sublittoral zone
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Author(s):  
Андрей Павлович Столяров

Изучены видовое разнообразие, пространственная и трофическая структура макробентосных сообществ сублиторали и нижних горизонтов литорали в 5-ти лагунных экосистемах Кандалакшского залива Белого моря. Всего в исследованных экосистемах было обнаружено 52 вида бентосных беспозвоночных животных и 6 видов морских трав и водорослей. В сублиторали наибольшим видовым разнообразием, общей плотностью и биомассой макробентоса характеризуется наиболее открытая к морю лагуна, расположенная на выходе из кутовой области Кислой губы, а наименьшим - наиболее закрытая и заиленная лагуна Никольской губы, где преобладали солоноватоводные и морские эвригалинные виды. Промежуточное положение занимали лагуна Ермолинской губы, лагуна, расположенная рядом с Ершовским озером и лагуна на Зеленом мысу. В нижней литорали общие показатели структуры сообщества макробентоса (общая плотность, биомасса и в меньшей степени видовое разнообразие) в отличие от сублиторали увеличивались от менее зарегулированных и открытых экосистем к более закрытым системам. Исключением является лагуна Никольской губы, значительное заиление которой приводит к существенному уменьшению видового разнообразия и снижению общей плотности и биомассы сообщества макробентоса. The species diversity, spatial and trophic structure of macrobenthos communities in the sublittoral and lower littoral horizons in five lagoon ecosystems of the Kandalaksha Bay of the White Sea have been studied. In total, 52 species of benthic invertebrates and 6 species of sea grasses and algae were found in the studied ecosystems. In the sublittoral zone, the highest species diversity, total density and biomass of macrobenthos is characterized by the lagoon most open to the sea, located at the exit from the innermost area of Kislaya Bay. The lowest diversity is found in the most closed and silted lagoon of Nikolskaya Bay, where brackish water and marine euryhaline species predominated. The lagoon of the Ermolinskaya Bay, the lagoon located next to the Ershov Lake and the lagoon on Cape Verde hold an intermediate position. In the lower littoral zone, the general indicators of the structure of the macrobenthos community (total density, biomass, and, to a lesser extent, species diversity), in contrast to the sublittoral one, increased from less regulated and open ecosystems to more closed systems. An exception is the lagoon of Nikolskaya Bay, the significant siltation of which leads to a significant decrease in species diversity and a decrease in the total density and biomass of the macrobenthos community.


2021 ◽  
Vol 151 (3) ◽  
pp. 305-326
Author(s):  
Vivien Csoma ◽  
Imre Magyar ◽  
Andrea Szuromi-Korecz ◽  
Krisztina Sebe ◽  
Orsolya Sztanó ◽  
...  

The large outcrop at Pécs-Danitzpuszta, southern Hungary, exposes a 65-meter-thick succession of calcareous marls, clay marls and calcareous sands that were deposited during the early history of Lake Pannon, a vast, Caspian-type lake in Central Europe in the late Miocene. Within the framework of the complex stratigraphic investigation of this succession, well preserved, relatively diverse benthic ostracod assemblages containing 39 taxa were recovered from 29 samples (16 samples were barren). Palaeoecological interpretation of the ostracod genera suggests that deposition took place in a low-energy environment, in the shallow sublittoral zone of Lake Pannon, in pliohaline (9–16‰ salinity) water. The entire succession was divided into four interval zones based on the first occurrences of assumedly useful marker fossils: Hemicytheria lorentheyi Zone (from sample D29), Hemicytheria tenuistriata Zone (from sample D17), Propontoniella candeo Zone (from sample D115) and Amplocypris abscissa Zone (from sample D209). Based on comparison to the Beočin section 150 km to the SE, where a lithologically and stratigraphically similar section was dated magnetostratigraphically by an international team, we tentatively assume that the Pannonian marl succession of the Pécs-Danitzpuszta outcrop represents the time interval of 11.6 to ca. 10 Ma.


Algologia ◽  
2021 ◽  
Vol 31 (3) ◽  
pp. 249-270
Author(s):  
S.Yu. Sadogurskiy ◽  
◽  
S.O. Sadogurska ◽  
T.V. Belich ◽  

The data on the composition and distribution of macrophytobenthos of marine and lagoon water areas of the Black Sea coastal zone in the west of the Tarkhankut Peninsula in the summer season are presented. It is shown that the occurrence and general characteristics of the vegetation cover are determined by the type of substrate. In the sea (where hydrological conditions are relatively homogeneous), the ratio of ecological-floristic groups and the species composition change with distance from the coast and along with it, depending on the depth and geomorphological features of coastal zone fragments. In the lagoon, the ratio of such groups changes along the complex gradient of environmental factors, formed by the groundwater runoff of fresh and marine waters. Within the surveyed area, 91 species of macrophytes were registered: Tracheophyta – 1 species (1.1%), Chlorophyta – 23 (25.3%), Ochrophyta (Phaeophyceae) – 21 (23.1%), and Rhodophyta – 46 (50.5%). Of these, 87 species were recorded in the sea (including 44 in the pseudolittoral zone and 81 – in the sublittoral zone). The macrophytobenthos has a pronounced marine oligosaprobic character. Short-vegetation Rhodophyta dominate by the number of species, and perennial Phaeophyceae dominate by biomass, reaching 1 kg∙m-2 in the pseudolittoral and almost 7 kg∙m-2 in the sublittoral. In the lagoon, 18 species of macrophytes were registered (4 exclusively in the lagoon). Mesosaprobic short-vegetation Rhodophyta dominate by the number of species; marine and brackish-water macrophytes are equally represented. Polysaprobic perennial Tracheophyta, which belong to the marine group, dominate by biomass, which is ranging from 0.04 to 1.2 kg∙m-2. It was found that at the time of the research, the macrophytobenthos of the surveyed area was characterized by high productivity, high species, and coenotic diversity. There were taxa and biotopes, which are subject to special protection under regional and international programs. In general, the nature of the vegetation, the composition of the flora and the ratio of the main ecological-floristic indicators corresponded to those indicated for the Tarkhankut-Sevastopol hydrobotanical region of the Black Sea. Considering the sozological value, the aquatic component of the territorial-aquatic complex was recommended for conservation and inclusion in the ecological networks (incl. the Emerald Network). The increased anthropogenic pressure and the threat of the coastal zone transformation actualize the problem of its conservation as one of the key reserves of the floristic and biotopic diversity of coastal-marine areas in the Northern Black Sea region.


Animals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2488
Author(s):  
Krystian Obolewski ◽  
Katarzyna Glińska-Lewczuk ◽  
Marcin Sidoruk ◽  
Monika Magdalena Szymańska

We investigated the response of benthic macroinvertebrates in the eulittoral, infralittoral, and sublittoral zones, in two segments of the freshwater Lake Wicko on the coast of the Baltic Sea. Our results showed that the morphometry of lakes plays a major role as a factor structuring the macroinvertebrates communities. Two parts of the lake, different in size and depth, show decreasing differences in the trophic state, abundance, diversity and number of indicator species of benthic fauna with the depth gradient. The most significant differences were observed between the littoral zones of both segments. Similar environmental conditions in the sublittoral zones corresponded to the simplified structure of the benthic macroinvertebrates communities. In the infralittoral zone, the most significant differences between the two segments, were recorded for mollusks and large crustaceans as well as the Oligochaeta/Chironomidae abundance ratio. In the sublittoral zone, the diversity of chironomids differed most strongly. Lower species diversity was found in the part of the lake with a slight depth decrease. Shredders reached significantly higher values in eulittoral and infralittoral of the deeper lake segment. Average Score Per Taxon increased with a depth gradient. We recommend testing benthic macroinvertebrates in lakes with different morphometrics individually for each depth zone.


2021 ◽  
Vol 20 (4A) ◽  
pp. 69-80
Author(s):  
Nguyen Thi Thu Hang ◽  
Nguyen Van Tu ◽  
Vo Van Phu ◽  
Nguyen Ngoc Lam

Results of four field surveys, conducted from June 2017 to June 2018 found that in the Phu Yen coastal water, a total of 103 seaweed species have been recorded, increasing the total number of seaweed species in Phu Yen province to 133 species, with 81 newly recorded species for Phu Yen geographic area. Among 103 seaweed species, 4 species belong to Cyanobacteria, 38 species belong to Rhdophytes, 24 species belong to Phaeophytes, and 37 species belong to Chlorophytes.  The number of species at surveyed sites V1 to V9 varies from 3 species/site (V3) to 83 species/site (V7) and on average 27 species/site. Sørensen’s similarity coefficient varies from 0.05 (between V3 and V7) to 0.86 (V3 and V4) and on average 0.25. 74/103 species were collected in the littoral zone, 67 species in sublittoral zone and most of them are distributed at 0-4 m water depth of subtidal zone. The marine algal flora is represented by mixing of subtropical and tropical characteristics as Cheney index was 3.


Author(s):  
L. L. Budnikova ◽  
R. G. Bezrukov

In 2005 in sublittoral zone of Koryak coast 79 species of amphipods belonged to 43 genera, 20 families and two suborders are revealed. The main part of the fauna was endemics of Pacific boreal area. The biomass varied from the several 100-th shares of gram to 15.6 g/m2. The maximum biomass of amphipods at population density 230 ind./m2 was registered at Cape Hajtyrka. The average biomass was 2.0 ± 0.6 g/m2 or 0.4% from the total biomass of a benthos. In places of amphipods accumulations their part in the total biomass of a benthos could reach 56.9%. Quantity indicators of amphipods on a shelf of Koryak coast above, than in Anadyr Bay. In different places of the investigated water area dominating species was different (Atylus bruggeni, Pontogeneia rostrata, Anisogammarus pugettensis, Caprella paulina). Rigid soil are extended on main parts of water area of narrow geosynclinal shelf of Koryak coast, mobile filter feeder, building small houses-tubes in thickness of a soil (Byblis erythrops, Ampelisca macrocephala and some other) had here no such wide development as in of Anadyr Bay. The shelf of Koryak coast distinguishes from the other areas of the Far East seas by small species wealth of amphipods at the stations – basically no more than five species.


2020 ◽  
Vol 200 (3) ◽  
pp. 767-788
Author(s):  
A. A. Dulenin

Dominant species are identified at infracenotic level for aquatic vegetation in the sublittoral zone of the northwestern Tatar Strait (Japan Sea) on the data collected in 2010–2019. Seven different methods of the identifying are considered based both on visual qualitative and quantitative assessments and on instrumental estimations of abundance for 44 macrophyte species. Depending on applied method, 19–25 species (7–22 % of total number of species) are identified as the dominants, including 10 species identified by all methods. List of these 10 species is defined as the core of vegetation that determines its general properties and the species are determined as unconditional dominants, in opposite to other ones identified by at least one method — conditional dominants. All macrophyte species in areas of low abundance do not meet the dominance criteria. All lists of dominants, including those based on visual estimates of projective cover and its physiognomy, are statistically indistinguishable (p = 0.55–0.92, by pairs of lists) and highly similar (Bray-Curtis index 0.80–0.95, Jacquard index 0.65–0.87), with one exception for the list identified by the method of ranking for the average projective cover (indices of similarity with other lists: 0.68–0.71 by Bray-Curtis, 0.46–0.56 by Jacquard). This visual method of projective cover assessment is combined with the procedure of species dividing to dominant and non-dominant groups. Quantitative criteria of projective cover and biomass, by species (thresholds 0.2 and 1.0 kg/m3, respectively) are used for dividing on cenotic and landscape levels and ranking with Brotskaya-Zenkevich index and its modification for projective cover is used for dividing on regional level. Visual methods are available for verification, but the lists of dominants based on visual and instrumental assessments should be mutually verified.


2020 ◽  
Vol 200 (3) ◽  
pp. 635-655
Author(s):  
Р. A. Dulenina ◽  
A. A. Dulenin

General patterns of bivalves distribution by depth in the northwestern Tatar Strait (within Khabarovsk region) are analyzed on the data of 384 trawl, 573 drag, and 1177 diving stations during research surveys in 2003–2016 where the samples were collected with commonly accepted methods. Depths from 0 to 600 m were surveyed. Besides, scientific publications and archival materials related to this area were taken into account. The species richness (y) decreases with depth (x) exponentially from 51 species at 1–20 m to 3 species at 400–600 m that could be approximated satisfactory by the equation y = 31.799. e–0.0502x (r2 = 0.89). Sublittoral and bathial faunas can be separated by cluster analysis of special composition in the depth range 0–150 m and 150–600 m, respectively, with similarity of 0.11 between them. Within these boundaries, 5 local faunas are distinguished: I (< 2 m, the surf zone at the upper boundary of the sublittoral zone), II (2–30 m, the upper sublittoral zone), III (30–150 m, the lower sublittoral zone), IV (150–400 m, the transitional zone) and V (400–600 m, the upper bathyal zone), with similarity between them from 0.14 to 0.36. The upper sublittoral zone has the maximum species richness — 64 species and is the habitat for a «core» of Bivalve fauna with almost ⅔ of its species, preserving the ratio of the main biogeographic groups typical for the researched area. Commercial fishery of scallop Mizuhopecten yessoensis exploited this zone mainly and now is banned to prevent reduction of its stock. Other commercial bivalves, as Callista brevisiphonata, Serripes laperousii, Keenocardium californiense, and Mercenaria stimpsoni, which commercial stocks are estimated in order of 105 t, are also concentrated in this zone but are not landed currently. Portion of moderately cold-water species (wide-boreal and low-boreal) increases and portion of warm-water species (subtropical-boreal and subtropical-low-boreal) decreases with depth, with the slope coefficients of the regressions α = 9.2 ± 4.1 (p = 0.11) and α = –9.6 ± 2.3 (p = 0.03), respectively. The coldwater species are absent in the surf and upper bathyal zones but their portion in other zones is 20–26 %. Rather high portion of boreal-arctic species on shallow depths reflects relative severity of the northwestern Tatar Strait that is the most cold-water area of the Japan Sea. The warm-water species are completely absent in the upper bathyal zone, i.e. at the depths > 400 m. On the other hand, portion of banal species increases and portion of specific species decreases with depth, also portion of rare species increases and portion of mass species decreases with depth, with the slope coefficients α = 9.10 ± 0.49 (p = 0.0003) and α = –4.5 ± 2.5 (p = 0.01), respectively. Vertical distribution of frequent species is rather uniform: 33–57 %. These patterns of the species distribution by zones almost do not change spatially: distribution of different biogeographic groups of species in three coastal areas (47–49о N, 49–51о N, and > 51о N) has no statistically significant differences. Distribution of species richness and composition by depth ranges relates to ecotopic variation (74 % of diversity), to the degree of exploration (22 %), and to the influence of such complex factor as a depth (4 %). Further faunistic studies are recommended in the most diverse areas, as bays, harbours, and capes vicinities with variable grounds and submarine vegetation, in all available depth ranges. Such surveys can provide faunistically representative information on the species wealth. The list of Bivalve mollusk species for the northwestern Tatar Strait can be enlarged possibly in 1/5 if detailed studies of their fauna will be conducted. The fauna on great depths is the most underexplored. The total expected number of bivalve species in this area is at least 120.


Animals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1351
Author(s):  
Anastasios Varkoulis ◽  
Konstantinos Voulgaris ◽  
Stefanos Zaoutsos ◽  
Antonios Stratakis ◽  
Dimitrios Vafidis

In the Mediterranean Sea, the species Arbacia lixula, Paracentrotus lividus and Sphaerechinus granularis often coexist, occupying different subareas of the same habitat. The mechanical and chemical properties of their calcitic skeletons are affected both by their microstructural morphology and chemical composition. The present study describes the main morphologic features and the possible temporal differences in elemental composition of the test and spines of the three species, while also determining the molar ratio of each element of their crystalline phase. Scanning electron microscopy showed major differences in the ultrastructure of the spines, while minor differences in the test were also noticed. More specifically, the spines of all three sea urchins possess wedges, however A. lixula exhibits bridges connecting each wedge, while barbs are observed in the wedges of S. granularis. The spines of P. lividus are devoid of both microstructures. Secondary tubercles are absent in the test of A. lixula, while the tests and spines of all three species are characterized by different superficial stereom. Energy dispersive x-ray spectroscopy detected that Ca, Mg, S, Na and Cl were present in all specimen. Mg and Mg/Ca showed significant differences between species both in test and spines with S. granularis having the highest concentration. The spines of P. lividus exhibited lowest values between all species. Differences between spines and test were observed in all elements for P. lividus except S. A. lixula exhibited different concentrations between test and spines for Ca, Mg and Mg/Ca, whereas S. granularis for Mg, Cl and Mg/Ca. Finally, temporal differences for Ca were observed in the test of P. lividus and the spines of S. granularis, for Mg in test of S. granularis, for S in the spines of A. lixula and the test and spine of S. granularis, for Na in the test of P. lividus and A. lixula and for Cl and Mg/Ca in the test P. lividus. Powder X-ray diffractometry determined that, out of all three species, the spines of P. lividus contained the least Mg, while the test of the same species exhibited higher Mg concentration compared to A. lixula and S. granularis. The current study, although not labeling the specimens attempts to estimate potential time-related elemental differences among other results. These may occur due to changes in abiotic factors, probably water temperature, salinity and/or pH. Divergence in food preference and food availability may also play a key role in possible temporal differences the skeletons of these species


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