Northwest Atlantic leatherback sea turtles (Dermochelys coriacea) are endangered and low hatch success limits potential for population recovery. We examined essential and nonessential metal concentrations in 43 eggs from nests on St. Kitts to determine if there was a relationship with hatch success. Whole homogenized embryos and undeveloped eggs contained detectable concentrations of arsenic, barium, copper, iron, selenium, vanadium, and zinc, but not beryllium, cadmium, chromium, cobalt, lead, mercury, molybdenum, and thallium. Of detected metals, only vanadium concentrations negatively correlated with hatch success (P = 0.01). Manganese and vanadium were associated with pneumonia occurring in the nest, and arsenic with renal mineralization. This study adds to the knowledge regarding baseline values for environmental contaminants in sea turtles, supporting the trend that leatherback eggs have relatively low concentrations of toxic metals, lacking a strong relationship with hatch success, and normally contain the essential elements copper, iron, selenium, and zinc.

Effects of microplastics on marine taxa have become a focal point in marine experimental biology. Almost all studies so far, however, assessed the influence of microplastics on animals only in relation to a zero-particle group. Documented microplastic impacts may thus be overestimated, since many marine species also experience natural suspended solids as a stressor. Here, we compared the effects of polyvinyl chloride (PVC) and red clay (mean for both particles: ~12–14 μm) on the Mediterranean mussel Mytilus galloprovincialis across three particle concentrations (1.5, 15, 150 mg l⁻¹). Exposure to PVC for 35 days lowered mussel body condition index by 14% in relation to clay, but no difference in byssus production, respiration and survival rates emerged between the two particle types. This suggests that the effects of synthetic particles on filter feeders may emulate those of natural suspended solids, and highlights the importance of including natural particles in microplastic exposure studies.

The blooms of harmful microalgae represent a prominent threat to fisheries, public health, and economies throughout the world. Recent studies have shown that certain macroalgae release allelochemicals that can inhibit the growth of bloom-forming microalgae. In this study, we found that the macroalga Pyropia haitanensis significantly inhibited growth of the harmful bloom-forming microalgae Pseudo-nitzschia pungens and Pseudo-nitzschia multiseries. The inhibitory-effect of the live thali of P. haitanensis was highest, followed by that of dry powder, water-soluble extract, and culture medium filtrate. The Pseudo-nitzschia species died 96 h after exposure to 5–10 g fresh-weight L⁻¹ of P. haitanensis live thalli. Furthermore, an aqueous extract of P. haitanensis suppressed the growth of P. pungens and P. multiseries, thereby indicating that P. haitanensis contains stable allelopathic substances that cause the observed inhibitory-effects. On the basis of these findings, we conclude that the macroalga P. haitanensis would have potential utility in controlling the blooms of Pseudo-nitzschia species.

Although marine plastic litter has been recognized as a global problem, there are insufficient data on the extent of plastic pollution in the Black Sea. The results from this pilot study of the floating marine litter and microplastics along the Bulgarian Black Sea coast revealed high quantities of floating litter (60.3–93.8 items.km⁻²). The microplastic concentrations (1.14 × 10⁴–1.91 × 10⁵ items.km⁻², 0.33–490.52 g.km⁻²) were on average lower than those found in other parts of the Black Sea, the Baltic Sea, and the Mediterranean Sea, although the observed ranges were similar. Further studies are needed to elaborate the extent and spatial distribution of this type of pollution in the Black Sea basin.

Plastic marine debris (PMD) is of global concern. To help address this problem, a novel approach for estimating PMD volumes using a combination of unmanned aerial vehicle (UAV) surveys and image processing based on deep learning is proposed. A three-dimensional model and orthoscopic image of a beach, constructed via Structure from Motion software using UAV-derived data, enabled PMD volumes to be computed by edge detection through image processing. The accuracy of the method was verified by estimating the volumes of test debris placed on a beach in known sizes and shapes. The proposed approach shows potential for estimating PMD volumes with an error of <5%. Compared with subjective methods based on beach surveys, this approach can accurately, rapidly, and objectively calculate the PMD volume on a beach and can be used to improve the efficiency of beach surveys and identify beaches that need preferential cleaning.

Pollution of marine environments is concerning for complex trophic systems. Two anthropogenic stresses associated with marine pollution are the introduction of marine plastic and their associated chemicals (e.g., trace elements) which, when ingested, may cause harm to wildlife. Here we explore the relationship between plastic ingestion and trace element burden in the breast muscle of Short-tailed Shearwaters (Ardenna tenuirostris). We found no relationship between the amount of plastic ingested and trace element concentration in the birds' tissues. Though the mass and number of plastic items ingested by birds during 1969–2017 did not change significantly, trace element concentrations of some elements (Cu, Zn, As, Rb, Sr and Cd), appeared to have increased in birds sampled in 2017 compared to limited data from prior studies. We encourage policy which considers the data gleaned from this sentinel species to monitor the anthropogenic alteration of the marine environment.

The invasive coral Tubastraea tagusensis (sun coral) is a habitat-forming species currently increasing its geographical range into the Atlantic Ocean, thereby causing negative ecological and socioeconomic impacts. Scuba divers observed this coral in the western equatorial Atlantic in January 2020, growing at high densities on a shipwreck from World War II (sunk in 1943) at a depth of approximately 32 m. Available footage from the beginning of the decade (2012–2018) shows no obvious signs of sun coral on this shipwreck, suggesting recent colonization and range expansion. The recent evidence of expansion was found 200 km east of the last record, which was also found on a WWII shipwreck (sunk in 1942) in 2016. We have identified hundreds of overlooked WWII shipwrecks, as well as new wrecks in shallow and mesophotic waters, that may provide stepping-stone habitats for this coral to expand its distribution in the Atlantic. We discuss the role of shipwrecks as a network of stepping stones for the sun coral spread, creating complementary paths for the invasiveness by overcoming physiological traits and the short lifespan of the coral larvae. Previous research underestimates the importance of these artificial stepping-stone patches in sustaining crucial dispersal events and range expansion of invasive species. These results are a call to action to manage the invasive Tubastraea corals at a national and international scale in the Atlantic basin.

Atmospheric aerosol particles, being composed of various types of chemical mixtures, affect significantly on human health and climate. During the last decade, many studies were focused on characterization of chemical and physical properties as well as source apportionment of atmospheric aerosols, which have made substantial implications for aerosol-induced air pollution and climate mitigation. Instrumental measurement techniques provide one of the most direct and effective ways to determine aerosol physicochemical characterization and thereby to constrain aerosol modeling. The Aerodyne soot particle aerosol mass spectrometer (SP-AMS), a state-of-the-art instrument, combines the advantages of both high-resolution time-of-flight AMS (HR-ToF-AMS) and single particle soot photometer (SP2). It can measure high-resolution chemical composition, size distribution, and mixing state of both non-refractory and refractory aerosol particles. Specially, chemical-resolved coating materials of refractory black carbon-containing particles can be quantified by SP-AMS. Moreover, same as HR-ToF-AMS, highly time-resolved organic mass spectral data can be applied for further identification and quantification of organic aerosol sources with receptor models, such as positive matrix factorization (PMF). This review summarizes results and findings obtained by recent SP-AMS measurements in field observations and laboratory studies. These SP-AMS measurements mainly cover the topics of soot cluster ions, trace metals, chemical composition and sources of non-refractory bulk aerosols, mixing state, and light absorption properties of black carbon-containing particles. Finally, we propose some potential prospects for future studies by using the SP-AMS.

The spatial distribution, sources and characteristics of marine litter (ML) from 36 locations spread over 12 beaches along the west coast of Qatar have been assessed. A total of 2376 ML items with varying sizes were found with an average abundance of 1.98 items/m². The order of abundance of ML along the coast was as follows: plastics (71.4%) > metal (9.3%) > glass (5.1%) > paper (4.4%) > fabric (4.0%) > rubber (3.9%) > processed wood (2.0%). Locations in the south and northwest coasts of Qatar had significantly higher concentrations of ML. Surprisingly, nearly 47% of the beached polyethylene terephthalate (PET) bottles were derived from the countries bordering the Arabian/Persian Gulf (Gulf), and most of them were produced in the last 2 years. The plastic materials were drifted by winds and currents to the Qatar coast. Gulf circulation provides evidence to the pathways of ML beached on the Qatar coast.

Uptake of microplastic (MP) particles has been detected in a large number of marine organisms, and humans may consequently be exposed to high MP levels in consumed seafood. Yet there remains a dearth of knowledge regarding uptake into commercially important finfish and tissues (fillets) most commonly consumed by humans. The current study detected translocation of MP into the fillet of European seabass (Dicentrarchus labrax) juveniles fed with a diet containing fluorescent MP particles (1–5 μm) for 16 weeks. Results indicate MP translocation to fillet, with mean fillet MP content calculated as 0.36 ± 0.29 MP/g⁻¹ fillet on the basis of manual fluorescent microscopy counts and 0.15 ± 0.28 MP/g⁻¹ fillet on the basis of automated fluorescent microscopy counts. The retention/translocation rate is estimated at approximately 1 MP reaching the fillet for every 1.87 × 10⁷ ingested in the experimental diet. This study presents first data of MP translocation from feed to the tissue fillet in European seabass and aids future examinations of the MP load in seafood for human consumption.