Three warm currents, the Kuroshio, its shelf intrusion branch in the northeast of Taiwan and the Taiwan Warm Current (hereafter TWC), dominate the circulation pattern in the East China Sea (hereafter ECS). Their origination, routes and variation in winter and summer are studied. Their relationship with four major high and low temperature centers is analyzed. Differing from the previous opinion, we suggest that the four major centers are generated to a great extent by the interaction of the currents in the ECS. In summer, a cold water belt in the northeast of Taiwan is preserved from winter between the Kuroshio and the TWC. The shelf intrusion branch of the Kuroshio separates the water belt, and two low temperature centers generate in the northeast of Taiwan. In the southern ECS, the TWC transports more heat flux northward to form a warm pool. But it is separated in the lower layer by the cold water driven by the intrusion branch of the Kuroshio. So the TWC and the intrusion branch of the Kuroshio play a dominating role to generate the high temperature center. The interaction among the eastward TWC, the northward Tsushima Warm Current (hereafter TSWC) and the southward Su Bei Coastal Flow (hereafter SBCF) generates the low temperature center in the northern ECS. In winter, the strengthening of the shelf intrusion branch of the Kuroshio obscures the two low temperature centers in the northeast of Taiwan. For the weakening of the TWC, the high temperature center in the southern ECS vanishes, and the low temperature center in the northern ECS shifts to south.

Intensive Pyropia aquaculture in the coast of southwestern Yellow Sea and its subsequent waste, including disposed Ulva prolifera, was speculated to be one of the major sources for the large-scale green tide proceeding in the Yellow Sea since 2007. It was, however, unclear how the detached U. prolifera responded and resumed growing after they detached from its original habitat. In this study, we investigated the growth and photosynthetic response of the detached U. prolifera to various temperature, salinity and irradiance in the laboratory. The photosynthetic rate of the detached U. prolifera was significantly higher at moderate temperature levels (14-27℃) and high salinity (26-32), with optimum at 23℃ and 32. Both low (<14℃) and highest temperature (40℃), as well as low salinity (8) had adverse effects on the photosynthesis. Compared with the other Ulva species, U. prolifera showed higher saturated irradiance and no significant photoinhibition at high irradiance, indicating the great tolerance of U. prolifera to the high irradiance. The dense branch and complex structure of floating mats could help protect the thalli and reduce photoinhibition in field. Furthermore, temperature exerted a stronger influence on the growth rate of the detached U. prolifera compared to salinity. Overall, the high growth rate of this detached U. prolifera (10.6%-16.7% d-1) at a wide range of temperature (5-32℃) and salinity (14-32) implied its blooming tendency with fluctuated salinity and temperature during floating. The environmental parameters in the southwestern Yellow Sea at the beginning of green tide were coincident with the optimal conditions for the detached U. prolifera.

Based on the CTD data obtained in the southern Taiwan Strait and its adjacent areas in August and September of 1994, the distributional features of the temperature and salinity in the studied area have been analyzed in detail.The results are as follows:(1) There are two low temperature and high salinity regions in the nearshore area between Dongshan and Shantou and in the southeastern Taiwan respectively, which may be caused by upwellings.(2) There exists a cold eddy in the northwestern sea area and a warm eddy with two high temperature cores in the eastern sea area of the Islands, which are related to the anti-cyclonic turning of the seawater near the Dongsha Islands.(3) A westward high temperature and high salinity water tongue extends through the northern Luzon Strait and reaches the sea areas near the Dongsha Islands and southern Taiwan Strait.

In this study, the sectional characteristics of temperature, salinity and density off the central Zhejiang coast were analyzed using three sections of observational data in the spring of 2016. The results are as follows:(1) a cold water patch was observed in the middle layer of sections from 10 to 25 m, and a weak upwelling was observed at the upper layer near the central Zhejiang coast; (2) several thermoclines, inverted thermoclines, and haloclines were observed in the survey area; (3) the Taiwan Warm Current Water (TWCW) climbing from the slope towards the survey area affected the thermocline, making it thinner and intensified; however, the TWCW was not strong enough to break through the thermocline to reach the sea surface.

Superoxide dismutase(SOD) is a crucial antioxidant enzyme playing the first defense line in antioxidant pathways against reactive oxygen species in various organisms including marine invertebrates. There exist mainly two specific forms, Cu/Zn-SOD(SOD1) and Mn-SOD(SOD2), in eukaryotes. SODs are known to be concurrently modulated by a variety of environmental stressors. By using central composite experimental design and response surface method, the joint effects of water temperature(18-34℃) and copper ion concentration(0.1-1.5 mg/L) on the total SOD activity in the digestive gland of Crassostrea ariakensis were studied. The results showed that the linear effect of temperature was highly significant(P<0.01), the quadratic effect of temperature was significant(P<0.05); the linear effect of copper ion concentration was not significant(P>0.05), while the quadratic effect of copper ion concentration was highly significant(P<0.01); the interactive effect of temperature and copper ion concentration was not significant(P>0.05); the effect of temperature was greater than that of copper ion concentration. The model equation of digestive gland SOD enzyme activity towards the two factors of interest was established, with R² and predictive R² as high as 0.9616 and 0.8207, respectively, suggesting that the goodness-of-fit to experimental data be very satisfactory, and could be applied to prediction of digestive gland SOD activity in C. ariakensis under the conditions of the experiment. Our results would be conducive to addressing the health of aquatic animals and/or to detecting environmental problems by taking SOD as a potential bioindicator.

The effects of temperature and different forms of nutrients on Chattonella marina growth have been investigated in strains isolated from the Daya Bay, the South China Sea. The strain of C. marina preferred high temperatures, with an optimal temperature of 25℃, and 18℃ was the minimum for its survival. Higher cell number and growth rate were obtained in high nitrogen and phosphorus concentrations (500 μg/L, 74 μg/L) than under nutrient limitation. Nitrogen influenced the growth most, as the specific growth rate and maximum cell density were lower in nitrogenlimited cultures than noted under phosphorus limitation or under limitation from both. C. marina was capable of using many kinds of organic nitrogen sources including L-serine (L-Ser), glycine (Gly), alanine (Ala), L-threonine (L-Thr), glutamic acid (Glu) and urea, but could not utilize uric acid. Various forms of organic phosphorus compound such as glucose-6-phosphate (G6P), sodium glycerophosphate (GYP), adenosine triphosphate (ATP), adenosine monophosphate (AMP), cytidine monophosphate (CMP), guanosine monophosphate (GMP), uridine monophosphate (UMP), 4-nitrophenylphosphate (NPP) and triethyl phosphate (TEP) supported the growth as well. Algal cells had the ability to sustain growth under nitrogen-and/or phosphorus-free conditions particularly under phosphorus depleted condition. These results led to the hypothesis that high loading of nitrogen has played an important role in frequent C. marina blooms in the past decade, and its capability for utilization of diverse forms of organic nutrients and growth in low nutrient conditions make this species a likely recurrent dominant in the Daya Bay phytoplankton assemblages, visible as more frequent blooms.

There were two severe coral bleaching events at Ko Khang Khao, the inner Gulf of Thailand, occurred during the prolonged period of the elevated sea surface temperature (SST) in 2010 and low salinity as well as turbidity due to heavy flooding in 2011. The bleaching index (BI) and mortality index (MI) are calculated to compare the susceptibilities of coral species in the two bleaching events. The BI and MI vary significantly among the study sites and bleaching events. The most susceptible corals during both bleaching events are Acropora millepora, Pocillopora damicornis and Pavona decussate, while the most resistant species were Galaxea fascicularis, Fungia fungites, Pavona frondifera, Oulastrea crispate, and Symphyllia recta. The corals Favia favus, Goniopora columna, Platygyra pini, Symphyllia agaricia were relatively more tolerant to high SST but they are relatively more susceptible to low salinity. Coral bleaching is a phenomenon that the dissociation stress of the symbiotic relationship between zooxanthellae and their cnidarian host results in the reduction in photosynthetic pigment concentration. Among stressors, both prolonged exposure of high SST and low salinity, above and below their thresholds, respectively. The long-term resilience of coral communities at Ko Khang Khao and other coral communities close to the mouth of large rivers may depend on the frequency and duration of the exposure on the elevated SST due to atmospheric heating and low salinity due to river flooding.

To understand the response of marine ecosystem to environmental factors, the oceanographic (physical and biochemical) data are analyzed to examine the spatio-temporal distributions of chlorophyll a (Chl a) associated with surface temperature, winds and height anomaly for long periods (1997-2008) in the western South China Sea (SCS). The results indicate that seasonal and spatial distributions of Chl a are primarily influenced by monsoon winds and hydrography. A preliminary Empirical Orthogonal Function (EOF) analysis of remotely sensed data is used to assess basic characteristics of the response process of Chl a to physical changes, which reveals interannual variability of anomalous low Chl a values corresponding to strong El Niño (1997-1998), high values corresponding to strong La Niña (1999-2000), low Chl a corresponding to moderate El Niño (2001-2003), upward Chl a after warm event in 2005 off the east coast of Vietnam. The variability of Chl a in nearshore and the Mekong River Estuary (MER) waters also suggests its response to these warm or cold processes. Considering the evidence for covariabilities between Chl a and sea surface temperature, winds, height anomaly (upwelling or downwelling), cold waters input and strong winds mixing may play important roles in the spatial and temporal variability of high Chl a. Such research activities could be very important to gain a mechanistic understanding of ecosystem responses to the climate change in the SCS.

Ecological adaptation and ecological groups of pelagic ostracods were examined in the East China Sea (23° 30'~33° 00'N, 118°30'~128°00'E), in relation to temperature and salinity. The data were collected in four surveys conducted from 1997 to 2000. The density, yield density, or negative exponent models were used to determine the optimal temperature and salinity of water for the thriving growth of pelagic ostracods. Thereafter,ecological groups and potential distribution patterns of pelagic ostracods were determined based on the predicted parameters such as optimal temperature and salinity, consulting the geographic distribution. The analytical results indicate that, among the numerical dominant pelagic ostracods in the East China Sea (ECS), Euconchoecia aculeata, E. elongata, E. chierchiae, E. maimai, and Cypridina dentata, etc. are offshore subtropical water species. These species are widely distributed in the area, and they can be brought by the warm current to north offshore during spring and winter. The predicated optimal temperature (OT) and optimal salinity (OS) for Paraconchoecia decipiens, P. echinata, P. spinifera, P. oblonga, Conchoecia magna and Porroecia porrecta are all greater than 25℃ and 34 separately. These species are mainly distributed in the waters of the Kuroshio, the Taiwan Warm Current, and the Taiwan Strait, and therefore are designated as oceanic tropical water species. On the other hand, Pseudoconchoecia concentrica is considered as offshore subtropical water species based on its geographical distribution although its OT is 19℃. The other species, though their OSs are approximately 34 and with OTs ranging from 20° to 25℃, are considered as offshore subtropical water species because they were found to be widely distributed from the South China Sea to the East China Sea.

The physical structures of snow and sea ice in the Arctic section of 150°-180°W were observed on the basis of snow-pit, ice-core, and drill-hole measurements from late July to late August 2010. Almost all the investigated floes were first-year ice, except for one located north of Alaska, which was probably multi-year ice transported from north of the Canadian Arctic Archipelago during early summer. The snow covers over all the investigated floes were in the melting phase, with temperatures approaching 0℃ and densities of 295-398 kg/m³. The snow covers can be divided into two to five layers of different textures, with most cases having a top layer of fresh snow, a round-grain layer in the middle, and slush and/or thin icing layers at the bottom. The first-year sea ice contained about 7%-17% granular ice at the top. There was no granular ice in the lower layers. The interior melting and desalination of sea ice introduced strong stratifications of temperature, salinity, density, and gas and brine volume fractions. The sea ice temperature exhibited linear cooling with depth, while the salinity and the density increased linearly with normalized depth from 0.2 to 0.9 and from 0 to 0.65, respectively. The top layer, especially the freeboard layer, had the lowest salinity and density, and consequently the largest gas content and the smallest brine content. Both the salinity and density in the ice basal layer were highly scattered due to large differences in ice porosity among the samples. The bulk average sea ice temperature, salinity, density, and gas and brine volume fractions were -0.8℃, 1.8, 837 kg/m³, 9.3% and 10.4%, respectively. The snow cover, sea ice bottom, and sea ice interior show evidences of melting during mid-August in the investigated floe located at about 87°N, 175°W.