Environment and Ecology

Poster Session Theme

Environment and Ecology

Poster session for OIST-RIKEN Collaboration 1st Symposium:
Green and Blue Planet How Can Ecological Research Shape Our Future?

Controlling biodiversity loss via spatial management -
Spatial structure mediates the balance between local and regional biodiversity

Yuka Suzuki, OIST

Biodiversity and Biocomplexity Unit

Economo Unit

Understanding how spatial structure contributes to biodiversity is a key for conservation planning with spatial management. Previous studies that used models with simple spatial structure have predicted that intermediate dispersal rate increases local diversity, resulting in the maintainance of regional diversity. However, we found this is an extreme case, rather than general, when a wider variety of spatial structures are considered. We determined that more complex linear and tree-like spatial structures maintain higher regional biodiversity. Finally, we show that these theoretical results are applicable to systems with more realistic and complex spatial structure in marine metacommunities.

Application of heavy-ion-beam irradiation to breeding large rotife

Kazuhide Tsuneizumi, RIKEN

RIKEN Nishina Center for Accelerator-Based Science

Ion beam breading team

In larviculture facilities, rotifers are generally used as an initial food source, while proper size of live feeds to connect rotifer and Artemia are needed associated with fish larval growth. The improper management of feed size and density induces mass mortality and abnormal development of fish larvae. To improve the survival and growth of target larvae, this study applied carbon and argon heavy-ion-beam irradiation in mutation breeding to select rotifer mutants with larger lorica sizes.
The optimal irradiation conditions of heavy-ion beam were determined with lethality, reproductivity, mutant frequency, and morphometric characteristics. Among 56 large mutants, TYC78, TYC176, and TYA41 showed active population growth also. In conclusion, (1) heavy-ion-beam irradiation was defined as an efficient tool for mutagenesis of rotifers and (2) the aforementioned three lines which have larger lorica length and active population growth may be used as a countermeasure of live feed size gap during fish larviculcure.

AlGaN UV LEDs for a low-carbon world

Masafumi Jo, RIKEN

RIKEN Cluster for Pioneering Research,RIKEN Center for Advanced Photonics

Quantum Optodevice Laboratory,Terahertz Quantum Device Research Team

Light-emitting diodes (LEDs) are solid light sources with small size, high durability, and high efficiency. The use of energy efficient LED technology could save a large amount of energy consumption and CO2 in the world. LEDs which emit UV light have wide applications in curing, water/air purification, and a bio-medical field. Here, we would like to introduce AlGaN UV LEDs that we have developed and to discuss possible applications.

On the way to heterotrophy: ecophysiology and genomics of Okinawan parasitic and mycoheterotrophic plants

Petra Svetlikova, OIST

Science and Technology Group

Not all plants rely solely on own photosynthesis for nutrition. More than 24,000 plant species acquire at least a part of their essential resources by exploiting other organisms. Parasitic plants exploit other plant species, while mycoheterotrophic plants exploit fungi. Both parasitic and mycoheterotrophic plants comprise photosynthetically active or partial heterotrophs and non-green or full heterotrophs. We combine traditional ecophysiological methods with microscopy and genomics to study how is the ecophysiology of these plants related to their genomics. We focus on Okinawan species of various trophic strategies from partial to full heterotrophs. This gives us an opportunity to evaluate multiple functional traits of these species and their changes crucial for the evolution of heterotrophy. First question we would like to answer is: How does the ecophysiology of parasitic and mycoheterotrophic plants relate to their plastid ultrastructure and genomes?

Hydrothermal Vent Community Assemblage Networks of the North-West Pacific

Otis Brunner, OIST

Marine Biophysics Unit

Mitarai Unit

Hydrothermal vent ecosystems are discrete ‘oases’ of high biological productivity and endemicity in the deep sea. Local communities of vent-endemic species are spatially isolated but can be demographically linked to one another through planktonic larval dispersal forming a network of inter-connected hydrothermal vent ‘islands. Understanding connectivity is important as it supports higher levels of local diversity and productivity while maintaining regional stability, all of which are targets of conservation management. Methods developed from network theory were used with observations of species presence at vent sites in the North-West Pacific to assess the role of each vent site in maintaining connectivity across the region. These networks suggest the presence of four distinct sub-regions within the North-West Pacific that are separated by both regional dispersal barriers and local environmental filters. Both networks show that a small number of vent sites play a disproportionately important role in maintaining regional connectivity.

The diversity and role of foraminiferal symbionts in the benthic ecosystem functioning in subtropical mudflats

Dewi Langlet, OIST

Evolution, Cell Biology, and Symbiosis Unit

Husnik Unit

Benthic foraminifera play an important role in mudflats benthic ecosystem functioning, yet the diversity of these unicellular eukaryotes in subtropical intertidal mudflats have been largely overlooked. In this preliminary study, we sampled seven intertidal environments in the central Okinawa island including mudflats, sandflats, salt marshes and mangroves. Our results show important species composition changes with the contrasted environmental conditions. This screening of foraminiferal faunas colonizing subtropical intertidal mudflats data will be useful for three projects we plan to conduct in the coming years: 1) study the diversity of symbionts in intertidal foraminifera 2) identify the functions of the foraminiferal symbionts 3) understand the role of foraminifera in mangrove ecosystem functioning

Dewi Langlet, Filip Husnik

Evolution, Cell Biology, and Symbiosis Unit, Okinawa Institute of Science and Technology Graduate University