There is limited understanding of how litter abundance, particularly plastic items, varies between coastal and inland regions with different population densities. The absence of standardised data collection methods further complicates comparisons. Moreover, the lack of data for inland areas hampers efforts to identify potential litter sources, pathways, and interventions. In this study, we address these gaps by quantifying and characterising litter across diverse settings in the United Kingdom (UK), encompassing coastal and inland regions, as well as urban and rural areas. Data were collected in collaboration with a major UK charity specialising in coastal litter removal, with 97 volunteers conducting monthly surveys along 200-m transects using a custom mobile application. Over five months, a total of 27,855 litter items were collected. Fragments (33 %), packaging (33 %), and cigarette-related debris (23 %) were the most prevalent litter types, each displaying varying trends in abundance across different locations. Litter density was higher in coastal areas (0.053 items/m2) compared to inland regions (0.030 items/m2), and urban areas consistently exhibited more litter than rural areas (urban 0.046 items/m2 vs. rural 0.038 items/m2). Over time, coastal areas experienced a significantly higher influx of new litter (p < 0.0001) compared to inland regions, where litter levels were stable or decreasing. Notably, while coastal areas showed no significant difference in litter accumulation between urban and rural communities, inland urban areas had significantly more litter than their rural counterparts (p < 0.0001). These findings underscore the importance of considering both geographic region and community type when developing waste management strategies. They also highlight the need for enhanced legislation targeting common litter sources.
Microplastics are omnipresent, raising significant concerns in marine environments. This study investigates how different beach morphodynamics and local management practices (i.e. pollutant sources, tourism, beach cleaning) influence microplastic pollution in sandy beach sediments in Vietnam by comparing tidal zonation patterns across three beaches with varying slopes and management approaches. Environmental variables (Chlorophyll a, total organic material, grain size) and microplastics polymer composition, size and concentrations were measured at the high and the low water marks of each beach. Microplastics were found on all beaches, with high variation. The dominance of denser MPs, like PET, on reflective beaches coupled with the prevalence of lighter MPs in the high tidal zone, demonstrates the role of beach morphodynamics and tidal flows in shaping microplastic distributions. Furthermore, local waste management practice and input from tourism activities can contribute to the patchy microplastics distribution. For instance, the larger size of microplastics at the beach with most macrolitter suggests the role of fragmentation down to microplastics as a pollution source which can pose risks to benthic ecology and human health in regional communities. Our findings highlight a complex interplay between beach morphodynamics and local pollution sources in driving microplastic distribution. Addressing the issue of MPs pollution on sandy beaches will therefore require targeted management strategies that reduce pollution sources in relation to natural processes that set the deposition of microplastics in beach sediments.
This study investigated the total arsenic (TAs) content and arsenic formation of three macroalgae, including Ulva lactuca (U. lactuca) in the Chlorophyta and Mazzaella japonica (M. japonica) and Neohodomela munita (N. munita) in the Rhodophyta, in different seasons. The results showed that TAs concentrations ranged from 6.4 to 13.7 mg kg-1 in M. japonica, 4.9 to 21.7 mg kg-1 in N. munita, and 0.7 to 20.3 mg kg-1 in U. lactuca, indicating significant seasonal variations in arsenic content. Arsenic content is higher in cold seasons (October 2022 and February 2023) and lower in hot seasons (July 2022 and July 2023). Additionally, arsenic speciation varied among different macroalgae, the content of arsenic betaine (AsB) in U. lactuca is relatively high, while the glycerol arsenide (AsS-OH) content in the Rhodophyta, such as the M. japonica and the N. munita, is also high, and the N. munita has a high content of inorganic arsenic AsV. Human exposure to toxic arsenic via macroalgae consumption was assessed using estimated daily intake (EDI) and target hazard quotient (THQ). Most macroalgae posed low health risks, but N. munita presented significant risks in warmer seasons due to high inorganic arsenic (IAs) content. Continuous monitoring and further research on climate impacts on arsenic in macroalgae are necessary to understand long-term consumption risks.
Disruptions to functionally important symbionts with global change will negatively impact plant fitness, with broader consequences for species' abundances, distribution, and community composition. Fungal endophytes that live inside plant leaves and roots could potentially mitigate plant heat stress from global warming. Conversely, disruptions of these symbioses could exacerbate the negative impacts of warming. To better understand the consistency and strength of warming-induced changes to fungal endophytes, we examined fungal leaf and root endophytes in three grassland warming experiments in the US ranging from 2 to 25 years and spanning 2000 km, 12°C of mean annual temperature, and 600 mm of precipitation. We found that experimental warming disrupted symbiosis between plants and fungal endophytes. Colonization of plant tissues by septate fungi decreased in response to warming by 90% in plant leaves and 35% in roots. Warming also reduced fungal diversity and changed community composition in plant leaves, but not roots. The strength, but not direction, of warming effects on fungal endophytes varied by up to 75% among warming experiments. Finally, warming decoupled fungal endophytes from host metabolism by decreasing the correlation between endophyte community and host metabolome dissimilarity. These effects were strongest in the shorter-term experiment, suggesting endophyte-host metabolome function may acclimate to warming over decades. Overall, warming-driven disruption of fungal endophyte community structure and function suggests that this symbiosis may not be a reliable mechanism to promote plant resilience and ameliorate stress responses under global change.
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