Journal Articles - UP - MSI
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- Microscopic stages of North Atlantic Laminaria digitata (Phaeophyceae) exhibit trait-dependent thermal adaptation along latitudesSchimpf, Nele M.; Liesner, Daniel; Franke, Kiara; Roleda, Michael Y.; Bartsch, Inka (Frontiers Media SA, 2022-06-17)Kelp forests in the North Atlantic are at risk of decline at their warm temperature distribution margins due to anthropogenic temperature rise and more frequent marine heat waves. To investigate the thermal adaptation of the cold-temperate kelp Laminaria digitata, we sampled six populations, from the Arctic to Brittany (Spitsbergen, Tromsø, Bodø [all Norway], Helgoland [Germany], Roscoff and Quiberon [both France]), across the species’ entire distribution range, spanning 31.5° latitude and 12-13°C difference in mean summer sea surface temperature. We used pooled vegetative gametophytes derived from several sporophytes to approximate the genetic diversity of each location. Gametophytes were exposed to (sub-) lethal high (20-25°C) and (sub-) optimal low (0-15°C) temperature gradients in two full-factorial, common-garden experiments, subjecting subsets of populations from different origins to the same conditions. We assessed survival of gametophytes, their ability to develop microscopic sporophytes, and subsequent growth. We hypothesized that the thermal performance of gametophytes and microscopic sporophytes corresponds to their local long-term thermal history. Integrated gametophyte survival revealed a uniform upper survival temperature (UST) of 24°C among five tested populations (Tromsø to Quiberon). In contrast, following two weeks of thermal priming of gametophytes at 20-22°C, sporophyte formation at 15°C was significantly higher in southern populations (Quiberon and Roscoff) compared to the high-latitude population of Tromsø. Between 0-15°C, survival of the Arctic population (Spitsbergen) was negatively correlated with increasing temperatures, while the southern-most population (Quiberon) showed the opposite. Thus, responses of survival at low, and sporophyte formation at high temperatures, support the concept of local adaption. On the other hand, sporophyte formation between 0-15°C peaked at 6-9°C in the Quiberon and at 9-12°C in the Spitsbergen population. Sporophyte growth rates (GR) both in length and width were similar for Spitsbergen, Tromsø and Quiberon; all had maximum GRs at 12-15°C and low GRs at 0-6°C. Therefore, responses of sporophyte formation and growth at low temperatures do not reflect ecotypic adaptation. We conclude that L. digitata populations display trait-dependent adaptation, partly corresponding to their local temperature histories and partly manifesting uniform or unpredictable responses. This suggests differential selection pressures on the ontogenetic development of kelps such as L. digitata.We would like to thank A. Wagner for the sampling and clonal isolation of kelp material and technical assistance in the laboratory, C. Daniel for support with the image analysis, L. Foqueau for the SST data, C. Gauci for statistical advice and S. DeAmicis for supervision in this BSc Thesis.
- Microbiome diversity and host immune functions influence survivorship of sponge holobionts under future ocean conditionsPosadas, Niño; Baquiran, Jake Ivan P; Nada, Michael Angelou L; Kelly, Michelle; Conaco, Cecilia (Oxford University Press, 2021-07-03)The sponge-associated microbial community contributes to the overall health and adaptive capacity of the sponge holobiont. This community is regulated by the environment and the immune system of the host. However, little is known about the effect of environmental stress on the regulation of host immune functions and how this may, in turn, affect sponge–microbe interactions. In this study, we compared the bacterial diversity and immune repertoire of the demosponge, Neopetrosia compacta, and the calcareous sponge, Leucetta chagosensis, under varying levels of acidification and warming stress based on climate scenarios predicted for 2100. Neopetrosia compacta harbors a diverse microbial community and possesses a rich repertoire of scavenger receptors while L. chagosensis has a less diverse microbiome and an expanded range of pattern recognition receptors and immune response-related genes. Upon exposure to RCP 8.5 conditions, the microbiome composition and host transcriptome of N. compacta remained stable, which correlated with high survival (75%). In contrast, tissue necrosis and low survival (25%) of L. chagosensis was accompanied by microbial community shifts and downregulation of host immune-related pathways. Meta-analysis of microbiome diversity and immunological repertoire across poriferan classes further highlights the importance of host–microbe interactions in predicting the fate of sponges under future ocean conditions.We thank Francis Kenith Adolfo, Robert Valenzuela, and Ronald De Guzman for field and hatchery assistance and staff of the Bolinao Marine Laboratory for logistical support. This study was funded by the Department of Science and Technology Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development (QMSR-MRRD-MEC-295-1449) to CC.
- Individual and interactive effects of ocean warming and acidification on adult Favites colemaniTañedo, Mikhael Clotilde S.; Villanueva, Ronald D.; Torres, Andrew F.; Ravago-Gotanco, Rachel; San Diego-McGlone, Maria Lourdes (Frontiers Media SA, 2021-09-09)Tropical coral reefs are threatened by local-scale stressors that are exacerbated by global ocean warming and acidification from the post-industrial increase of atmospheric CO2 levels. Despite their observed decline in the past four decades, little is known on how Philippine coral reefs will respond to ocean warming and acidification. This study explored individual and synergistic effects of present-day (pH 8.0, 28°C) and near-future (pH 7.7, 32°C) scenarios of ocean temperature and pH on the adult Favites colemani, a common massive reef-building coral in Bolinao-Anda, Philippines. Changes in seawater temperature drive the physiological responses of F. colemani, whereas changes in pH create an additive effect on survival, growth, and photosynthetic efficiency. Under near-future scenarios, F. colemani showed sustained photosynthetic competency despite the decline in growth rate and zooxanthellae density. F. colemani exhibited specificity with the Cladocopium clade C3u. This coral experienced lower growth rates but survived projected near-future ocean warming and acidification scenarios. Its pH-thermal stress threshold is possibly a consequence of acclimation and adaptation to local environmental conditions and past bleaching events. This research highlights the importance of examining the susceptibility and resilience of Philippine corals to climate-driven stressors for future conservation and restoration efforts in the changing ocean.We are grateful to the Marine Biogeochemistry Laboratory and Bolinao Marine Laboratory of the Marine Science Institute, University of the Philippines for the valuable logistical and laboratory support provided. We would also like to thank Drs. Haruko Kurihara, Atsushi Watanabe, and Toshihiro Miyajima for the design of the mass flow controller used in the experiments. This is UP-MSI contribution number 484.
- Passive greenhouse heating, recirculation, and nutrient addition for nursery phase Tridacna gigas: Growth boost during winter monthsBraley, Richard D.; Sutton, David; Mingoa, S. Suzanne M.; Southgate, Paul C. (Elsevier, 1992-11)The impetus for this study was winter-related mortality of juvenile Tridacna gigas along Australia's Great Barrier Reef. Heating nursery tank water by passive solar heating in a greenhouse and the addition of dissolved inorganic nitrogen (DIN) was assessed for effect on the growth and survival of cultured juvenile clams. Two age classes of T. gigas were used, with means of 1.2 cm and 17.0 cm shell length. Treatments consisted of nutrient-spikes of 20 μ M and 40 μ M ammonium chloride daily or on alternate days, plus s spike of 2.3 μ M phosphate once per week vs. controls without nutrient addition. Three rearing systems were used: (1) recirculating water enclosed in a greenhouse; (2) flow-through water enclosed in a greenhouse; (3) flow-through water with ambient conditions. In the older clams growth in weight was best in system 2, while growth in shell length (SL) was best in system 1, and DIN treatments significantly increased growth compared with controls. In the younger clams, growth in SL was best in system 1. DIN treatments produced significantly greater growth than controls, but there was no difference between 20-μ M and 40-μ M treatments. Survival was 100% for larger clams but for smaller clams mean survival was highest overall in system 1, while 20-μ M DIN treatments within systems produced the best overall survival. The highest levels of DIN in the nursery tanks were found in the 40-μ M DIN treatments, particularly in system 1. The wet tissue weight/shell length ratio for 40-μ M DIN treatments was highest in system 1 and decreased in systems 2 and 3, while controls were similar. Dry shell weight/shell length was highest in the 40-μ M DIN treatment over the control in system 1 only. The zooxanthellae index (no. of algal cells/g clam) was significantly higher in the 40-μ M DIN treatment than in the control in all three systems. Biochemical analysis of whole animals showed higher carbohydrate content in system 2 and in treatments receiving 20 μ M DIN. Tissue protein content did not differ significantly between systems but increased with increasing nutrient concentration. Lipid content was highest in system 1 and decreased with increasing nutrient concentration. Tissue water content of clams at the 20-μ M DIN level was lower than clams in other treatments, indicating superior condition. The combination of passive solar heating, recirculated water, and nutrient addition for the giant clam land nursery phase opens possibilities for culture of this tropical bivalve in subtropical zones or in the tropics distant from the ocean.