Average Surface Water Temperature Research Articles

Flow cytometric investigation and comparison of Synechococcus spp. pico-, nano- and microplankton in the Arctic and Antarctic polar regions during the summer period of 2019

ABSTRACT In the present study, Synechococcus spp. pico-, nano- and microplankton community compositions in the Arctic and Antarctic surface coastal waters were compared during the summer of 2019 using flow cytometry. The average surface water temperatures in Antarctica and the Arctic were −0.29 ± 0.28°C and 3.71 ± 0.71°C, respectively. While plankton abundance in Antarctica exhibited a relative increase with temperature, plankton abundance in the Arctic exhibited a relative decrease with temperature. However, no significant correlation was found between plankton abundance and temperature. Synechococcus spp. cell abundance dominated in both polar regions, followed by picoeukaryotes, microautotrophs and nanoeukaryotes. Overall, plankton abundance across sampling sites was highly variable. In Antarctica, the abundance of Synechococcus spp., picoeukaryotes, nanoeukaryotes and microautotrophs were the highest in S4 (151,400 cells/ml), S1 (2180 cells/ml), S2 (1080 cells/ml) and S4 (6100 cells/ml), respectively. On the other hand, the most abundant stations in the Arctic in terms of Synechococcus spp., picoeukaryotes, nanoeukaryotes and microautotrophs were N2 (19600 cells/ml), N3 (6400 cells/ml), N3 (500 cells/ml) and N4 (6100 cells/ml), respectively. While Synechococcus spp. and nanoeukaryote abundance were higher in Antarctica, only Synechococcus spp. abundance was significantly higher in Antarctica.

Impact of Phytoplankton Community Structure Changes in the South Sea of Korea on Marine Ecosystems Due to Climate Change

Herein, we conducted surveys during the 2018–2022 summers to investigate the impact of climate change-related changes in the phytoplankton community structure on the marine ecosystem in the South Sea of Korea. The average surface water temperature increased by ~1.07 °C at 0.0195 °C·yr−1 between 1968 and 2022. During the summers, the rate was 0.0211 °C·yr−1, with a total increase of ~1.16 °C, indicating a stronger increase in summer surface water temperature. Over the last 30 years, nutrient levels in the South Sea have decreased, particularly at the surface. Moreover, 29.3–90.0% of the phytoplankton community structure was dominated by nanoflagellates (≤20 μm). Based on the size of the phytoplankton chl-a, the average contribution rate of picophytoplankton was the highest (60.1%). Redundancy analysis revealed negative correlations between nutrients and water depth, excluding NH4. Increased stratification due to climate change is causing reduced nutrient availability at the surface mixed layer, and the size of the phytoplankton structure is progressively reducing. These changes are expected to manifest in a complex microbial food web centered on smaller phytoplankton with low primary productivity. This can reduce the efficiency of carbon transfer to higher consumer levels, suggesting a potential decrease in marine productivity.

Spatial and seasonal fluctuations of Ichthyoplankton assemblage in the Mediterranean coast of Morocco (Southwestern Alboran Sea)

Ichthyoplankton represent the first life stages of fish. The study of ichthyoplankton is crucial to understanding marine ecosystems and plays an important role in the management and durability of fisheries resources. During March and October of 2019, two oceanographic ichthyoplankton surveys were conducted in the Mediterranean Sea of Morocco from Tanger to Saadia by studying the horizontal structure of the ichthyoplankton species assemblage and its relation to environmental parameters. The average surface water temperature was (15.8°C in spring and 16.4°C in autumn). The fish eggs and larvae were more abundant in March than in October (21268 eggs/10m² and 14084 larvae/10m² in spring and 10094 eggs/10m² and 13796 larvae/10m²). In both seasons, fish eggs from the families Sternoptychidae and Sparidae were dominant (10101 eggs/10m² and 7527 eggs/10m² in spring and 4422 eggs/10m² and 3928 eggs/10m² in fall, respectively). However, Myctophidae larvae were the most abundant in the study area, reaching 7601 larvae/10m² in spring and 11021 larvae/10m² in autumn. The environmental parameters: temperature, salinity and chlorophyll-a (surface) seem to directly influence the spatial distribution of ichtyoplancton. On the other hand, it seems that predation by jellyfish (Pelagia noctiluca)was a very important factor that added to the factors that influenced the distribution of the species of fish eggs and larvae. This work represents the first survey conducted in the southwestern Alboran Sea, which studies the horizontal structure of the ichthyoplankton species assemblage and its relation to environmental factors in the spring and autumn of 2019.

The Surface Temperature of Water in Polish and Belarusian Lakes during the Period of Climate Change

The paper presented the results of surface water temperature measurements from 17 lakes located in northern Poland and Belarus over the period of 50 years (1971–2020). Using the Excel computer program, Corel Quattro Pro 8, and graphic Draw 9, annual and monthly averages, extreme values, and annual and monthly trends were calculated and presented. These were supplemented by the monthly average air temperatures for 13 weather stations. The research showed that the temperature in all lakes was characterized by a positive trend at the level of 0.044 °C year−1. The largest lake was characteristic for the Chervonoe Lake—0.066 °C year−1—and the smallest 0.029 °C year−1 for the deep Lake Hańcza. In the course of the average monthly surface water temperatures, a positive trend was also observed, ranging from 0.015 °C year−1 in January to 0.069 °C year−1 in May. These values correlated with the average air temperatures in the winter months (December–March) and with the winter NAO index (DJFM).

The impacts of climate change on thermal stratification and dissolved oxygen in the temperate, dimictic Mississippi Lake, Ontario

This study investigates and reports the climate change's effects on the Mississippi Lake thermal structure and dissolved oxygen (DO) for baseline (1986–2005) and future (2081–2100) periods. Future meteorological variables were derived from the second-generation Canadian Earth System Model (CanESM2) under three emission scenarios (RCP2.6, RCP4.5, and RCP8.5). The long-term lake inflow was modelled using the Thornthwaite monthly water balance model (TMWB) coupled with an Artificial Neural Network (ANN) to simulate the water level in the lake. Several methods were analyzed to assure the above is the best for estimating the water budget in this region. The water quality of Mississippi Lake was analyzed using a calibrated CE-QUAL-W2 model for the years 2017 and 2018. A major challenge in setting up the model was limitations in some essential water quality indicator inputs, which were estimated using reliable experimental relationships. Our results show that the baseline average surface water temperature of 14.6 °C would increase by 1.31 °C, 1.34 °C, and 2.69 °C under RCP2.6, RCP4.5, and RCP8.5 scenarios, respectively. In contrast, the baseline average hypolimnetic DO of 7.1 mg/L would decrease by 1.4%, 6.2%, and 14.3% in RCP2.6, RCP4.5, and RCP8.5 scenarios, respectively. Such a rise in water temperature and the consequent diminishment of DO in deep waters would threaten the future sustainable growth of warm-water fish species in Mississippi lake.

Ecosystem-based fisheries risk assessment and forecasting considering a spatio-temporal component in Korean waters

Integrated fisheries risk analysis method for ecosystems (IFRAME) was originally developed to accomplish the goals of an ecosystem approach to fisheries (EAF) to overcome the limitations of the single-species approach. This approach performs ecosystem-based fisheries assessment, forecasting, and management. However, this IFRAME approach does not explain spatial variations in ecosystem components. Although this approach has a number of advantages in mitigating the risks associated with developing macroscopic management measures, its limitation is apparent when microscopic management measures that reflect the spatial features of the species or the fisheries within the ecosystem are required. In this study, the IFRAME was extended to assess and forecast ecosystem dynamics and risk indices in a spatio-temporal context. The distribution of biomass and changes in risk of chub mackerel were predicted using the extended IFRAME, based on scenarios considering changes in climate and variations in fishing mortality. A total of 87% of chub mackerel resources were distributed in the East China Sea in 2019, but they are expected to rise northward due to the rise of the average sea surface water temperature (SST) as per the RCP4.5 and RCP8.5 IPCC scenarios. Based on these scenarios, a major fishing ground was predicted to form around the Yellow Sea in 2069. The species risk index (SRI) of mackerel in 2069 showed relatively low in the East and Yellow Seas, but as climate change continues, the risks in the East China Sea increased. The forecasting results can be used in the management component of IFRAME to assess alternative harvest strategies and tactics in the rapidly changing marine ecosystems. Since food web relationships and water temperature scenarios were only considered as input data for the Ecospace module used in the prediction of mackerel biomass distribution, more quantitative spatial information should be incorporated in the analysis to better explain the complex nature of the marine ecosystems. In conclusion, based on the spatio-temporal IFRAME approach, it could be possible to establish a proper fisheries management plan by incorporating spatial variations in the ecosystem for sustainable fisheries.

Detection of mucilage phenomenon in the Sea of Marmara by using multi-scale satellite data

Marine mucilage outbreaks occurred in the Sea of Marmara in 2021 which severely affected the marine ecosystem. The thick mucilage blankets with different colors became a public concern due to the toxicity potential related to pathogens that accumulate in prolonged presence of mucilage. The mucilage-covered areas in the Sea of Marmara detected by remote sensing data acquired in 2021 were previously reported. However, the areal extents and spectral characteristics of the different colored mucilage types remain unknown. This study presents the spectral characteristics of different types of mucilage in the İzmit Bay in the Sea of Marmara by using medium- (Sentinel-2) and high-spatial resolution (Worldview-3) satellite images. Also, the sea surface temperatures (SST) were studied in relation with the mucilage formation from January 2015 to August 2021 by using NOAA data. Two multispectral satellite sensors Sentinel-2 and Worldview-3 were studied for their potential for mucilage mapping and characterization in the sub-region İzmit Bay. Support vector machine (SVM) classifier was used to detect three different types of mucilage with distinguishable spectral differences in infrared region ranging from 725 to 950nm. Three different types of mucilage were characterized based on color and texture including (a) the white mucilage aggregates with dispersed patterns which are likely freshly formed, (b) the yellow mucilage accumulations in the coasts that are wind/current transported, and (c) the brown mucilage accumulations that are probably the most-aged. Our results showed that brown mucilage and white mucilage showed similar reflectance values between 425 and 545nm region, while yellow mucilage showed higher and more distinctive spectral reflectance than white and brown mucilages. The NOAA data showed that average surface water temperature has been increased over the years from 2015 (16.1°C) to 2021 (17.6°C). This increase trend in SSTs points out a likely relation with the mucilage formation and hence may suggest a potential of repeating mucilage events in the near future. This study provides a practical methodology for monitoring, classification, and efficient site selection for mucilage cleaning areas in the Sea of Marmara.

Long-term trend of heat waves and potential effects on phytoplankton blooms in Lake Qiandaohu, a key drinking water reservoir.

Global warming is increasing the frequency and duration of heat waves, which is defined as when air temperature exceeds a threshold for more than specific consecutive days. Ecosystem around the globe will be impaired by heat waves just like the exposures to dangerously high temperatures as a public health threat to human. However, the knowledge of the response of lake and reservoir ecosystem to heat waves is largely unknown although it has been argued that climate warming may increase the incidence of harmful algal blooms. We examined the long-term trend of heat waves and how the variability of phytoplankton biomass responds to lake heat waves on a deep reservoir (Lake Qiandaohu). Long-term (1980–2020) meteorological observation in the lake watershed showed a significant warming trend of 0.36 °C per decade for the yearly average of daily average air temperature and the yearly average of daily maximum air temperature of 18.32 °C was observed in 2016. Meanwhile, a significant increasing number of heat wave events lasting longer was observed, and Lake Qiandaohu suffered an unusually severe lake heat wave in summer 2016. Significant correlations were found between the yearly average of daily maximum air temperature and heat days, heat wave events, and heat wave days. Nuisance phytoplankton bloom was found in Lake Qiandaohu by high frequency observation and remote sensing monitoring in summer 2016. Remote sensing estimation from two Landsat 8 Operational Land Imager (OLI) images showed that the average chlorophyll a (Chla) was 7.45 ± 4.89 μg/L on July 18 before heat wave and 18.96 ± 0.98 μg/L on August 19 during the heat wave. Two heat wave events lasting from July 20 to August 2 and August 11 to 26 with average surface water temperature of 29.93 and 31.99 °C promoted two marked phytoplankton blooms with average Chla concentrations of 11.75 ± 4.08 and 10.53 ± 1.65 μg/L in the central lake region, respectively, as evidenced by high-frequency buoy data. These findings suggest that heat waves are likely to yield an increased threat of harmful algal bloom in freshwater ecosystems. With lake heat waves projected to increase in frequency, duration, and spatial extent with global climate change, more studies are needed to improve our understanding of lake heat waves and their potential effects on the species, communities, frequency of phytoplankton bloom, and also help providing advanced schemes of water quality management.

Analysis of Momentary Variations in the Quality of Water on Specific Criteria in Cole Mere

Momentary changes in some criteria regarding the quality of water were examined by conducting field test and laboratory examination in Cole Mere during the summer months (June, July and August) of 2013. 10 locations were chosen (inside the lake) and each was sampled nearly one month away from the other. The average surface water temperature was documented in June, July and August samplings were 14.1 °C, 21.9 °C and 18.2 °C respectively. The variations in the average temperature were numerically notable (p=<0.001). The average absorption levels of Cholorophyll a were 9.3 μgl⁻ ¹, 15.2 μgl⁻ ¹ and 39.8 μgl⁻ ¹for June, July and August respectively and there was a noticeable difference observed between the months at p=0.001. The detected momentary change and the rising levels of summer chlorophyll a absorption are exact evidence of eutrophic estate. However, no notable variations were observed regarding pH and declined oxygen between the months.

Precipitation events impact on urban lake surface water temperature under the perspective of macroscopic scale.

Lake surface water temperature (LSWT) is an important factor affecting a lake's ecological environment. In recent decades, LSWT worldwide has shown an increasing trend in the context of global climate change. This rising trend has been more evident in urban lakes. With the rapid development of urbanization, urban lakes are affected not only by climate warming but also by human activities. Among these factors, due to the increase in impervious surface coverage (ISC), the impact of thermal runoff pollution caused by precipitation events on urban lakes cannot be ignored. Therefore, this study used the Dianchi Lake watershed as a study area, and the surface water temperature of Dianchi Lake, the precipitation data, and the land use data were collected and analyzed. Based on these data, the influence of precipitation events on the surface water temperature of Dianchi Lake was analyzed. The research results show that under the background of different ISC levels and different growth rates of impervious surface area (ISA), precipitation events have different effects on the LSWT. When ISC is low and the growth rate of ISA is slow, the annual precipitation is negatively correlated with the annual average surface water temperature of Dianchi Lake (r = - 0.183). When ISC is high and the growth rate of ISA is fast, the annual precipitation is positively correlated with the average annual surface water temperature of Dianchi Lake (r = 0.65). With the increase in ISC, the correlation between seasonal precipitation and the average surface water temperature in Dianchi Lake changed from negative to positive in spring and autumn. Under the action of impervious surfaces, precipitation events have a warming effect on the surface water temperature of the lake, and this effect will be intensified with the increase in ISC.

Temperature Profiling of Waterbodies with a UAV-Integrated Sensor Subsystem

Evaluation of thermal stratification and systematic monitoring of water temperature are required for lake management. Water temperature profiling requires temperature measurements through a water column to assess the level of thermal stratification which impacts oxygen content, microbial growth, and distribution of fish. The objective of this research was to develop and assess the functions of a water temperature profiling system mounted on a multirotor unmanned aerial vehicle (UAV). The buoyancy apparatus mounted on the UAV allowed vertical takeoff and landing on the water surface for in situ measurements. The sensor node that was integrated with the UAV consisted of a microcontroller unit, a temperature sensor, and a pressure sensor. The system measured water temperature and depth from seven pre-selected locations in a lake using autonomous navigation with autopilot control. Measurements at 100 ms intervals were made while the UAV was descending at 2 m/s until it landed on water surface. Water temperature maps of three consecutive depths at each location were created from the measurements. The average surface water temperature at 0.3 m was 22.5 °C, while the average water temperature at 4 m depth was 21.5 °C. The UAV-based profiling system developed successfully performed autonomous water temperature measurements within a lake.

Observation of Surface Water Temperature and Wave Height along the Coast of Pohang using Wave Gliders

ABSTRACT Ko, S. H.; Hyeon, J. W.; Lee, S. J, and Lee, J. H., 2018. Observation of Surface Water Temperature and Wave Height at the Coast of Pohang using Wave Glider.. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 1211–1215. Coconut Creek (Florida), ISSN 0749-0208. Wave Gliders were launched to observe the surface water temperature and wave height at Hwajin-ri and Josa-ri on the coast of Pohang for the 11 days from March 24th to April 3rd. Wave Gliders SV2 and SV3 were operated within a radius of 100 m at two sites at depths of about 30~40 m. Both vehicles were equipped with a weather sensor, wave height sensor, and camera. Additionally, a conductivity sensor was installed in the SV2. During the observation period, the average surface water temperature and significant wave height were 13.0°C and 0.7 m, respectively. The differences in the surface water temper...

The Warming of Large Lakes on the Tibetan Plateau: Evidence From a Lake Model Simulation of Nam Co, China, During 1979–2012

AbstractLakes are considered as indicators of climate change on the Tibetan Plateau (TP). In the present study, we use the General Lake Model to simulate water temperature changes in Nam Co, the second largest lake on the central TP, for the period 1979–2012. The calibration and validation results demonstrate that this model is well suited for thermal simulation of Nam Co. The simulation results indicate that Nam Co has responded to the recent warming climate. The average summer surface water temperature fluctuated yearly, but its trend is positive at a rate of 0.52 ± 0.25°C per decade. At the same time, the onset of summer stratification advanced by 4.20 ± 2.02 d per decade, and the duration increased at a rate of 6.00 ± 3.54 d per decade. To explore the roles of air temperature and longwave radiation in lake warming, three sensitivity experiments are conducted by removing long‐term trends from time series of air temperature and longwave radiation in the forcing data. These experiments prove that both increased air temperature and downward longwave radiation are two driving factors responsible for the warming of Nam Co.

Infestation of Pseudione tuberculata (Isopoda: Bopyridae) on juveniles of Lithodes santolla (Magellan region, Chile): a spatial mesoscale analysis

We document latitudinal patterns of infestation of the bopyrid parasite isopod Pseudione tuberculata on southern king crab Lithodes santolla juveniles (20-77 mm carapace length) recruited to fishing grounds in the southern Chilean fjord system. Seven hundred and fifty individuals were collected by semiautonomous diving in 11 of 21 sampling locations in the study area, along the western margin of the Magellan region between August and October 2013.The prevalence of P. tuberculata varied between 0 and ~22%, and displayed a spatial pattern associated with three areas: i) northern Beagle Channel (10 to ~22%; lengths between 37 and 47 mm), ii) northwestern Navarino Island without infestations (0%; 26-55 mm), and iii) Piazzi Island-Capitan Aracena Island (0-12%; 50-77 mm). Infestations were independent of host sex, while parasite prevalence decreased with host length. No parasites were observed on crabs longer than 60 mm. A comparison of slopes between linearized length-weight regressions suggests that parasitized individuals had lower weight growth than uninfested individuals. Both southern king crab juvenile density and P. tuberculata prevalence were higher in fishing areas towards Beagle Channel where previous research reported lower average surface water temperatures ( 30). The study area covers five zones relevant for the conservation and protection of sub Antarctic biodiversity, and provides opportunities for large-scale geographic studies of the host-parasite relationship

长江口及邻近海域浮游水螅水母、管水母和栉水母的丰度分布与季节变化

PDF HTML阅读 XML下载 导出引用 引用提醒 长江口及邻近海域浮游水螅水母、管水母和栉水母的丰度分布与季节变化 DOI: 10.5846/stxb201403210505 作者: 作者单位: 中国水产科学研究院东海水产研究所,中国水产科学研究院东海水产研究所,中国水产科学研究院东海水产研究所,国家海洋局第二海洋研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点基础研究发展计划(973计划)(2010CB428705);海洋公益性行业科研专项经费项目(201305027-8) Abundance distribution and seasonal variation of medusae, siphonophores, and ctenophores in the Changjiang (Yangtze River) Estuary and the adjacent East China Sea Author: Affiliation: East China Sea Fisheries Research Institute,East China Sea Fisheries Research Institute,East China Sea Fisheries Research Institute,Second Institute of Oceanography, SOA Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:依据2002-2003年长江口及邻近海域(29°00'-32° 00' N、122° 00 -123° 30' E)4个季节的海洋调查资料,探讨了该水域小型水母(含水螅水母、管水母和栉水母)总丰度的空间分布特征及季节差异.结果显示,该海域共出现小型水母41种,其中水螅水母28种,管水螅11种,栉水母2种.主要优势种包括管水母大西洋五角水母(Muggiaea atlantica)、双生水母(Diphyes chamissonis)和气囊水母(Physophora hydrostatica)以及水螅水母四叶小舌水母(Liriope tetraphylla)、两手筐水母(Solmundella bitentaculata)和短柄和平水母(Eirene brevistylus),其中大西洋五角水母为冬、春季第一优势种,双生水母则为夏、秋季第一优势种.该水域小型水母总丰度呈明显季节差异,夏季丰度最高((337.33±55.68) 个/m2),春、秋季次之(分别为(142.09±67.71) 个/m2和(132.84±35.17) 个/m2),冬季最低((113.69±32.72)个/m2).水温是影响调查区小型水母总丰度季节变化的主要环境因子,小型水母丰度与表层温度显著正相关(P < 0.01).盐度是影响小型水母平面分布格局的主要环境因子,春季小型水母丰度与底层盐度正相关(P < 0.05),夏季与10 m层盐度正相关(P < 0.01),全年则是与10 m层盐度正相关(P < 0.01).此外,调查水域小型水母丰度与其饵料——小型桡足类亦存在显著正相关关系(P < 0.01). Abstract:Small jellyfish (here including medusae, siphonophores, and ctenophores) are widespread in the marine pelagic realm. They usually constitute one of the most important assemblages of predators in pelagic food webs by serving as a direct link between zooplankton and higher trophic levels. They can at times be the most abundant non-crustacean invertebrate predators due to their great voracity and their rapid population growth, resulting in extensive seasonal blooms. Thus, studies on small jellyfish have become popular in marine ecology. Studies concerning zooplankton distribution at large spatial scales, particularly for weak swimmers like small jellyfish, emphasize the importance of the physical characteristics of water masses, including salinity and temperature. In our study, the seasonal abundance and horizontal distribution of small jellyfish were assessed in the Changjiang Estuary (Yangtze River) and the adjacent East China Sea (29°00'-32°00'N, 122°00'-123°30'E) in 2002-2003. The Changjiang Estuary and the adjacent East China Sea are one of the most productive aquatic ecosystems. High primary production supports high fishery production in adjacent coastal waters, including the Changjiang and Zhoushan fishery grounds. A total of 41 species of small jellyfish (11 siphonophores, 28 medusae, 2 ctenophores) were collected. Numerically, siphonophores were most abundant (58.56%-91.05% of the total collection by number). The dominant species were the siphonophores Diphyes chamissonis, Muggiaea atlantica, and Physophora hydrostatica and medusae Liriope tetraphylla, Solmundella bitentaculata, and Eirene brevistylus. Muggiaea atlantica was dominant all year round, particularly in spring (76.19% of the total collection by number) and winter (39.12%). D. chamissonis was dominant in summer and autumn, with abundances of 249.03 ind./m2 (73.82% of the total collection by number), and 98.04 ind./m2 (73.80%), respectively. The numerical abundance of small jellyfish was highest in summer ((337.33±55.68) ind./m2), lowest in winter ((113.69±32.72) ind./m2), and intermediate in spring and autumn ((142.09±67.71) ind./m2 and (132.84±35.17) ind./m2). Seasonal variations in the abundance of small jellyfish were closely associated with the surface water temperature. The average surface water temperature peaked in summer ((27.26±0.02) ℃). Then, both the temperature and salinity in the studied area were suitable for the development and reproduction of D. chamissonis. In addition, the summer upwelling and its associated high productivity might also benefit the jellyfish because large numbers of carnivores ultimately require an elevated level of primary production. There were strong correlations between temperature, 10-m water salinity, and small jellyfish abundances (P < 0.01), suggesting that they are important in determining the spatial distribution of small jellyfish. The bottom salinity in spring was positively related with the abundance (P < 0.05), and the 10-m water salinity in summer was also positively correlated with abundance (P < 0.01). In winter, the abundance was obviously increased from inshore to offshore. In addition, small jellyfish abundance was also strongly correlated with their food, small copepods (P < 0.01), which proved the importance of food availability for carnivores. This study provides basic knowledge on the distribution patterns of small jellyfish, which is essential to further understand the ecological roles played by small jellyfish and their responses to the hydrological conditions in the Changjiang Estuary and the adjacent East China Sea. 参考文献 相似文献 引证文献

Remotely sensed surface temperature variation of an inland saline lake over the central Qinghai–Tibet Plateau

Research on surface water temperature (SWT) variations in large lakes over the Qinghai–Tibet Plateau (QTP) has been limited by lack of in situ measurements. By taking advantage of the increased availability of remotely sensed observations, this study investigated SWT variation of Siling Co in central QTP by processing complete MODIS Land surface temperature (LST) images over the lake covering from 2001 to 2013. The temporal (diurnal, intra-annul and inter-annul) variations of Siling Co SWT as well as the spatial patterns were analyzed. The results show that on average from late December to mid-April the lake is in a mixing state of water and ice and drastic diurnal temperature differences occur, especially along the shallow shoreline areas. The extent of spatial variations in monthly SWT ranges from 1.25°C to 3.5°C, and particularly large at nighttime and in winter months. The spatial patterns of annual average SWT were likely impacted by the cooling effect of river inflow from the west and east side of the lake. The annual cycle of spatial pattern of SWT is characterized by seasonal reversions between the shallow littoral regions and deep parts due to different heat capacity. Compared to the deep regions, the littoral shallow shoreline areas warms up quickly in spring and summer, and cool down drastically in autumn and winter, showing large diurnal and seasonal variation amplitudes of SWT. Two cold belt zones in the western and eastern side of the lake and warm patches along the southwestern and northeastern shorelines are shaped by the combined effects of the lakebed topography and river runoff. Overall, the lake-averaged SWT increased at a rate of 0.26°C/decade during 2001–2013. Faster increase of temperature was found at nighttime (0.34°C/decade) and in winter and spring, consistent with the asymmetric warming pattern over land areas reported in prior studies. The rate of temperature increase over Siling Co is remarkably lower than that over Bangoin station, which is probably attributable to the large heat capacity of water and partly reflects the sensitive of alpine saltwater lake to climate change.

Evaluation of spatial-temporal dynamics in surface water temperature of Qinghai Lake from 2001 to 2010 by using MODIS data

Lake surface water temperature (SWT) is an important indicator of lake state relative to its water chemistry and aquatic ecosystem, in addition to being an important regional climate indicator. However, few literatures involving spatial-temporal changes of lake SWT in the Qinghai-Tibet Plateau, including Qinghai Lake, are available. Our objective is to study the spatial-temporal changes in SWT of Qinghai Lake from 2001 to 2010, using Moderate-resolution Imaging Spectroradiometer (MODIS) data. Based on each pixel, we calculated the temporal SWT variations and long-term trends, compared the spatial patterns of annual average SWT in different years, and mapped and analyzed the seasonal cycles of the spatial patterns of SWT. The results revealed that the differences between the average daily SWT and air temperature during the temperature decreasing phase were relatively larger than those during the temperature increasing phase. The increasing rate of the annual average SWT during the study period was about 0.01°C/a, followed by an increasing rate of about 0.05°C/a in annual average air temperature. The annual average SWT from 2001 to 2010 showed similar spatial patterns, while the SWT spatial changes from January to December demonstrated an interesting seasonal reversion pattern. The high-temperature area transformed stepwise from the south to the north regions and then back to the south region from January to December, whereas the low-temperature area demonstrated a reversed annual cyclical trace. The spatial-temporal patterns of SWTs were shaped by the topography of the lake basin and the distribution of drainages.

A Model to Approximate Lake Temperature from Gridded Daily Air Temperature Records and Its Application in Risk Assessment for the Establishment of Fish Diseases in the UK

Ambient water temperature is a key factor controlling the distribution and impact of disease in fish populations, and optimum temperature ranges have been characterised for the establishment of a number important aquatic diseases exotic to the UK. This study presents a simple regression method to approximate daily average surface water temperature in lakes of 0.5-15 ha in size across the UK using 5 km(2) gridded daily average air temperatures provided by the UK Meteorological Office. A Geographic information system (GIS) is used to present thematic maps of relative risk scores established for each grid cell based on the mean number of days per year that water temperature satisfied optimal criteria for the establishment of two economically important pathogens of cyprinid fish (koi herpesvirus (KHV) and spring viraemia of carp virus (SVCV)) and the distribution and density of fish populations susceptible to these viruses. High-density susceptible populations broadly overlap the areas where the temperature profiles are optimal for KHV (central and south-east England); however, few fish populations occur in areas where temperature profiles are most likely to result in the establishment of spring viremia of carp (SVC) (namely northern England and Scotland). The highest grid-cell risk scores for KHV and SVC were 7 and 6, respectively, out of a maximum score of 14. The proportion of grid cells containing susceptible populations with risk scores of 5 or more was 37% and 5% for KHV and SVC, respectively. This work demonstrates a risk-based approach to inform surveillance for exotic pathogens in aquatic animal health management, allowing efficient use of resources directed towards higher risk animals and geographic areas for early disease detection. The methodology could be used to examine the change in distribution of high-risk areas for both exotic and endemic fish diseases under different climate change scenarios.

득량만의 조개류 생산량과 환경요인 관계 분석

This study was carried out to determine marine environments and phytoplankton community in Deukryang Bay during the period of summer in 1987-2010. Water temperature, salinity, pH and dissolved oxygen were shown in much yearly fluctuations. In August, water temperatures in surface and on bottom were the highest, compared with average surface (24.54<TEX>$^{\circ}C$</TEX>) and bottom (22.90<TEX>$^{\circ}C$</TEX>) water temperature for 18 years in Deukryang Bay. The main reason is assumed to longer duration of sunshine during the period of August. Although the amount of the rainfall in August was the highest, significant impact of marine environment did not show. Most of dissolved inorganic nitrogen and phosphate in Deukryang were lower concentration during summer and N:P ratio also showed below 18 in Redfield. In particular, extreme increasing of N:P ratio in August was occurred by intensive precipitation. Distribution of phytoplankton community was a consistent occurrence for 18 years. The genus of Chaetoceros, Cosinodisucs and Skeletonema were regarded as the represent diatom, whereas the highest occurrence of genus among dinofagellates was Ceratium. It is thought that the relationship between phytoplankton and nutrient has a strong positive signal, although nutrients persist a little concentration and much fluctuations in marine environments were observed. High availability in phytoplankton is contributed to consistently provide the food organism of shellfish. Consequently, recent decreasing production of shellfish and seed are probably associated with higher temperature during the period of summer. However, higher temperature is also occurred ago and after 2000. On the basis of geography, Deukryang Bay had a small mouth and long channel, which is attributed to decreasing genetic diversity. It is assumed that higher temperature and lower genetic diversity have a extreme impact of larvae and shellfish for reproduction in Deukryang. It is necessary to persistently monitor based on water quality and phytoplankton community.

A new record of the freshwater jellyfish Craspedacusta sowerbii Lankester, 1880 (Hydrozoa) in Southeastern Anatolia (Turkey)

We report the first record of the invasive freshwater jellyfish Craspedacusta sowerbii Lankester in Kralkizi Dam Lake, Southeastern Anatolia, Turkey. The medusa was found only in August, 2008 when average surface water temperatures were 26.9°C.