Effects of temperature and salinity on the growth of Gracilaria verrucosa and G. chorda, with the potential for mariculture in Korea

Environmental conditions can have spatially complex effects on the dynamics of marine fish stocks that change across life-history stages. Yet the potential for non-stationary environmental effects across multiple dimensions, e.g. space and ontogeny, are rarely considered. In this study, we examined the evidence for spatial and ontogenetic non-stationary temperature effects on Pacific hake Merluccius productus biomass along the west coast of North America. Specifically, we used Bayesian additive models to estimate the effects of temperature on Pacific hake biomass distribution and whether the effects change across space or life-history stage. We found latitudinal differences in the effects of temperature on mature Pacific hake distribution (i.e. age 3 and older); warmer than average subsurface temperatures were associated with higher biomass north of Vancouver Island, but lower biomass offshore of Washington and southern Vancouver Island. In contrast, immature Pacific hake distribution (i.e. age 2) was better explained by a nonlinear temperature effect; cooler than average temperatures were associated with higher biomass coastwide. Together, our results suggest that Pacific hake distribution is driven by interactions between age composition and environmental conditions and highlight the importance of accounting for varying environmental effects across multiple dimensions.

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Effect of temperature during the synthesis process of CdSe nanoparticles using the colloidal technique

MRS Advances ◽

10.1557/adv.2020.441 ◽

2020 ◽

Vol 5 (63) ◽

pp. 3389-3395

Author(s):

R. González-Díaz ◽

D. Fernández-Sánchez ◽

P. Rosendo-Francisco ◽

G. Sánchez-Legorreta

Keyword(s):

Scanning Tunneling Microscope ◽

Electron Cloud ◽

Cdse Nanoparticles ◽

Effect Of Temperature ◽

Synthesis Process ◽

Scanning Tunneling ◽

Tunneling Microscope ◽

First Results ◽

Effects Of Temperature ◽

Scanning Electron

AbstractIn this work, the first results of the effects of temperature during the production of Se2- ions and the effect during the interaction of Cd2+ and Se2- ions in the synthesis process of CdSe nanoparticles are presented. The synthesis of CdSe was carried out by the colloidal technique, in the first one we used a temperature of 63 °C to produce Se2- ions and in the second one an interaction temperature of 49 °C. The samples were characterized using a Scanning Electron Microscope (SEM) and a Scanning Tunneling Microscope (STM). From the SEM micrographs it was possible to identify the thorns formation and irregular islands. STM micrographs reveal elliptical shapes with a regular electron cloud profile.

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PEUBAH KUALITAS AIR YANG MEMPENGARUHI PERTUMBUHAN RUMPUT LAUT (Gracilaria verrucosa) DI TAMBAK TANAH SULFAT MASAM KECAMATAN ANGKONA KABUPATEN LUWU TIMUR PROVINSI SULAWESI SELATAN

Jurnal Riset Akuakultur ◽

10.15578/jra.4.1.2009.125-138 ◽

2009 ◽

Vol 4 (1) ◽

pp. 125

Author(s):

Akhmad Mustafa ◽

Rachmansyah Rachmansyah ◽

Dody Dharmawan Trijuno ◽

Ruslaini Ruslaini

Keyword(s):

Water Quality ◽

Growth Rate ◽

Ammonium Phosphate ◽

Gracilaria Verrucosa ◽

Acid Sulfate Soils ◽

Acid Sulfate Soil ◽

Acid Sulfate ◽

Independent Variables ◽

Water Quality Variables ◽

Sulfate Soils

Rumput laut (Gracilaria verrucosa) telah dibudidayakan di tambak tanah sulfat masam dengan kualitas dan kuantitas produksi yang relatif tinggi. Oleh karena itu, dilakukan penelitian yang bertujuan untuk mengetahui peubah kualitas air yang mempengaruhi laju pertumbuhan rumput laut di tambak tanah sulfat masam Kecamatan Angkona Kabupaten Luwu Timur Provinsi Sulawesi Selatan. Pemeliharaan rumput laut dilakukan di 30 petak tambak terpilih selama 6 minggu. Bibit rumput laut dengan bobot 100 g basah ditebar dalam hapa berukuran 1,0 m x 1,0 m x 1,2 m. Peubah tidak bebas yang diamati adalah laju pertumbuhan relatif, sedangkan peubah bebas adalah peubah kualitas air yang meliputi: intensitas cahaya, salinitas, suhu, pH, karbondioksida, nitrat, amonium, fosfat, dan besi. Analisis regresi berganda digunakan untuk menentukan peubah bebas yang dapat digunakan untuk memprediksi peubah tidak bebas. Hasil penelitian menunjukkan bahwa laju pertumbuhan relatif rumput laut di tambak tanah sulfat masam berkisar antara 1,52% dan 3,63%/hari dengan rata-rata 2,88% ± 0,56%/hari. Di antara 9 peubah kualitas air yang diamati ternyata hanya 5 peubah kualitas air yaitu: nitrat, salinitas, amonium, besi, dan fosfat yang mempengaruhi pertumbuhan rumput laut secara nyata. Untuk meningkatkan pertumbuhan rumput laut di tambak tanah sulfat masam Kecamatan Angkona Kabupaten Luwu Timur dapat dilakukan dengan pemberian pupuk yang mengandung nitrogen untuk meningkatkan kandungan amonium dan nitrat serta pemberian pupuk yang mengandung fosfor untuk meningkatkan kandungan fosfat sampai pada nilai tertentu, melakukan remediasi untuk menurunkan kandungan besi serta memelihara rumput laut pada salinitas air yang lebih tinggi, tetapi tidak melebihi 30 ppt.Seaweed (Gracilaria verrucosa) has been cultivated in acid sulfate soil-affected ponds with relatively high quality and quantity of seaweed production. A research has been conducted to study water quality variables that influence the growth of seaweed in acid sulfate soil-affected ponds of Angkona Sub-district East Luwu Regency South Sulawesi Province. Cultivation of seaweed was done for six weeks in 30 selected brackishwater ponds. Seeds of seaweed with weight of 100 g were stocked in hapa sized 1.0 m x 1.0 m x 1.2 m. Dependent variable that was observed was specific growth rate, whereas independent variables were water quality variables including light intensity, salinity, temperature, pH, carbondioxide, nitrate, ammonium, phosphate, and iron. Analyses of multiple regressions were used to determine the independent variables which could be used to predict the dependent variable. Research result indicated that relative growth rate of seaweed in acid sulfate soils-affected brackishwater ponds ranged from 1.52% to 3.63%/day with 2.88% ± 0.56%/day in average. Among nine observed water quality variables, only five variables namely: nitrate, salinity, ammonium, phosphate and iron influence significantly on the growth of seaweed in acid sulfate soils-affected brackishwater ponds. The growth of seaweed in acid sulfate soils-affected brackishwater ponds of Angkona District East Luwu Regency, can be improved by using nitrogen-based fertilizers to increase ammonium and nitrate contents and also fertilizers which contain phosphorus to improve phosphate content to a certain level. Pond remediation to decrease iron content and also rearing seaweed at higher salinity (but less than 30 ppt) can also be alternatives to increase the growth of seaweed.

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