Sandy Substrate Research Articles

Seasonal variability of living benthic foraminifera from the West-Gironde mud patch (Bay of Biscay, NE Atlantic): Three contrasted periods under the stereomicroscope

Living continental shelf foraminifera were studied at three stations along a shore to open ocean transect between 39 and 69 m depth in the West-Gironde Mud Patch (WGMP) (Bay of Biscay, NE Atlantic). The aim of this work was to understand how the complex temporal variability of the environmental conditions (e.g., hydrosedimentary processes, sedimentary organic matter, oxygenation levels) controls foraminiferal ecological patterns (i.e., diversity, faunal composition, standing stock, and microhabitats). The WGMP was sampled during three different seasons (boreal summer – August 2017; winter – February 2018 and spring – April 2018), with very different meteorological patterns and benthic environmental conditions. The sedimentary facies at the shallowest station (Station 1, 39 m) varies significantly due to hydrometeorological constraints (strong storms and swells), which are extremely marked in late autumn and during the winter. The erosion of the sandy substrate by strong bottom currents and the deposition of a silty surface layer leads to the recorded spectacular drop in foraminiferal diversity and density recorded in February and April 2018. All foraminiferal species were affected by this hydrosedimentary instability, likely due to the partial destruction of their microhabitat by intense erosional and depositional processes. At the middle WGMP station (Station 2, 47 m), benthic fauna changed much more gradually. The sedimentary imprint of the spring phytoplankton bloom is clearly recorded in April 2018 with an increase in fresh and altered phytopigment content in surface sediments. Eggerelloides scaber, a deposit feeder and hypoxia-tolerant species, dominated the 2017 summer foraminiferal fauna but was gradually replaced by Ammonia falsobeccarii, a phytophagous taxon considered quite reactive to spring bloom inputs. At the distal WGMP (Station 4, 69 m), E. scaber and A. falsobeccarii were outcompeted and gradually replaced by Nonion faba and Nonionoides turgidus, both highly adaptable species able to settle down in surface and subsurface sediments during the spring bloom periods. Able to endure a range of microhabitats and food availability, there they rely on both fresh and altered phytodetritus. We propose a conceptual scheme summarizing the putative interconnexion between foraminiferal faunas, geochemistry and physics in the WGMP.

Macroinvertebrates reveal environmental gradients: methods and method development in the Ob River basin

AbstractThe Ob is the seventh longest river in the world and its length (including the largest tributary Irtysh) is 5410 km. The huge size of the Ob River catchment and diverse natural resources of the region give rise to numerous anthropogenic factors affecting aquatic ecosystems. The patterns of longitudinal changes in the composition aquatic communities are still uncertain, especially for large rivers. To assess the role of environmental factors in the structure of communities, we analyzed longitudinal changes in the species richness, abundance, and biomass of macroinvertebrate communities along a 3363-km section of the Ob River. The trends of longitudinal changes in macroinvertebrate communities differed significantly on sandy, silty, and rocky substrates. For sandy substrates, an important factor in the separation of communities was the Novosibirsk Reservoir, for rocky substrates—the influence of the Altai Mountains, and for silty substrates—the location of large cities. The results emphasize the importance of taking into account the differences in bottom sediments and the patterns of longitudinal changes in bottom communities for bio-assessment of the ecological status of large rivers. Overall, we propose macroinvertebrates for bioindication along the Ob River, with regard to type, anthropogenic impact, stress factors, and response of benthic communities.

Relationship between Submerged Marine Debris and Macrobenthic Fauna in Jeju Island, South Korea

Pollution associated with marine debris is of global ecological concern, as it threatens wildlife and local economies. Submerged marine debris alters local benthic species composition and community characteristics. The study site of Jaguri, Jeju Island, where a variety of submerged marine debris was found, was used to investigate the impact of submerged marine debris on the macrobenthic fauna of sandy and rocky substrates. The dominant macrobenthos taxon differed by sediment type; the polychaete Armandia lanceolata was dominant in sandy bottom environments and the mollusk Leiosolenus lischkei was dominant in rocky bottom environments. The presence of marine debris was associated with differences in biomass in both the soft and rocky areas. The site without debris had higher biomass in the soft area, and the site with nets had a higher density of benthic animals within the site with debris. In the rocky area. the site with debris had a higher biomass. Macrobenthos were affected by the type of deposited marine debris and the type of sediment substrate. This study provides a basis for future studies on the impact of debris on marine ecosystems and identified the benthos species affected by marine debris.

Diversity and Dominance of Sea Urchins (Echinoidea) on Sambalagi Beach, Siompu Island, South Buton Regency

Many species of sea urchins (Echinoidea) can be found in the waters of Sembalagi Beach, Siompu Island. However, the diversity of sea urchins (Echinoidea) on the coast has not been scientifically researched and published. This study aims to determine the types, hunting, poaching and dominance of sea urchins (Echinoidea) at Sambalagi Beach, Siompu Island, South Buton Regency. This study uses a quantitative descriptive method with observation techniques. There are three research stations, namely station I (rocky and seagrass substrate), station II (sandy and seagrass substrate), and station III (rocky and seagrass substrate). The data obtained were analyzed using the formulation of documents, documents, secrecy and Shannon-Winner domination. The results showed that there were 5 species of sea urchins (Echinoidea) which namely Diadema setosum, Echinothrix calamaris, Tripneustes gratilla, Echinometra mathaei and Salmacis sphaeroides. The species diversity index (H') for the three abnormalities was classified as moderate, namely station I (H' 1,34), station II (H' 1,18) and station III (H' 1,22). The highest relative abundance of Echinoidea was found in Tripneustes gratilla species at Station II (37,67%) which had a lot and the lowest relative decline index was found in Echinothrix calamaris and Echinometra mathaei at Station III (1,52%) less abundant. The highest evenness index is at station II (0,85) which is very even and the lowest is at station III (0,76) which is more evenly distributed. And the highest dominance index is at station II (0,32) with moderate dominance and the lowest dominance index is at station I (0,29) with low dominance.

Characteristics of Xanthidae Crab in the Intertidal Zone at Gili Meno Beach, West Nusa Tenggara

Gili Meno is one of the leading small (gili) tourist islands in North Lombok Regency, West Nusa Tenggara Province. Massive tourism activities have an impact on marine biota, including crabs. This research is to determine the characteristics of the crab family of Xanthidae in the intertidal zone of Gili Meno Beach, North Lombok Regency, West Nusa Tenggara Province. The research was conducted using an exploratory method by measuring the abiotic factors of the aquatic environment which is the habitat of crabs. Based on the research, two species of crab from the family of Xanthidae were obtained: Actaeodes tomentosus and Atergatis floridus. A. tomentosus has a relatively rough carapace while A. floridus has a relatively smooth carapace. Both like habitats with sandy substrates with reefs and coral rubble as protection from predators and waves. Abiotic factors: temperature and pH in the intertidal waters of Gili Meno Beach which are suitable for the growth, development and distribution of the two crab species.

Habitat development and species arrival drive succession of the benthic invertebrate community in restored urban streams

BackgroundUrban streams are characterised by species-poor and frequently disturbed communities. The recovery of heavily polluted urban streams is challenging but the simple community structure makes recolonisation patterns more transparent. Therefore, they are generally applicable model systems for recolonisation of restored streams. Principal questions of stream restoration concern the drivers and patterns of recolonisation processes. Rarely, recolonisation of restored streams is recorded for a sufficient time to observe patterns of habitat and community development in detail. Over 10 years, we monitored benthic habitat changes and macroinvertebrate communities of eight restored sites in an urban stream network that was formerly used as an open sewer and thus, almost uninhabitable for macroinvertebrates prior to restoration. We analysed changes in environmental variables and communities with a selection of multi-variate analyses and identified indicator species in successional stages.ResultsProportions of stony substrate and conductivity decreased over time since restoration, while the riparian vegetation cover increased along with the amount of sandy substrate. The communities fluctuated strongly after restoration but began to stabilise after around eight years. TITAN analysis identified 9 species, (e.g. the mayfly Cloeon dipterum and the beetle Agabus didymus), whose abundances decreased with time since restoration, and 19 species with an increasing abundance trend (e.g. several Trichopteran species, which colonised once specific habitats developed). Woody riparian vegetation cover and related variables were identified as major driver for changes in species abundance. In the last phase of the observation period, a dry episode resulted in complete dewatering of some sites. These temporarily dried sections were recolonised much more rapidly compared to the recolonisation following restoration.ConclusionsOur results underline that community changes following urban stream restoration are closely linked to the evolving environmental conditions of restored streams, in particular habitat availability initialised by riparian vegetation. It takes about a decade for the development of a rich and stable community. Even in streams that were almost completely lacking benthic invertebrates before restoration, the establishment of a diverse macroinvertebrate community is possible, underlining the potential for habitat restoration in formerly heavily polluted urban areas.

DISTRIBUTION OF AN INVASIVE SPECIES OF HERACULUM SOSNOWSKYI MANDEN. (APIACEAE) IN THE LENINGRAD REGION

In the Leningrad Region, Heracleum sosnowskyi hogweed prefers well-developed fertile light and medium loamy sod-podzolic and sod-carbonate soils; it is practically absent in swamps and wetlands, in territories occupied by spruce forests, as well as pine forests with infertile low-power soils on sandy and rocky substrates. The most favorable hydrothermal, orographic, hydrological, soil, and ecological conditions for the development and spread of Sosnovsky hogweed are observed in the western, agriculturally developed areas (Slantsevsky, Kingisepp, Lomonosov, Volosovsky, Gatchina) with dismembered hilly relief, cultivated fields, occupying 7-13% of their territory, fallow lands. To the south, east and north of the area the conditions for development and spreading of hogweed become markedly worse that is stipulated mainly to the south and east by flat-low character of relief, its waterlogging, the spread of spruce and pine forests that are little and unfavorable for hogweed, low-power and poor soils on rocky substrates, especially to the north on the Karelian Isthmus and in the Podporozhsky district in the northeast.

Does littoral substrate affect macroinvertebrate assemblages in Mediterranean lakes?

The objective of this study was to investigate the effects of substrate type in macroinvertebrate assemblages in Mediterranean lakes. Samplings have taken place in the littoral zone of 21 lakes in Greece, between 2015 and 2018. We compared benthic macroinvertebrate assemblages among three substrate types of their littoral zones; sandy, covered with macrophytes and stony substrate. Benthic macroinvertebrate assemblages at sites with extended macrophyte cover differed only slightly in composition and abundance from the ones found in stony and sandy substrates. Coenagrionidae were indicative of sites covered with macrophytes and Oligochaeta and Erpobdellidae were representative of stony substrates. The type of substrate proved to be a statistically significant factor influencing the number of benthic macroinvertebrate taxa, the relative abundance of Oligochaeta and the relative abundance of Odonata. In the context of designing site-adapted management measures, priority could be given to the conservation and restoration of aquatic vegetation in lake littoral zones, which host rich macroinvertebrate assemblages with abundant taxa of Odonata.

Morphology of the gastric mill teeth in dotillid crabs (Crustacea: Brachyura: Dotillidae) from Indonesia.

The gastric mill is a prominent structure in the digestive system of brachyuran crabs, consisting of a median tooth plate and a pair of lateral tooth plates. Among crab species that are deposit feeders, the morphology and size of the gastric mill teeth are correlated with the preferred substrate types and food spectrum. In this study, we provide a detailed description of the morphology of the median and lateral teeth of the gastric mills in eight species of dotillid crabs from Indonesia, and compare them in relation to habitat preferences and molecular phylogeny. Ilyoplax delsmani, Ilyoplaxorientalis, and Ilyoplaxstrigicarpus have comparatively simple shapes of their median and lateral teeth, with fewer teeth on each lateral tooth plate compared to Dotilla myctiroides, Dotillawichmanni, Scopimera gordonae, Scopimeraintermedia, and Tmethypocoelis aff. ceratophora, which have more complexly shaped median and lateral teeth, with a greater number of teeth on each lateral tooth plate. The number of teeth on lateral tooth correlates with habitat preference, that is, dotillid crabs inhabiting muddy substrata have fewer teeth on the lateral tooth plate, and those inhabiting sandy substrata have a more teeth. Phylogenetic analysis using partial COI and 16S rRNA genes supports that teeth morphology is similar among closely related species. Therefore, the description of median and lateral teeth of the gastric mill is expected to contribute to the systematic study of dotillid crabs.

Analysis of distribution and characteristics of mangrove forest in Serasan District, Natuna Regency

Mangrove forest habitat has its characteristics, generally growing in intertidal areas with muddy, loamy, or sandy substrates. This study aims to determine the characteristic and distribution the mangrove forests at the coastal of Serasan District, Natuna Regency. This study uses a mix method with a spatial approach. The distribution of mangrove forest was analyzed by LANDSAT ETM-7 while the characteristics of mangrove forests were observed through image interpretation and field observations. Based on the data analize can conclude that (1) Distribution of mangrove forests in the sub-district of Saran, especially in the bay area in the southern part of Serasan Island, with a thickness that varies greatly from 30 m to more than 1000 m. (2) The mangrove vegetation in Serasan District is dominated by Rhizophora stylosa and Bruguiera gymnorrhyza with different densities. The people of Serasan District have not used and managed mangrove forests in their area.

Effects of the ridge‐and‐runnel system on macrofaunal spatial distribution on a macrotidal sandy beach in the Brazilian Amazon coast

AbstractRidge‐and‐runnel systems are common morphological features across the intertidal zone of dissipative macrotidal beaches. However, these systems have often been overlooked by macrofaunal zonation studies. The present study investigated the effects of this system on the spatial distribution of the macrofaunal community on an Amazonian macrotidal sandy beach. Samples (macrobenthos and sediments) were collected at seven equidistant levels (50 m apart) from the high tide water mark to the swash zone, in two different areas: (1) with and (2) without ridge‐and‐runnel systems. The results showed a significant increase in macrofaunal abundance and richness in area with runnels, associated with muddier sediment and higher organic content. The macrofauna in the runnels, both in upper‐intertidal and lower‐intertidal zones, had higher density and richness than that in the sandbars. There was no difference between tidal levels in area 2, although we observed an increasing tendency of abundance and richness towards the low tide line. Taxonomic composition and trophic groups also differed between areas, with predominance of species that are typical of sandy‐mud substrate and higher participation of nonselective deposit feeders in area 1. Predatory species typical of sandy substrates prevailed in area 2. These findings add knowledge to sandy beach ecology and indicate the importance of including aspects of habitat complexity in both across‐ and alongshore macrofaunal distribution studies.

Measuring Water Parameters Around Pamayangsari Port in Tasikmalaya

Pamayangsari Beach provides facilities and infrastructure supporting fishermen's activities in Pamayangsari, such as docks, TPI, boats and fishing gear. Pamayangsari Port or pier is a fishing port that is quite actively operating. Fish loading and unloading activities at ports can also produce waste, both liquid waste and solid waste. This research activity was carried out to assess how much impact might arise on the biophysical environment around Pamayangsari Port, especially for its water quality parameters. The method used in this activity is a survey method with direct collection of field data where the water quality parameters measured include temperature, salinity, pH, DO, Brightness and Substrate. Based on the results of measuring water parameters, namely temperature, salinity, DO, pH, Brightness and Substrate, the waters around the port of Pamayangsari are still in the category of water quality standards of the Ministry of Environment and Forestry where the value of pamayangsari waters ranges from 31-34 ppt, temperature values are in the range of values of 28.5 – 29.1 °C, pH values are in the range of 9.72 to 9.97, DO values are 7.9-9.2 ml / g. for the brightness level of the waters around the port of pamayangsari is in the range of values 0.2 – 1.3 meters and the substrate type is dominated by sandy substrate.

A chromosome-scale reference of Chenopodium watsonii helps elucidate relationships within the North American A-genome Chenopodium species and with quinoa.

Quinoa (Chenopodium quinoa), an Andean pseudocereal, attained global popularity beginning in the early 2000s due to its protein quality, glycemic index, and high fiber, vitamin, and mineral contents. Pitseed goosefoot (Chenopodium berlandieri), quinoa's North American free-living sister species, grows on disturbed and sandy substrates across the North America, including saline coastal sands, southwestern deserts, subtropical highlands, the Great Plains, and boreal forests. Together with South American avian goosefoot (Chenopodium hircinum) they comprise the American tetraploid goosefoot complex (ATGC). Superimposed on pitseed goosefoot's North American range are approximately 35 AA diploids, most of which are adapted to a diversity of niche environments. We chose to assemble a reference genome for Sonoran A-genome Chenopodium watsonii due to fruit morphological and high (>99.3%) preliminary sequence-match similarities with quinoa, along with its well-established taxonomic status. The genome was assembled into 1377 scaffolds spanning 547.76 Mb (N50=55.14 Mb, L50=5), with 94% comprised in nine chromosome-scale scaffolds and 93.9% Benchmarking Universal Single-Copy Orthologs genes identified as single copy and 3.4% as duplicated. A high degree of synteny, with minor and mostly telomeric rearrangements, was found when comparing this taxon with the previously reported genome of South AmericanC. pallidicaule and the A-subgenome chromosomes ofC. quinoa. Phylogenetic analysis was performed using 10,588 single-nucleotide polymorphisms generated by resequencing a panel of 41 New World AA diploid accessions and the Eurasian H-genome diploid Chenopodium vulvaria, along with three AABB tetraploids previously sequenced. Phylogenetic analysis of these 32 taxa positioned the psammophyte Chenopodium subglabrum on the branch containing A-genome sequences from the ATGC. We also present evidence for long-range dispersal of Chenopodium diploids between North and South America.

Diversity and ecology of molluscs (Gastropods) in mountain streams, Nurota mountain range, Uzbekistan

Abstract. Kudratov J, Pazilov A, Maxammadiyev Z, Urazova R, Otakulov B, Bazarov B, Keldiyarov K, Soatova Z, Urinova X. 2023. Diversity and ecology of molluscs (Gastropods) in mountain streams, Nurota mountain range, Uzbekistan. Biodiversitas 24: 2402-2408. Characterization of the faunal biodiversity of the regions is one of the important tasks in today's era when the influence of the anthropogenic factor has increased, and the natural ecosystems are undergoing drastic changes. Therefore, the faunal composition analysis of molluscs as a part of the natural food chain, the development of measures related to their protection, the disclosure of bioecological features, and the substantiation of scientific solutions are of great scientific and practical importance. This study provides information on the species composition of gastropod molluscs in the streams of the Nurota Mountains of Uzbekistan. Sampling was carried out at 11 stations from April to November 2019. Molluscs include 4 families (Belgrandiellidae, Lymnaeidae, Physidae and Planorbidae), 5 genera, and 15 species. The dominant family in the malacofauna of the study area is Lymnaeidae, one genus and eight species belonging to this family are found in the area. Most molluscs are found on rocky, sandy substrates around plants. This article describes the biological diversity of animals in streams in the Nurota Mountains of Uzbekistan.

Holocene vegetation dynamics of Horqin Sandy Land in northern China inferred from the phytolith record of a sand-paleosol section

Ecosystems in arid regions with sandy substrates are vulnerable to various environmental challenges. Understanding the vegetation evolution of such regions over a long timescale and the possible drivers of change is important for optimizing ecological restoration. In this paper, we present multi-proxy data to understand Holocene vegetation dynamics and their drivers in the Horqin Sandy Land in northern China. Phytoliths are used to reconstruct vegetation; grain size and magnetic susceptibility are used to reconstruct the climate; and sedimentary charcoal contents and the numbers of regional archaeological sites are used to reconstruct the fire activity and human activity intensity, respectively. Results indicate that the Horqin Sandy Land was covered mainly by grassland vegetation during the Holocene, and that the trajectory of vegetation evolution was as follows: sparse and species-poor Leymus chinensis grassland from 9300 to 6150 cal yr BP, relatively sparse and species-rich mesophytic herb grassland from 6150 to 2300 cal yr BP, and dense and species-rich L. chinensis grassland from 2300 to 250 cal yr BP. Climate change was the main driver of vegetation evolution, but fire and human activities also influenced the vegetation to varying degrees. Fire made the greatest contribution to the vegetation change during the 6150–2300 cal yr BP interval, and human activities contributed throughout the 8200–2300 cal yr BP interval. The evolution of plant species richness and the number of C3 plants show a significant ∼1000-yr periodicity during 9300–4500 cal yr BP, which we speculate was caused by the effect of solar activity on East Asian monsoon intensity, which likely controlled the vegetation change on a millennial timescale.

Studi Komparasi Kuantitas Bivalvia pada Zona Intertidal di Pantai Ntana Kabupaten Bima sebagai Upaya Penyusunan Brosur Konservasi

Bivalves belong to the Phylum mollusca. Bivalve are found and live in the Intertidal area. Ntana Beach is the easiest area and has the most interaction with human activities, because this area is a transitional area between aquatic ecosystems and land ecosystems. This study aims to: 1) identify the types of bivalves that make up the Intertidal zone on the Ntana coast, Bima Regency; 2) analyzing the abundance, diversity index, and evenness of Bivalvia in the Intertidal zone on the Ntana coast, Bima Regency; 3) describe the population of bivalve species that dominate the Intertidal zone on the Ntana coast, Bima Regency; 4) analyzing the abundance of bivalves in the sandy, muddy and rocky substrate areas on the Ntana beach, Bima Regency; 5) analyzing the diversity of bivalve species in the area of ​​sandy substrate, muddy substrate, and coral substrate on the Ntana beach, Bima Regency; 6) knowing the differences in the dominance of Bivalvia in the sandy, muddy and rocky substrate areas on the Ntana beach, Bima Regency; and 7) to develop research results on a comparative study of the quantity of bivalves in the intertidal zone on the Ntana coast, Bima district as an effort to prepare a conservation brochure. This type of research is descriptive comparative. Sampling used a 1x1 M plot. The results showed that as many as 540 individual bivalves consisting of 15 species were found on the Ntana beach, Bima district. 15 species of bivalves found include Anadara antiquata, Anadara granosa, Anadara brasilliana, Panopea generosa, Fausta pultenei, Dosina crebra, Eurytellina alternate, Dosina discus, Nactula acuta, Gafrarium divaricatum, Dosinia exoleta, Caestoderma edule, Gafrarium disparm, Cyclocardia ventricosa, and Crassostrea gigas. The abundance on sandy and silty substrates is categorized as moderate, whereas on coral substrates it is categorized as low. Species diversity on rocky substrates is less, whereas on muddy and sandy substrates each has a fairly high level of species diversity. The evenness value on sandy and muddy substrates is close to zero (0), so that the evenness of Bivalvia species on both substrates is not evenly distributed. There are no species that dominate other species because D <0.5. The average value of the brochure validation test is 75.4%, with this result, the brochures that have been compiled are in the good category and do not need to be revised.

A new species of Nama (Namaceae) from the Vizcaino Desert, Mexico

Background: Although most of the Nama taxa grow on sandy substrates, none of them is restricted to the coastal dune environment. A small population of a unique looking taxon was found on the Pacific coast of the Baja California peninsula, which is here presented as a new species.
 Question and/or Hypothesis: In the morphological analysis in the individuals of a putative new taxon, some peculiarities stand out, such as a suffruticose herbaceous perennial growth form with erect and compact branching, featuring a small cushion, unlike the rest of the known species, which are rather procumbent, or erect in form. It also has revolute leaf margins in the blade.
 Studied Species: Nama asuncionensis sp. nov. (Namaceae) and morphologically similar species. 
 Study Site: Central Pacific coast of Baja California, Mexico.
 Method: Through bibliographic consultation, review of herbarium specimens, and photographs, a comparative morphological analysis was carried out with other Nama species of the peninsula and mainland Mexico.
 Results: Based on the comparative analyses, Nama asuncionensis is here presented and illustrated as a new species.
 Conclusions: Nama asuncionensis is a micro-endemic species restricted to the Pacific coastal environment of the peninsula. We propose that this new taxon be included in the Eunama section of the genus based on its morphological characteristics, including a membranous loculicidal dehiscent capsule, free styles, and sepals divided to the base. This taxon seems to be limited to a narrow coastal strip, with high relative humidity, where it develops its fresh leaves and flowers during the mild season.

Microplastics in jellifying algae in the Bay of Biscay. Implications for consumers' health

Microplastics pollution is widespread throughout the world, affecting all marine ecosystems and their organisms. The red alga Gelidium sp. is the source of best quality agar and is directly consumed as seafood in many countries. Here we quantified microplastics in Gelidium corneum harvested along the Asturias coast (southwest Bay of Biscay) from locations differently affected by factors that influence microplastics concentration like substrate size, ports, rivers, etc. Results showed that G. corneum collected near sandy substrates accumulates more microplastics than those from rocks, suggesting that the substrate's dynamics is key to allow microplastics to reach these algae and enter the human diet. Considering their composition, polyethyleneimine and polyester were identified and classified as harmful according to the European Chemicals Agency. The polyethyleneimine is present in the 28,6 % analysed from the algae and may pose a risk to consumers. The amount of microplastics potentially ingested by consumers would be lower than mussels and eels of the same region; but could potentially increase in agar if microplastics are not retained during processing. More research to identify microplastics sources and measures to prevent them in coastal areas are recommended.

TAPHONOMIC SIGNATURES IN DEAD SHELLS OF THE INVASIVE GASTROPOD RAPANA VENOSA (VALENCIENNES, 1846) AFTER TWO DECADES IN THE RÍO DE LA PLATA, URUGUAY

ABSTRACT Rapana venosa (Valenciennes, 1846) is an invasive gastropod, the arrival of which in the Río de La Plata estuary 22 years ago is well-documented. Rapana venosa shells were collected during two sampling events from four beaches with different substrate types and wave energy regimes to compare the taphonomic attributes under different environmental conditions. We analyzed the samples by comparing frequencies of taphonomic attributes. Our results show that intermediate-reflective beaches with rocky substrates were dominated by intermediate- to highly fragmented specimens, with high corrasion, intermediate to high bioerosion, low bioencrustation, and medium to large sizes. In contrast, intermediate-dissipative beaches with sandy substrate, mobile stones, and occasional consolidated sediments were dominated by less fragmented shells, high to intermediate corrasion, scarcer bioerosion, low bioencrustation, and small- to medium-sized specimens. Results suggest that significant taphonomic differences arise within two decades under natural conditions. These findings imply that paleoenvironmental signals derived from the taphonomic attributes of fossil assemblages emerge much faster than the potential duration of time averaging of shelly fossils in shallow marine settings.

Checklist of mangrove snails (Gastropoda: Mollusca) on the coast of Lamongan District, East Java, Indonesia

Abstract. Isroni W, Sari PDW, Sari LA, Daniel K, South J, Islamy RA, Wirabuana PYAP, Hasan V. 2023. Checklist of mangrove snails (Gastropoda: Mollusca) on the coast of Lamongan District, East Java, Indonesia. Biodiversitas 24: 1676-1685. Mangroves are crucial transition zone ecosystems providing sheltered nursery zones and abundant marine and terrestrial biota resources. Mangrove snails (Gastropoda: Mollusca) are ecologically important ecosystem engineers, trophic links for higher predators, and a source of human food and livelihoods. Mangrove snails are also ideal bioindicators to monitor environmental pollution. A strong baseline understanding of current richness and distribution is therefore important. Thus, this study provides data on the species composition of mangrove snails on the north coast of Lamongan District, East Java, Indonesia. Sampling was conducted during low tide at four stations from September to November 2022 using square transects. Ten families consisted of Cerithiidae, Cypraeidae, Fasciolariidae, Muricidae, Naticadae, Neritidae, Plaxidae, Potamididae, Trochidae, and Turbinidae comprising 20 genera and 24 species. The most dominant family found is Muricidae, with six genera and eight species. Most mangrove snails were found in rocky, sandy substrates, around trees, and mangrove roots. Gastropods observed in this study were alive and dead (i.e., empty shells). We suspect that there is still much-hidden diversity of Gastropoda in this region. Therefore, we suggest that future work addresses differences in microhabitat and snail morphology with quantitative and semi-quantitative methods to understand distribution drivers and ecological roles better.