24 research outputs found
Lipid biomarkers in Symbiodinium dinoflagellates : new indicators of thermal stress
Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Coral Reefs 32 (2013): 923-934, doi:10.1007/s00338-013-1076-3.Lipid content and fatty acid profiles of corals and their dinoflagellate endosymbionts are known to vary in response to high temperature stress. To better understand the heat stress response in these symbionts, we investigated cultures of Symbiodinium goreauii type C1 and Symbiodinium clade subtype D1 grown under a range of temperatures and durations. The predominant lipids produced by Symbiodinium are palmitic (C16) and stearic (C18) saturated fatty acids and their unsaturated analogs, docosahexaenoic (C22:6, n-3) polyunsaturated fatty acid (PUFA), and a variety of sterols. The relative amount of unsaturated acids within the C18 fatty acids in Symbiodinium tissue decreases in response to thermal stress. Prolonged exposure to high temperature also causes a decrease in abundance of fatty acids relative to sterols. These shifts in fatty acids and sterols are common to both types C1 and D1, but the apparent thermal threshold of lipid changes is lower for type C1. This work indicates that ratios among free fatty acids and sterols in Symbiodinium can be used as sensitive indicators of thermal stress. If the Symbdionium lipid stress response is unchanged in hospite, the algal heat stress biomarkers we have identified could be measured to detect thermal stress within the coral holobiont.. These results provide new insights into the potential role of lipids in the overall Symbiodinium thermal stress response.This research was supported by Award No. USA 00002 to K. Hughen made by King Abdullah University of Science and Technology (KAUST).2014-12-0
Incidence of lesions on Fungiidae corals in the eastern Red Sea is related to water temperature and coastal pollution
Author Posting. © The Author(s), 2014. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Marine Environmental Research 98 (2014): 29-38, doi:10.1016/j.marenvres.2014.04.002.As sea surface temperatures rise and the global human population increases, large-scale
field observations of marine organism health and water quality are increasingly
necessary. We investigated the health of corals from the family Fungiidae using visual
observations in relation to water quality and microbial biogeochemistry parameters along
1300 km of the Red Sea coast of Saudi Arabia. At large scales, incidence of lesions
caused by unidentified etiology showed consistent signs, increasing significantly from the
northern to southern coast and positively correlated to annual mean seawater
temperatures. Lesion abundance also increased to a maximum of 96% near the populous
city of Jeddah. The presence of lesioned corals in the region surrounding Jeddah was strongly correlated with elevated concentrations of ammonium and changes in microbial
communities that are linked to decreased water quality. This study suggests that both high
seawater temperatures and nutrient pollution may play an indirect role in the formation of
lesions on corals.This research was supported by Award No. USA 00002 to K. Hughen by King Abdullah
University of Science and Technology (KAUST) and a WHOI Ocean Life Institute
postdoctoral scholar fellowship to A. Apprill
Symbiont Diversity of Zooxanthellae (Symbiodinium Spp.) In Porities Astreoides and Montastraea Cavernosa from a Reciprocal Transplant in the Lower Florida Keys
In recent years, coral reefs worldwide have suffered high mortality rates due to coral bleaching, a phenomenon contributing to a 40% decrease in coral cover in the Florida Keys since the 1997/98 El Niño event. In the Florida Keys, coral from inshore reefs are known to be more thermotolerant than their conspecifics from offshore reefs but the mechanism behind this difference is unclear. In this study we conducted a two-year, reciprocal transplant of Porites astreoides and Montastraea cavernosa from an inshore and offshore reef in the lower Florida Keys to determine if changes in the dominant symbiotic algae (Symbiodinium spp.) could explain variation in holobiont tolerance as well as to assess the possibility of acclimatization to a changing stress regime. Increased complexity and diversity was demonstrated in the composition of Symbiodinium spp. from both coral species collected at the offshore reef when compared to conspecifics collected inshore. As a result of this complexity, the offshore reef samples displayed higher numbers of transitions of zooxanthellae subclade types between seasons, while inshore fragments demonstrated more stability and may explain previously measured thermotolerance. Additionally, the known thermotolerant subclade type D1 was associated with one M. cavernosa fragment from the inshore reef. When fragments were transplanted, compositional patterns of Symbiodinium spp. were retained from site of collection, indicating a lack of acclimatization to a new environment over the lengthy two-year experiment. These results demonstrate variability in the dominant Symbiodinium spp. of P. astreoides and M. cavernosa conspecifics from inshore and offshore reefs in the lower Florida Keys and point to possible patterns in holobiont thermotolerance. This variability may be key to the continued persistence of these species in the face of climate change, but future studies are needed to determine the mechanisms and range in which these subclade types withstand thermal stress
Coral-based proxy calibrations constrain ENSO-driven sea surface temperature and salinity gradients in the Western Pacific Warm Pool
© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Mohtar, A. T., Hughen, K. A., Goodkin, N. F., Streanga, I., Ramos, R. D., Samanta, D., Cervino, J., & Switzer, A. D. Coral-based proxy calibrations constrain ENSO-driven sea surface temperature and salinity gradients in the Western Pacific Warm Pool. Palaeogeography Palaeoclimatology Palaeoecology, 561, (2021): 110037, doi:10.1016/j.palaeo.2020.110037.Constraining past variability in ocean conditions in the Western Pacific Warm Pool (WPWP) and examining how it has been influenced by the El-Niño Southern Oscillation (ENSO) is critical to predicting how these systems may change in the future. To characterize the spatiotemporal variability of the WPWP and ENSO during the past three decades, we analyzed climate proxies using coral cores sampled from Porites spp. from Kosrae Island (KOS) and Woleai Atoll (WOL) in the Federated States of Micronesia. Coral skeleton samples drilled along the major growth axis were analyzed for oxygen isotopes (δ18Oc) and trace element ratios (Sr/Ca), used to reconstruct sea surface salinity and temperature (SSS and SST). Pseudocoral δ18O time series (δ18Opseudo) were calculated from gridded instrumental observations and compared to δ18Oc, followed by fine-tuning using coral Sr/Ca and gridded SST, to produce age models for each coral. The thermal component of δ18Oc was removed using Sr/Ca for SST, to derive δ18O of seawater (δ18Osw), a proxy for SSS. The Sr/Ca, and δ18Osw records were compared to instrumental SST and SSS to test their fidelity as regional climate recorders. We found both sites display significant Sr/Ca-SST calibrations at monthly and interannual (dry season, wet season, mean annual) timescales. At each site, δ18Osw also exhibited significant calibrations to SSS across the same timescales. The difference between normalized dry season SST (Sr/Ca) anomalies from KOS and WOL generates a zonal SST gradient (KOSWOLSST), capturing the east-west WPWP migration observed during ENSO events. Similarly, the average of normalized dry season δ18Osw anomalies from both sites produces an SSS index (KOSWOLSSS) reflecting the regional hydrological changes. Both proxy indices, KOSWOLSST and KOSWOLSSS, are significantly correlated to regional ENSO indices. These calibration results highlight the potential for extending the climate record, revealing spatial hydrological gradients within the WPWP and ENSO variability back to the end of the Little Ice Age.We also thank the crew of the M/V Alucia for assistance during the 2012 coral drilling expedition to FSM, funded by the Dalio Family Foundation through a WHOI Access to The Sea grant to KAH (#25110104). Geochemical analysis was funded by Singapore Ministry of Education Academic Research Fund Tier-2 (# MOE2016-T2-1016) to NFG and KAH, and by the WHOI Summer Student Fellowship Program (00450400) and Coastal Preservation Network 501c to IMS
Identification of PLCL1 Gene for Hip Bone Size Variation in Females in a Genome-Wide Association Study
Osteoporosis, the most prevalent metabolic bone disease among older people, increases risk for low trauma hip fractures (HF) that are associated with high morbidity and mortality. Hip bone size (BS) has been identified as one of the key measurable risk factors for HF. Although hip BS is highly genetically determined, genetic factors underlying the trait are still poorly defined. Here, we performed the first genome-wide association study (GWAS) of hip BS interrogating ∼380,000 SNPs on the Affymetrix platform in 1,000 homogeneous unrelated Caucasian subjects, including 501 females and 499 males. We identified a gene, PLCL1 (phospholipase c-like 1), that had four SNPs associated with hip BS at, or approaching, a genome-wide significance level in our female subjects; the most significant SNP, rs7595412, achieved a p value of 3.72×10−7. The gene's importance to hip BS was replicated using the Illumina genotyping platform in an independent UK cohort containing 1,216 Caucasian females. Two SNPs of the PLCL1 gene, rs892515 and rs9789480, surrounded by the four SNPs identified in our GWAS, achieved p values of 8.62×10−3 and 2.44×10−3, respectively, for association with hip BS. Imputation analyses on our GWAS and the UK samples further confirmed the replication signals; eight SNPs of the gene achieved combined imputed p values<10−5 in the two samples. The PLCL1 gene's relevance to HF was also observed in a Chinese sample containing 403 females, including 266 with HF and 177 control subjects. A SNP of the PLCL1 gene, rs3771362 that is only ∼0.6 kb apart from the most significant SNP detected in our GWAS (rs7595412), achieved a p value of 7.66×10−3 (odds ratio = 0.26) for association with HF. Additional biological support for the role of PLCL1 in BS comes from previous demonstrations that the PLCL1 protein inhibits IP3 (inositol 1,4,5-trisphosphate)-mediated calcium signaling, an important pathway regulating mechanical sensing of bone cells. Our findings suggest that PLCL1 is a novel gene associated with variation in hip BS, and provide new insights into the pathogenesis of HF
Variation in immune-related gene expression provides evidence of local adaptation in Porites astreoides (Lamarck, 1816) between inshore and offshore meta-populations inhabiting the lower Florida Reef Tract, USA
© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Haslun, J. A., Hauff-Salas, B., Strychar, K. B., Cervino, J. M., & Ostrom, N. E. Variation in immune-related gene expression provides evidence of local adaptation in Porites astreoides (Lamarck, 1816) between inshore and offshore meta-populations inhabiting the lower Florida Reef Tract, USA. Water, 13(15), (2021): 2107, https://doi.org/10.3390/w13152107.Coral communities of the Florida Reef Tract (FRT) have changed dramatically over the past 30 years. Coral cover throughout the FRT is disproportionately distributed; >70% of total coral cover is found within the inshore patch reef zone (5 km from shore). Coral mortality from disease has been differentially observed between inshore and offshore reefs along the FRT. Therefore, differences between the response of inshore and offshore coral populations to bacterial challenge may contribute to differences in coral cover. We examined immune system activation in Porites astreoides (Lamarck, 1816), a species common in both inshore and offshore reef environments in the FRT. Colonies from a representative inshore and offshore site were reciprocally transplanted and the expression of three genes monitored biannually for two years (two summer and two winter periods). Variation in the expression of eukaryotic translation initiation factor 3, subunit H (eIF3H), an indicator of cellular stress in Porites astreoides, did not follow annual patterns of seawater temperatures (SWT) indicating the contribution of other stressors (e.g., irradiance). Greater expression of tumor necrosis factor (TNF) receptor associated factor 3 (TRAF3), a signaling protein of the inflammatory response, was observed among corals transplanted to, or located within the offshore environment indicating that an increased immune response is associated with offshore coral more so than the inshore coral (p < 0.001). Corals collected from the offshore site also upregulated the expression of adenylyl cyclase associated protein 2 (ACAP2), increases which are associated with decreasing innate immune system inflammatory responses, indicating a counteractive response to increased stimulation of the innate immune system. Activation of the innate immune system is a metabolically costly survival strategy. Among the two reefs studied, the offshore population had a smaller mean colony size and decreased colony abundance compared to the inshore site. This correlation suggests that tradeoffs may exist between the activation of the innate immune system and survival and growth. Consequently, immune system activation may contribute to coral community dynamics and declines along the FRT.We thank the Annis Water Resources Institute for both a graduate fellowship and research funding associated with this project, and Grand Valley State University for a Presidential Research Grant. We thank Michigan State University RTSF and the Integrative Biology Department at Michigan State University (Graduate Fellowship), and the Coastal Preservation Network (Award 250542). We also thank Erich Bartels and the Mote Marine Tropical Research Laboratory staff for their help with field and laboratory help and Jeff Landgraf for qRT-PCR help. This work could not have been completed without the help of the staff at Florida Keys National Marine Sanctuary (FKNMS) for providing permit number FKNMS-2011-10 allowing this research to take place
Decreased photosynthetic efficiency in response to site translocation and elevated temperature is mitigated with LPS exposure in Porites astreoides symbionts
© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Harman, T. E., Hauff-Salas, B., Haslun, J. A., Cervino, J. M., & Strychar, K. B. Decreased photosynthetic efficiency in response to site translocation and elevated temperature is mitigated with LPS exposure in Porites astreoides symbionts. Water, 14(3), (2022): 366, https://doi.org/10.3390/w14030366.Coral reefs have been detrimentally impacted causing health issues due to elevated ocean temperatures as a result of increased greenhouse gases. Extreme temperatures have also exacerbated coral diseases in tropical reef environments. Numerous studies have outlined the impacts of thermal stress and disease on coral organisms, as well as understanding the influence of site-based characteristics on coral physiology. However, few have discussed the interaction of all three. Laboratory out-planting restoration projects have been of importance throughout impacted areas such as the Caribbean and southern Florida in order to increase coral cover in these areas. This study analyzes photosynthetic efficiency of Porites astreoides from the lower Florida Keys after a two-year reciprocal transplant study at inshore (Birthday reef) and offshore (Acer24 reef) sites to understand acclimation capacity of this species. Laboratory experiments subjected these colonies to one of three treatments: control conditions, increases in temperature, and increases in temperature plus exposure to an immune stimulant (lipopolysaccharide (LPS)) to determine their influence on photosynthetic efficiency and how stress events impact these measurements. In addition, this study is a continuation of previous studies from this group. Here, we aim to understand if these results are static or if an acclimation capacity could be found. Overall, we observed site-specific influences from the Acer24 reef site, which had significant decreases in photosynthetic efficiencies in 32 °C treatments compared to Birthday reef colonies. We suggest that high irradiance and lack of an annual recovery period from the Acer24 site exposes these colonies to significant photoinhibition. In addition, we observed significant increases in photosynthetic efficiencies from LPS exposure. We suggest host-derived antioxidants can mitigate the negative impacts of increased thermal stress. Further research is required to understand the full complexity of host immunity and symbiont photosynthetic interactions.We thank the Annis Water Resources Institute for both a graduate fellowship and research funding associated with this project, and Grand Valley State University for a Presidential Research Grant. We also thank Michigan State University RTSF and the Integrative Biology Department at Michigan State University (Graduate Fellowship), and the Coastal Preservation Network (Award 250542) for additional funding opportunities
Sediment input and evolution of lacustrine deltas:The Breggia and Greggio rivers case study (Lake Como, Italy).
<div><p>Scleractinian coral are experiencing unprecedented rates of mortality due to increases in sea surface temperatures in response to global climate change. Some coral species however, survive high temperature events due to a reduced susceptibility to bleaching. We investigated the relationship between bleaching susceptibility and expression of five metabolically related genes of <i>Symbiodinium</i> spp. from the coral <i>Porites astreoides</i> originating from an inshore and offshore reef in the Florida Keys. The acclimatization potential of <i>Symbiodinium</i> spp. to changing temperature regimes was also measured <i>via</i> a two-year reciprocal transplant between the sites. Offshore coral fragments displayed significantly higher expression in <i>Symbiodinium</i> spp. genes <i>PCNA</i>, <i>SCP2</i>, <i>G3PDH</i>, <i>PCP</i> and <i>psaE</i> than their inshore counterparts (p<0.05), a pattern consistent with increased bleaching susceptibility in offshore corals. Additionally, gene expression patterns in <i>Symbiodinium</i> spp. from site of origin were conserved throughout the two-year reciprocal transplant, indicating acclimatization did not occur within this multi-season time frame. Further, laboratory experiments were used to investigate the influence of acute high temperature (32°C for eight hours) and disease (lipopolysaccharide of <i>Serratia marcescens</i>) on the five metabolically related symbiont genes from the same offshore and inshore <i>P</i>. <i>astreoides</i> fragments. Gene expression did not differ between reef fragments, or as a consequence of acute exposure to heat or heat and disease, contrasting to results found in the field. Gene expression reported here indicates functional variation in populations of <i>Symbiodinium</i> spp. associated with <i>P</i>. <i>astreoides</i> in the Florida Keys, and is likely a result of localized adaptation. However, gene expression patterns observed in the lab imply that functional variation in zooxanthellae observed under conditions of chronic moderate stress is lost under the acute extreme conditions studied here.</p></div
Relationship of Vibrio Species Infection and Elevated Temperatures to Yellow Blotch/Band Disease in Caribbean Corals
The bacterial and temperature factors leading to yellow blotch/band disease (YBD), which affects the major reef-building Caribbean corals Montastrea spp., have been investigated. Groups of bacteria isolated from affected corals and inoculated onto healthy corals caused disease signs similar to those of YBD. The 16S rRNA genes from these bacteria were sequenced and found to correspond to four Vibrio spp. Elevating the water temperature notably increased the rate of spread of YBD on inoculated corals and induced greater coral mortality. YBD-infected corals held at elevated water temperatures had 50% lower zooxanthella densities, 80% lower division rates, and a 75% decrease in chlorophyll a and c(2) pigments compared with controls. Histological sections indicated that the algal pyrenoid was fragmented into separate segments, along with a reconfiguration and swelling of the zooxanthellae, as well as vacuolization. YBD does not appear to produce the same physiological response formerly observed in corals undergoing temperature-related bleaching. Evidence indicates that YBD affects primarily the symbiotic algae rather than coral tissue