Benthic Biota Research Articles

Low pharmaceutical pollution of epibenthic organisms from Admiralty Bay, Antarctica (King George Island, South Shetland Islands)

The presence of medicinal products has been reported in the Antarctic marine environment but still little is known about the bioaccumulation of these compounds. This study was set up to detect and quantify pharmaceutical residues in benthic biota from Admiralty Bay, King George Island (South Shetland Islands, Antarctica). Pharmaceuticals and stimulants were analysed using LC-MS/MS in dominant epibenthic macroorganisms that were collected at eight nearshore sublittoral sites (water depth 3–30 m) by a SCUBA diving team during austral summer (February 2023). Out of 22 analytes, only the stimulant caffeine (CAF) and the antiepileptic carbamazepine (CBZ) have been identified in the macrobenthic algae and invertebrates indicating a relatively low contamination level of the bay. The analytes were detected predominantly in the northern part of the bay (Mackellar Inlet and Martel Inlet) which reflects likely their elevated environmental concentrations in this area and suggests that local research stations represent the main source of pharmaceutical contamination. Irrespective of the sampling site, both compounds were found almost exclusively in brown and red macroalgae highlighting their potential for uptake and accumulation of CAF and CBZ. This study provided the first evidence of the presence of medicinal substances in the Antarctic macrobenthic organisms and can serve as a baseline for environmental risk assessment.

Ecological control of the Pelsonian colonisation event (Anisian, Triassic) leading to the first settlement of Tetractinella-beds (Brachiopoda) in the Iberian palaeomargins. Palaeobiogeographical and biostratigraphical significance

Marine benthic biota recovery after the Permian/Triassic extinction is still a challenging topic in several fossil clades such as brachiopods. In fact, available data from the Early-Middle Triassic are scarce worldwide and their global record derives from limited localities throughout the Tethys Ocean. This work presents the first record of the Anisian Tetractinella-beds (Brachiopoda, Athyridida) in the peri-Iberian epicontinental platforms established in the westernmost Tethys margins. Their utility as a reliable biohorizon marker is emphasised as they provide an effective tool for age calibration and correlation in the middle Anisian (Pelsonian) successions, also supported by the co-occurring fossil assemblage. In the South-Iberian Palaeomargin, Tetractinella-beds occur in an intensively-burrowed shallow-marine succession. The rich ichnological content has been exhaustively evaluated in order to assess the ecological factors controlling the development of the brachiopod fauna. Three ichnoassemblages are documented dominated by Oravaichnium, Balanoglossites and Thalassinoides, respectively. The gathered faunal, ichnological, taphonomical, and sedimentological data reveal an alternation of sea-level changes influencing the composition of the Anisian marine communities. The first stage consists of near-shore restricted environments sporadically disturbed by short-term shallow-marine interludes, characterised by the presence of Oravaichnium and its associated fauna. Subsequently, the Pelsonian transgression event is recorded (MID-2), documented by a firm-ground surface pointed out by the development of a Balanoglossites surface, followed by the highstand, when shallow epicontinental environments developed in connection with open-marine areas. This phase involved the spreading of Tetractinella and deep-water bivalves. Finally, near-shore restricted conditions were re-established typified by Oravaichnium and the last occurrences of Tetractinella, with the disappearance of the open sea-water fauna. The maximum flooding reached after the Pelsonian transgression facilitated new palaeobiogeographical migration routes, allowing for an Alpine-Germanic dispersion of taxa throughout the North-South epicontinental Tethyan seaway as well as the earliest first faunal migration event from the Sephardic Bioprovince northwards to the South-Iberian palaeomargin.

The temperate marine Peruvian Province: How history accounts for its unusual biota.

The Peruvian Province, from 6° S in Peru to 42° S in Chile, is a highly productive coastal marine region whose biology and fossil record have long been studied separately but never integrated. To understand how past events and conditions affected today's species composition and interactions, we examined the role of extinction, colonization, geologic changes to explain previously unrecognized peculiar features of the biota and to compare the Peruvian Province's history to that of other climatically similar temperate coasts. We synthesized all available data on the benthic (or benthically feeding) biota, with emphasis on fossilizable taxa, for the interval from the Miocene (23-5.4 Ma) and Pliocene (5.4-2.5 Ma) to the present. We outline the history of ecological guilds including primary producers, herbivores, predators, and suspension-feeders and document patterns of extinction, colonization, and geographic restriction. We identify twelve unusual attributes of the biota, most of which are the result of repeated episodes of extinction. Several guilds present during the Miocene and Pliocene are not represented in the province today, while groups such as kelps and perhaps intertidal predatory sea stars are relative newcomers. Guilds on soft bottoms and in sheltered habitats were severely affected by extinction, whereas those on hard bottoms were most affected by colonists and held their own in diversity. The Peruvian Province has not served as a biogeographic refuge, in contrast to the coasts of Australasia and Argentina, where lineages no longer present in the Peruvian Province survive. The loss of sheltered habitats since the Pliocene explains many of the present-day peculiarities of the biota. The history of the province's biota explains its unique attributes. High productivity, a rich Southern Hemisphere heritage, and colonization from the north account for the present-day composition and unusual characteristics of the biota.

Marine redox dynamics and biotic response to the mid-Silurian Ireviken Extinction Event in a mid-shelf setting

The early Silurian Llandovery–Wenlock boundary interval is marked by significant marine perturbations and biotic turnover, culminating in the Ireviken Extinction Event and the Early Sheinwoodian Carbon Isotope Excursion. Here, we apply multiple independent redox proxies to the early Wenlock Buttington section, which was deposited in a mid-shelf location in the Welsh Basin, UK. To account for the regional geochemical variability in marine sediments due to factors such as sediment provenance, we first define oxic baseline values for the Welsh Basin, utilizing deeper water, well-oxygenated intervals of late Llandovery age. Our approach documents unstable, oscillating redox conditions on the mid-shelf at Buttington. We suggest that these dynamic redox fluctuations are likely to relate to changes in the position of the chemocline or a migrating oxygen minimum zone. Benthic biota, such as trilobites, brachiopods, bivalves and gastropods, appear to have been relatively unaffected by fluctuating oxic-ferruginous conditions, but were more severely impacted by the development of euxinia, highlighting the inhibiting role of toxic sulfides. By contrast, the redox perturbations appear to have placed extreme stress on graptolites, causing many extinction losses regardless of the specific development of euxinia. Supplementary material: The geochemical data for the Buttington section is available at https://doi.org/10.6084/m9.figshare.c.7165009 Thematic collection: This article is part of the Chemical Evolution of the Mid-Paleozoic Earth System and Biotic Response collection available at: https://www.lyellcollection.org/topic/collections/chemical-evolution-of-the-mid-paleozoic-earth-system

Safe and sustainable fish and seafood system and per- and poly-fluorinated substances occurrence: the role of PFAS toxicity in the assessment.

Fish and seafood are valuable sources of both nutrients and organic contaminants. The expansion of the analytical per- and polyfluoroalkyl substances (PFAS) panel with toxicological characterisation necessitates an update of PFAS intake assessment and management within the context of cumulative exposure. Benthic and demersal seafood, such as clams, squid, and cuttlefish, are more prone to contamination with C9-C14 perfluorocarboxylic acids, exhibiting the highest relative potency factors in terms of immunotoxicity, according to the grid recently proposed by the European Commission Scientific Committee on Health, Environment, and Emerging Risk. Based on the Italian food consumption database referring to demersal and benthic biota such as squid, cuttlefish, crustaceans, and clams, a toxicology-based intake scenario was drafted to highlight the relevant contribution of such wild species to PFAS intake, well above the provisional health-based guidance value of 4.4ng/kg body weight per week. Ensuring consistency between PFAS reduction and substitution policies, environmental quality standards for water bodies, and the issuance of advisories and regulations regarding safe and sustainable intake of fish and seafood is crucial. This is done to prevent a loss of accountability for institutional bodies, which aim to protect fragile (sensitive and vulnerable) groups from PFAS exposure and simultaneously promote 'blue growth' as a sustainable food production system.

Hypoxia impairs cellular energy allocation in the juvenile horseshoe crab Tachypleus tridentatus

Although hypoxia is a serious environmental concern for marine ecosystems globally, its biological effects on the benthic biota remain mostly unclear for some endangered species. To provide an deep understanding of the possible effects of hypoxia on the tri-spine horseshoe crab Tachypleus tridentatus, the cellular energy allocation (CEA) approach was utilized to examine the cellular responses and adaption potential of horseshoe crabs. We examined the energetic responses of T. tridentatus under low dissolved oxygen level (2 mg O2/L). The horseshoe crabs first experienced 14 days of hypoxic stress, and then recovered in a normal dissolved oxygen environment for 7 days. On the 7th and 14th day of hypoxic exposure, the levels of available energy, electron transport system activity, protein, lipids, and carbohydrates were decreased in T. tridentatus (p < 0.05). All measured parameters in the hypoxic group partially or completely recovered after seven days of re‑oxygenation, reaching a level that was significantly up-regulated (p < 0.05) compared with the 14th day and non-significantly different from the 0th day exposure (p ˃ 0.05). In conclusion, hypoxic stress has adverse effects on the energy balance of juvenile T. tridentatus, but these adverse effects can be alleviated in a short recovery period. As a result, our findings provide novel perspectives on the physiology of T. tridentatus under hypoxia acclimation, which is essential information for establishing ideal conditions for the cultivation of this endangered species.

Fate and effects of microplastic particles in a periphyton-grazer system

In the aquatic environment, microplastic particles (MP) can accumulate in microbial communities that cover submerged substrata, i.e. in periphyton. Despite periphyton being the essential food source for grazers in the benthic zones, MP transfer from periphyton to benthic biota and its ecotoxicological consequences are unknown. Therefore, in this study, we investigated the effects of 1) MP on embryonal development of freshwater gastropod Physa acuta embryos, 2) MP on adult Physa acuta individuals through dietary exposure and 3) on the MP surface properties. Embryonal development tests were carried out with spherical polyethylene MP in the size of 1–4 μm (MP). Over a period of 28 days, embryonal development and hatching rate were calculated. In the feeding experiments, periphyton was grown in the presence and absence of MP and was then offered to the adult Physa acuta for 42–152 h. The snails readily ingested and subsequently egested MP, together with the periphyton as shown by MP quantification in periphyton, snail soft body tissue and feces. No selective feeding behavior upon MP exposure was detected. The ingestion of MP had no effect on mortality, feeding and defecation rate. Yet, the reproductive output of snails, measured as the number of egg clutches and numbers of eggs per clutch, decreased after the ingestion of MPs, while the hatching success of snail embryos those parents were exposed remained unaffected. In contrast, hatching rate of snail embryos was significantly reduced upon direct MP exposure. MP optical properties were changed upon the incorporation into the periphyton and the passage through the digestive tract. Our results indicate that MP incorporated in periphyton are bioavailable to aquatic grazers, facilitating the introduction of MP into the food chain and having direct adverse effects on the grazers’ reproductive fitness.

PANABIO: a point-referenced PAN-Arctic data collection of benthic BIOtas

Abstract. Profound environmental changes, such as drastic sea-ice decline, leave large-scale ecological footprints on the distribution and composition of marine biota in the Arctic. Currently, the impact of such stressors is not sufficiently understood due to the lack of pan-Arctic data that allow for estimating ecological baselines as well as modelling current and forecast potential changes in benthic biodiversity and ecosystem functioning. Here, we introduce the PAN-Arctic data collection of benthic BIOtas (PANABIO) and discuss its timeliness, potential, and details of its further development. The data collection contains individual datasets with records (presence, counts, abundance, or biomass) of benthic fauna, usually at genus level or species level, which were identified in field samples obtained at point-referenced locations (stations) by means of grabs, towed gear, or seabed imaging. The data cover the entire pan-Arctic realm, i.e. the central Arctic Ocean, Chukchi Sea, East Siberian Sea, Laptev Sea, Kara Sea, Barents Sea (including the White Sea), Svalbard waters, Greenland Sea, Norwegian Sea, Canadian Archipelago, Beaufort Sea, and Bering Sea as well as some adjacent sub-Arctic regions (Sea of Japan, Gulf of Okhotsk). Currently (as of 14 December 2023), PANABIO includes 27 datasets with a total of 126 388 records of 2978 taxa collected from 11 555 samples taken at 10 596 stations during 1095 cruises between 1800 and 2014. These numbers will increase with more data becoming available over time through contributions from PANABIO users. The data collection is available in a PostgreSQL-based data warehouse that can be accessed and queried through an open-access front-end web service at https://critterbase.awi.de/panabio (last access: 27 February 2024). A snapshot of the current data collection and its 27 individual datasets is also available from the data publisher PANGAEA (https://doi.org/10.1594/PANGAEA.963640, Piepenburg et al., 2023).

Bioaccumulation and Trophic Transfer of Short-, Medium-, and Long-Chain-Chlorinated Paraffins in Benthic Biotas of the Haima Cold Seep, South China Sea

Bioaccumulation and Trophic Transfer of Short-, Medium-, and Long-Chain-Chlorinated Paraffins in Benthic Biotas of the Haima Cold Seep, South China Sea

Ecological risks assessment of fishery commodities from heavy metal in The East Java Province, Indonesia

Heavy metals are a crucial group of chemicals extensively used in materials to meet human needs, eventually leading to contamination of aquatic ecosystems and accumulation in organism’s tissues. Heavy metals enter the aquatic ecosystem from various sources. Those metals that pollute aquatic waters are deposited in sediments, remain dissolved in water or accumulate in the food web of aquatic organisms. Benthic biota is believed to accumulate the highest levels of these metals, while other aquatic animals, such as fish, shrimp, and macroalgae, serve as significant sources of heavy metals intake through food and the environmental exposure. Ina study conducted in and around the east Java, Indonesia, the concentration of heavy metals in commercially important fish species, shellfish, and macroalgae were evaluated using an inductive couple plasma-mass spectrometer (ICP-MS). This study is very important because fishery resources are not only vital for exports but also serve as a primary source of essential food for local communities. The results showed that heavy metal concentration (Pb, Cd, and Hg) in samples were 12.3 mg∙dm –3, 0.171 mg∙dm –3, and undetectable, respectively. This study showed that different metals were present in the samples at different levels, all of which fell within the maximum residual levels set by the EU and USFDA. The results of an analysis of food safety based on the Hazard Index showed values below 1 point, indicating that fishery products (fish, shrimp, and macroalgae) from the East Java Province are generally safe for human consumption.

Spatial Distribution and Pollution Assessment of Metals in Sediments of the Babon River, Central Java, Indonesia.

The Babon River is one of the drainage channels in Semarang, Indonesia, that is used for drinking water, irrigated agriculture of paddy fields and gardens, fish farming media, and the disposal of industrial wastewater. This study aimed to assess the spatial distribution of metals in the sediment of the Babon River through the utilization of different pollution indices. These indices included concentration factor (Cf), contamination factor (CF), enrichment factor (EF), geoaccumulation index (Igeo), sediment pollution index (SPI), threshold effect level (TEL), and probable effect level (PEL). Seven sampling locations were sampled for water and sediment in April, June, and September of 2021. The measurement of the metal was conducted using an atomic absorption spectrophotometer. The findings of the study demonstrated that sediments with a predominant sand texture exhibited higher levels of Cd and Pb, while the sediments characterized by a predominant clay texture had a higher concentration of Cr. Upon analyzing the Cf, CF, EF, Igeo, and SPI data, it has been confirmed that the sediment in the Babon River has substantial levels of Cd, Cr, and Pb. According to the TEL and PEL values, it can be observed that the presence of Cd and Pb has detrimental effects on the biological health of the benthic biota. The aquatic biota and the benthic environment may be subject to adverse effects in the event where the concentration of metals in the sediment is higher than the natural concentration of metals.

Occurrence, Distribution, and Trophic Transfer of Pharmaceuticals and Personal Care Products in the Bohai Sea.

The ubiquitous presence of pharmaceuticals and personal care products (PPCPs) in environments has aroused global concerns; however, minimal information is available regarding their multimedia distribution, bioaccumulation, and trophic transfer in marine environments. Herein, we analyzed 77 representative PPCPs in samples of surface and bottom seawater, surface sediments, and benthic biota from the Bohai Sea. PPCPs were pervasively detected in seawater, sediments, and benthic biota, with antioxidants being the most abundant PPCPs. PPCP concentrations positively correlated between the surface and bottom water with a decreasing trend from the coast to the central oceans. Higher PPCP concentrations in sediment were found in the Yellow River estuary, and the variations in the physicochemical properties of PPCPs and sediment produced a different distribution pattern of PPCPs in sediment from seawater. The log Dow, but not log Kow, showed a linear and positive relationship with bioaccumulation and trophic magnification factors and a parabolic relationship with biota-sediment accumulation factors. The trophodynamics of miconazole and acetophenone are reported for the first time. This study provides novel insights into the multimedia distribution and biomagnification potential of PPCPs and suggests that log Dow is a better indicator of their bioaccumulation and trophic magnification.

Toxicity assessment of microplastics within the Loire River in the clam Corbicula fluminea exposed to environmentally relevant exposure conditions.

The dispersed pollution caused by microplastics (MPs) represents a current and global concern. While the fragmentation of plastic debris into smaller particles occurs in rivers, little MP research is done on freshwater species and is published compared to the marine environment. The Loire River is the longest river in France and is subject to moderate to high anthropic pressure while it represents major societal and economic issues. However, there are not many studies that have been put forward with regards to the effect of environmental MPs (EMPs) on aquatic organisms and no policies have been enacted to monitor the plastic pollution. In this study, freshwater bivalves, Corbicula fluminea, were exposed for 21 days to environmentally relevant concentrations of a mixture of <200 µm MPs generated from plastic litter collected directly along the banks of the Loire River. This mixture was composed of 40% polyethylene (PE), 40% polypropylene (PP), 10% polyethylene terephthalate (PET) and 10% polyvinylchloride (PVC) (mass percentage). Ecotoxicological effects were assessed from the individual to the molecular levels on several endpoints: condition index, filtration efficiency, enzyme activities, lipid peroxidation, energy reserves and gene expression. The ingestion of EMPs caused damages at the biochemical level. Indeed, we reported an increase in catalase activity in gills and digestive mass, a decrease in TBARs in gills, a decrease in acetylcholinesterase activity in the digestive mass, a decrease of glycogen and lipid contents in the whole organisms and a significant induction of the expression of gst, cat, mp, acp genes. The current results suggest therefore that long-term exposure to realistic doses of EMPs causes toxicity towards freshwater benthic biota. The analysis of biomarker activities and the analysis of gene expression are complementary to prevent the effects of a plastic contamination at higher biological levels in aquatic organisms.

Navigating a broken river: Understanding the ecological consequences of fragmentation on benthic life

AbstractHabitat fragmentation is emerging as a leading cause of biodiversity decline in riverine ecosystems. Several natural and human factors contribute to the fragmentation of rivers. River fragmentation is a growing problem that is widely spread and poses a significant challenge to the conservation of freshwater biodiversity, but its impact is not fully documented and acknowledged. Fragmentation impedes the movement of aquatic organisms and alters natural flow regimes, disrupting habitats and trophic supplies for aquatic biodiversity. It can also affect the adaptive ability of organisms to natural environmental changes, leading to a change in the structure and function of biotic communities. To understand the effects of fragmentation on river ecology, it is crucial to link its spatial and structural implications. This article examines the occurrence and frequency of fragmentation and its effects on the ecological community of benthic biota. This review aims to elucidate the overall effects of fragmentation on river ecology and recommends the possible measures to mitigate its impact. Urgent action is required to establish a comprehensive global network of free‐flowing river systems and revive previously exploited rivers in different regions to enhance the protection and sustainable utilization of river ecosystems.

Toxicopathic effects of waterborne Cd in sole juveniles, a prospective pollution monitoring sentinel for estuarine ecosystems

IntroductionEstuarine ecosystems are under high anthropogenic pressure and receive a wide Q7 variety of contaminants, including metals. They can remain trapped in estuarine sediments at high concentrations for long periods but eventually they can be released to the overlying water and become toxic for the resident benthic biota. As a consequence, biomonitoring programs surveying the health status of estuaries and coastal areas count with benthic species for the assessment of health disturbances in these specific ecosystems. The present investigation aims at recognizing toxicopathic effects elicited in estuarine life stages of the benthic fish Solea senegalensis on exposure to waterborne Cd, a model compound for metal contamination.MethodsBiological responses to metal exposure were assessed based on the application of a “biomarker + histopathology” approach. Two-year old sole juveniles were exposed to various concentrations of waterborne Cd for 3 and 7 days (Control; Low Cd: 1 µg/l; Mid Cd: 10 µg/l and High Cd: 1000 µg/l). Liver samples were collected for chemical analysis at day 7. Biological samples were collected at days 3 and 7 for biochemical (brain and liver), histochemical (liver) and histopathological analysis (liver, gills and gonad).ResultsBrain acetyl cholinesterase was inhibited after 7 days exposure, indicating neurotoxic effects on exposure to 1000 µg Cd/l. Hepatic catalase and glutathione-Stransferase were induced at day 3 and inhibited at day 7, which suggests a bell-shaped response. A dose-dependent lysosomal membrane destabilization in hepatocytes was recorded at day 7. In parallel, histopathological lesions in gills, liver and gonad were more frequent at day 7 in soles exposed to high Cd concentrations.DiscussionOverall, the “biomarker + histopathology” approach revealed that waterborne Cd causes toxicopathic effects in sole juveniles upon exposure to environmentally relevant concentrations (10 µg Cd/l). The effects were clearly time dependent, and thus it is conceivable that more severe biological effects would be elicited by these low concentrations of Cd at longer exposure periods. Therefore, biomarkers and histopathology in combination provide early-warning indications of altered health status after waterborne Cd exposure in sole juveniles, a prospective sentinel for biological effects assessment of metal contamination in pollution monitoring programs in estuaries and coastal areas.

Linkages between pelagic and benthic biota in a deteriorated coastal lake after restoration, Maruit, Egypt

Until the 1960s, Lake Maruit was one of Egypt’s most productive coastal brackish lakes. Continuous polluted discharge from Alexandria city resulted in long-term deterioration. The Egyptian government started a lake restoration program in 2010. Biological linkages between pelagic and benthic communities were assessed in November 2012 using parasitism and predation. This study examined ectoparasites infesting tilapia fish from 300 samples. The platyhelminth ectoparasite, Monogenea, and parasitic-copepod Ergasilus lizae were detected. Platyhelminthes parasitized Oreochromis niloticus and Oreochromis aureus, whereas the crustacean parasitized Coptodon zillii. The parasitic prevalence was low for Cichlidogyrus sp. and Ergasilus lizae. Benthic biotas were similar across basins. Fish abundance does not respond directly to benthic biotic components. Phytoplankton and benthic microalgae were not the main fish diet. Data on Halacaridae and fish clustered, indicating that either Halacaridae responds to their environment like fish or fish prey upon them because of their size. Linear correlations between pelagic, benthic biota, and parasite-infected fish indicate parasites may control their hosts. Some bioindicators indicate that stressed ecosystems differ from unstressed ecosystems. Fish species and biota abundances were low. Inconsistency in the food web and an absence of direct interactions between prey and predators are bioindicators of disturbed ecosystems. The low prevalence of ectoparasites and lack of heterogenous distribution of the various examined biota are bioindicators of habitat rehabilitation. Ongoing biomonitoring to better understand habitat rehabilitation is suggested.

Benthic biota (nummulites) response to a hyperthermal event: Eccentricity-modulated precession control on climate during the middle Eocene warming in the Southern Mediterranean

Earth's future environment depends critically on how the marine ecosystems react to the current greenhouse conditions. Past warming events from the Middle Eocene can shed light on the nature of these reactions. Middle Eocene sedimentary archives from the Tethyan margins record the Middle Eocene Climatic Optimum (MECO) with varying carbon isotope excursions from site to site. The present study integrates stable isotopes, the abundance of benthic fauna, and astrochronology to look for the timing of the MECO peak warming and the maximum abundance of nummulites in the Southern Mediterranean (Tunisia). A mesotrophic environment during the lower Bartonian with high eustatic sea level promotes the formation of a shallow water carbonate platform in central Tunisia from 40.6 Ma to 39.8 Ma. Nummulites occur in low abundance in the Lower Reneiche Limestone unit (LRL, Bey et al., 2015) from 40.6 to 40.2 Ma, then increase, reaching maximum abundance at the Upper Reneiche Limestone unit (URL, 40.1 to 40 Ma). Maximum accumulation of nummulites and negative excursion of δ18O in the URL occurred during the MECO's warming peak (40.07 to 40 Ma), 200 kyr after the middle Eocene third-order maximum flooding surface. The nummulitic beds represent warmer climates and higher sea levels (arid to semi-arid climate), and the short marl intervals reflect enhanced detrital input (humid climate and lower sea level). The eccentricity modulations were extracted using a lowpass filter applied on a wide-band precession filter then we computed the instantaneous amplitude using Hilbert Transform. The Spearman-rank correlation assesses the potential introduction of amplitude modulations during tuning. Power Decomposition Analysis (PDA) indicates a dominant short eccentricity forcing on the regional climate during the MECO with a minor obliquity component. Variations in magnetic susceptibility and CaCO3 content suggest a combined control of climate and sea-level cycles controlled by eccentricity-modulated precession cycles.

Assessment of Sediment Quality Through Multiple Geochemical Proxies in a Heavily Industrialized Harbor Area in South America, Santos Estuarine Channel, São Paulo, Brazil

ABSTRACT The aim of the present study was to evaluate bottom sediments quality in 32 stations at Santos Estuarine Channel, home to one of the main international ports in South America, and to the Cubatão industrial complex, the most important petrochemical and metallurgical area in Brazil. Sediment quality was approached through contamination (mCd), ecological (PEI, SQG-Q, PLI) and geoaccumulation (Igeo) indices. Phosphorus Enrichment Index (PEI) revealed phosphorus enrichment, with potential risk to biota regarding eutrophication effects. Index of geoaccumulation (Igeo) revealed accumulation of Pb, Cu, Zn, Ni, Cr, Cd and As, all reaching class 6 of contamination, pointing to extreme contamination. Contamination index revealed null to moderate contamination for most stations. Pollution Load Index (PLI) revealed no contamination, and Sediment Quality Guideline (SQG-Q) pointed to moderate impact, suggesting risk to benthic biota. The mud content of the samples did not correlate with arsenic, phosphorus and trace metals. Organic matter seemed to be the main carrier of these elements in the system. Results revealed accumulation of trace metals and As in bottom sediments of Santos estuarine channel, which can be used to develop guidelines for monitoring these pollutants in anthropogenic activities along the harbor area.

Untreated wastewater impact and environmental risk assessment of artificial sweeteners in river water and sediments of the Danube River Basin in Serbia.

Artificial sweeteners are receiving increasing attention as newly recognized emerging contaminants that mainly reach the aquatic environment through the discharge of municipal wastewater containing large amount of these compounds. In this study, the impact of raw untreated wastewater discharges on the levels and the water/sediment distribution of artificial sweeteners in the Danube River and its largest tributaries in Serbia was evaluated, and a comprehensive assessment of environmental risks for freshwater and benthic organisms was performed. Acesulfame and sucralose were detected in all river water samples (100%), while saccharin (59%) and cyclamate (12%) were less frequently found, indicating long-term continuous sewage-derived pollution. Aspartame (100%) and neotame (60%) were the only artificial sweeteners recorded in the sediment samples due to their preference to sorb to particulate matter in the water/sediment system. In terms of ecotoxicological risk, a low risk for aquatic organisms was determined at the detected levels of saccharin in river water, while a high to medium risk was found for benthic biota at the concentrations of neotame and aspartame detected in sediments. The largest contribution to the pollution of the Danube River Basin with artificial sweeteners, and consequently the highest environmental risk, was determined in the two largest cities, the capital Belgrade and Novi Sad, which raises the issue of transboundary pollution.

Cretaceous to Palaeogene boundary events and palaeoenvironmental responses across pelagic sequences of the Žilina core section, Slovakia: Rock magnetic, biotic, and geochemical characterization

The Žilina-Hradisko borehole in Slovakia intersects a succession from the Cretaceous Hradisko formation to the Paleocene Hričovské Podhradie formation. In this paper, we mainly focus on the Cretaceous–Palaeogene (K–Pg) boundary interval, which is marked by an abrupt change in planktonic biota and magnetic properties. Micropalaeontological findings suggest a rapid change from a stable, oxygen-rich, oligotrophic environment during the Maastrichtian to an unstable, cooler environment with reduced oxygenation and evidence of biotic stress in the lowermost Danian strata. An abrupt change in the magnetite concentration in the same interval indicates increased detrital input and probably biogenic (soft) magnetite production. Evidence recorded in borehole with enhanced Hg input into the Maastrichtian Ocean suggests that the Deccan eruptions mostly occurred prior to the K–Pg boundary, whereas no volcanic Hg input was detected at the K–Pg boundary itself. Double peaks in multiple magnetic properties mark the Danian hyperthermal Dan-C2 event, which was characterised by a series of environmental changes, including enhanced terrigenous input, oxygen deficit, increased nutrient supply, high benthic productivity, and Parasubbotina acme. Prior to the Latest Danian event, foraminiferal assemblages were significantly affected by dissolution and oxygen depletion, followed by warming, water column stratification, and diversification of calcareous plankton groups. An increase in detrital input and nutrient export drove the productivity of deep-dwelling subbotinids and globanomalinids and were correlated with the mid-Paleocene biotic event (MPBE). The seafloor biota associated with the MPBE implies oxygen deficiency and the prevalence of benthic infauna. The Selandian–Thanetian strata markedly differ from planktonic foraminifera of older formations, with their rich content of large, diversified, and heavily calcified morozovellid and igorinid foraminifera, revealing the existence of water column stratification with surface-water productivity and meso- to oligotrophic conditions. The microfauna of ornate morozovellids and benthic biota from the lowermost formation implies the onset of environmental stress and CaCO3 dissolution during the Paleocene-Eocene Thermal Maximum (PETM).