Jiunn-Tzong Wu

• Academia Sinica

Untangling causal links and feedbacks among biodiversity, ecosystem functioning, and environmental factors is challenging due to their complex and context-dependent interactions (e.g., a nutrient-dependent relationship between diversity and biomass). Consequently, studies that only consider separable, unidirectional effects can produce divergent co...

Understanding how ecosystems will respond to climate changes requires unravelling the network of functional responses and feedbacks among biodiversity, physicochemical environments, and productivity. These ecosystem components not only change over time but also interact with each other. Therefore, investigation of individual relationships may give...

Late Holocene vegetation, climate and human impacts were investigated using palynologiacal and marco-charcoal data from lacustrine sediments from a lowland lake of eastern Taiwan. On the basis of sixteen ²¹⁰Pb dates and six radiocarbon dates, a reliable stratigraphic chronology was established. The 2680 year records of vegetation history and fire f...

Despite the consensus that warming will affect biodiversity, alter physicochemical environments, and disrupt biological interactions, the relative importance of these key processes and how they interact to determine overall ecosystem function is poorly understood. Here, we analyze long-term (16~39 years) time series data from ten aquatic ecosystems...

Reproductive isolation is essential for the process of speciation. In order to understand speciation, it is necessary to compare one mating group with other phylogenetically related but reproductively isolated groups. The Closterium peracerosum–strigosum–littorale (C. psl.) complex is a unicellular isogamous zygnematophycean alga, which is believed...

Background: Volvox carteri f. nagariensis is a model taxon that has been studied extensively at the cellular and molecular level. The most distinctive morphological attribute of V. carteri f. nagariensis within V. carteri is the production of sexual male spheroids with only a 1:1 ratio of somatic cells to sperm packets or androgonidia (sperm packe...

This study was conducted to identify the key factors related to the spatiotemporal variations in phytoplankton abundance in a subtropical reservoir from 2006 to 2010 and to assist in developing strategies for water quality management. Dynamic factor analysis (DFA), a dimension-reduction technique, was used to identify interactions between explanato...

Chlamydomonas (Cd.) is one of the largest but most polyphyletic genera of freshwater unicellular green algae. It consists of 400–600 morphological species and requires taxonomic revision. Towards reclassification, each morphologically defined classical subgenus (or subgroup) should be examined using culture strains. Chlamydomonas subg. Amphichloris...

Existing individual size distribution (ISD) theories assume that the trophic level (TL) of an organism varies as a linear function of its log-transformed body size. This assumption predicts a power-law distribution of the ISD, i.e., a linear relationship between size and abundance in log space. However, the secondary structure of ISD (nonlinear dom...

The purpose of this study was to characterize the diversity and abundance of indigenous soil photomicrobes with respect to the physico-chemical environment at a highly eroded loamy sand mountain situated in mid-Taiwan. Denaturing gradient gel electrophoresis and clone library were employed to characterize the operational taxonomic unit of photomicr...

Tolerance to drought stress in soil crust microorganisms is essential for exploiting suitable organisms for restoring soil. In this study, the responses to drought stress of two drought-tolerant species, a green alga and a cyanobacterium, were compared with those of two non-tolerant green algae. In response to drought stress, induced by treatment w...

Very little information is available about soil algae in Taiwan. In this study, we investigated for the first time the soil algae inhabiting five types of farmland in mid-Taiwan: rice paddies, vegetable farms, tea plantations, sugar cane farms, and orchards. Sixty-four taxa belonging to 33 genera of cyanobacteria, diatoms, green algae, and euglenoi...

A sediment-trap monitoring program measured the fluxes of settling particles and organic carbon in Yuanyang Lake, northern Taiwan, from July 2004 to July 2006 and assessed their relations to the amounts of normal monthly and typhoon-event precipitation. The flux of settling particles varied from 0.7 mg cm−2 month−1 to 14.7 mg cm−2 month−1, and the...

We studied diatoms in a 55.5-cm-long sediment core from a subalpine lake in northern Taiwan, Tsuifong Lake (TFL), to investigate environmental changes from AD 490 to present. Diatom assemblages of the last century were dominated by acidophilous species, whereas alkaliphilous taxa dominated the record between AD 1480 and 1910. Over the studied time...

Investigations of multiple temporal distributions of phytoplankton dynamics through environmental variables in water bodies over extensive areas remain relatively scarce. This study focused on the determination of the key factors regulating temporal and spatial variations of phytoplankton abundance at three monitoring sites in Shihmen Reservoir wit...

Yellow cypress, Chamaecyparis obtusa var. formosana, is a relic species and one of the most important trees in Taiwan. This is the first study of the epiphyllous algae in a yellow cypress forest. The forest surrounding Yuan-Yang Lake (YYL) in northern Taiwan was chosen for this study. Algal samples collected from leaves and trunks were isolated and...

The atlas describes the specific characteristics of extant coccolithophore, with delicate micrographs using scanning electron microscopy (SEM), sampled from the East and South China Sea and Kuroshio Current. This compilation displays 19 plates with 114 micrographs of sixty-nine coccolithophore species belonging to four Orders, ten Families and thir...

We studied how typhoon strength affects the daily dynamics of ecosystem metabolism of a subtropical alpine lake in Taiwan. We identified proximal agents of typhoon disturbance and assessed the resistance (the extent of change induced by a disturbance) and resilience (the rate of recovery after a disturbance) of lake metabolism to them. Gross primar...

In this study, we synthesized the fossil pollen data from 10 lake sediments and 2 land cores to integrate the alteration of forest covered areas in northern Taiwan with changes in humidity and temperature over the last 2000 years. The abundance of arboreal pollen, fern spores and Tsuga pollen in the pollen and spore assemblages were used as indicat...

Annual fog deposition and atmospheric chemical deposition were evaluated for a strongly fog-affected coniferous forest at Chi-Lan, Taiwan. Fog capture efficiencies of Chamaecyparis obtusa var. formosana leaves were measured at three heights within the canopy using in situ exposure experiments under contrasting climatic conditions. The efficiencies...

Feitsui Reservoir is a subtropical water reservoir constructed in 1986 for supplying the domestic water of Taipei metropolitan area. During long-term monitoring conducted from 1990 to 2007, we observed a remarkable alteration in dominant phytoplankton groups, showing a succession of chlorophytes versus Microcystis spp. Analysis of such change with...

Phthalate esters are widely distributed pollutants which originate from synthetic plasticizer and are known to act as toxicants as well as environmental pheromones in the aquatic ecosystems. From investigating sixteen species of freshwater algae and cyanobacteria we revealed that some of them were capable of producing either di(n-butyl)phthalate (D...

Phthalate esters (PEs) are endocrine-disrupting pollutants that are ubiquitous in the environment and can be degraded by microorganisms. In this study, we investigated the kinetics and pathway of biodegradation of di-n-butyl phthalate (DBP), diethyl phthalate (DEP), and dimethyl phthalate (DMP) by cyanobacteria Anabaena flos-aquae G. S. West (strai...

This study described the diatoms appeared in the sediments of Liyu Lake, a lowland natural lake situated at Hualen, eastern Taiwan. A total of 50 species was found in the sediments of this eutrophic lake. In them, 8 species were reported for the first time in Taiwan. They are: Cymbella thienemannii, Navicula absoluta, Navicula bacillum, Frustulia r...

Dynamic modification of target proteins by small ubiquitin-like modifier (SUMO) is known to modulate many important cellular processes and is required for cell viability and development in all eukaryotes. However, understanding of SUMO systems in plants, especially in unicellular green algae, remains elusive. In this study, Chlamydomonas reinhardti...

To explore typhoon effects on dissolved organic carbon (DOC) dynamics, field investigations (tributary and dam site) and laboratory experiments (bioassay and DOC consumption) were conducted in a subtropical reservoir. A tributary survey indicated that after typhoon disruption, upstream areas were the sources of phosphate (P) but not DOC for the dam...

We examined how tidal changes and which physical factors affected holo- and meroplankton assemblages in a subtropical estuary in Taiwan in February 1999. A factor analysis showed that during tidal flooding, the water mass properties changed from low salinity (5-16) and high particulate organic carbon (POC, 2.6-4.5 mg L(-1)) content to increasing sa...

The Danshuei River embouchure is the largest estuarine ecosystem in northern Taiwan. The interacting effects of wastewater discharge from Taipei City and Taipei County into the river and seawater intrusion are the main determinants of the community composition, distribution, and abundance of zooplankton in this estuarine ecosystem. In the present s...

The Ser-Su-Ken Lake is a landslide-dammed lake caused by the Chi-Chi Earthquake. The morphological and area change of the lake was monitored by satellite remote sensing. The contribution degree of lake water physico-chemical variables to the simple ratio water reflectance index (SRWRI), i.e. IR/R, calculated from satellite digital data, was compare...

Hydrological variability inferred from palynological composition and organic proxies extracted from a sediment core of Lake Dahu, northeastern subtropical Taiwan is presented for the last two millennia. The lake is situated at the foot of northeastern Shuehshan Range and the northwestern margin of Ilan Plain, an alluvial fan, which is formed by Lan...

Eutrophication is a serious problem of water resource management in Taiwan. The occurrence of annoying algal species as well as abnormally abundant algal mass threatens the quality of water supply. The growth and decline of a specific phytoplankton species are affected by environmental factors, including light, nutrients, temperature, etc. There ha...

A thin layer of poly(N-isopropyl acrylamide) (pNIPAAm) was synthesized in situ on the surface of hydrolyzed polyacrylonitrile (PAN) membrane. This thin layer exhibited both pH response due to the poly(acrylic acid) moiety and temperature response due to the pNIPAAm moiety. The swelling behavior of the membranes was evaluated under various temperatu...

This is the last part of study about the diatom flora found in the Mystery Lake, a slightly acidic lake situated within a hardwood nature preserve in northeastern Taiwan. In this article, we reported 17 species, belonging to 4 genera, 4 families, and 2 orders, based on scanning electron microscopic observations. The species described here, 9 are ne...

Blooms of the colonial green algae, Botryococcus braunii, have been widely known to exert toxic effects on a variety of aquatic organisms and have been noted to cause fish deaths in some environments. In this study, a monitoring of the abundance and distribution of B. braunii in Paoay Lake was done in 2006. Samples were taken from the surface and d...

We analyzed pollen, spores, diatoms, organic carbon, nitrogen, and δ13C of organic matter in lake sediments to infer climate changes and reconstruct the paleo-environment of subtropical Taiwan over the past ∼1300years. A 31.5-cm sediment core that represents deposition from 650 AD to present was taken from a mountain lake, Duck Pond, located 760m a...

Butylated hydroxytoluene (BHT) is one of the synthetic antioxidant agents commonly used for food additives. In the present study, we determined that four freshwater phytoplankton, including a green alga (Botryococcus braunii Kütz.) and three cyanobacteria [Cylindrospermopsis raciborskii (Wolłosz.) Seenaya et Sabba Raju, Microcystis aeruginosa (Kütz...

1. We used high‐frequency in situ dissolved oxygen measurements to investigate the seasonal variability and factors regulating metabolism in a subtropical alpine lake in Taiwan between May 2004 and October 2005, specifically exploring how the typhoon season (from June or July to October) affects lake metabolism. 2. Gross primary production (GPP) an...

We explored patterns of change in bacterioplankton and phytoplankton community composition in response to typhoons in a subtropical, subalpine freshwater humic lake in Taiwan. Thermal profiles with depth, near-surface dissolved oxygen, and meteorological conditions were measured at high temporal resolution using an instrumented buoy. We collected s...

The intracellular proline level in Anacystis nidulans cells was enhanced when the cells were exposed to sublethal concentrations of Cu2+; the degree of enhancement was positively related to the concentration of Cu2+. Analysis by high-performance liquid chromatography confirmed that the enhancement of proline levels was the most pronounced change in...

Little is known about carbon budgets for tropical and subtropical montane cloud forest (TMCF) ecosystems. Information about the soil CO2 efflux from these ecosystems is particularly scarce, although they have been shown to have special hydrological regimes which might be important in controlling soil respiration. In this study, we used an automatic...

A water quality and ecosystem model is developed to simulate nutrients, heavy metals, and aquatic plants in the Erh-Chung Flood Way wetland in Taiwan. A sediment system was incorporated into the model. The RMA2 and WASP/EUTRO5 models were adopted as the basic framework with modifications and enhancement of kinetics to incorporate ecosystem dynamics...

Yellow cypress (Chamaecyparis obtusa (Siebold & Zucc.) Endl. var. formosana (Hayata) Rehder) is the predominant tree species of Taiwan's nutrient-poor, mountain fog forests. Little is known about the potential contribution of solute uptake from fog to the overall nutrition of these trees. Shoots of yellow cypress seedlings were misted with artifici...

An ecosystem model was developed to simulate the water quality and plankton dynamics in the Danshuei River estuary, Taiwan. The model simulates the hydrodynamics with a laterally integrated 2-dimensional intratidal numerical model, which supplies the physical transport processes for simulation of water quality and plankton state variables. The appl...

Some free fatty acids are toxic to phytoplankton, and the toxic effects are multiple. However, precisely how they kill phytoplankton is debatable. Here we show that fatty acids result in damage to plasma membranes, which might account for their lethal effects on phytoplankton. In this study, we used two chlorophytes (Chlorella vulgaris Beij. and Mo...

To better understand the climatic characteristics in a subtropical mountainous cloud forest at the Yuanyang Lake long-term ecological research site, weather data collected from January 1994 to December 2004 were analyzed in the present study. The obvious seasonal changes in climatic factors were observed at this site. The annual mean air temperatur...

A new approach for quantifying fog deposition rate was conducted in a mountainous forested ecosystem (Chamaecyparis obtusa var. formosana) in northeastern Taiwan where the frequency and duration of fog occurrence is extremely high and the annual number of foggy days often exceeds 350. The significance of fog in the hydrological budget of such ecosy...

Chamaecyparis obtusa var. formosana and Chamaecy-paris formosensis are congener gymnosperm tree species native to Taiwan cloud forests; occupying different niches there. While the seedlings of C. formosensis occur predom-inantly under bright conditions in large forest gaps, seed-lings of C. obtusa var. formosana are mainly found below the canopy of...

In an outbreak of food poisoning involving a dried purple laver product (called nori), four persons had allergic-like symptoms such as inflammation and red rash on their face, mouth and belly. The causative nori was extracted and smeared on the arm-skin of five volunteers. Three out of five volunteers had a slight allergic reaction after 5 to 30 mi...

The alga Botryococcus braunii Kützing (Chlorophyceae) present in Liyu Lake (Huanlien County, Taiwan) has toxic effects on a variety of aquatic organisms. Blooms of this alga, which typically occur in autumn, are associated with fish deaths in this lake. Experiments using 15 phytoplankton and 5 zooplankton isolated from Liyu Lake indicate that these...

To improve the drug absorption into and across the skin, fatty acids extracted from Botryococcus braunii were evaluated using in vitro and in vivo techniques with Wistar rats as the animal model. Palmitic acid (C16:0), oleic acid (C18:1), linoleic acid (C18:2), and linolenic acid (C18:3) were the major components in the B. braunii extract. Topical...

One hundred and eighty lakes, ponds and reservoirs in Taiwan, and the offshore islands have been investigated since 1985. Effects such as warming/cooling, mixing, photosynthesis and respiration on pH have been identified. These effects were found to be less profound than those resulting from the geology. Since there is little rain or lake water pH...

The estuary of Tamsui River, located in the northern subtropical area of Taiwan, is eutrophic as a result of municipal sewage discharges from the Taipei metropolitan area. The primary productivity is rather low in this estuary, compared with other estuaries. The objective here was to determine whether nutrient limitation might explain the decreasin...

Chamaecyparis obtusa Sieb. & Zucc. var. formosana (Hayata) Rehder (Taiwan yellow false cypress) is one of the most important sources of timber in Taiwan. For sustainable use of this species, basic information about its regeneration under natural conditions is required, but this has been few until now. In this paper, the composition, population stru...

The fog meteorology, fog chemistry and fog deposition on epiphytic bryophytes were investigated from July 2000 to June 2001 in the Yuanyang Lake forest ecosystem. The elevation of the site ranges from 1650 to 2420 m, at which the high frequency of fog occurrence throughout the year has been thought to be of benefit to the establishment of the prima...

A generic index (GI) utilizing epilithic diatom assemblages as abioindicator of water pollution in subtropical rivers in Taiwan was applied toastudy of a tropical river. Seven sites on the River Tsanwun were sampledseasonally from August 1995 to June 1998. Although there is a marked differencein water chemistry between tropical and subtropical rive...

Yuanyang Lake is an acidic alpine lake located in northern Taiwan. The lake's acidity displays both spatial and temporal variations and is correlated with concentrations of organic and inorganic carbon, and with some cations in the lake water. The factors relating to such characteristics were studied, with particular focus on acid precipitation and...

Cyanobacterial biofilms were collected in the subtropical part of Taiwan from wet and irrigated rocks, stone and concrete walls, and drains. The biofilms developed in unpolluted freshwater and consisted of various genera, including Phormidium, Lyngbya, Oscillatoria, Microcoleus, Aphanothece and Scytonema. Ethanolic extracts of these biofilms were u...

Allergic contact dermatitis and its animal model, contact hypersensitivity (CHS), have long been documented as type 1 T-cell-predominant immune responses. Although type 1/type 2 T-cell deviation has been repeatedly demonstrated to play an important role in many human diseases and their animal models, the potential of tilting type 1/type 2 T-cell di...

The Keelung River (Taiwan) is heavily polluted by domestic, industrial and agricultural wastes. Water quality, particularly in ammonium, nitrite, silicate, and turbidity, negatively correlated with dissolved oxygen. A generic index (GI) – the ratio of abundance of Achnanthes, Cocconeis and Cymbella, to that of Cyclotella, Melosira and Nitzschia – w...

Yuanyang Lake (2435N, 12124E), located at an altitude of 1,670 m within a nature preserve in northern Taiwan, is an acidic lake. Remains of diatoms and pollen from a 3.72-m sediment core were used to elucidate the relationships between the vegetation of the watershed and the paleolimnological environment. Past pH, saprobity level, and total P of th...

Sufficient CD4+ T cell help is very important in generating specific cytotoxic T cell responses. The inadequate activation of tumor-specific Th cells leads to failure of antitumor immunity. In general, each individual consists of some primed Th cells responding to certain antigens. If these tumor non-specific pre-primed Th cells can provide suffici...

Peridinium bipes exerted an inhibitory effect on the growth of Microcystis aeruginosa. The algicidal action of water-soluble extract from P. bipes was studied. After treatment with P. bipes extract, the absorption spectrum of M. aeruginosa culture changed markedly, particularly in the ranges of 500∼650 and 420∼460 nm. An increase in absorption in t...

In Feitsui Reservoir, dinoflagellate association was composed of three species: Ceratium furcoides (Levander) Langhans, Peridinium bipes Stein, and P. umbonatum Stein var. umbonatum. The environmental factors affecting their occurrence were studied at eight sites in the reservoir between January 1990 and December 1994. The peak occurrence of dinofl...

The green alga Chlorella sp. (strain 2350) was found to accumulate proline, up to a maximum of 0.027 fmol·cell−1, under stressful concentrations of cupric ions. The function of the accumulated proline was studied with respect to its effect on copper (Cu) uptake. By induction with salt stress, cells with various levels of intracellular proline were...

Yuanyang Lake is an acidic alpine lake at an altitude of 1,670 m located in northern Taiwan that shows a pH gradient, up to 1.5 pH units between inlet and outlet. The diatoms in the surface sediment were studied with respect to such a gradient. The results show that the species and diversity of diatom assemblages vary with the pH of the lakewater....

The addition of the proper amount of ammonium to the culture medium containing nitrate as nitrogen source enhanced the growth rate of Anabaena viguieri. The amount of geosmin produced by these cells varied with the concentrations of ammonium added. A negative correlation between the amount of geosmin produced and of the growth rate of cells was rev...

A study of the sorption and desorption of strontium-90 and yttrium-90 by Anacystis cells showed a concentration factor of 4 × 104 mlg−1. The uptake of both radionuclides by the cells was very rapid and a linear relationship exists between the amount of radionuclides accumulated in the cells and those in the surrounding medium. The results show that...

The production of geosmin by axenic cultures of Fischerellamuscicola (ATCC 29114) was analysed by gas chromatography and mass spectrometry. A methanol based extraction procedure preceding closed loop stripping was successfully applied for quantitative analysis. The major part of geosmin produced by this cyanobacterium was bound in the cells. Less t...

A newly isolated strain of Oscillatoria tenuis produces geosmin and 2-methylisoborneol (MIB) simultaneously. The intra- and extracellular distribution of both compounds was studied. Geosmin was much less released to the medium compared to MIB. Different amounts of each of the compounds were in different cellular fractions. The geosmin and MIB in th...

Chlorella sorokiniana cells grew synehronously under different light-dark changes at temperatures between 30 and 40 °C. The productivity of synchronous cultures (increase in cell number) oscillated when darkness, i.e. waiting time, was added supplementarily after the light-dark cycle. At 31 °C a circadian oscillation in the production of daughter c...

Chlorella fusca var vacuolata cells were transferred to continuous darkness or weak light (0.07 watts per square meter) (both were called waiting time, WT) after a 12-hour light and 12-hour dark schedule. A daily dilution is performed at the end of the light/dark schedule, resulting in always the same average production of 18 autospores per mother...