Journal of Tropical Oceanography >
Effects of the decomposition of Gracilaria lemaneiformis on seawater quality
Received date: 2020-09-02
Request revised date: 2020-11-25
Online published: 2020-11-19
Supported by
National Natural Science Foundation of China(41977268)
Copyright
Large-scale cultivation of seaweed Gracilaria lemaneiformis has important economic and environmental benefits. However, the litter decomposition of the seaweed may affect water quality in the cultivation area and its adjacent waters. To investigate the effects of the decomposition of G. lemaneiformis on water quality, a decomposition experiment was carried out for 45 days. The results showed that the concentration of dissolved oxygen (DO) reduced 82.81% in the dried seaweed group compared with the control group, and the concentrations of total nitrogen and phosphorus increased 161.78% and 759.93%, respectively. While DO concentrations in the treatment of fresh seaweed+seawater+sediment (FWS) continuously decreased from 5.56mg·L-1 to 0.26mg·L-1 from Day 0 to 21, and then gradually recovered to the control level at the end of the experiment. Significantly increase of nitrogen (36.65%) and phosphorus (177.80%) concentrations in water bodies were also observed in FWS treatment in the mid-late period of the experiment. Meanwhile, the change curves of nitrogen and phosphorus in fresh seaweed treatment were slower and gentler than those of the dried seaweed treatment. The nutrients release rates of fresh seaweed were lower than those of dried seaweed during the litter decomposition process. Sediment promoted the decomposition of fresh seaweed and the release rates of carbon, nitrogen and phosphorus, but had opposite effects on dried seaweed. The weight loss rate and the decomposition rate and the nutrients release rates of G. lemaneiformis followed a descending order of dried seaweed+seawater treatment (DW), dried seaweed+seawater+sediment treatment (DWS), fresh seaweed+seawater+sediment treatment (FWS), and fresh seaweed+seawater treatment (FW). To avoid secondary pollution to the sea water, we suggest that shedding or senescent algae be removed in time during the large-scale cultivation period, and the harvested seaweed should be properly deposed.
Key words: macroalgae; Gracilaria lemaneiformis decomposition; litter; nutrient; sediments
DAI Xiaojuan , HU Ren , LUO Hongtian , WANG Qing , HU Xiaojuan , BAI Mindong , YANG Yufeng . Effects of the decomposition of Gracilaria lemaneiformis on seawater quality[J]. Journal of Tropical Oceanography, 2021 , 40(1) : 91 -98 . DOI: 10.11978/2020099
图1 龙须菜凋落物分解实验设置W组表示海水组; S组表示海水+沉积物组; DW组表示干龙须菜+海水组; FW组表示鲜龙须菜+海水组; DWS组表示干龙须菜+海水+沉积物组; FWS组表示鲜龙须菜+海水+沉积物组 Fig. 1 Experimental design of G. lemaneiformis litter decomposition W represents seawater, S represents sediment, DW represents dried seaweed+seawater, FW represents fresh seaweed+seawater, DWS represents dried seaweed+seawater+sediment, and FWS represents fresh seaweed+seawater+sediment |
表1 龙须菜的失重率、分解速率和营养盐释放率Tab. 1 The weight loss rate, decomposition rate and release rate of nutrients in G. lemaneiformis |
组别 | 失重率/% | 分解速率/d-1 | TN释放率/% | TP释放率/% | TC释放率/% |
---|---|---|---|---|---|
鲜龙须菜+海水组(FW组) | 12.42±3.55b | 0.003±0.001b | -1.13±7.38b | 15.95±4.90b | 6.96±6.49b |
鲜龙须菜+海水+沉积物组(FWS组) | 62.50±13.39ab | 0.02±0.01ab | 53.18±12.86ab | 58.38±14.35ab | 56.84±15.39ab |
干龙须菜+海水组(DW组) | 89.58±3.03a | 0.05 ± 0.01a | 73.96±5.61a | 86.0±4.70a | 86.20±3.32a |
干龙须菜+海水+沉积物组(DWS组) | 81.04±12.67a | 0.04±0.02a | 57.06±22.34ab | 81.70±8.16a | 80.80±10.11a |
注: 数值为平均值±标准差; 同列数据右上角不同小写字母表示不同实验组之间有显著差异(P<0.05) |
表2 龙须菜TN、TP单位累积释放量Tab. 2 Unit cumulative release of TN and TP from G. lemaneiformis |
组别 | TN/(mg·g-1) | TP/(mg·g-1) |
---|---|---|
鲜龙须菜+海水组(FW组) | -1.81 | 0.33 |
干龙须菜+海水组(DW组) | 52.35 | 10.50 |
鲜龙须菜+海水+沉积物组(FWS组) | 14.84 | 3.20 |
干龙须菜+海水+沉积物组(DWS组) | 47.36 | 8.68 |
[1] |
曹勋, 韩睿明, 章婷曦, 等, 2015. 冬季水生植物分解过程及其对水质的影响研究[J]. 农业环境科学学报, 34(2):361-369.
|
[2] |
陈洪森, 叶春, 李春华, 等, 2020. 入湖河口区水生植物群落衰亡分解释放营养盐过程模拟研究[J]. 环境工程技术学报, 10(2):220-228.
|
[3] |
杜立刚, 2013. 三峡库区消落带植被淹水碳氮磷释放及消落带氮磷交换通量研究[D]. 重庆: 重庆大学.
|
[4] |
刘湘庆, 王宗灵, 辛明, 等, 2016. 浒苔衰亡过程中营养盐的释放过程及规律[J]. 海洋环境科学, 35(6):801-805, 813.
|
[5] |
刘之威, 罗洪添, 武宇辉, 等, 2019. 汕头南澳龙须菜规模栽培对水质和浮游植物的影响[J]. 中国水产科学, 26(1):99-107.
|
[6] |
孟祥森, 邵雪琳, 高丽, 等, 2016. 绿潮硬毛藻衰亡分解过程中营养盐的释放规律[J]. 海洋环境科学, 35(4):495-500.
|
[7] |
农业农村部渔业渔政管理局, 2019. 中国渔业年鉴[M]. 北京: 中国农业出版社.
Fisheries and Fisheries Administration Bureau of the Ministry of Agriculture and Rural Areas, 2019. China fisheries yearbook[M]. Beijing: China Agricultural Press (in Chinese).
|
[8] |
童雄, 罗沛, 刘锋, 等, 2019. 绿狐尾藻分解及其氮磷释放特征[J]. 环境科学, 40(7):3118-3125.
|
[9] |
王博, 叶春, 杨劭, 等, 2009. 腐解黑藻生物量对高硝态氮水体氮素的影响[J]. 环境科学研究, 22(10):1198-1203.
|
[10] |
王立志, 王国祥, 2013. 衰亡期沉水植物对水和沉积物磷迁移的影响[J]. 生态学报, 33(17):5426-5437.
|
[11] |
王立志, 宋红丽, 董彬, 等, 2020. 黑藻与金鱼藻自然衰亡过程中营养盐释放规律研究[J]. 环境科学研究, 33(1):138-146.
|
[12] |
王云祥, 李正, 秦传新, 等, 2016. 不同季节江蓠脱落物对大型海藻场上覆水的影响[J]. 南方水产科学, 12(2):13-20.
|
[13] |
叶春, 王博, 李春华, 等, 2014. 沉水植物黑藻腐解过程中营养盐释放过程[J]. 中国环境科学, 34(10):2653-2659.
|
[14] |
中华人民共和国国家质量监督检验检疫总局, 中国国家标准化管理委员会, 2008. GB/T 12763.4-2007 海洋调查规范第4部分: 海水化学要素调查[S]. 北京: 中国标准出版社.
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China, Standardization Administration , 2008. GB/T 12763.4-2007 Specifications for oceanographic survey-Part 4: Survey of chemical parameters in sea water[S]. Beijing: Standards Press of China (in Chinese).
|
[15] |
|
[16] |
|
[17] |
|
[18] |
|
[19] |
|
[20] |
|
[21] |
|
[22] |
|
[23] |
|
[24] |
|
[25] |
|
[26] |
|
[27] |
|
[28] |
|
[29] |
|
[30] |
|
[31] |
|
[32] |
|
[33] |
|
[34] |
|
[35] |
|
[36] |
|
/
〈 |
|
〉 |