Stable isotopic evidence of nitrogen sources and C4 metabolism driving the world’s largest macroalgal green tides in the Yellow Sea

Abstract The Ulva prolifera green tides in the Yellow Sea, China, which have been occurring since 2007, are a serious environmental problem attracting worldwide attention. Despite extensive research, the outbreak mechanisms have not been fully understood. Comprehensive analysis of anthropogenic and natural biotic and abiotic factors reveals that human activities, regional physicochemical conditions and algal physiological characteristics as well as ocean warming and biological interactions (with microorganism or other macroalgae) are closely related to the occurrence of green tides. Dynamics of these factors and their interactions could explain why green tides suddenly occurred in 2007 and decreased abruptly in 2017. Moreover, the consequence of green tides is serious. The decay of macroalgal biomass could result in hypoxia and acidification, possibly induce red tide and even have a long-lasting impact on coastal carbon cycles and the ecosystem. Accordingly, corresponding countermeasures have been proposed in our study for future reference in ecosystem management strategies and sustainable development policy.

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Comparative transcriptome analysis of four co-occurring Ulva species for understanding the dominance of Ulva prolifera in the Yellow Sea green tides

Journal of Applied Phycology ◽

10.1007/s10811-019-01810-z ◽

2019 ◽

Vol 31 (5) ◽

pp. 3303-3316 ◽

Cited By ~ 5

Author(s):

Yu Wang ◽

Feng Liu ◽

Xingfeng Liu ◽

Shitao Shi ◽

Yuping Bi ◽

...

Keyword(s):

Transcriptome Analysis ◽

Yellow Sea ◽

Ulva Prolifera ◽

The Yellow Sea ◽

Comparative Transcriptome ◽

Green Tides ◽

Comparative Transcriptome Analysis

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A dynamic growth model of Ulva prolifera: Application in quantifying the biomass of green tides in the Yellow Sea, China

Ecological Modelling ◽

10.1016/j.ecolmodel.2020.109072 ◽

2020 ◽

Vol 428 ◽

pp. 109072 ◽

Cited By ~ 1

Author(s):

Ke Sun ◽

Jeffrey S. Ren ◽

Tao Bai ◽

Jihong Zhang ◽

Qing Liu ◽

...

Keyword(s):

Growth Model ◽

Yellow Sea ◽

Ulva Prolifera ◽

The Yellow Sea ◽

Green Tides ◽

Dynamic Growth

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Assessing Herbivorous Impacts of Apohale sp. on the Ulva prolifera Green Tide in China

Frontiers in Plant Science ◽

10.3389/fpls.2021.795560 ◽

2021 ◽

Vol 12 ◽

Author(s):

Xiaoxiang Miao ◽

Jie Xiao ◽

Shiliang Fan ◽

Yu Zang ◽

Xuelei Zhang ◽

...

Keyword(s):

Yellow Sea ◽

Algal Biomass ◽

Large Scale ◽

Algal Growth ◽

Ulva Prolifera ◽

The Yellow Sea ◽

Green Tide ◽

Species Identity ◽

Green Tides ◽

The Southern Yellow Sea

An epiphytic gammarid species, Apohyale sp., was abundant in the floating Ulva prolifera (U. prolifera), which forms large-scale green tides in the Yellow Sea (YSGT). Field observation and laboratory experiments were subsequently conducted to study the species identity, abundance, and grazing effects on the floating algal biomass. The abundance of Apohyale sp. showed great spatial variation and varied from 0.03 to 1.47 inds g−1 in the YSGT. In average, each gram of Apohyale sp. body mass can consume 0.43 and 0.60 g algal mass of U. prolifera per day, and the grazing rates varied among the algae cultured with different nutritional seawaters. It was estimated that grazing of Apohale sp. could efficiently reduce ~0.4 and 16.6% of the algal growth rates in Rudong and Qingdao, respectively. The U. prolifera fragments resulting from gnawing of Apohyale sp. had a higher growth rate and similar photosynthetic activities compared to the floating algae, indicating probably positive feedback on the floating algal biomass. This research corroborated the significant impact of Apohyale sp. on the floating algal mass of YSGT through the top-down control. However, further research is needed to understand the population dynamics of these primary predators and hence their correlation with the expansion or decline of YSGT, especially under the complex food webs in the southern Yellow Sea.

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Summer Wind Effects on Coastal Upwelling in the Southwestern Yellow Sea

Journal of Marine Science and Engineering ◽

10.3390/jmse9091021 ◽

2021 ◽

Vol 9 (9) ◽

pp. 1021

Author(s):

Bin Wang ◽

Lei Wu ◽

Ning Zhao ◽

Tianran Liu ◽

Naoki Hirose

Keyword(s):

Summer Monsoon ◽

Wind Stress ◽

Yellow Sea ◽

Coastal Upwelling ◽

Circulation Model ◽

Tidal Mixing ◽

The Yellow Sea ◽

Observation Data ◽

Wind Stress Curl ◽

Green Tides

The features of coastal upwelling in the southwestern Yellow Sea were investigated based on oceanology data from a research cruise and a regional circulation model. The observation data suggest that a relatively colder and saltier water core exists from the deeper layer to the surface, off the Subei Bank. The concentrations of nutrients also suggest that coastal upwelling is beneficial for nutrient enrichment in the upper layer. The numerical simulations are in good agreement with oceanology observations. Furthermore, sensitivity experiments indicate that, in addition to the tidal-induced upwelling and tidal mixing proposed in previous studies, the summer monsoon is also critical to vertical circulation in the southwestern Yellow Sea. The southwesterly wind stress and positive wind stress curl make considerable contributions to upwelling off the Subei coast compared with tidal motions. Moreover, this study also proposes that changes in the summer monsoon and its curl may have been helpful to the formation of upwelling during the past decade, which may have provided a favorable marine environment for the frequent occurrence of green tides. This study provides a theoretical basis for the mechanisms of coastal upwelling and the nitrogen cycle in the Yellow Sea.

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Distribution and species diversity of the floating green macroalgae and micro-propagules in the Subei Shoal, southwestern Yellow Sea

PeerJ ◽

10.7717/peerj.10538 ◽

2020 ◽

Vol 8 ◽

pp. e10538

Author(s):

Xiaoxiang Miao ◽

Jie Xiao ◽

Qinzeng Xu ◽

Shiliang Fan ◽

Zongling Wang ◽

...

Keyword(s):

Species Diversity ◽

Environmental Factors ◽

Yellow Sea ◽

Source Region ◽

The Yellow Sea ◽

Green Tide ◽

Distributional Pattern ◽

Green Tides ◽

Green Macroalgae ◽

Subei Shoal

Massive floating green macroalgae have formed harmful green tides in the Yellow Sea since 2007. To study the early development and the associated environmental factors for the green tide, a field survey was carried out in the Subei Shoal, southwestern Yellow Sea. Multiple species were identified in both floating green macroalgae and micro-propagules , while their abundances showed distinct spatial variations. The floating macroalgal biomass was widespread in the northern Subei Shoal and most abundant at 34°N. Ulva prolifera dominated (91.2% in average) the floating macroalgae, and the majority (88.5%) of U. prolifera was the ‘floating type’. In comparison, the micro-propagules were most abundant around the aquaculture rafts, and decreased significantly with the distance to the rafts. The dominant species of micro-propagules was U. linza (48.5%), followed by U. prolifera (35.1%). Their distinct distribution patterns and species diversity suggested little direct contribution of micro-propagules for the floating macroalgae. The spatial variation of the floating macroalgae was probably a combined result from the biomass source and environmental factors, while the abundance of micro-propagules was closely associated with the rafts. A positive correlation between the floating macroalgae and DO was observed and suggested active photosynthesis of the initial biomass in Subei Shoal. This study revealed specific distributional pattern and relationships among the floating macroalgae, micro-propagules and the environmental factors in the source region, which helps understanding the early blooming dynamics of the green tides in Yellow Sea.

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A Lagrangian-based Floating Macroalgal Growth and Drift Model (FMGDM v1.0): application in the green tides of the Yellow Sea

10.5194/gmd-2021-20 ◽

2021 ◽

Author(s):

Fucang Zhou ◽

Jianzhong Ge ◽

Dongyan Liu ◽

Pingxing Ding ◽

Changsheng Chen

Keyword(s):

Remote Sensing ◽

Yellow Sea ◽

Surface Wind ◽

Ocean Model ◽

Biological Data ◽

The Yellow Sea ◽

Green Tide ◽

Observation Data ◽

Green Tides ◽

Drift Model

Abstract. Massive floating macroalgal blooms in the ocean have had an array of ecological consequences; thus, tracking their drifting pattern and predicting their biomass are important for their effective management. However, a high-resolution ecological dynamics model is lacking. In this study, a physical–ecological model, Floating Macroalgal Growth and Drift Model (FMGDM v1.0), was developed to determine the dynamic growth and drift pattern of floating macroalgal, based on the tracking, replication and extinction of Lagrangian particles. The position, velocity, quantity and represented biomass of particles are updated synchronously between the tracking module and the ecological module. The former is driven by ocean flows and sea surface wind, while the latter is controlled by the temperature, salinity, and irradiation. Based on the hydrodynamic models of the Finite-Volume Community Ocean Model and parameterized using a culture experiment of Ulva prolifera, which caused the largest bloom worldwide of the green tide in the Yellow Sea, China, this model was applied to simulate the green tides around the Yellow Sea in 2014 and 2015. The simulation result, distribution and biomass of green tides, was validated using remote sensing observation data and reasonably modeled the entire process of green tide bloom and its extinction from early spring to late summer. Given the prescribed spatial initialization from remote sensing observation, the model could provide accurate short-term (7–8 d) predictions of the spatial and temporal developments of the green tide. With the support of the hydrodynamic model and biological data of macroalgae, this model can forecast floating macroalgae blooms in other regions.

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