Secondary Production: Shooting a Halcyon for Its Feathers

Author(s):  
M. J. Kokkinn ◽  
A. R. Davis
Keyword(s):  
Author(s):  
Sosuke Otani ◽  
Sosuke Otani ◽  
Akira Umehara ◽  
Akira Umehara ◽  
Haruka Miyagawa ◽  
...  

Fish yields of Ruditapes philippinarum have been decreased and the resources have not yet recovered. It needs to clarify food sources of R. philippinarum, and relationship between primary and secondary production of it. The purpose on this study is to reveal transfer efficiency from primary producers to R. philippinarum and food sources of R. philippinarum. The field investigation was carried out to quantify biomass of R. philippinarum and primary producers on intertidal sand flat at Zigozen beach in Hiroshima Bay, Japan. In particular, photosynthetic rates of primary producers such as Zostera marina, Ulva sp. and microphytobenthos were determined in laboratory experiments. The carbon and nitrogen stable isotope ratios for R. philippinarum and 8 potential food sources (microphytobenthos, MPOM etc) growing in the tidal flat were also measured. In summer 2015, the primary productions of Z. marina, Ulva sp. and microphytobenthos were estimated to be 70.4 kgC/day, 43.4 kgC/day and 2.2 kgC/day, respectively. Secondary production of R. philippinarum was 0.4 kgC/day. Contribution of microphytobenthos to R. philippinarum as food source was 56-76% on the basis of those carbon and nitrogen stable isotope ratios. Transfer efficiency from microphytobenthos to R. philippinarum was estimated to be 10-14%. It was suggested that microphytobenthos might sustain the high secondary production of R. philippinarum, though the primary production of microphytobenthos was about 1/10 compared to other algae.


Resources ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 72
Author(s):  
Gabriela Jarrín Jácome ◽  
María Fernanda Godoy León ◽  
Rodrigo A. F. Alvarenga ◽  
Jo Dewulf

Aluminium is a metal of high economic importance for the European Union (EU), presenting unique properties (e.g., light weight and high corrosion resistance) and with applications in important sectors (e.g., transportation, construction and packaging). It is also known for its high recyclability potential, but relevant losses occur in its life cycle, compromising the amount of aluminium available for secondary production. A novel methodology that allows the identification of these losses and their impact on the aluminium flows in society is the MaTrace model. The objective of this article is to perform a dMFA of the secondary production of aluminium in the EU technosphere using the modified version of MaTrace, in order to estimate flows of the metal embedded in 12 product categories. Twelve scenarios were built in order to assess the impact of changes in policies, demand and technology. The flows were forecasted for a period of 25 years, starting in 2018. The results of the baseline scenario show that after 25 years, 24% of the initial material remains in use, 4% is hoarded by users, 10% has been exported and 61% has been physically lost. The main contributor to the losses is the non-selective collection of end-of-life products. The results of the different scenarios show that by increasing the collection-to-recycling rates of the 12 product categories, the aluminium that stays in use increase up to 32.8%, reaffirming that one way to keep the material in use is to improve the collection-to-recycling schemes in the EU.


Author(s):  
Xi Cheng ◽  
Qi Chen ◽  
Yongjie Li ◽  
Guancong Huang ◽  
Ying Liu ◽  
...  

2021 ◽  
Vol 124 ◽  
pp. 107405
Author(s):  
Wataru Nishijima ◽  
Akira Umehara ◽  
Keigo Yamamoto ◽  
Satoshi Asaoka ◽  
Naoki Fujii ◽  
...  

2021 ◽  
Vol 203 (9) ◽  
pp. 5547-5559
Author(s):  
Piotr Perliński ◽  
Zbigniew J. Mudryk ◽  
Marta Zdanowicz ◽  
Łukasz Kubera

AbstractThe aim of this paper was to determine the abundance and secondary production by bacteria inhabiting the surface microlayer and subsurface water in a specific water basin, i.e., polluted estuarine harbour channel. In a 3-year seasonal cycle, the total number of bacteria and their biomass were higher in the surface microlayer (SML) 7.57 × 108cells dm−3 and 15.86 µg C dm−3 than in the subsurface water (SSW) 4.25 × 108cells dm−3 and 9.11 µg C dm−3 of the studied channel. The opposite relationship was noted in the level of the secondary production (SML—37.16 μg C dm−3 h−1, SSW—60.26 μg C dm−3 h−1) in this water basin. According to the analysed microbiological parameters, the total number of bacteria and secondary production varied along the horizontal profile in the water of the studied channel. The total number of bacteria and their secondary production showed the seasonal variation as well.


2004 ◽  
Vol 313 (1) ◽  
pp. 29-46 ◽  
Author(s):  
Catherine Rey-Rassat ◽  
Delphine Bonnet ◽  
Xabier Irigoien ◽  
Roger Harris ◽  
Robert Head ◽  
...  

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