Complex interactive effects of several abiotic factors on ecophysiology of two Japanese seaweeds

Tohoku University博士（農学）博士学位論文 (Thesis(doctor))thesi

The effect of temperature on the growth of two pest seaweeds in Fiji

Macroalgal blooms are becoming problematic worldwide which is further exacerbated by climate change. This study looks at the effects of temperature on the growth of two pest macroalgae from Fiji, Sargassum polycystum and Gracilaria edulis, under laboratory conditions. The two algal species were subjected separately to different temperature regimes (28 , 30 , 32 and 34 Results showed a significant difference in the Specific Growth Rate (SGR) of G. edulis between the four temperatures with optimal growth at 28-30 . The SGR of S. polycystum could not be determined for experimental reasons due to biomass loss. The optimal temperature for rhizoidal length (RL) of G. edulis was 32-34 , while for S. polycystum RL was 28°C

Threats posed by Asian subterranean termites in the Fiji Islands and their potential controls: a review

Termites belong to the infraorder Isoptera, which contains almost 3,000 described species worldwide. These social insects cause substantial damage globally leading to billions of dollars of losses annually. Damage can occur to timber, wooden goods, paper, cotton, certain plastics, trees and many crops. Consequently, termite control and management is a major sector in the global pest-control industry. However, economic losses due to termite damage have not been quantified in the Fiji Islands to date. A review of published literature was conducted to assess the geographic range of Asian subterranean termites that occur in the Fiji Islands and to identify existing and potential control measures. The most common termite species that is known to cause millions of dollars of damage each year in the Fiji Islands is Coptotermes gestroi. This species is currently controlled primarily using the chemical fipronil but integrated termite management is the preferred long-term solution. Other possible control methods include physical, cultural, chemical and biological options

Decreased Irradiance and Nutrient Enrichment Mitigate the Negative Effect of Ocean Warming on Growth and Biochemical Compositions of a Canopy-Forming Marine Macroalga

Heatwaves under global warming have negative impacts on ecosystem primary producers. This warming effect may be synergized or antagonized by local environments such as light and nutrient availability. However, little is known about the interactive effects of warming, irradiance, and nutrients on physiology of marine macroalgae, which are dominant in coastal ecosystems. The present study examined the combined effects of warming (23 and 26 °C), irradiance (30 and 150 µmol photon m−2 s−1), and nutrients (enriched and non-enriched) on specific growth rate (SGR) and biochemical compositions of the canopy-forming marine macroalga Sargassum fusiforme. The negative effect of warming on SGR and ratio of chlorophyll (Chl) c to Chl a was antagonized by decreased irradiance. Moreover, the negative effect of temperature elevation on carbon content was antagonized by nutrient enrichment. These results suggest that the effect of warming on the growth and carbon accumulation of this species can be mitigated by decreased irradiance and nutrient enrichment

Decreased Irradiance and Nutrient Enrichment Mitigate the Negative Effect of Ocean Warming on Growth and Biochemical Compositions of a Canopy-Forming Marine Macroalga

Heatwaves under global warming have negative impacts on ecosystem primary producers. This warming effect may be synergized or antagonized by local environments such as light and nutrient availability. However, little is known about the interactive effects of warming, irradiance, and nutrients on physiology of marine macroalgae, which are dominant in coastal ecosystems. The present study examined the combined effects of warming (23 and 26 °C), irradiance (30 and 150 µmol photon m−2 s−1), and nutrients (enriched and non-enriched) on specific growth rate (SGR) and biochemical compositions of the canopy-forming marine macroalga Sargassum fusiforme. The negative effect of warming on SGR and ratio of chlorophyll (Chl) c to Chl a was antagonized by decreased irradiance. Moreover, the negative effect of temperature elevation on carbon content was antagonized by nutrient enrichment. These results suggest that the effect of warming on the growth and carbon accumulation of this species can be mitigated by decreased irradiance and nutrient enrichment