Drivers of phytoplankton blooms in the northeastern Black Sea

Силкин, В. А.; Паутова, Л. А.; Giordano, Mario; Часовников, В. К.; Востоков, С. В.; Подымов, О. И.; Pakhomova, Svetlana; Москаленко, Л. В.

doi:10.1016/j.marpolbul.2018.11.042

Cited by 59 publications

(55 citation statements)

References 85 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The intensity of autumn-winter [1,2] and spring [3,4] blooming of diatoms directly depends on the vertical mixing processes. Summer blooming of coccolithophorids on an interannual scale correlates with winter cooling and the amount of phosphates involved in ML [5,6]. If the MLD significantly exceeds the photic layer thickness, in winter the phytoplankton blooming in the Black Sea can be suppressed [2] due to the general lack of illumination in ML [1,7].…”

Section: Introductionmentioning

confidence: 99%

The Black Sea Mixed Layer Depth Variability and Its Relation to the Basin Dynamics and Atmospheric Forcing

Kubryakov¹,

Белокопытов²,

Zatsepin³

et al. 2019

PhO

View full text Add to dashboard Cite

Spatio-temporal variability of the mixed layer depth (MLD) in different areas of the Black Sea in 1985-2017, its relationship with basin dynamics and atmospheric forcing are studied. Methods and Results. The study is based on the hydrological data archive for 1985-2017 including the measurements of the ship expeditions, the Argo buoys and the moored buoy "Aqalog". Seasonal and interannual variability of the mixed layer depth was determined using the density criterion (dr = = 0.07kg/m 3) between the surface layers and the base of the upper mixed layer. Conclusions. In January-March, the large-scale and mesoscale dynamics significantly affects the mixed layer depth variability. Minimum monthly average values of the mixed layer depth in winter are observed in the mesoscale cyclonic eddies and in the center of the sea (20-30 m), the moderate valueson the periphery of the basin (40-45 m) and the maximum onesin the mesoscale anticyclones (60-70 m). Several times the mixed layer depth values exceeding 150 m were detected in the downwelling areas of the basin. Analysis of the whole period (1985-2017) shows that the mixed layer density was never more than 1015 kg/m 3. This isopycnal limits the maximum possible depth of the upper mixed layer. The impact of wind velocity on the spatial and temporal variability of the mixed layer thickness is the largest in spring and autumn when the seasonal thermocline is weak. It is less important in summer when solar heating stabilizes the upper layer, and in winter when the mixed layer depth is large. Rise of the mixed layer depth in summer is observed in recent years that is associated with rise of the wind speed in a warm period of a year.

show abstract

Section: Introductionmentioning

confidence: 99%

The Black Sea Mixed Layer Depth Variability and Its Relation to the Basin Dynamics and Atmospheric Forcing

Kubryakov¹,

Белокопытов²,

Zatsepin³

et al. 2019

PhO

View full text Add to dashboard Cite

show abstract

“…Journal of Geophysical Research: Biogeosciences growth strategy" in the ambient abundant nutrients in spring, to coccolithophorids (e.g., Emiliania huxhleyi) with an "affinity growth strategy" in the ambient low N and high P conditions in late spring and early summer, and then to large diatoms with a "storage growth strategy" (e.g., Pseudosolenia calcaravis, same as L. danicus) when the nutrients deplete in the summer and autumn (Silkin et al, 2019). Thus, controlling the land-based load of nitrogen and maintaining the balance of nutrient regimes are necessary to the health of the coastal ecosystems.…”

Section: 1029/2020jg005643mentioning

confidence: 99%

Effect of Ambient Nitrogen on the Growth of Phytoplankton in the Bohai Sea: Kinetics and Parameters

et al. 2020

View full text Add to dashboard Cite

Changes in nitrogen forms and levels affect biogeochemical processes, but little is known about the quantitative effect of ambient nitrogen on phytoplankton growth in biogeochemical kinetics. Based on a new experimental data analysis method, we investigated the phytoplankton growth and nitrogen uptake processes of typical phytoplankton subjected to different nitrogen forms in the Bohai Sea. We employed a nonlinear differential model to fit the kinetic processes of phytoplankton growth, death, and nutrient uptake considering multiple equations and parameters. The maximum nitrogen uptake rate (k up), half-saturation coefficient (k s), and maximum phytoplankton growth rate (k G) were obtained based on the multivariate nonlinear differential mothed. The k up and k s were related with k G for different ambient nitrogen forms (urea, ammonium, and nitrate) in the N sufficiency experiment group I (SGI) treatment, showing that phytoplankton grew faster in the presence of ammonium and nitrate than in the presence of urea, owing to quicker nitrogen uptake rate. The k up , k s , and k G in the N-Starvation experiment group II (SGII) treatment were lower than that in the SGI treatment, indicating higher nutrient affinity of phytoplankton at lower nitrogen concentrations. Hence, we can infer that eutrophic algae such as Nitzschia closterium may easily become the dominant species in the SGI treatment with abundant nitrogen supply and high k G , k up , and k s. In contrast, oligotrophic algae such as Leptocylindrus danicus and Asterionellopsis glacialis may easily become the dominant species in the SGI or SGII treatments with an insufficient supply of ambient nitrogen and low k G , k up , and k s. Plain Language Summary The ecosystem is vulnerable in coastal waters, suffering by human activities associated with anthropogenic nutrients, such as harmful algae bloom. The forms and levels of nutrients affect phytoplankton growth, while little is known about the biogeochemical kinetics. We investigated the phytoplankton growth and nitrogen uptake kinetics of typical phytoplankton subjected to different nitrogen forms (e.g., urea, ammonium, and nitrate) in the Bohai Sea. We proposed a multivariate nonlinear differential fitting method to analyze ecological experimental data, considering multiple kinetic equations and parameters of phytoplankton growth, death, and nutrient uptake. Based on the in situ batch culture experiment, the phytoplankton grew faster in ambient ammonium and nitrate than in ambient urea in the N sufficiency experiment group conditions, whereas, they grew and acquired nutrient significantly lower in the N starvation experiment group conditions. The phytoplankton domain community was different in different ambient nitrogen forms and levels, where eutrophic algae such as Nitzschia closterium might easily become the dominant species in the N sufficiency treatment with abundant nitrogen supply, whereas, oligotrophic algae such as Leptocylindrus danicus and Asterionellopsis glacialis might easily become the dominant spe...

show abstract

“…We set out to investigate the processes which are responsible for these premature blooms in autumn. Erosion of the thermocline and vertical mixing, due to surface cooling and strong winds typically start at the end of November, hence, they cannot be directly responsible for the early autumn bloom observed in References [9,55,59]. Figure 12 illustrates possible mechanisms for the early autumn bloom.…”

Section: Mechanism Behind Autumn Blooms In the Black Seamentioning

confidence: 99%

Seasonal and Inter-Annual Variability of the Phytoplankton Dynamics in the Black Sea Inner Basin

Miladinova

Adolf

Moy

et al. 2020

Oceans

View full text Add to dashboard Cite

We explore the patterns of Black Sea phytoplankton growth as driven by the thermohaline structure and circulation system and the freshwater nutrient loads. Seasonal and inter-annual variability of the phytoplankton blooms is examined using hydrodynamic simulations that resolve mesoscale eddies and online coupled bio-geochemical model. This study suggests that the bloom seasonality is homogeneous across geographic locations of the Black Sea inner basin, with the strongest bloom occurring in winter (February–March), followed by weaker bloom in spring (April–May), summer deep biomass maximum (DBM) (June–September) and a final bloom in autumn (October–November). The winter phytoplankton bloom relies on vertical mixing of nitrate from the intermediate layers, where nitrate is abundant. The winter bloom is highly dependent on the strength of the cold intermediate layers (CIL), while spring/summer blooms take advantage of the CIL weakness. The maximum phytoplankton transport across the North Western Shelf (NWS) break occurs in September, prior to the basin interior autumn bloom. Bloom initiation in early autumn is associated with the spreading of NWS waters, which in turn is caused by an increase in mesoscale eddy activity in late summer months. In summary, the intrusion of low salinity and nitrate-rich water into the basin interior triggers erosion of the thermocline, resulting in vertical nitrate uplifting. The seasonal phytoplankton succession is strongly influenced by the recent CIL disintegration and amplification of the Black Sea circulation, which may alter the natural Black Sea nitrate dynamics, with subsequent effects on phytoplankton and in turn on all marine life.

show abstract

Drivers of phytoplankton blooms in the northeastern Black Sea

Cited by 59 publications

References 85 publications

The Black Sea Mixed Layer Depth Variability and Its Relation to the Basin Dynamics and Atmospheric Forcing

The Black Sea Mixed Layer Depth Variability and Its Relation to the Basin Dynamics and Atmospheric Forcing

Effect of Ambient Nitrogen on the Growth of Phytoplankton in the Bohai Sea: Kinetics and Parameters

Seasonal and Inter-Annual Variability of the Phytoplankton Dynamics in the Black Sea Inner Basin

Contact Info

Product

Resources

About