scholarly journals Seasonal variation of sea surface pH and its controls in the Jiaozhou Bay, China

2021 ◽  
pp. 104613
Author(s):  
Yunxiao Li ◽  
Hong Yang ◽  
Jiajia Dang ◽  
Xufeng Yang ◽  
Liang Xue ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Jiaozhou Bay ◽  
Sea Surface ◽  
Surface Ph

Seasonal variation of microplastics in seawater and zooplankton in Jiaozhou Bay, the Yellow Sea

2020 ◽  
Author(s):  
Xiaoxia Sun
Keyword(s):  
Seasonal Variation ◽  
Chemical Composition ◽  
Surface Water ◽  
Yellow Sea ◽  
Jiaozhou Bay ◽  
Coastal Areas ◽  
Average Concentration ◽  
The Yellow Sea ◽  
Plastic Pollution ◽  
Four Seasons

<p>Plastic pollution is a globally concerning issue in marine environments. There is currently little research about the seasonal changes in microplastics in coastal areas. Here, we report a seasonal study on the concentrations and characteristics of microplastics in the surface seawater and zooplankton of Jiaozhou Bay, a typical bay in the west Yellow Sea. The concentrations of microplastics in the surface water of Jiaozhou Bay were 0.063, 0.174, 0.094, and 0.050 pieces/m<sup>3 </sup>in February, May, August and November, respectively, with an annual average concentration of 0.095 pieces/m<sup>3</sup>, a low value compared with the plastic concentrations of other coastal areas. The size of the collected microplastics ranged from 346 to 155200 μm, with an average of 5093 μm. The overall percentages of fibers, fragments and plastic foams were 29%, 55% and 16%, respectively. Fragments were the most dominant shape in four seasons. Nine plastic polymers were detected from the surface water of Jiaozhou Bay. The dominant chemical composition was polypropylene (PP), accounting for 51.04% of polymers, followed by polyethylene (PE), accounting for 26.04% of polymers. The seasonal variation of plastic characteristics in Jiaozhou Bay, including the shape, color and chemical composition, was significant. The highest concentration of plastics occurred in May and the lowest concentration of plastics occurred in November. Strong rainfall resulted in an increase in the plastic concentration in May, and winds and eddies affected the spatial distribution of plastics in Jiaozhou Bay. Focused on the dominant zooplankton groups in Jiaozhou Bay, the morphology, color, size, chemical composition and quantity of MPs in zooplankton were investigated in Jiaozhou Bay. The results showed that the MPs in zooplankton of the Jiaozhou Bay were dominated by fibers. The proportions of fiber in February, May, August and November were 91%, 88%, 89% and 88%, respectively. The average size of MPs in zooplankton was 441±2, 468±2, 576±2, and 379±4μm in the four seasons. For the 2 common zooplankton groups in the 4 seasons, the MP/zooplankton was 0.3, 0.26, 0.17, 0.19 for copepod, and 0.22, 0.19, 0.17, 0.45 for chaetognath, respectively.</p>

Viscosity of sea surface microlayer in Jiaozhou Bay and adjacent sea area

2003 ◽  
Vol 21 (4) ◽  
pp. 351-357 ◽  
Author(s):  
Zhang Zhengbin ◽  
Zhang Anhui ◽  
Liu Liansheng ◽  
Liu Chunying ◽  
Ren Chunyan ◽  
...  
Keyword(s):  
Jiaozhou Bay ◽  
Sea Surface ◽  
Surface Microlayer ◽  
Sea Surface Microlayer ◽  
Sea Area

scholarly journals Evidence of intense climate variation and reduced ENSO activity from δ<sup>18</sup>O of <i>Tridacna</i> 3700 years ago

2019 ◽  
Author(s):  
Yue Hu ◽  
Xiaoming Sun ◽  
Hai Cheng ◽  
Hong Yan
Keyword(s):  
Seasonal Variation ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Surface Salinity ◽  
Tropical Ocean ◽  
Xisha Islands ◽  
The North

Abstract. Tridacna is the largest marine bivalves in the tropical ocean, and its carbonate shell can shed light on high-resolution paleoclimate reconstruction. In this contribution, δ18Oshell was used to estimate the climatic variation in the Xisha Islands of the South China Sea. We first evaluate the sea surface temperature (SST) and sea surface salinity (SSS) influence on modern rehandled monthly (r-monthly) resolution Tridacna gigas δ18Oshell. The obtained results reveal that δ18Oshell seasonal variation is mainly controlled by SST and appear insensitive to local SSS change. Thus, the δ18O of Tridacna shells can be roughly used as a proxy of the local SST: a 1 ‰ δ18Oshell change is roughly equal to 4.41 °C of SST. R-monthly δ18O of a 40-year Tridacna squamosa (3673 ± 28 BP) from the North Reef of Xisha Islands was analyzed and compared with the modern specimen. The difference between the average δ18O of fossil Tridacna shell (δ18O = −1.34 ‰) and modern Tridacna specimen (δ18O = −1.15 ‰) probably implies a warm climate with roughly 0.84°C higher in 3700 years ago. The seasonal variation in 3700 years ago was slightly decreased compared with that suggested by the instrument data, and the switching between warm and cold-seasons was rapid. Higher amplitude in r-monthly and r-annual reconstructed SST anomalies implies an enhanced climate variability in this past warm period. Investigation of the El Ninõ-Southern Oscillation (ENSO) variation (based on the reconstructed SST series) indicates a reduced ENSO frequency but more extreme El Ninõ events in 3700 years ago.

scholarly journals Biogeographic classification of the Caspian Sea

2014 ◽  
Vol 11 (22) ◽  
pp. 6451-6470 ◽  
Author(s):  
F. Fendereski ◽  
M. Vogt ◽  
M. R. Payne ◽  
Z. Lachkar ◽  
N. Gruber ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Caspian Sea ◽  
Benthic Invertebrate ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Agglomerative Clustering ◽  
The Caspian Sea ◽  
Surface Salinity ◽  
Chl A

Abstract. Like other inland seas, the Caspian Sea (CS) has been influenced by climate change and anthropogenic disturbance during recent decades, yet the scientific understanding of this water body remains poor. In this study, an eco-geographical classification of the CS based on physical information derived from space and in situ data is developed and tested against a set of biological observations. We used a two-step classification procedure, consisting of (i) a data reduction with self-organizing maps (SOMs) and (ii) a synthesis of the most relevant features into a reduced number of marine ecoregions using the hierarchical agglomerative clustering (HAC) method. From an initial set of 12 potential physical variables, 6 independent variables were selected for the classification algorithm, i.e., sea surface temperature (SST), bathymetry, sea ice, seasonal variation of sea surface salinity (DSSS), total suspended matter (TSM) and its seasonal variation (DTSM). The classification results reveal a robust separation between the northern and the middle/southern basins as well as a separation of the shallow nearshore waters from those offshore. The observed patterns in ecoregions can be attributed to differences in climate and geochemical factors such as distance from river, water depth and currents. A comparison of the annual and monthly mean Chl a concentrations between the different ecoregions shows significant differences (one-way ANOVA, P < 0.05). In particular, we found differences in phytoplankton phenology, with differences in the date of bloom initiation, its duration and amplitude between ecoregions. A first qualitative evaluation of differences in community composition based on recorded presence–absence patterns of 25 different species of plankton, fish and benthic invertebrate also confirms the relevance of the ecoregions as proxies for habitats with common biological characteristics.

scholarly journals Evidence from giant-clam <i>δ</i><sup>18</sup>O of intense El Ninõ–Southern Oscillation-related variability but reduced frequency 3700 years ago

2020 ◽  
Vol 16 (2) ◽  
pp. 597-610
Author(s):  
Yue Hu ◽  
Xiaoming Sun ◽  
Hai Cheng ◽  
Hong Yan
Keyword(s):  
Seasonal Variation ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Giant Clam ◽  
Xisha Islands

Abstract. Giant clams (Tridacna) are the largest marine bivalves, and their carbonate shells can be used for high-resolution paleoclimate reconstructions. In this contribution, δ18Oshell was used to estimate climatic variation in the Xisha Islands of the South China Sea. We first evaluate sea surface temperature (SST) and sea surface salinity (SSS) influence on the modern resampled monthly (r-monthly) resolution of Tridacna gigas δ18Oshell. The results obtained reveal that δ18Oshell seasonal variation is mainly controlled by SST and appears to be insensitive to local SSS change. Thus, the δ18O of Tridacna shells can be roughly used as a proxy of local SST: a 1 ‰ δ18Oshell change is roughly equal to 4.41 ∘C of SST. The r-monthly δ18O of a 40-year-old Tridacna squamosa (3673±28 BP) from the North Reef of the Xisha Islands was analyzed and compared with the modern specimen. The difference between the average δ18O of the fossil Tridacna shell (δ18O =-1.34 ‰) and the modern Tridacna specimen (δ18O =-1.15 ‰) probably implies a warm climate, roughly 0.84 ∘C, 3700 years ago. The seasonal variation 3700 years ago was slightly lower than that suggested by modern instrumental data, and the transition between warm and cold seasons was rapid. Higher amplitudes of reconstructed r-monthly and r-annual SST anomalies imply an enhanced climate variability during this warm period. Investigation of the El Ninõ–Southern Oscillation (ENSO) variation (based on the reconstructed SST series) indicates reduced ENSO frequency but increased ENSO-related variability and extreme El Ninõ winter events 3700 years ago.

Seasonal variation of micro- and meso-plastics in the seawater of Jiaozhou Bay, the Yellow Sea

2020 ◽  
Vol 152 ◽  
pp. 110922 ◽  
Author(s):  
Tao Liu ◽  
Yongfang Zhao ◽  
Mingliang Zhu ◽  
Junhua Liang ◽  
Shan Zheng ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Yellow Sea ◽  
Jiaozhou Bay ◽  
The Yellow Sea
Sign in / Sign up

Export Citation Format

Share Document