI) in the ganglion zone of the otic anlage is similar to that in nonmigratory regions. In more advanced stages, however, when cell migration becomes accelerated, the MI in the migratory zone of the otic wall is significantly higher than that in the rest of the otic epithelium. This suggests an intimate relationship between the migration of otic epithelial cells and a high rate of cell proliferation, the possible nature of which is discussed. Although the majority of mitoses in the otic anlage are located at the apical surface of the epithelium, from stage 13 onward, a few dividing cells are seen in the basal third of the epithelium. Furthermore, these basal mitoses appear exclusively in the migratory zone of the otic anlage, thus suggesting a possible relationship between epithelial cell migration and basal mitosis. During the developmental period prior to stage 18, no significant differences in mitotic spindle orientation are noted between migratory and nonmigratory zones of the otic anlage. In contrast, in stages of maximal otic epithelial cell migration (stages 19 to 21), the frequency of mitoses with the spindle axis oriented radially is significantly higher in the migratory zone. These findings point toward a close correlation between increased frequency of radial mitotic spindle orientation and intense cell migration, although the exact nature of this relationship is as yet unknown.
Abstract:Coral reefs have largely declined across the northeastern Caribbean following the 2005 massive bleaching event. Climate change-related sea surface warming and coral disease outbreaks of a white plague-like syndrome and of yellow band disease (YBD) have caused significant coral decline affecting massive reef building species (i.e., Orbicella annularis species complex) which show no apparent signs of recovery through larval sexual recruitment. We addressed coral recruit densities across three spur and groove reef locations along the western shelf of remote Mona Island, Puerto Rico: Punta Capitán (PCA), Pasa de Las Carmelitas (PLC), and Las Carmelitas-South (LCS). Data were collected during November 2012 along 93 haphazard transects across three depth zones (<5m, 5-10m, 10-15m). A total of 32 coral species (9 octocorals, 1 hydrocoral, 22 scleractinians) were documented among the recruit community. Communities had low densities and dominance by short-lived brooder species seven years after the 2005 event. Mean coral recruit density ranged from 1.2 to 10.5/m 2 at PCA, 6.3 to 7.2/m 2 at LCS, 4.5 to 9.5/m 2 at PLC. Differences in coral recruit community structure can be attributed to slight variation in percent macroalgal cover and composition as study sites had nearly similar benthic spatial heterogeneity. Dominance by ephemeral coral species was widespread. Recovery of largely declining massive reef-building species such as the O. annularis species complex was limited or non-existent. The lack of recovery could be the combined result of several mechanisms involving climate change, YBD disease, macroalgae, fishing, urchins and Mona Island's reefs limited connectivity to other reef systems. There is also for rehabilitation of fish trophic structure, with emphasis in recovering herbivore guilds and depleted populations of D. antillarum. Failing to recognize the importance of ecosystem-based management and resilience rehabilitation may deem remote coral reefs recovery unlikely. Rev. Biol. Trop. 62 (Suppl. 3): 49-64. Epub 2014 September 01.Key words: Climate change, coral decline, coral recruitment, community trajectory, Mona Island, Puerto Rico, transitional state.Coral larval recruitment is critical for the maintenance of reef biodiversity, ecosystem resilience and benthic community recovery after disturbances across multiple spatial scales (Gittings, Bright, Choi & Barnett, 1988;Sammarco, 1991;Connell, Hughes & Wallace, 1997;Hughes & Tanner, 2000). Coral recruitment refers to the stage when new members of the recently settled juvenile corals become visible to be censused (Harrison & Wallace, 1990). Open reef space is necessary for settling larvae (Hughes & Connell, 1999;Kuffner et al., 2006; Díaz-Pulido et al., 2009), particularly substrates along cryptical microhabitats and areas dominated by crustose coralline algae (CCA), which are recognized by coral larvae (Doropoulos, Ward, Díaz-Pulido, Hoegh-Guldberg & Mumby, 2012). Dynamic processes leading to the creation of free space open for colonization are impor...
Timely information is critical for coral reef managers and decision-makers to implement sustainable management measures. A Coral Reef Resilience Index (CRRI) was developed with a GIS-coupled decision-making tool applicable for Caribbean coral reef ecosystems. The CRRI is based on a five-point scale parameterized from the quantitative characterization of benthic assemblages. Separate subindices such as the Coral Index, the Threatened Species Index, and the Algal Index also provide specific information regarding targeted benthic components. This case study was based on assessments conducted in 2014 on 11 reef sites located across 3 geographic zones and 3 depth zones along the southwestern shelf of the island of Puerto Rico, Caribbean Sea. There was a significant spatial and bathymetric gradient (p < 0.05) in the distribution of CRRI values indicating higher degradation of inshore reefs. Mean global CRRI ranged from 2.78 to 3.17 across the shelf, ranking them as "fair." The Coral Index ranged from 2.60 to 3.76, ranking reefs from "poor" to "good," showing a general cross-shelf trend of improving conditions with increasing distance from pollution sources. Turbidity and ammonia were significantly correlated to CRRI scores. Multiple recommendations are provided based on coral reef conditions according to observed CRRI rankings.
In addition to mitoses of neuroepithelial cells at the ventricular surface of the chick embryo optic stalk, mitoses in nonventricular stalk zones begin to be observed from stage 19 on. These latter represent the division phase of glioblasts detached from the ventricular surface. Thus, the topographical location of mitotic cells could be considered a morphological marker of neuroepithelial and glioblast populations in the optic stalk. Quantitative analysis of ventricular (VMCs) and extraventricular (EMCs) mitotic cells revealed that the total number of VMCs decreases through the developmental stages studied, while the number of EMCs simultaneously increases exponentially. These results suggest that the glioblast population arises from both division of the early glioblasts and progressive transformation of neuroepithelial cells. The first EMCs in the ventral region of the stalk wall are observed in stage 19, previous to the stages in which the first EMCs appear in the dorsal region. Moreover, EMCs are much more numerous in the ventral than in the dorsal stalk wall in all stages analysed. Keeping in mind that the invasion of the stalk by optic fibre fascicles occurs essentially in the ventral region, these results suggest that EMCs are strongly related to axon fascicle outgrowth in the stalk. Cell division features are different in neuroepithelial cell and glioblast populations, as the proportions of the mitotic phases differ in VMCs and EMCs. In addition, the patterns of mitotic spindle orientation in VMCs and EMCs are also different. In the former, orientations are predominantly longitudinal parallel and transverse parallel, with a smaller proportion of radial mitoses, which are slightly more frequent through stages 23 to 28 than in earlier development.(ABSTRACT TRUNCATED AT 250 WORDS)
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.