scholarly journals Investigating densities of Symbiodiniaceae in two species of Antipatharians (black corals) from Madagascar

2021 ◽  
Author(s):  
Erika Gress ◽  
Igor Eeckhaut ◽  
Mathilde Godefroid ◽  
Philippe Dubois ◽  
Jonathan Richir ◽  
...  

AbstractHere, we report the first methodological approach to investigate the presence and estimate the density of Symbiodiniaceae cells in corals of the order Antipatharia subclass Hexacorallia, known as black corals. Antipatharians are understudied ecosystem engineers of shallow (<30 m depth), mesophotic (30-150 m) and deep-sea (>200 m) reefs. They provide habitat to a vast number of marine fauna, enhancing and supporting coral reefs biodiversity globally. Nonetheless, little biological and ecological information exists on antipatharians, including the extent at which global change disturbances are threatening these corals. The assumption that they were exempted from threats related to climate change was challenged by findings of high density of dinoflagellates within three antipatharian colonies. Further methodical studies were necessary to investigate the regularity of these findings. An integrated design combining microscopy and molecular techniques was used to investigate the presence and estimate density of Symbiodiniaceae cells within two antipatharians species -Cupressopathes abies and Stichopathes maldivensis -from shallow and mesophotic reefs of SW Madagascar. Symbiodiniaceae-like cells were found within the two species from both shallow and mesophotic reefs, although the overall cell density was very low (0-4 cell mm-3). These findings suggest that high abundance of Symbiodiniaceae is not characteristic of antipatharians, which has relevant implications considering disruptions associated to climate change affecting other corals. However, the high densities of dinoflagellates found in antipatharian colonies exposed to higher light irradiance in other studies should be further examined.

Oceans ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 772-784
Author(s):  
Erika Gress ◽  
Igor Eeckhaut ◽  
Mathilde Godefroid ◽  
Philippe Dubois ◽  
Jonathan Richir ◽  
...  

Here, we report a new broad approach to investigating the presence and density of Symbiodiniaceae cells in corals of the order Antipatharia subclass Hexacorallia, commonly known as black corals. Antipatharians are understudied ecosystem engineers of shallow (<30 m depth), mesophotic (30–150 m) and deep-sea (>200 m) reefs. They provide habitat to numerous organisms, enhancing and supporting coral reef biodiversity globally. Nonetheless, little biological and ecological information exists on antipatharians, including the extent to which global change disturbances are threatening their health. The previous assumption that they were exempted from threats related to the phenomenon known as bleaching was challenged by the recent findings of high densities of dinoflagellates within three antipatharian colonies. Further studies were thus necessary to investigate the broader uniformity of these findings. Here we report results of an integrated methodology combining microscopy and molecular techniques to investigate the presence and estimate the density of Symbiodiniaceae cells within two antipatharians species—Cupressopathes abies and Stichopathes maldivensis—from both shallow and mesophotic reefs of SW Madagascar. We found that Symbiodiniaceae-like cells were present within samples of both species collected from both shallow and mesophotic reefs, although the overall cell density was very low (0–4 cell mm−3). These findings suggest that presence or high abundance of Symbiodiniaceae is not characteristic of all antipatharians, which is relevant considering the bleaching phenomenon affecting other corals. However, the possibility of higher densities of dinoflagellates in other antipatharians or in colonies exposed to higher light irradiance deserves further investigation.


2020 ◽  
Vol 637 ◽  
pp. 159-180
Author(s):  
ND Gallo ◽  
M Beckwith ◽  
CL Wei ◽  
LA Levin ◽  
L Kuhnz ◽  
...  

Natural gradient systems can be used to examine the vulnerability of deep-sea communities to climate change. The Gulf of California presents an ideal system for examining relationships between faunal patterns and environmental conditions of deep-sea communities because deep-sea conditions change from warm and oxygen-rich in the north to cold and severely hypoxic in the south. The Monterey Bay Aquarium Research Institute (MBARI) remotely operated vehicle (ROV) ‘Doc Ricketts’ was used to conduct seafloor video transects at depths of ~200-1400 m in the northern, central, and southern Gulf. The community composition, density, and diversity of demersal fish assemblages were compared to environmental conditions. We tested the hypothesis that climate-relevant variables (temperature, oxygen, and primary production) have more explanatory power than static variables (latitude, depth, and benthic substrate) in explaining variation in fish community structure. Temperature best explained variance in density, while oxygen best explained variance in diversity and community composition. Both density and diversity declined with decreasing oxygen, but diversity declined at a higher oxygen threshold (~7 µmol kg-1). Remarkably, high-density fish communities were observed living under suboxic conditions (<5 µmol kg-1). Using an Earth systems global climate model forced under an RCP8.5 scenario, we found that by 2081-2100, the entire Gulf of California seafloor is expected to experience a mean temperature increase of 1.08 ± 1.07°C and modest deoxygenation. The projected changes in temperature and oxygen are expected to be accompanied by reduced diversity and related changes in deep-sea demersal fish communities.


Metabolites ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 107
Author(s):  
Rafael de Felício ◽  
Patricia Ballone ◽  
Cristina Freitas Bazzano ◽  
Luiz F. G. Alves ◽  
Renata Sigrist ◽  
...  

Bacterial genome sequencing has revealed a vast number of novel biosynthetic gene clusters (BGC) with potential to produce bioactive natural products. However, the biosynthesis of secondary metabolites by bacteria is often silenced under laboratory conditions, limiting the controlled expression of natural products. Here we describe an integrated methodology for the construction and screening of an elicited and pre-fractionated library of marine bacteria. In this pilot study, chemical elicitors were evaluated to mimic the natural environment and to induce the expression of cryptic BGCs in deep-sea bacteria. By integrating high-resolution untargeted metabolomics with cheminformatics analyses, it was possible to visualize, mine, identify and map the chemical and biological space of the elicited bacterial metabolites. The results show that elicited bacterial metabolites correspond to ~45% of the compounds produced under laboratory conditions. In addition, the elicited chemical space is novel (~70% of the elicited compounds) or concentrated in the chemical space of drugs. Fractionation of the crude extracts further evidenced minor compounds (~90% of the collection) and the detection of biological activity. This pilot work pinpoints strategies for constructing and evaluating chemically diverse bacterial natural product libraries towards the identification of novel bacterial metabolites in natural product-based drug discovery pipelines.


2021 ◽  
Vol 13 (12) ◽  
pp. 6517
Author(s):  
Innocent Chirisa ◽  
Trynos Gumbo ◽  
Veronica N. Gundu-Jakarasi ◽  
Washington Zhakata ◽  
Thomas Karakadzai ◽  
...  

Reducing vulnerability to climate change and enhancing the long-term coping capacities of rural or urban settlements to negative climate change impacts have become urgent issues in developing countries. Developing countries do not have the means to cope with climate hazards and their economies are highly dependent on climate-sensitive sectors such as agriculture, water, and coastal zones. Like most countries in Southern Africa, Zimbabwe suffers from climate-induced disasters. Therefore, this study maps critical aspects required for setting up a strong financial foundation for sustainable climate adaptation in Zimbabwe. It discusses the frameworks required for sustainable climate adaptation finance and suggests the direction for success in leveraging global climate financing towards building a low-carbon and climate-resilient Zimbabwe. The study involved a document review and analysis and stakeholder consultation methodological approach. The findings revealed that Zimbabwe has been significantly dependent on global finance mechanisms to mitigate the effects of climate change as its domestic finance mechanisms have not been fully explored. Results revealed the importance of partnership models between the state, individuals, civil society organisations, and agencies. Local financing institutions such as the Infrastructure Development Bank of Zimbabwe (IDBZ) have been set up. This operates a Climate Finance Facility (GFF), providing a domestic financial resource base. A climate change bill is also under formulation through government efforts. However, numerous barriers limit the adoption of adaptation practices, services, and technologies at the scale required. The absence of finance increases the vulnerability of local settlements (rural or urban) to extreme weather events leading to loss of life and property and compromised adaptive capacity. Therefore, the study recommends an adaptation financing framework aligned to different sectoral policies that can leverage diverse opportunities such as blended climate financing. The framework must foster synergies for improved impact and implementation of climate change adaptation initiatives for the country.


Eos ◽  
1988 ◽  
Vol 69 (25) ◽  
pp. 668
Author(s):  
S.I. Rasool

Author(s):  
Phillip J Turner ◽  
Matthew Gianni ◽  
Ellen Kenchington ◽  
Sebastian Valanko ◽  
David E Johnson

Abstract The European Union’s deep-sea fisheries regulations (Regulation (EU) No. 2016/2336) established obligations to manage deep-sea fisheries and to protect vulnerable marine ecosystems (VMEs). The European Commission is scheduled to complete a review of the regulations in 2021, providing an opportunity for new scientific information to be incorporated into the implementation of the regulations. Here, we summarise research outputs from the EU-funded Horizon 2020 ATLAS Project and explain their relevance to the regulation of deep-sea fisheries in EU waters. ATLAS research has increased our understanding of the distribution of VMEs and their importance in terms of ecosystem functioning. ATLAS research has also highlighted the utility of molecular techniques to understand fish population structure and the potential for habitat suitability models to help incorporate climate change into decision-making. Building on these scientific advances, we provide recommendations to help increase the effectiveness of management measures to conserve deep-sea fish stocks and protect VMEs.


Zootaxa ◽  
2018 ◽  
Vol 4526 (4) ◽  
pp. 401 ◽  
Author(s):  
ÁNGEL VALDÉS ◽  
LONNY LUNDSTEN ◽  
NERIDA G. WILSON

Increased exploration of northeastern Pacific deep-sea habitats has revealed a diverse and often poorly-known invertebrate community, including a number of undescribed species of nudibranchs studied herein. We used morphology to distinguish several new species from their congeners, and generated data where possible for mitochondrial (COI, 16S) and nuclear markers (H3) to place them in a phylogenetic context. We described here Tritonia nigritigris sp. nov., Dendronotus claguei sp. nov., Ziminella vrijenhoeki sp. nov., Cuthona methana sp. nov., Aeolidia libitinaria sp. nov. and redescribed Zeusia herculea (Bergh, 1894). Another species of Tritonia is described but not named due to the absence of reproductive system information. Although there are difficulties in collection from deep-sea habitats, only two of our new species are known from single specimens. As with many other deep-sea regions, we expect the number of new species from this region to increase with further exploration. Because the deep regions of the northeast Pacific are particularly vulnerable to the effects of decreasing oxygenation due to climate change, we consider that documenting this fauna has some level of urgency. 


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