海带养殖在桑沟湾多营养层次综合养殖系统中的生态功能

采用现场和实验生态学方法研究了大型经济海藻——海带(Saccharina japonica)的生长、光合作用和氮营养盐的吸收特性。实验结果表明:在1个生长周期内(约200d),海带的湿重与养殖天数呈明显的幂函数(W=1.3886 t~(1.362),R~2=0.9611),海带湿重是长度的幂函数(W=0.0071 L~(2.0882),R~2=0.9392);海带的光合作用放氧速率(O_2mg/h)与湿重(g)具有明显的线性相关(R~2范围为0.950—0.981),直线斜率(反应单位时间单位重量光合作用放氧速率)的变化范围为0.096—0.195(平均0.191),养殖初期单位鲜重的光合放氧能力较弱,后期趋于稳定;不同部位海带藻片对TIN的吸收速率不同,中带部上部(60—110cm)和基部(20—50cm)的吸收速率大于中带部下部(150—200cm)和边缘部,氮饥饿后最初0.5—1h对TIN的吸收速率最高(0.6μmol/g WW),培养24h可去除介质中TIN(初始浓度24.2μmol/L,密度4g/L)的64.2%—97.1%,10℃条件下藻片对营养盐的吸收率和去除率均大于4℃。海带藻片对NO_3-N的吸收速率大于对NH_4-N的吸收速率,24h后对NO_3-N的收速率趋于稳定。结果显示,海带具有较高的生长速度、光合作用产氧和营养盐吸收能力。海带养殖后期,每天可以增加氧气28.8g/m2(光周期按14h计算),收获时海带的平均碳氮含量分别为33.1%和1.8%,以桑沟湾海带养殖产量8.45万t计算,每年可移除2.8万t碳和1538t氮,海带在多营养层次综合养殖系统中具有较高的生态功能。     

海带藻际微生物抗菌活性及其多样性的初步研究

从浙江台州海域健康海带、病烂海带(Laminaria japonica)及其周围海水中分离纯化海带藻际微生物, 利用双层琼脂扩散法对获得的菌株进行抗菌活性筛选, 比较活性菌株与来源的相关性, 并对具有抗菌活性的菌株进行16S rRNA系统发生学分析。结果显示, 在分离的143株海带藻际微生物中, 有42株细菌具有抗菌活性, 其中来源于健康海带和海水的活性菌株比例(35%和29%)大于来源于病烂海带的细菌(23%)。对其中16株具有广谱抗菌活性的菌株进行的16S rRNA系统发生学分析显示, 分别属于Pseudoalteromonas、Rahnella、Donghaeana、Bacillus和Exiguobacterium 5个属。为从藻际微环境的微生物多样性入手了解海带病烂机制以及寻找新的抗菌药物提供研究材料。       

海带发酵降解中相关海洋功能菌的分离、鉴定与筛选CSCD

目的从海带养殖环境中筛选有效降解海带的海洋功能菌,对海带进行降解处理,提高利用率,增加海带原料价值。方法采用以果胶或海藻酸钠为唯一碳源的选择性培养基挑选含有果胶酶、褐藻酸裂解酶的菌株;测定海带发酵液中海藻酸含量,复筛降解效果好的单菌及复合菌;16S rDNA测序对菌种进行鉴定。结果使用含10%鲜海带的富集培养基培养48 h,其中降解效果较好的为1-2和3-10菌种的组合,其降解量为95%。结论经上述研究选出有效的降解海带功能菌1-2和3-10,其降解海带效果较好,对海带利用率高。     

海带发酵降解中相关海洋功能菌的分离、鉴定与筛选

目的 从海带养殖环境中筛选有效降解海带的海洋功能菌,对海带进行降解处理,提高利用率,增加海带原料价值。方法 采用以果胶或海藻酸钠为唯一碳源的选择性培养基挑选含有果胶酶、褐藻酸裂解酶的菌株;测定海带发酵液中海藻酸含量,复筛降解效果好的单菌及复合菌;16S rDNA测序对菌种进行鉴定。结果 使用含10%鲜海带的富集培养基培养48 h,其中降解效果较好的为1-2和3-10菌种的组合,其降解量为95%。结论 经上述研究选出有效的降解海带功能菌1-2和3-10,其降解海带效果较好,对海带利用率高。     

欲食疗吃海带

在民间早有“药补不如食补”之说,而海带则是一种食疗佳品。经常食用海带,可以对多种疾病进行治疗或调理,对人的身体健康大有裨益。通过研究发现,海带中的海带聚糖有降血脂作用,可用于预防动脉粥样硬化;藻胶酸对锶、镉等盐类在肠道被吸收前有解毒作用,可防止重金属中毒;海带氨酸有降压作用,可有效地预防高血压;甘露醇有脱水利尿作用,可用于治疗肾功能衰竭、药物中毒、浮肿和腹水等症。流行病学证据表明,经常食用海带具有预防乳腺癌的作用;由于海带中含纤维较多而难消化,可刺激肠壁蠕动、调顺肠胃,有助于消除肠内积滞的致癌物…     

不同氮、磷配比人工海水对海带胚孢子早期发育的影响

利用不同氮、磷配比的人工海水培养海带胚孢子,观察其对海带早期发育的影响.结果表明：培养于人工海水中的海带胚孢子80%能够正常发育,但与培养于天然海水中的对照组仍存在显著差异,且人工海水中海带胚孢子的萌发和配子体的形成时间滞后,人工海水培养所形成的海带雌配子体数量显著高于雄配子体（P<0.001）;不同氮、磷配比的人工海水对海带胚孢子萌发率的影响不同,N∶P＞15∶1的氮磷比会降低海带胚孢子的萌发率,而缺乏氮或磷营养盐的人工海水则极显著抑制海带胚孢子的萌发（P<0.001）;海带胚孢子能够在人工海水中进行早期发育,但人工海水中的氮、磷营养盐浓度以及氮/磷比均会对海带发育初期胚孢子的萌发率产生影响;人工海水中氮、磷营养盐的缺乏会导致海带配子体形成时间的滞后,并对其雌雄分化产生一定影响.     

施肥对金盏菊生长、开花及养分吸收的影响

研究了氮、磷、钾不同施肥处理对金盏菊（Calendula officinalisL.）生长、开花、干物质积累量及养分吸收的影响。结果表明：推荐施肥[N-P2O5-K2O：（0.4-0.2-0.3）g/kg]能有效促进金盏菊的生长及花朵开放,其中干物质积累量和总花朵数,分别比不施肥处理增加了264.3%和323.1%,比习惯施肥增加了16.0%和25.0%;不施肥、习惯施肥和推荐施肥三者干物质日积累量高峰均出现在移栽后29～35 d,分别为0.15、0.43、0.42 g/d;各处理氮、磷、钾吸收量之间均存在显著差异,推荐施肥处理N、P、K养分累积量分别为0.33、0.04、0.39 g/株,分别是不施肥处理的6.93倍、3.94倍和3.61倍,为习惯施肥的1.49倍、1.35倍和1.24倍,各处理金盏菊对N、P、K养分吸收比例变幅为1∶（0.13～0.24）∶（1.20～2.30）,平均比例为1∶0.17∶1.65。     

刺参海带饲料原料褐藻胶降解菌的分离与鉴定

从海带及刺参养殖环境中筛选有效降解褐藻胶,且对刺参无致病性的微生物,对海带饲料原料进行降解处理,以降低海带饲料中刺参难以消化的褐藻胶成分,显著提高饲料利用率,增加海带原料价值。以褐藻胶为唯一碳源选择培养基初筛;DNS法测定褐藻胶裂解酶酶活;16S r DNA测序及生理生化试验对菌种进行鉴定;高浓度腹腔攻毒试验考察筛选所得菌株对刺参的潜在致病性;分子排阻色谱及高效凝胶色谱法对微生物酶解褐藻胶的终产物进行分析。系统发育树分析表明,菌株WB1与Bacillus amyloliquifaciens有最高同源性,对刺参无潜在致病性;其褐藻胶裂解酶酶解褐藻胶的终产物主要为二糖和三糖,相对含量分别为74.1%和25.9%,平均分子量为516 Da。解淀粉芽胞杆菌WB1可作为一种安全的有益微生物用于刺参海带饲料原料中褐藻胶成分的降解。     

不同硝化抑制剂对红壤氮素硝化作用及玉米产量和氮素利用率的影响

本研究分析添加不同种硝化抑制剂及其组合的高效稳定性氯化铵氮肥对红壤硝化作用、玉米产量和氮肥利用率的影响,旨在筛选出适合酸性红壤的高效稳定性氯化铵态氮肥。在氯化铵中分别添加硝化抑制剂2-氯-6-三甲基吡啶(CP)、3,4-二甲基吡唑磷酸盐(DMPP)和双氰胺(DCD)及其组合,制成6种高效稳定性氯化铵态氮肥,以不施氮肥(CK)和施氯化铵(N)为对照,进行等氮量玉米盆栽试验。结果表明: 与N处理相比,CP+DMPP和DMPP+DCD处理红壤中铵态氮含量提高56%～62%,显著高于CP、DMPP和DCD处理;土壤表观硝化率显著降低33%～34%。添加硝化抑制剂及其组合的6个处理均显著提高了玉米生物量和氮肥吸收利用率。与N处理相比,单独添加硝化抑制剂处理生物量均显著高于硝化抑制剂组合处理,平均提高1.3倍;添加DCD处理效果最显著,玉米籽粒产量、吸氮量和氮肥吸收利用率分别显著提高4.1、6.3和4.4倍。为了达到既能低成本又能提高产量和氮肥利用率的效果,在红壤上添加硝化抑制剂DCD是最佳选择。     

海带活性碘的提取

用751-GW紫外分光光度法测定了不用条件下海带水浸泡对海带中碘的溶出影响.结果表明:浸泡过程中,浸出的无机碘性质不稳定,随着温度的升高、浸提周期的延长、浸泡水量的增加、不同的浸泡液酸碱度,浸提液中的I-存在一个浸出与挥发之间的平衡,约在40～45℃,浸泡2～3h,海带与水浸泡比例在1∶600,溶液pH值在6.5左右时,无机碘含量达到最高峰,其后,溶液中的I-逐渐降低;而有机碘虽然浸出速度较I-慢,但性质稳定,不挥发,随着浸提时间的延长,含量逐渐增高,到10～11 h直至趋平.     

PHYLOGENETIC AND BIOGEOGRAPHIC AFFINITIES OF THE HALYMENIALES AND RHODYMENIALES (RHODOPHYTA) FROM THE GULF OF MEXICO

A kelp/red algal symbiosis is described from nature based on extensive collections from the San Juan Islands, Washington. Kelp gametophytes were found as endophytes in the cell walls of seventeen species of red algae in three different kelp communities. Host red algae were mostly filamentous (e.g., Pleonosporium vancouverianum ) or polysiphonous (e.g. Polysiphonia paniculata ). The kelp gametophytes completed vegetative and reproductive development in the hosts with gametangia formed at the host surface and with sporophytes up to several mm in height being produced while still attached to the host. To date, none of the kelp gametophytes from nature have been identified to genus or species, although the gametophyte of Nereocystis luetkeana is a potential candidate for the symbiosis. Preliminary observations from Nova Scotia and the Isle of Man have not found the association in the Atlantic Ocean. Laboratory studies in Korea successfully reconstructed the symbiosis in the red alga Aglaothamnion oosumiense using zoospores of Undaria pinnatifida but not Laminaria religiosa. Here we outline the development of the symbiosis and discuss the potential adaptive significance of the kelp/red algal interaction.     

BIOGEOGRAPHY AND ECOLOGY OF THE KELP/RED ALGAL SYMBIOSIS

A kelp/red algal symbiosis is described from nature based on extensive collections from the San Juan Islands, Washington. Kelp gametophytes were found as endophytes in the cell walls of seventeen species of red algae in three different kelp communities. Host red algae were mostly filamentous (e.g., Pleonosporium vancouverianum) or polysiphonous (e.g. Polysiphonia paniculata). The kelp gametophytes completed vegetative and reproductive development in the hosts with gametangia formed at the host surface and with sporophytes up to several mm in height being produced while still attached to the host. To date, none of the kelp gametophytes from nature have been identified to genus or species, although the gametophyte of Nereocystis luetkeana is a potential candidate for the symbiosis. Preliminary observations from Nova Scotia and the Isle of Man have not found the association in the Atlantic Ocean. Laboratory studies in Korea successfully reconstructed the symbiosis in the red alga Aglaothamnion oosumiense using zoospores of Undaria pinnatifida but not Laminaria religiosa. Here we outline the development of the symbiosis and discuss the potential adaptive significance of the kelp/red algal interaction.     

GRAZING ON GIANT KELP MICROSCOPIC PHASES AND THE RECRUITMENT SUCCESS OF ANNUAL POPULATIONS OF MACROCYSTIS PYRIFERA (LAMINARIALES,PHAEOPHYTA) IN SOUTHERN CHILE1

The giant kelp Macrocystis pyrifera (L.) C. Agardh is widely distributed in the Northern Hemisphere and Southern Hemisphere, yet it exhibits distinct population dynamics at local to regional spatial scales. Giant kelp populations are typically perennial with the potential for year‐round reproduction and recruitment. In southern Chile, however, annual giant kelp populations exist and often persist entirely on secondary substrata (e.g., shells of the slipper limpet Crepipatella fecunda [Gastropoda, Calyptraeidae]) that can cover up to 90% of the rocky bottom. In these populations, the macroscopic sporophyte phase disappears annually during winter and early spring, leaving a 3–4 month period in which a persistent microscopic phase remains to support the subsequent year’s recruitment. We tested the effects of a suite of grazers on the recruitment success of this critical microscopic phase at two sites in southern Chile. Field experiments indicated that the snail Tegula atra negatively impacted M. pyrifera sporophyte recruitment, but that recruitment was highest in the presence of sessile female limpets, C. fecunda. Conversely, small male C. fecunda (biofilm grazers) did not regulate kelp recruitment. Laboratory observations showed that C. fecunda males only grazed on microscopic kelp gametophytes and small (<250 μm) sporophytes, rejecting larger sporophytes, whereas T. atra grazed on all the kelp stages. Recruitment to the C. fecunda treatments far exceeded that to bare rock in the absence of grazers but was not due to the physical presence of C. fecunda shells. We concluded that the key to M. pyrifera recruitment success in southern Chile is its capacity to colonize secondary substrates provided by the slipper limpet C. fecunda.     

Importance of phlorotannin content and C : N ratio of Laminaria hyperborea in determining its palatability as food for consumers

The importance of the tissue C : N ratio and the content of phlorotannins for the suitability of kelp, Laminaria hyperborea, as food for consumers was tested. Laminas from kelp were sampled in winter. In the laboratory, the kelp was experimentally degraded for 3, 14 and 44 days by kelp-associated bacterial communities under aerobic conditions. The kelp C : N ratio and phlorotannin contents decreased with degradation. The kelp was fed to the kelp-associated amphipods Ampithoe rubricata and Gammarus locusta in no-choice feeding experiments. The growth of amphipods was higher on kelp that was not degraded or degraded for short periods than on kelp degraded for long periods. The results show that the content of phlorotannins in L. hyperborea lamina is of little importance for their suitability as food. An earlier study using kelp with a high C : N ratio showed increased amphipod growth after long degradation and the results from both studies suggest that the C : N ratio of kelp varies greatly with season and the degree of degradation and is important for their suitability as food. Kelp is only palatable when the C : N ratio is not too high or too low.     

Marine protected areas can be useful but are not a silver bullet for kelp conservation

Kelp forests are among the most valuable ecosystems on Earth, but they are increasingly being degraded and lost due to a range of human-related stressors, leading to recent calls for their improved management and conservation. One of the primary tools to conserve marine species and biodiversity is the establishment of marine protected areas (MPAs). International commitments to protect 30% of the world's ecosystems are gaining momentum, offering a promising avenue to secure kelp forests into the Anthropocene. However, a clear understanding of the efficacy of MPAs for conserving kelp forests in a changing ocean is lacking. In this perspective, we question whether strengthened global protection will create meaningful conservation outcomes for kelp forests. We explore the benefits of MPAs for kelp conservation under a suite of different stressors, focusing on empirical evidence from protected kelp forests. We show that MPAs can be effective against some drivers of kelp loss (e.g., overgrazing, kelp harvesting), particularly when they are maintained in the long-term and enforced as no-take areas. There is also some evidence that MPAs can reduce impacts of climate change through building resilience in multi-stressor situations. However, MPAs also often fail to provide protection against ocean warming, marine heatwaves, coastal darkening, and pollution, which have emerged as dominant drivers of kelp forest loss globally. Although well-enforced MPAs should remain an important tool to protect kelp forests, successful kelp conservation will require implementing an additional suite of management solutions that target these accelerating threats.     

海带发酵制取生物乙醇的影响因素与优化条件

针对海带的碳水化合物不易被单一菌株发酵转化为乙醇的难题,通过酸化、匀浆和消化等预处理和正交试验,利用多酶系多菌种微生物复合发酵剂的酿酒曲,研究海带发酵制取生物乙醇的影响因素与优化条件。结果表明:在预处理试验中,加入一定量的Na2CO3,可以提高海带液中还原性糖和总糖的含量;消化温度对总糖影响相对较大,而对还原性糖的影响较小;过滤不利于得到较高浓度的乙醇;在优化条件中,发酵液的初始酸碱度是最重要的,其次是发酵温度和基质浓度,发酵液体积的影响程度相对较小。在基质(海带)质量浓度为0.15 g/L、温度34℃、起始pH 6.5和发酵液体积200 mL时,可以获得最大的乙醇产量4.09 g(以100 g海带计)。     

REPEAT AND SINGLE COPY SEQUENCES ARE DIFFERENTIALLY CONSERVED IN THE EVOLUTION OF KELP CHLOROPLAST DNA1

A method for the isolation of total blade, chloroplast and nuclear DNAs from kelp is described. Total blade DNA was isolated from various kelp species at yields of about 1.0 μg.g^?1 wet weight of tissue extracted. Purified chloroplast and nuclear DNAs were isolated from Macrocystis integrifolia at respective yields of about 0.05 μg.g^?1 and 1.0 μg.g^?1 wet weight of tissue extracted. Hybridization experiments with a cloned portion of the 23S rRNA gene of M. integrifolia as probe (pMiR23S) showed that the M. integrifolia chloroplast genome contains two copies of the 23S rRNA gene. Three regions of the kelp chloroplast genome were studied by restriction analysis of the cpDNA of five genera. Respective differences were assessed by comparing the restriction fragment patterns produced with five restriction endonucleases for each of three cloned M. integrifolia cpDNA hybridization probes. The kelp cpDNA sequences that hybridized to the repeated sequence probe pMiR23S were less divergent (100 × p = 2.53) than were the sequences that hybridized to the single copy probes pMiR432 and pMiH7 (100 × p = 7.48–7.74). Sequence variation (100 × p) between kelp species ranged from 3.38–6.82. Sequence variation between kelp species and Fucus gardneri ranged from 9.08–12.04. Chloroplast DNA restriction fragment length data were used to derive two most parsimonious phylogenetic trees. Both trees had consistency indexes of 0.78 and indicated that the three lessoniacean genera in the comparison do not comprise a single distinct lineage.     

A Comparison of Various Seaweed-Based Diets and Formulated Feed on Growth Rate of Abalone in a Land-Based Aquaculture System

The effects of different diets on growth in the cultured South African abalone, Haliotis midae (Linnaeus), was investigated. Growth of juvenile Haliotis midae was monitored on a commercial abalone farm over a period of 9 months in an experiment consisting of 9 treatments with 4 replicates (n = 250 individuals per replicate). The treatments were: fresh kelp (Ecklonia maxima) blades (seaweed control); Abfeed^® (formulated feed control); kelp + Abfeed^® dried kelp pellets; dried kelp blades; dried kelp stipes; fresh kelp with the epiphyte Carpoblepharis flaccida; a mixed diet (Gracilaria gracilis, Ulva lactuca, and kelp) and a rotational diet (abalone were fed 1 of the 9 treatments for the first week and them kelp for the next 3 weeks). Results show that abalone grow well on all fresh seaweed combinations, but grow best on a mixed diet. The likely reason for the success of the mixed diet is that the red and green seaweed was farm grown, with an increased protein content. Dried kelp in any form produced poor growth. Abalone fed on the mixed diet grew at 0.066 mm day^?1 shell length and 0.074 g day^?1 body weight; this corresponds to 24.09 mm shell length and 27.01 g body weight increase per annum. Abalone fed on dried kelp grew at only 0.029 mm day^?1 shell length and of 0.021 g day^?1 body weight. Abalone grown on Abfeed^® grew at 0.049 mm day^?1 shell length and 0.046 g day^?1 body weight which corresponds to 17.88 mm and 16.79 g increase per annum; this is better than the dried seaweed feeds, but poorer than the fresh seaweed combinations. This study shows that seaweed diets, particularly if the diets include seaweeds grown in animal aquaculture effluent, are good substitutes for the formulated feed generally used today.     

THE SECRET LIFE OF KELPS: PLANKTONIC PROCESSES AND POPULATION DYNAMICS

Understanding spatio‐temporal variability in recruitment is vital to studies of kelp population dynamics. Research on settlement and post‐settlement processes has suggested that arrival of kelp zoospores to suitable substrate is important in limiting kelp recruitment, yet the role of planktonic processes in kelp population dynamics has not been studied due to difficulties in sampling and identifying zoospores. I developed a method to estimate kelp zoospore abundance from in situ plankton samples and used it to study various processes regulating the availability of giant kelp (Macrocystis pyrifera) zoospores for settlement. My studies focused on (1) identifying temporal scales over which zoospore abundance is most variable, (2) describing physical and biological processes that regulate this variability, and (3) determining the relationship between zoospore abundance and settlement. I found that short‐term variability in zoospore abundance (<24 hrs) was not due to changes in supply but rather dispersion, caused by oscillating hydrodynamic forces (e.g. waves). Long‐term variability in zoospore abundance, however, was best explained by the size and density of reproductive adult plants, with zoospore abundance being most variable at the scale of days to months. Changes in adult reproductive condition caused rapid changes in zoospore abundance suggesting that the supply of kelp zoospores is sensitive to environmental regulation of adult physiology. Thus, unlike with marine animals, these results indicate that variability in kelp propagule supply, over scales most likely to affect subsequent settlement and recruitment, is more tightly coupled to demographic and reproductive mechanisms than to physical transport processes.     

LET THERE BE LIGHT (BUT NOT TOO MUCH): MOLECULAR EVOLUTION OF LIGHT-HARVESTING COMPLEXES

Understanding spatio-temporal variability in recruitment is vital to studies of kelp population dynamics. Research on settlement and post-settlement processes has suggested that arrival of kelp zoospores to suitable substrate is important in limiting kelp recruitment, yet the role of planktonic processes in kelp population dynamics has not been studied due to difficulties in sampling and identifying zoospores. I developed a method to estimate kelp zoospore abundance from in situ plankton samples and used it to study various processes regulating the availability of giant kelp ( Macrocystis pyrifera ) zoospores for settlement. My studies focused on (1) identifying temporal scales over which zoospore abundance is most variable, (2) describing physical and biological processes that regulate this variability, and (3) determining the relationship between zoospore abundance and settlement. I found that short-term variability in zoospore abundance (<24 hrs) was not due to changes in supply but rather dispersion, caused by oscillating hydrodynamic forces (e.g. waves). Long-term variability in zoospore abundance, however, was best explained by the size and density of reproductive adult plants, with zoospore abundance being most variable at the scale of days to months. Changes in adult reproductive condition caused rapid changes in zoospore abundance suggesting that the supply of kelp zoospores is sensitive to environmental regulation of adult physiology. Thus, unlike with marine animals, these results indicate that variability in kelp propagule supply, over scales most likely to affect subsequent settlement and recruitment, is more tightly coupled to demographic and reproductive mechanisms than to physical transport processes.