Controlling dissolved oxygen (DO) level in rearing tank is one of the most important for intermediate breeding of abalones with land based production facilities. Continuous DO measurement was conducted for two rearing tanks of 15.5 m3 seawater each and containing 19,000 abalone of 50 mm length and 60,000 abalone of 23 mm length in running seawater condition of 17.6 m3 per hour. Oxygen consumption of abalone was also examined. A model formula expressing oxygen distribution in rearing tank was made based on these data. There are diurnal changes in DO concentration in rearing tank, higher in afternoon and lower in midnight, and DO decreased to less than 80% of saturation couple of times, harmful level for good growth.
A remotely sensed observation of an evergreen forest phenology is more difficult than that of a deciduous forest, as seasonal changes on leaves are relatively small. In this research, we estimated spring phenological transition dates of evergreen coniferous forest using GRVI (Green red ratio vegetation index), which can detect changes in leaf color. Using plantations of Japanese cedar, hinoki cypress and sawara cypress located in the Ashio mountainous region in Tochigi, Japan, as test sites, we derived GRVI time-series data from the MODIS 500 m reflectance data (MCD43A4) during a 12-year period between 2001−2012. By fitting a logistic function to the GRVI time-series data from winter to summer for each pixel, we estimated two phenological transition dates, the onset of greenup and the onset of maturity. The GRVI time-series data showed a bell-shaped seasonal pattern for each year. The averages of estimated dates of greenup and maturity onset were DOY (Day-of-year) 92 and DOY 142, respectively, and there was a 50-day difference between the two phenological dates. There were significantly negative relationships between the average of the two estimated phenological transition dates and the spring air temperature (the onset of greenup, r=−0.73; the onset of maturity, r=−0.74) for the 12 years. In comparison with results based on EVI (Enhanced vegetation index) from MODIS-MCD12Q2 data, our estimations showed a low degree of spatial phenological variability. Based on the statistical relationships with spring temperature, the satellite monitored GRVI could estimate the interannual of variations in onset of greenup and maturity for evergreen coniferous forest.
Virus-like particles (VLPs) play key ecological roles in coral ecosystem. They can regulate the phytoplankton and prokaryotes dynamics and communities. Yet, the factors that regulate the abundance of VLPs within coastal coral ecosystem are not clearly established. The link between phytoplankton, microorganisms (VLPs, bacteria, and coccoid cyanobacteria) abundance and hydrographic factors (temperature, salinity, dissolved oxygen and pH), as well as nutrient availability (nitrates, nitrites, ammonium, total dissolved nitrogen, dissolved organic nitrogen, dissolved organic phosphorus and total dissolved phosphorus) was studied in coral coastal seawater within 5 m depth at Bise (BE, Okinawa, Japan) and Tang Kheng Bay (TKB, Phuket, Thailand). Enumeration by epifluorescence microscopy revealed that VLPs were more abundant than bacteria and coccoid cyanobacteria. Phytoplankton carbon biomass was significantly higher in TKB than BE, but BE showed more planktonic diversity than TKB. VLPs abundance was strongly linked to phytoplankton, bacteria and inorganic nutrients. However, the ratio of virus:plankton and virus:bacteria differed between TKB and BE. The abundance of VLPs could be linked to the nutrient availability rather than the hydrographical parameters. Multiple regression analysis showed that ammonium had greater influence on the abundance of VLPs. Thus, marine viruses in coastal coral areas fulfill their ecological roles mostly in accordance to the prevailing nutrient availability.
Ginkgo trees were scanned in May, September and November by a high resolution portable scanning lidar to estimate leaf inclination angle (LIA) distributions of different three seasons. From the obtained data, 150 leaves were selected in each season and a plane was fitted to each leaf by a least-squares method. LIA was estimated from the zenith angles of the fitted plane's normals. By aggregating these angles, the LIA distributions in each season were obtained. The resultant distributions were different each other and the seasonal change was observed. The difference seemed to reflect the growth conditions such as bud break, leaf expansion, defoliation. The results were compared with the ones of Japanese zelkova trees that grow in the same site and difference was observed between the distributions of ginkgo trees and Japanese zelkova ones. Several factors such as structural difference, species specific characteristics seemed to be causes of the difference.