A role for the cell-wall protein silacidin in cell size of the diatom Thalassiosira pseudonana

Diatoms contribute 20% of global primary production and form the basis of many marine food webs. Although their species diversity correlates with broad diversity in cell size, there is also an intraspecific cell-size plasticity due to sexual reproduction and varying environmental conditions. However, despite the ecological significance of the diatom cell size for food-web structure and global biogeochemical cycles, our knowledge about genes underpinning the size of diatom cells remains elusive. Here, a combination of reverse genetics, experimental evolution and comparative RNA8 sequencing analyses enabled us to identify a previously unknown genetic control of cell size in the diatom Thalassiosira pseudonana. In particular, the targeted deregulation of the expression of the cell-wall protein silacidin caused a significant increase in valve diameter. Remarkably, the natural downregulation of the silacidin gene transcript due to experimental evolution under low temperature also correlated with cell-size increase. Our data give first evidence for a genetically controlled regulation of cell size in Thalassiosira pseudonana and possibly other centric diatoms as they also encode the silacidin gene in their genomes

Impacts of climate change on marine resources in the Pacific Island region

In the Pacific Island region, marine resources make vital contributions to food security, livelihoods and economic development. Climate change is expected to have profound effects on the status and distribution of coastal and oceanic habitats, the fish and invertebrates they support and, as a result, the communities and industries that depend on these resources. To prepare for and respond to these impacts—and ensure the ongoing sustainability of marine ecosystems, and the communities and industries that rely on them economically and culturally—it is necessary to understand the main impacts and identify effective adaptation actions. In particular, declines in coral reef habitats and associated coastal fisheries productivity, more eastward distribution of tuna and impacts of more intense storms and rainfall on infrastructure are expected to present the greatest challenges for Pacific communities and economies. Some species of sharks and rays, and aquaculture commodities with calcareous shells, will also be impacted by habitat degradation, ecosystem changes, increasing temperature and ocean acidification. The projected declines in coastal fish and invertebrate populations will widen the gap between fish needed by growing human populations and sustainable harvests from coastal fisheries, with shortages expected in some nations (e.g. Papua New Guinea, Solomon Islands) by 2035. There will also be a need to diversify livelihoods based on fisheries, aquaculture and tourism because some of these operations are expected to be negatively affected by climate change. In some cases, building the resilience of Pacific communities to climate change will involve reducing dependence on, or finding alternatives, vulnerable marine resources

Impacts of climate change on marine resources in the Pacific Island region

Springer Nature Switzerland AG 2020. In the Pacific Island region, marine resources make vital contributions to food security, livelihoods and economic development. Climate change is expected to have profound effects on the status and distribution of coastal and oceanic habitats, the fish and invertebrates they support and, as a result, the communities and industries that depend on these resources. To prepare for and respond to these impacts-and ensure the ongoing sustainability of marine ecosystems, and the communities and industries that rely on them economically and culturally-it is necessary to understand the main impacts and identify effective adaptation actions. In particular, declines in coral reef habitats and associated coastal fisheries productivity, more eastward distribution of tuna and impacts of more intense storms and rainfall on infrastructure are expected to present the greatest challenges for Pacific communities and economies. Some species of sharks and rays, and aquaculture commodities with calcareous shells, will also be impacted by habitat degradation, ecosystem changes, increasing temperature and ocean acidification. The projected declines in coastal fish and invertebrate populations will widen the gap between fish needed by growing human populations and sustainable harvests from coastal fisheries, with shortages expected in some nations (e.g. Papua New Guinea, Solomon Islands) by 2035. There will also be a need to diversify livelihoods based on fisheries, aquaculture and tourism because some of these operations are expected to be negatively affected by climate change. In some cases, building the resilience of Pacific communities to climate change will involve reducing dependence on, or finding alternatives, vulnerable marine resources