NFT재배에서 $\textrm{CO}_2$ 시용과 배양액의 $\textrm{NO}_3$:$\textrm{NH}_4$비율이 결구상추의 생육 및 품질에 미치는 영향

원선이,조영렬,이용범 (사)한국생물환경조절학회 1996 생물환경조절학회지 Vol.5 No.2

본 실험은 NFT재배에서 배양액내 NO$_3$-N과 NH$_4$-N의 비율과 $CO_2$ 시용이 결구상추의 생육, 수량 및 품질에 미치는 영향을 구명하고자 실시하였는데, 그 결과는 다음과 같다. 1. 배양액의 pH와 EC를 보정하지 않았을 경우, NO$_3$-N:NH$_4$-N이 100:0인 구에서의 pH는 점차적으로 증가하였고, NH$_4$-N의 비율이 높을수록 급격히 저하하여 pH4.0까지 낮아졌다. 2. 배양액을 보정하지 않은 상태에서 NO$_3$-N 및 NH$_4$-N의 일 변화를 측정하여 본 결과, NO$_3$-N의 흡수율은 NO$_3$-N:NH$_4$-N이 75:25, 50:50 처리구에서 각각 27.7%, 26.1% 였으나 NH$_4$-N의 흡수율은 87.9%, 71.2%로 결구상추는 NH$_4$-N을 우선적으로 흡수하였다. 3. 엽내 무기성분 함량에서 T-N는 NO$_3$-N과 NH$_4$-N 비율에 따른 큰 차이를 보이지 않았으나, P$_2$O$_{5}$, $K_2$O, CaO, MgO는 생육이 가장 좋았던 $CO_2$ 1500ppm 시용과 NO$_3$-N:NH$_4$-N이 100:0에서 높게 나타났다. 4. $CO_2$ 시용에 의한 각 처리별 $CO_2$ 동화율도 수량과 같은 경향을 나타내어 $CO_2$ 1500ppm 시용과 NO$_3$-N:NH$_4$-N이 100:0 처리에서 가장 높았고, 배양액의 NH$_4$-N비율이 높아질수록 현저히 떨어졌다. 5. 결구상추의 생육은 $CO_2$ 1500ppm 시용과 NO$_3$-N:NH$_4$-N이 100:0 처리에서 가장 좋았고, $CO_2$ 무처리구에 비하여 $CO_2$ 1500ppm 처리구에서 대체로 양호하였으나, NO$_3$-N:NH$_4$-N이 75:25, 50:50인 처리에서는 $CO_2$ 시용에 의한 수량의 증가가 경미하여 처리간 차이가 인정되지 않았다. 6. 엽중 nitrate함량은 배양액의 NO$_3$-N함량과 비례하여 NO$_3$-N:NH$_4$-N 이 100:0에서 가장 높았고, vitamin C 함량은 NO$_3$-N:NH$_4$-N이 100:0인 처리에서 가장 낮고, NH$_4$-N의 비율이 많을수록 높아졌다. $CO_2$ 시용에 의하여 엽중 질산염함량은 경감할 수는 있었으나 그 효과는 경미하였다.다. Crisphead lettuce(Lactuca sativa L.) was grown in NFT to investigate the effects of NO$_3$-N and NH$_4$-N ratio in nutrient solution and elevated $CO_2$ treatment in the crisphead lettuce growth. This experiment has been conducted under three different ratios of NO$_3$-N:NH$_4$-N(100:0, 75:25, 50:50) with two $CO_2$ concentration (control, 1500ppm ). The results are as follows; 1. In the case of not controlling pH and EC in nutrient solution, pH was gradually increased in NO$_3$-N:NH$_4$-N=100:0 treatment but rapidly decreased in the nutrient solution 2. Daily changes of NO$_3$-N and NH$_4$-N were observed without controlling the nutrient solution. In the treatments of NO$_3$-N:NH$_4$-N ratios were 75:25 and 50:50, NO$_3$-N absorption rates were 27.7% and 26.1%, while NH$_4$-N absorption rates were 87.9% and 71.2%, respectively. 3. There was little differences in total nitrogen of leaves. However phosphorus, potassium, calcium and magnesium contents were highly shown in the treatment of $CO_2$ 1500ppm and 100:0 ratio of NO$_3$-N:NH$_4$-N. 4. Higher $CO_2$ assimilation rate was shown in plants grown under $CO_2$ 1500ppm and 100:0 ratio of NO$_3$-N:NH$_4$-N. It dropped significantly with the increase of NH$_4$- N rates in nutrient solution. 5. Fresh weight, leaf number, root length and root weight of crisphead lettuce were far better in the treatment of $CO_2$ 1500ppm and 100:0 ratio of NO$_3$-N:NH$_4$-N. Growth differences by $CO_2$ elevation were not shown in other NO$_3$-N:NH$_4$-N treatments. 6. The highest nitrate contents of leaves were shown in NO$_3$-N single treatment but shown the lowest vitamin C contents. Nitrate contents of leaves were decreased by $CO_2$ but the effect was slight treatment.

양돈 폐수로부터 고농도 암모니아성 질소의 감소를 위한 화학적 첨가제의 영향

배수호,김은,유건상 한국환경생물학회 2022 환경생물 : 환경생물학회지 Vol.40 No.3

Excess nitrogen (N) flowing from livestock manure to water systems poses a serious threat to the natural environment. Thus, livestock wastewater management has recently drawn attention to this related field. This study first attempted to obtain the optimal conditions for the further volatilization of NH3 gas generated from pig wastewater by adjusting the amount of injected magnesia (MgO). At 0.8 wt.% of MgO (by pig wastewater weight), the volatility rate of NH3 increased to 75.5% after a day of aeration compared to untreated samples (pig wastewater itself). This phenomenon was attributed to increases in the pH of pig wastewater as MgO dissolved in it, increasing the volatilization efficiency of NH3. The initial pH of pig wastewater was 8.4, and the pH was 9.2 when MgO was added up to 0.8 wt.%. Second, the residual ammonia nitrogen (NH4+-N) in pig wastewater was removed by precipitation in the form of struvite (NH4MgPO4·6H2O) by adjusting the pH after adding MgO and H3PO4. Struvite produced in the pig wastewater was identified by field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) analysis. White precipitates began to form at pH 6, and the higher the pH, the lower the concentration of NH4 +-N in pig wastewater. Of the total 86.1% of NH4+-N removed, 62.4% was achieved at pH 6, which was the highest removal rate. Furthermore, how struvite changes with pH was investigated. Under conditions of pH 11 or higher, the synthesized struvite was completely decomposed. The yield of struvite in the precipitate was determined to be between 68% and 84% through a variety of analyses. 양돈 폐수로부터 NH3를 제거하기 위해서 양돈 폐수의 무게 대비 MgO (wt. %)의 양을 변화시키면서 양돈 폐수에 주입하였다. 24시간 동안 폭기시키면서 MgO (0.8 wt. %)로 처리한 양돈 폐수는 미처리 양돈 폐수에 비하여 NH3 가스 발생량이 75.5% 감소하였으며, 1개월 동안 밀폐된 상태에서도 NH3 가스가 거의 발생하지 않았다. 본 연구에서 사용한 MgO는 양돈 폐수의 pH를 상승시켜 NH3가 가스 형태로 탈기될 수 있는 조건을 제공해 주었으며, 과량 주입할 경우에도 호기성 미생물 활동에 악영향을 줄 수 있는 pH 10.5를 초과하지 않았다. 양돈 폐수에서 제거되지 않고 남아 있는 NH4+는 인산과 MgO를 첨가하여 스트루바이트의 형태로 침전시켜 제거하였다. 스트루바이트를 합성하기 위해서 NH4+의 몰비와 동일하게 인산과 MgO를 주입하고 황산을 첨가하여 양돈 폐수의 초기 pH를 5로 조정한 후 점진적으로 폐수의 pH를 상승시켰다. pH 6에서 흰 침전물 소위 스트루바이트가 생성되기 시작하여 pH 10까지 지속적으로 합성이 이루어졌다. 총 86.1%의 NH4+ 제거 중에서 62.4%가 약산성인 pH 6에서 제거되었다. 침전물 중에 스트루바이트의 존재를 XRD로 조사하였고 그 결과 pH 6에서 침전물이 스트루바이트의 결정성을 갖는다고 확인되었다. pH 7~10인 조건에서는 스트루바이트가 비결정질 형태로 존재하며, pH가 11인 이상에서는 생성된 스트루바이트가 완전히 붕괴되었다. 침전물 내에서 스트루바이트의 수득률은 에너지 분산형 X-ray, 열중량분석기, 원소분석기의 결과치를 바탕으로 하여 68%~84%임을 확인할 수 있었다. 만약 NH3가 제거된 양돈 폐수를 건조 퇴비에 뿌려 부숙하게 된다면 퇴비의 부숙 기간 동안 NH3로 인한 악취를 상당히 감소시킬 수 있을 것이다. 이와 더불어, MgO로 처리한 양돈 폐수는 가축 퇴비에 인과 질소를 보충하는 역할을 담당할 수 있을 것이다. 앞으로도 본 연구를 계속적으로 진행하여 국내에서 친환경퇴비를 생산할 수 있는 기틀을 마련하고자 한다.

잎상추의 수경재배시 NO3-N과 NH4-N의 비율이 엽중 nitrate 함량에 미치는 효과

김혜진,김영식 (사) 한국생물환경조절학회 2001 시설원예‧식물공장 Vol.10 No.1

Effect of NO3:NH4 ratio and pH of nutrient solution on nitrate content of leaves was investigated forleaf lettuce (Lactuca sativa L.) grown by a deep flow technique. Ratios (in me L-1) of NO3:NH4 testedwere 12:1, 10:3 and 8:5. The treatment of 8:5 NO3:NH4 ratio had two solutions, one with uncontrolledpH and the other with automatically controlled pH. Solution pH continuously increased in 12:1NO3:NH4 treatment. Solution pH decreased gradually more as NH4 ratio increased. Treatment of 8:5NO3:NH4 with automatic pH control satisfactorily maintained the solution pH in the range of pH 5.5-6.0. Nitrate content in leaves was the greatest in treatment of 12:1 NO3:NH4 and the least in treatmentof 8:5 NO3:NH4 with automatic pH control. Fresh weight decreased in treatments of 10:3 and 8:5NO3:NH4, whereas it increased in treatments of 12:1 and 8:5 NO3:NH4 with pH control. It was con-cluded that the growth and leaf nitrate content were the greatest in high NH4 treatment with auto-matic pH control.

양액내 NO3--N과 NH4+-N의 비율이 체리 세이지와 파인애플 세이지의 생육 및 생리반응에 미치는 영향

정효훈,이영현 한국인간·식물·환경학회 2007 인간식물환경학회지 Vol.10 No.4

체리 세이지(Salvia coccinea L.)와 파인애플 세이지(Salvia officinalis L.)을 수경재배 할 때, 양액내 NO3--N : NH4+-N의 비율이 두 품종 허브의 생육에 미치는 영향과 성분에 미치는 영향을 알아보고자 질산태질소와 암모늄태 질소의 비를 100:0, 75:25, 50:50, 25:75, 0:100의 다섯 개의 처리구를 나누어 실험하였으며 아래와 같은 결론을 얻었다. 체리 세이지와 파인애플 세이지의 생육에서는 NO3--N : NH4+-N의 비가 50:50과 75:25인 처리구의 생장이 21.9cm, 23.4cm로 NH4+-N 단용 처리구보다 생장율이 높았다. NH4+-N 의 함유량은 체리세이지의 shoot의 25:75 혼용구에서 38mg/g DW로 가장 낮은 함유량을 보였으며, 75:25의 혼용구에서 44mg/g DW를 보였고, 파인애플 세이지는 45mg/g DW의 가장 높은 함유량과 38mg/g DW의 가장 낮은 함유량을 보였으며 50:50의 비에서 40mg/g DW의 함유량을 보였다. NRA의 함유량은 시간이 지나면서 shoot에서 많은 활성을 보였고 체리세이지는 NO3--N : NH4+-N비가 50:50인 혼용 처리구에서 0.81nmole/g FW ․ h-1의 함유량을 보였고 파인애플 세이지는 50:50 혼용구에서 최대 0.86nmole/g FW ․ h-1의 함량을 나타내었다. GSA(glutamine synthtase activity)의 활성에서 12주후, 체리 세이지는 질산태 질소 단용구에서 9.2umole/g FW ․ h-1의 함량을 파인애플 세이지는 11umole/g FW ․ h-1의 높은 함량을 보였다. 이상의 결과로 NO3-의 단용구 또는 NH4+의 단용구보다는 NO3--N : NH4+-N의 혼용구에서 생육의 증가를 보였고, NRA의 함량과 생장 또한 단용구보다는 혼용구에서 높게 나타났음을 알 수 있었다. 특히 NO3--N : NH4+-N의 처리비가 75:25 에서의 혼용 처리구에서 다른 혼용구보다 생육의 높은 증가를 보였다. 따라서 75:25의 혼용비가 두 종의 세이지 생육에 적합한 비라고 생각된다. This study was conducted to investigate the effect of five different NO3--N : NH4+-N ratio (100:0, 75:25, 50:50, 25:75, 0:100) in nutrient solution on the growth responses of cherry sage(Salvia coccinea L.) and pineapple sage(Salvia officinalis L.). Cherry sage and pineapple sage were grown under the condition of those treatments for twelve weeks. Cherry sage was showed that shoot length remarkably increased was grown the greatest when NO3--N : NH4+-N treatment was 75:25, but pineapple sage was 50:50. However, when NO3--N : NH4+-N ratio was 100:0 or 0:100, those shoot length was showed the poorest. NRA(nitrate reductase activity) was increased in the condition of those treatments for twelve weeks. In the shoot case, NRA of cherry sage was the highest when NO3--N : NH4+-N treatment was 50:50, and pineapple sage was 75:25. At 25:75 or 50:50 ratio, those of soluble protein, total nitrogen, free amino acid and nitrate contents were increased, but was not showed significant. At 0:100 ratio, those contents was showed more lower. After 12 weeks, GSA(glutamine synthetase activity) was increased in the shoot of both cherry sage and pineapple sage, and NO3--N : NH4+-N treatment was 75:25 ratio that was appearanced the highest in those GSA content. So, the growth responses of cherry sage and pineapple sage were suitable at NO3--N : NH4+-N ratio(75: 25).

¹H and ¹³³Cs nuclear magnetic resonance study of the NH₄ and Cs occupation rates of mixed (NH₄)_2-xCs_xZnCl₄ (x=0, 1, and 2) crystals

Elsevier Science Publishers [etc.] 2012 Chemical physics Vol.400 No.-

The NMR spectra and the spin-lattice relaxation times, T<SUB>1</SUB>, of the <SUP>1</SUP>H and <SUP>133</SUP>Cs nuclei in (NH<SUB>4</SUB>)<SUB>2-x</SUB>Cs<SUB>x</SUB>ZnCl<SUB>4</SUB> (x=0, 1, and 2) single crystals were determined by using NMR spectroscopy. We investigated the crystallographic structures of these crystals by determining the NH<SUB>4</SUB> and Cs occupation probabilities of the two cationic sites. Our NMR experimental results confirm that in (NH<SUB>4</SUB>)<SUB>2</SUB>ZnCl<SUB>4</SUB> there are two crystallographically inequivalent NH<SUB>4</SUB> groups, NH<SUB>4</SUB>(1) and NH<SUB>4</SUB>(2), occupying the A<SUB>1</SUB> and A<SUB>2</SUB> sites, and that in Cs<SUB>2</SUB>ZnCl<SUB>4</SUB> there are two crystallographically inequivalent Cs ions, Cs(1) and Cs(2), occupying the A<SUB>1</SUB> and A<SUB>2</SUB> sites. Both types of NH<SUB>4</SUB> ions and both types of Cs ions are found in mixed NH<SUB>4</SUB>CsZnCl<SUB>4</SUB> crystals; the occupation rates of the two different sites are 1 and 1 for Cs(1) and Cs(2), respectively, and 1 and 1 for NH<SUB>4</SUB>(1) and NH<SUB>4</SUB>(2), respectively.

가시오갈피의 부정근 배양시 부정근의 생육과 eleutheroside류의 함량에 미치는 NO₃^-와 NH₄⁺ 비율 및 농도의 영향

안진권,이위영,박영기,Ahn, Jin-Kwon,Lee, Wi-Young,Park, Young-Ki 한국산림과학회 2007 한국산림과학회지 Vol.96 No.1

This study was carried out to investigate the effect of $NO_3{^-}$ and $NH_4{^+}$ on the adventitious root growth and eleuthroside synthesis of Eleutherococcus senticosus during 3 L-bioreactor culture. The change of medium component ratio was also measured during culture. The fresh weignt of adventitious root reached to the greatest level of 24.4g FW/L in the presence of 50 mM $NO_3{^-}$ and 10 mM $NH_4{^+}$, representing 3.4-fold increase compared to the 60 mM $NH_4{^+}$. However, as the increase of the portion of $NH_4{^+}$, the root growth was decreased. Maximum eleutheroside B and E1 production were $249{\mu}g/g$ and $43{\mu}g/g$, respectively, with 30 mM total nitrogen source. The maximum production of eleutheroside E were $788{\mu}g/g$ with 120 mM total nitrogen source. The greatest weight of adventitious root increased up to 6.2 fold of inoculum size within 9 weeks. The change of pH was influenced from 4.81 to 6.35 and the amounts of $NH_4{^+}$ and $K^+$ were decreased during culture periods. From these results we suggest, need further study of various treatment to increase the growth of biomass and the accumulation of useful secondary metabilites. 생물반응기를 이용하여 가시오갈피 부정근 증식시 부정근의 생장과 유용 이차대사산물인 eleuthroside 류 생산에 미치는 $NO_3{^-}$와 $NH_4{^+}$의 영향 및 배양기간에 따른 배지성분의 변화량을 분석하였다. 부정근 증식은 질소농도가 50 mM $NO_3{^-}$와 10 mM $NH_4{^+}$ 농도비율로 참가된 처리구에서 최대(24.4g FW/L)에 이르러 60 mM $NH_4{^+}$ 첨가에 비해서는 3.4배 증식되었다. 또한 $NH_4{^+}$의 첨가농도비율이 높아질수록 부정근의 증식은 감소하였다. Eleutheroside B와 E1은 총 질소량이 30 mM 처리에서 각각 $249{\mu}g/g$와 $43{\mu}g/g$을 생산하여 가장 우수하였으나, eleutheroside E는 총 질소농도가 높아질수록 생산량도 높아져 120 mM에서 $788{\mu}g/g$로 가장 우수하였다. 부정근 생장은 초기 접종량 대비 배양 9주만에 6.2배가 증식되었고, 배양기간별 배지 성분의 변화에서는 산도는 4.81-6.35로 변화가 비교적 심했고, $NH_4{^+}$와 $K^+$는 배양기간이 경과할수록 함유량이 낮았다. 이러한 결과로 보아 부정근의 생장과 유용이차대사산물의 함량을 높이기 위하여 다양한 처리의 연구가 수행되어야 할 것으로 생각된다.

MLE 공정에서 PAC 응집제 첨가에 따른 질소 및 인 제거 효율 평가와 질신화 저해에 관한 연구

안찬현 ( Chan Hyun An ),전동걸 ( Dong Jie Tian ),임현숙 ( Hyun Sook Lim ),정진 ( Jin Chung ),전항배 ( Hang Bae Jun ) 충북대학교 건설기술연구소 2015 建設技術論文集 Vol.34 No.1

80 일간의 운전 결과 본 MLE 공정 내 Al(III) 계 응집재인 PAC 를 주입한 결과 유기물 제거에는 영향을 미치지 않는 것으로 나타났다. 다만 단일 반응조 내에서 Al(III) 이 수화물 및 침전물 형태로 장기적인 축적으로 미생물의 대사활동에 영향을 미친 것으로 보고되었지만 본 실험에서는 무산소조, 호기조 및 침전조 등 일련의 연속공정으로 구성한 결과 실제Al(III) 축적에 의한 영호t은 관찰되지 않았다. 또한 질소 재거에 있어서도 유기물과 마찬가지로 제거효율 영향은 거의 없다 즉, TN 제거효율은 각각 Run 1 70%, Run 2 73%, Run 3 78%이였으며, 마지막으로 Al/P몰비 5인 Run 4에서는 70% TN 제거효율을 나타내었다. 인의 경우 Run 1에서는 인 제거가 이루어지지 않음을 관찰할 수가 있다. 하지만 Al/P몰비를 3.6,4,5로 응집제를 주입한 Run 2, Run 3 및 Run 4에서는 각각 92%, 96%, 97%의 높은 인 제거효율을 나타내었다. 그 외 DO농도 3.0~4.0 mg/L의 조사결과로부터 농어촌진흥원 회분식 실험결과 Al/P 몰비 증가에 따라 NH4+-N 제거 속도는 마마하게 감소하였다. 즉, Al/P=0인 NH4+-N 제거 속도는 5.0 g-NH4+-N/kg -MLSS·hr 이었고, Al/P=3.6 및 Al/P=4일 경우에는 모두 4.9 g- NH4--N/kg-MLSS·hr이었으며, 마지막으로 Al/P=5일 경우에는 4.8 g- NH4+-N/kg -MLSS·hr 를 나타내었다. After 80 days of a continuous operation of a MLE(Modified Ludzack Ettinger) process, addition of PAC as a coagulant did not affect on COD removal. When Al(III) was hydrated and precipitated and they were accumulated for a long period of time in a single phase reactor, it has been reported that it might influence the microbial metabolism. However in this study Al(III) accumulation was not apparent in a series of anoxic-aerobic-clarification process. PAC coagulation did not affect the nitrogen removal as well TN removal efficiency was found to be 70%, 73 %, and 78% for Run 1, 2, and 3 respectively. At Run 4 with Al/P mole ratio of 5, 70% of TN was removed. In case of phosphorus, at Run 1 P was not removed. However when Al(III) was added as Al/P mole ratios of 3.6, 4, and 5, 92%, 96%, and 97% of P were removed respectively. When DO was 3.0~4.0 mg/L, as Al/P mole ratio increased NH4+,-N was removed insignificantly. In other word, when Al/P = 0, NH4+-N removal rate was 5.0 g-NH4+-N/kg-MLSS·hr. When AJ/P = 3.6 and AJ/P = 4, NH,+-N removal rate was 4.9 g-NH,+-N/kg-MLSS·hr for both cases. Finally when Al/P = 5, NH4+-N removal rate was 4.8 g-NH4+-N/kg-MLSS·hr.

Characterization and expression analysis of BcAMT1;4, an ammonium transporter gene in flowering Chinese cabbage

Lihua Zhong,Xinmin Huang,Yunna Zhu,Erfeng Kou,Houcheng Liu,Guangwen Sun,Riyuan Chen,Shiwei Song 한국원예학회 2019 Horticulture, Environment, and Biotechnology Vol.60 No.4

Ammonium (NH 4+ ) is generated during many endogenous metabolic processes in the leaves of plants, and there is increasing evidence that ammonium transporters (AMTs) play important roles in NH 4 + transmembrane transport and distribution. However, the expression of diff erent AMT genes is tissue-type specifi c and their functions diff er. Information about AMT genes and their expression under diff erent environmental conditions in fl owering Chinese cabbage ( Brassica campestris L.) is currently limited. Here, we isolated and characterized an AMT gene, BcAMT1;4 , in fl owering Chinese cabbage. BcAMT1;4 was localized to the plasma membrane and complemented NH 4+ transport in NH 4+ uptake-defi cient yeast. The highest expression levels of BcAMT1;4 were detected in the fl owers and leaves of fl owering Chinese cabbage. The expression of BcAMT1;4 was induced by nitrogen defi ciency and signifi cantly inhibited by the reapplication of NH 4+ (NH 4 Cl or NH 4 NO 3 ). In contrast, when plants pre-cultured in nitrate were transferred to an NH 4+ nutrient solution, BcAMT1;4 expression was signifi cantly enhanced. BcAMT1;4 exhibited a diurnal expression pattern, with higher expression levels during the light period than during the dark period, and a peak expression at the later stage of the light period. Knowledge of AMT genes in fl owering Chinese cabbage will lay a foundation for enhancing our understanding of the functional roles of diff erent AMT members in the regulation of its growth by NH 4+ , as BcAMT1;4 seems to play an important role in leaf NH 4+ transport.

The Effects of Elevated CO2 and Ammonium Levels in Seawater on the Physiology of Gracilariopsis chorda (Holmes) Ohmi

( Jin Woo Kang ),( Ik Kyo Chung ) 한국환경과학회 2016 한국환경과학회지 Vol.25 No.4

We examined the effects of ocean acidification (OA) and eutrophication on the physiology of a red alga, Gracilariopsis chorda, using specimens collected at Wando Island, Korea, in July of 2015. The samples were transported to a laboratory and placed on growth media for treatments involving low or high levels of ammonium (4 μM or 60 μM NH4+) and low or high pH (7.5 or 8.2). The control treatment used filtered seawater (pH 8.2 and 4 μM NH4+). All experiments were conducted at 20°Cand under a lighting intensity of 80 μmol photons m-2 s-1, with or without an injection of CO2 (pH 7.5). In addition, we calculated rates of respiration under darkness, at a pH of 7.5 and 60 μM NH4+. Fluctuations in pH as well as the evolution of photosynthetic oxygen and NH4+ uptake rates were monitored for 6 h. The greatest increase in pH levels, from 7.50 to 8.65, occurred in response to 60 μM NH4+, whereas the largest decrease, from 7.50 to 7.42, was associated with elevated respiration rates. At a pH of 7.5, rates of oxygen evolution were higher (236% saturation) for samples treated with 60 μM NH4+ than for the control (121% saturation). Ammonium uptake was highest at pH 7.5 and 60 μM NH4+, with a rate of 0.526±0.002 μmol g-1 FW h-1, followed in order by the treatments of pH 8.2/60 μM NH4+, pH 7.5/4 μM NH4+, and the control (pH 8.2/4 μM NH4+). We speculated that the rates of photosynthesis and NH4+ uptake could be enhanced at a higher ammonium concentration and lower pH because CO2 concentrations were increased through greater photosynthetic activity. Therefore, these findings suggest that the physiology of G. chorda populations can be improved by the interaction of optimized CO2 concentrations and an adequate supply of essential nutrients such as ammonium.

Role of NH4 and H2O in Tutton Salt (NH4)2M(SO4)2·6H2O (M=Fe and Zn) Single Crystals Studied by 1H and 14N NMR at High Temperatures

박성수,임애란 한국자기공명학회 2017 Journal of the Korean Magnetic Resonance Society Vol.21 No.2

At high temperature, the roles of NH4 and H2O in (NH4)2Fe(SO4)2·6H2O and (NH4)2Zn(SO4)2·6H2O single crystals were investigated using a pulse NMR spectrometer. Temperature was shown to have a significant influence, causing changes in the deformation of NH4 and H2O. From the 1H NMR and 14N NMR spectrum, the forms of environment surrounding 14N in NH4 groups is more important than the loss of H2O groups. NMR studies indicate that NH4+ ions in Tutton salts play an important role in the changes of the crystal structure at high temperatures.