Hindawi e Scientific World Journal Volume 2019, Article ID 8456371, 7 pages https://doi.org/10.1155/2019/8456371 Research Article Phytoplankton and Its Role in Accumulation of Microelements in Bottom Deposits of Azov Sea Irina V. Dotsenko and Anna V. Mikhailenko Southern Federal University, Institute of Earth Science, Rostov-on-Don 344090, Russia Correspondence should be addressed to Anna V. Mikhailenko; [email protected] Received 7 November 2018; Revised 9 January 2019; Accepted 19 February 2019; Published 12 March 2019 Academic Editor: Adriano Sfriso Copyright © 2019 Irina V. Dotsenko and Anna V. Mikhailenko. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Te importance of phytoplankton is high in transformation of substances in aquatic ecosystems and in formation of suspension’s material structure. Its main functions are consumption of the dissolved biogenic components and chemical elements and their conversion to a frm phase. Te article is devoted to the bioaccumulation of microelements by phytoplankton in the ecosystem of the Azov Sea. Te fact that the algal biomass during the periods of blooming in the sea reaches 1,400 g/l makes this study especially urgent. Te authors defne the rates of biogeochemical cycle and the intensity of chemical elements’ consumption and also investigate the role of phytoplankton in the formation chemical peculiarities of bottom deposits and its involvement in sedimentogenesis in the Azov Sea. Te cause of the reduced trace element content in bottom deposits relatively to suspended material is established. It is noted that the amount of some elements annually consumed by algae of the Azov Sea is up to 75% from their maximum delivery by terrigenous material. 1. Introduction Strakhov [12] rightly called the processing of less labile compounds of elements that had come from the continent Te organic world plays an important role in the formation into more mobile organic compounds as the main geo- of chemical peculiarities of bottom deposits of epeiric seas of chemical function of biota. It is quite obvious that phy- the arid belt. Such seas are characterized by high productivity toplankton, which is the main producer of organic matter of the entire ecosystem, and the Azov Sea is a typical and the most powerful link of marine ecosystems, takes example. Phytoplankton fulflling a mobilizing function and the greatest biogeochemical signifcance at the stage of enhancing geochemical mobility promotes separation of marine sedimentogenesis [13]. Algae with their huge geo- some chemical elements from others. Such a phytogenic chemical energy play leading role in the biogenic cycling selection determines their further diferentiation at the stages of chemical elements being responsible also for various of sedimentogenesis (synsedimentary processes) and diagen- biogeochemical functions. Te calculations carried out by esis (postsedimentary processes). Diferent degrees of metal Datsko [14] showed that the turnover ratio of nutrients (the consumption can be an indirect evidence of the possibility of ratio between the annual phytoplankton’s consumption of one element extraction from suspended matter. Various degrees or another chemical element and its amount in dissolved of microelement consumption can be an indirect evidence of form in the photosynthesis zone and in the main sources of extraction possibility from suspended matter [1–5]. Complex nutrition) in the Azov Sea during the growing period reaches studies of various phases of marine sedimentogenesis imply 8. the relevant processes in the water layer began rather recently [6, 7]. Te studied chemical compounds have been found in marine and oceanic ecosystems for about forty years 2. Materials and Methods ago. Over the last years, a new phase of such studies has begun, that is due to the interest in studying bioavailability Te present study is based on fndings of feld researches in of microelements [8–11]. the Azov Sea in 2004, 2006, and 2009 [15]. Phytoplankton 2 Te Scientifc World Journal 37∘％38∘％ 39∘％ Rostov-on-Don Taganrog 8p Mariupol 8t Don 1t 0 ∘ 32 Bataysk 47 ． 4 3 1 42 2 Azov 6 5 10 11 Berdyansk 9 13 8 Ye ya Yeysk 27 26 15 Azov 16 25 Sea 22 24 46∘． Primorsko-Akhtarsk 17 23 Protoka 18 19 02550 km Figure 1: Location of sampling stations. and hydrochemical water sampling was undertaken with a Table 1: Interannual changes in average trace elements content in ship bathometer from two horizons (surface and bottom total phytoplankton of the Azov Sea, �g/g of dry weight. layer) at monitoring stations (Figure 1). Ten, the algae were precipitated on membrane flters with a pore size of 0.9 Elements 2004 2006 2009 microns. Biomass was determined by the calculation method, Mn 52.0 250.0 280.0 i.e., the leveling algal cells’ shape to geometric pattern and Ni 17.0 40.0 45.0 considering the specifc gravity equal to unity. Te total Co 5.0 4.0 - number of samples was 120. At the same time, concentrations Cr 42.0 67.0 56.0 ofMn,Co,Ni,Cr,V,Mo,Cu,andZnweremeasuredinthe V 30.0 103.0 30.0 samples by the atomic absorption spectrometry method. Te Mo 1.0 1.3 1.0 � errors in the metal content evaluation are as follows: 0.1 g/g Cu 85.0 93.0 48.0 � � for Mo and Co, 3 g/g for Cu, Zn, V, and Ni, and 5 g/g for Zn 95.0 130.0 110.0 Mn. 3. Results It is determined that phytoplankton’s productivity in the Taganrog Bay was 2.5 million tons, and it was 26.0 million Te fndings from this study allow us to conclude that the tons of dry matter in the Azov Sea. Table 2 presents data on intensity of the biogeochemical cycling of diferent metals is the annual consumption of phytoplankton micronutrients in diferent. Manganese, vanadium, copper, cobalt, and molyb- the Azov Sea. denum are most actively consumed (Table 1). Te remaining To defne the role of phytoplankton in the formation metals are intermediate. of the chemical constitution of bottom deposits and its It is signifcant that a similar situation is registered in participation in the geochemistry of sedimentogenesis the the Black Sea. According to Denisov et al., manganese (up data given in Table 3 are used. Tese data show that the to 1283 �g/g),copper(upto599�g/g), and vanadium amount of some elements annually consumed in the Azov (up to 80 �g/g) difer by the highest concentrations in total Sea is up to 75% of their maximum delivery together with plankton on the northeastern Black Sea shelf [16, 17]. On terrigenous material. Tese values are the highest for vana- the northwestern shelf, despite lower metal concentrations, dium and zinc, and these are the lowest for manganese and the leading positions are kept by copper (up to 33 �g/g), nickel. According to L.I. Tolokonnikova [18], only 17.5% of manganese (average 6 �g/g), and zinc (up to 72 �g/g) [17]. the organic matter produced by phytoplankton is precipitated Te Scientifc World Journal 3 Table 2: Te annual consumption of phytoplankton micronutrients in the Azov Sea. Taganrog Bay Open sea Entire sea Elements 2 3 2 3 2 3 tmg/Nmmg/Nm tmg/Nmmg/Nm tmg/Nmmg/Nm Mn 565.0 106.6 22.4 3257.0 86.2 10.0 3822.0 89.2 10.8 Ni 71.3 13.5 2.8 279.7 7.4 0.9 351.0 8.3 1.1 Co 10.5 2.0 0.4 20.8 0.6 0.1 31.3 0.8 0.1 Cr 132.5 25.0 5.3 280.8 7.4 0.9 413.3 10.0 1.2 V 175.0 33.0 6.9 1255.0 22.8 2.6 1430.0 24.3 2.9 Mo 205 0.5 0.1 5.2 0.2 0.1 7.7 0.3 0.1 Cu 222.5 42.0 8.8 462.8 12.2 1.4 485.3 16.6 2.0 Zn 505.1 95.4 20.0 2614.9 69.1 8.9 3120.0 73.0 9.8 Table 3: Consumption of microelements by phytoplankton and their deposition with remnants of planktonic algae in the bottom deposits of the Azov Sea, t. Elements Delivery to the sea with Consumption by Precipitation with Transition of algae rest during their Deposition on terrigenous material phytoplankton the rest of algae mineralization into silt solutions bottom Mn 16265,0 3822,0 668,8 473,9 194,9 V 1951,8 1430,0 250,2 177,3 72,9 Zn 4879,5 3120,0 546,0 386,9 159,1 Ni 2277,1 351,0 122,8 87,0 35,8 Table 4: Trace minerals in components of bottom deposits of the Azov Sea, %%. Content ratio Elements Average content in bottom deposits, % organic substance mollusc shell terrigenous and authigenic (mainly phytoplankton) components Cr 0.007 0.4 0.2 99.4 Ni 0.006 2.6 0.9 96.5 V0.01 5.1 0.2 94.7 Mn 0.025 3.1 17.6 79.3 Cu 0.001 4.5 21.9 73.6 on the sea bottom, and, therefore, almost the same portion can be the technique proposed by Strakhov [21]. Its essence of chemical elements associates with it. Of this amount, only is as follows. Element’s concentration in biological objects about 1/4 remains in the bottom deposits afer the mineral is multiplied by the organic content (for phytoplankton) or formation, whereas the most of the organic substances are CaCO3 (for mollusks) in sediments, and then the result oxidized and elements in algae go into solution enriching the is divided by the average element concentration in bottom entrapped water.