Polychaete Species Composition Research Articles

ТАКСОЦЕН POLYCHAETA В ПРИБРЕЖНОЙ АКВАТОРИИ ОЗЕРА ДОНУЗЛАВ

This work is based on the data collected during the benthic survey of soft sediments in the coastal area of the of Lake Donuzlav conducted in August, 2020. The current status of the species composition of polychaetes in Lake Donuzlav was investigated. The samples were collected using a manually operated grab sampler with a capture area of 0.04 m2 at the depths from 1 to 8 m. The following indicators were used to describe the quantitative development of benthos: abundance, biomass, occurrence, density index, and Czekanowski-Sørensen index. A total of 31 species of polychaetes have been found. The average values of polychaetes abundance and biomass in the investigated area were 239±51 ind./m2 and 1.537± 0.599 g/m2, respectively. The main contribution to the total abundance is made by Spio decorata , and to the total biomass by Lagis neapolitana. The largest number of species and the highest abundance were recorded at the depths of 1.1-2 m. The largest biomass was recorded at the depths of 6.1-7 m. The ranked series according to the density index is headed by L. neapolitana , Glycera tridactyla , and S. decorata . The trophic structure of polychaetes is represented by poly-, phyto-, detritophages, carnivores, and the animals, the food spectrum of which has not been studied. The most widely represented group is carnivores; it comprises 10 species of polychaetes. The least number of species (1) was recorded for phytophages. Over 1990-2020, 73 species of polychaetes were identified; they belonged to 29 families and 56 genera.

Effects of the summer monsoon on the polychaete assemblages and benthic environment of three mangrove swamps along the Sindh coast, Pakistan

Polychaetes are an important component of marine ecosystems. Monsoons are a common climate condition in the tropics and subtropics and are characterized by high temperatures, low annual temperature changes and high precipitation. Despite the potential importance of monsoons, little is known about their impact on the marine environment and fauna, including polychaete assemblages. We compared the polychaete species composition and abundance at Sandspit, Port Qasim, and Ketibunder mangrove swamps of the Sindh coast, Pakistan, collected during the premonsoon, monsoon, and postmonsoon seasons in 2020. We also measured six environmental parameters to correlate environmental and biological changes. A total of 17 species of polychaetes were collected. Except for the mean evenness index (J), Two-way ANOVA detected significant changes in the mean polychaete species number, abundance, diversity index (H’), abundance index (d) and dominance index (D), with lower values in the monsoon season than in the premonsoon and postmonsoon seasons at the three mangrove swamps. Two-way ANOVA also revealed significant changes in the six environmental parameters between the seasons and sampling sites. Our data suggested that the heavy rainfall resulting in reduced salinity was the main driver of reduced polychaete abundance and diversity during the monsoon season. The polychaete assemblages and benthic environment appeared to recover quickly after the monsoon at three mangrove swamps, indicating their adaptation to such annual dramatic fluctuations in environmental conditions.

Distinctive Community Patterns With Exceptional Diversity of Polychaetes Around a Tectonically Active Archipelago in the Tropical Indian Ocean

Marine soft-sediments sustain functionally important benthic assemblages that are critical for remineralization of organic matter and supply of nutrients to the water column. While these assemblages are well studied along continental margins, investigations from insular margin that surround oceanic islands are very limited. This paper examines the distribution and standing stock of macrozoobenthos at 50, 100, and 200 m depth contours surrounding the Andaman and Nicobar archipelago in the tropical Indian Ocean. The standing stock of macrozoobenthos decreased from the mesophotic reef areas (50 m depth) to the deeper strata (200 m), particularly in the case of the dominant groups, the polychaetes and crustaceans. Smaller-sized, interstitial polychaetes and crustaceans were abundant in the coarser sandy sediments at the shallower sites. The polychaetes were represented by 606 species (279 genera) in the study, of which >50% were rare species. Based on polychaete species composition, three regions were delineated in the study area - the Nicobar margin, the western margin of the Andaman (Bay of Bengal sector), and the eastern margin of the Andaman (Andaman Sea sector). The long, uninterrupted Andaman Island chain formed a geographic barrier separating the eastern and western margins, resulting in the regional distinctions in sediment nature and hydrographic characteristics, which in turn influenced species distribution. Corresponding differences were absent in the case of the Nicobar Islands, which are widely separated by transecting channels, permitting exchange of water between the Bay of Bengal and the Andaman Sea. Within the three regions, polychaete communities changed significantly in taxonomic and functional composition with increasing depth. The well oxygenated, coarse sandy sediments around mesophotic reefs (50 m) harboured predator-dominated assemblages. The 200 m sites, which were characterised by oxygen minimum conditions (<0.5 ml.l-1), particularly around the Andaman Island mass, were dominated by deposit feeders. This study provides the first comprehensive dataset on distribution and standing stock of macrozoobenthos, and community structure of polychaetes along the Andaman and Nicobar insular margin. It also revealed the highest number of polychaete species ever recorded in the northern Indian Ocean, indicating that the Andaman and Nicobar margin is a significant marine biodiversity hotspot.

Distribution of Polychaeta Communities in the West Spitsbergen Area in Winter (December 2015).

Using the materials collected in 2015, modern data have been obtained on the polychaete species composition and quantitative distribution in the West Spitsbergen area in winter. Polychaete species complexes corresponding to different habitat conditions have been identified in the outer and inner parts of the bays. The distribution of the Polychaeta communities proved to be dependent on the bottom sediment composition, depth, and specific hydrological regime.

Brackish-water polychaetes, good descriptors of environmental changes in space and time

1 - The aim of this study is to review the knowledge on the distribution of soft bottoms polychaete assemblage in Mediterranean brackish-waters. 2 - The Polychaete distribution of several biotopes located along the Tyrrhenian and Adriatic coast, which has been the object of authors’ past studies, is reported and discussed. 3 -Polychaete species composition was used to identify patterns of distribution inside the same biotope and among different biotopes, as well as changes in time in the same biotope. 4 - Polychaetes was revealed good descriptors of biotope characteristics, reflecting a pattern similar to that arising from the examination of the entire benthic community. 5 - We propose the use of polychaete assemblage fearures in assessing the ecological quality status of brackish-water bodies. For this purpose a general model of species distribution is given.

Changes in the soft-bottom macrobenthic diversity and community structure from the ports of Mumbai, India

Soft-bottom macrobenthic diversity and community structure were assessed at Mumbai and Jawaharlal Nehru ports during three different periods between 2001 and 2002 (November 2001 post-monsoon 1, April/May 2002 pre-monsoon, and October 2002 post-monsoon 2). A total of 43 macrobenthic invertebrate species belonging to five phyla were recorded. Macrofaunal abundance (PM1 186, PreM 106, and PM2 31 ind m(-2)) and species diversity index (PM1 0.87, PreM 0.73, and PM2 0.30) were very low in all the seasons. Polychaetes were the most dominant macrobenthic group (72.09%) followed by decapoda, amphipoda, and bivalves (4.56%). Canonical correspondence analysis showed that sediment texture, temperature, and suspended particulate matter were the most important environmental variables influencing polychaete species composition. Significant seasonal variations were observed, influenced by dissimilar monsoonal patterns. Macrobenthic population density during November 2001 was higher than that of October 2002 post-monsoon season. Pre-monsoon season recorded more carnivorous polychaete species than post-monsoon seasons. The present study showed lower values of polychaete diversity index in all the seasons compared to earlier studies. Out of 31 polychaete species, 19 have been reported for the first time from this area. Polychaete species and Glycera longipinnis, Paraprionospio pinnata, and Cossura coasta recorded from 1985 to 1986 were also observed in the present study. Species like Sigambra constricta, Perinereis cavifrons, Prionospio polybranchiata, and Parheteromastus tenuis were not recorded in the present study, although they were observed during earlier studies in this area.

Modern distribution of polychaetes along the Kola section (Barents Sea)

282 Among sea bottom invertebrates dwelling in the Barents Sea, polychaetes (Polychaeta) are the most widespread in terms of both biolodiversity and quantitative characteristics [1, 2]. They are present in all biocenoses, being the dominant or background species in many of them and accounting from 50 to 80% of the total benthos biomass. Previously, it was shown that the biodiversity and structure of polychaete settlements reflected the tendency in the development of bottom communities [3]. Therefore, the changes in the settlements of this taxonomic group may serve for assessment of the general state of benthos. The purpose of this study was investigation of changes in the species composition and quantitative characteristics of polychaetes in the latitudinal direction. As the model area, we used the standard sixth section referred to as the Kola meridian. The Kola section is situated in the central part of the Barents Sea at a longitude of 33°30 ′ E. It crosses the waters of the Murmansk Coastal Current ( 69°30 ′ – 70°30 ′ N, stations 1–3), Murmansk Current 70°30 ′ – 72°30 ′ N, stations 3–7), and the central branch of the North Cape Current ( 73°00 ′ –74°00 ′ N, stations 8–12) [4]. Standard stations have a depth of more than 200 m in the section, except stations 2 and 12, with depths of 140–150 m (Fig. 1). The study was based on the materials of zoobenthos quantitative collection obtained by the expedition of Murmansk Marine Biological Institute on the research ship Dal’nie Zelentsy in 2000. The samples were taken using a van Veen grab with a grab area of 0.1 m 2 . The bottom sediment samples were washed using a kapron sieve with a mesh diameter of 0.5 mm and postfixed with neutral 4% formalin. Invertebrates were then placed into 70 % ethanol. The cameral treatment and data analysis was performed using standard methods. E.A. Frolova assisted me in identifying Polychaetes. Subdivision of the studied area according to similarity of the polychaete species composition was perModern Distribution of Polychaetes along the Kola Section (Barents Sea)

Meiobenthic polychaetes in the northwestern Black Sea

Abstract Polychaetes of the northwestern Black Sea (NWBS) were sampled in January 2005 at 4 sites comprising 32 stations. The 4 sites have different anthropogenic loads, different depths (<10 m, 11-20 m, 21-30 m, >30 m) and different substrates (shelly, silty). The species composition of polychaetes in Black Sea meiobenthic communities has not previously been studied. Twenty polychaete species belonging to 11 families, the Phyllodocidae, Nephtyidae, Polynoidae, Sigalionidae, Nereidae, Syllidae, Hesionidae, Protodrilidae, Spionidae, Capitellidae and Ampharetidae, were recorded. The polychaete density varied with depth and type of substrate from 500 ind. m-2 to 66,000 ind. m-2.

Polychaete assemblages and sediment pollution in a harbour with two opposing entrances

The harbour at Ceuta is one of the most important harbours in the Strait of Gibraltar. The sediments are moderately polluted with organic matter and heavy metals but the harbour has two opposing entrances and a connecting channel which increases water renewal and dissolved oxygen across the harbour. For these special conditions, the value of the soft bottom polychaete community as a bioindicator, and possible advantages of the presence of two harbour entrances on biotic assemblages, were studied. Twenty-one stations were selected, and 27 variables were measured in the sediment of each station. The polychaete species richness and Shannon diversity values were similar inside and outside the harbour. Nevertheless, the Pielou evenness index was significantly higher in the external stations due to high densities of some species of polychaetes such as Pseudomalacoceros tridentata and Capitella capitata inside the harbour. The multivariate approach based on polychaete species composition was much more sensitive than univariate analyses at discriminating between internal and external stations. The pollution gradient and granulometric parameters were the main factors affecting polychaete distribution. Polychaete species richness and diversity in sediments inside Ceuta harbour were higher than in conventional harbours due to the positive effects of increased water renewal. These results should be taken into consideration in design, construction and remodelling of future harbours.

Influence of Spartina alterniflora and tide level on the structure of polychaete associations in an euryhallne salt marsh in cananéia lagoon estuarine region (SE Brazil)

Polychaete species composition, abundance and seasonal variation were analyzed in relation to Spartina alterniflora cover and tide level at Ponta do Arrozal, Cananéia, during 1989/1990. Two intertidal stations were located on the S. alterniflora bellt, one ca mean high water of neap tides (MHWN) and the other ca mean high water of spring tides (MHWS). Two other stations were established at corresponding tide levels at an adjacent site devoid of vegetation. A total of 17 species were collected. Each station was sampled twice seasonally with a 20 cm of diameter corer. Capitella capitata, Isolda pulchella, Nereis oligohalina and Lumbrineris sp were the most abundant species. Statistically significant differences bettween the vegetated and bare sites considered were observed for the number of species, density, diversity and evenness, with their values being higher at the vegetated site. Multivariate analysis showed spatial variations of the fauna according to vegetation cover and tide level. In relation to vegetation cover, polychaetes assemblages were distinguishable mainly by individual species densities of the more common species, since the most abundant species were present at the vegetated and bare sites. In relation to tide level, the faunal densities and number of species at the MHWN station were significantly higher than those at the MHWS station mainly at the bare site.