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Oceans, Volume 4, Issue 2 (June 2023) – 5 articles

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20 pages, 4428 KiB  
Article
Comparative Microbial Community Analysis of Fur Seals and Aquaculture Salmon Gut Microbiomes in Tasmania
by Erin D’Agnese, Ryan J. McLaughlin, Mary-Anne Lea, Esteban Soto, Woutrina A. Smith and John P. Bowman
Oceans 2023, 4(2), 200-219; https://doi.org/10.3390/oceans4020014 - 16 Jun 2023
Cited by 1 | Viewed by 2051
Abstract
In Tasmania, Australian fur seals (Arctocephalus pusillus doriferus) regularly interact with Atlantic salmon (Salmo salmar L.) aquaculture lease operations and opportunistically consume fish. The microbial communities of seals and aquaculture salmon were analyzed for potential indicators of microbial sharing and [...] Read more.
In Tasmania, Australian fur seals (Arctocephalus pusillus doriferus) regularly interact with Atlantic salmon (Salmo salmar L.) aquaculture lease operations and opportunistically consume fish. The microbial communities of seals and aquaculture salmon were analyzed for potential indicators of microbial sharing and to determine the potential effects of interactions on wild seal microbiome composition. The high-throughput sequencing of the V1–V3 region of the 16S rRNA genes from the gut microbial communities of 221 fur seals was performed: 41 males caught at farms, 50 adult scats from haul-outs near farms, 24 necropsied seals, and controls from Bass Strait breeding colonies, encompassing 56 adult scats and 50 pup swabs. QIIME2 and R Studio were used for analysis. Foraging at or near salmon farms significantly shifted seal microbiome biodiversity. Taxonomic analysis showed a greater divergence in Bacteroidota representatives in male seals captured at farms compared to all other groups. Pathogens were identified that could be monitoring targets. Potential indicator amplicon sequence variants were found across a variety of taxa and could be used as minimally invasive indicators for interactions at this interface. The diversity and taxonomic shifts in the microbial communities of seals indicate a need to further study this interface for broader ecological implications. Full article
(This article belongs to the Special Issue Marine Mammals in a Changing World, 2nd Edition)
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15 pages, 1706 KiB  
Article
Microbiome of Sri Lankan Coral Reefs: An Indian Ocean Island Subjected to a Gradient of Natural and Anthropogenic Impacts
by Mohamed F. M. Fairoz, Kevin T. Green, Kuwaja N. M. Sajith, Weerathunga A. S. Chamika, Amarasingha M. K. N. Kularathna, Saichetana Macherla, Douglas S. Naliboff, Ana Cobián-Güemes, Linda Wegley-Kelly and Forest Rohwer
Oceans 2023, 4(2), 185-199; https://doi.org/10.3390/oceans4020013 - 4 May 2023
Viewed by 2769
Abstract
Coral reefs around Sri Lanka have coexisted with human communities for thousands of years and are a continual source of food, economic productivity, and tourism. Although these reef systems sustain nearby populations, little is known about the presence or functional role of microbial [...] Read more.
Coral reefs around Sri Lanka have coexisted with human communities for thousands of years and are a continual source of food, economic productivity, and tourism. Although these reef systems sustain nearby populations, little is known about the presence or functional role of microbial communities on reefs dominated by hard corals or fleshy algae. Coral reef benthos cover was recorded, and reef-associated water samples were collected, sequenced and analyzed from seven coral reefs around Sri Lanka. Microbial metagenomes were analyzed to reveal both the taxonomic and metabolic makeup of the microbial communities present at each site. A metagenomic analysis of microbial phyla showed that Alphaproteobacteria and Gammaproteobacteria were most abundant, constituting up to 79.4% of microbial communities. At the order level, Rhodobacterales dominated the microbial communities across all sites, with the exception of the Paraviwella coral reef, where the order Alteromonadales dominated. A Principal Component Analysis (PCA) was performed using metagenomic sequence data to find the possible trends of interactions and drivers of taxonomic and metabolic community structure. This study is the first microbial metagenome dataset of coral reef associated water from the Indian Ocean continental island, Sri Lanka. These data further confirm the need for a comprehensive study of reefs in Sri Lanka aimed at elucidating the processes involved in microbial energy utilization. Full article
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15 pages, 2544 KiB  
Article
Seasonal Upwelling Conditions Modulate the Calcification Response of a Tropical Scleractinian Coral
by Carlos E. Gómez, Andrés Acosta-Chaparro, Cesar A. Bernal, Diana I. Gómez-López, Raúl Navas-Camacho and David Alonso
Oceans 2023, 4(2), 170-184; https://doi.org/10.3390/oceans4020012 - 18 Apr 2023
Cited by 2 | Viewed by 2369
Abstract
Natural processes such as upwelling of deeper-water masses change the physical-chemical conditions of the water column creating localized ocean acidification events that can have an impact on the natural communities. This study was performed in a coral reef system of an archetypical bay [...] Read more.
Natural processes such as upwelling of deeper-water masses change the physical-chemical conditions of the water column creating localized ocean acidification events that can have an impact on the natural communities. This study was performed in a coral reef system of an archetypical bay within the Tayrona National Natural Park (PNNT) (Colombia), and aimed to quantify net calcification rates of a foundational coral species within a temporal context (6 months) taking into account the dynamics of seasonal upwelling that influence the study area. Net calcification rates of coral fragments were obtained in situ by the alkalinity anomaly technique in short-term incubations (~2.5 h). We found a significant effect of the upwelling on net calcification rates (Gnet) (p < 0.05) with an 42% increase in CaCO3 accretion compared to non-upwelling season. We found an increase in total alkalinity (AT) and dissolved inorganic carbon (DIC) with decreased aragonite saturation (Ωara) for the upwelling months, indicating an influence of the Subtropical Under Water mass (SAW) in the PNNT coral community. Significant negative correlations between net calcification with temperature and Ωara, which indicates a positive response of M. auretenra with the upwelling conditions, thus, acting as “enhancer” of resilience for coral calcification. Full article
(This article belongs to the Special Issue Coral Reef Ecology and Biology)
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19 pages, 13085 KiB  
Article
Volatile Organic Compounds Released by Oxyrrhis marina Grazing on Isochrysis galbana
by Charel Wohl, Queralt Güell-Bujons, Yaiza M. Castillo, Albert Calbet and Rafel Simó
Oceans 2023, 4(2), 151-169; https://doi.org/10.3390/oceans4020011 - 4 Apr 2023
Viewed by 2424
Abstract
A range of volatile organic compounds (VOCs) have been found to be released during zooplankton grazing on microalgae cultivated for commercial purposes. However, production of grazing-derived VOCs from environmentally relevant species and their potential contribution to oceanic emissions to the atmosphere remains largely [...] Read more.
A range of volatile organic compounds (VOCs) have been found to be released during zooplankton grazing on microalgae cultivated for commercial purposes. However, production of grazing-derived VOCs from environmentally relevant species and their potential contribution to oceanic emissions to the atmosphere remains largely unexplored. Here, we aimed to qualitatively explore the suite of VOCs produced due to grazing using laboratory cultures of the marine microalga Isochrysis galbana and the herbivorous heterotrophic dinoflagellate Oxyrrhis marina with and without antibiotic treatment. The VOCs were measured using a Vocus proton-transfer-reaction time-of-flight mass spectrometer, coupled to a segmented flow coil equilibrator. We found alternative increases of dimethyl sulfide by up to 0.2 nmol dm−3 and methanethiol by up to 10 pmol dm−3 depending on the presence or absence of bacteria regulated by antibiotic treatment. Additionally, toluene and xylene increased by about 30 pmol dm−3 and 10 pmol dm−3, respectively during grazing only, supporting a biological source for these compounds. Overall, our results highlight that VOCs beyond dimethyl sulfide are released due to grazing, and prompt further quantification of this source in budgets and process-based understanding of VOC cycling in the surface ocean. Full article
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19 pages, 1404 KiB  
Article
Need for the Scuba Diving Industry to Interface with Science and Policy: A Case of SIDS Blue Workforce
by Zahidah Afrin Nisa
Oceans 2023, 4(2), 132-150; https://doi.org/10.3390/oceans4020010 - 23 Mar 2023
Cited by 1 | Viewed by 3439
Abstract
To achieve coral reef resilience under Agenda 2030, island governments need to institutionalise a competent blue workforce to expand their reef resilience initiatives across economic organisations and industries. The ability of island governments to shape new policies for sustainable island development relying on [...] Read more.
To achieve coral reef resilience under Agenda 2030, island governments need to institutionalise a competent blue workforce to expand their reef resilience initiatives across economic organisations and industries. The ability of island governments to shape new policies for sustainable island development relying on natural capital, such as coral reefs, has been hampered by structural and institutional deficiencies on both sides of the science-policy interface (SPI) at the UN. Using a qualitative research design, this article explores the science-policy interface (SPI) policy paper, Rebuilding Coral Reefs: A Decadal Grand Challenge and the role of this SPI in guiding UN coral reef financing for island states. This article uses the dive industry to investigate the needs of policymakers in island states via a conceptual framework for policy analysis. This article highlights the gaps of the SPI from the perspective of the global south and is beneficial for the islands selected under the Global Coral Reef Investment Plan. The article highlights the results of the SPI to island decision makers, which indicate that, without a policy framework that includes space for industrial policy within UN SPI, island governments will continue to fall into financial traps that constrain their efforts in operationalising their blue workforce. The study concludes that interlinked SDGs, such as SDG 9 and SDG 8, which focus on linking industrial innovation and infrastructure with decent work, as well as SDG 16 and 14.7, provide SIDS institutions with integrated policy approaches capable of bridging the divides between the scientific community, the diving industry, and island governments and that this needs to be further explored at all levels. Full article
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