What lies underneath: Comparison among beach litter in the underwater bathing area and exposed beach.

The standard techniques for monitoring beach litter focus on the litter that is accumulated on beaches. Therefore, the underwater bathing area is usually overlooked. Our study aims to start the discussion about the litter in the bathing area, an important connection between the exposed beach and the ocean. We aimed to compare sampling methodologies between the underwater bathing area and the exposed beach. We highlighted litter's similarities and differences regarding the amount, material, possible sources, and interaction with the biota. We also performed a brand audit on the underwater bathing area litter. In the underwater region, 106 items were collected while 1706 items were collected from the exposed beach region. Plastic was the dominant type of material in both sites, exposed beach (89.92 %) and bathing area (83.96 %). The litter's possible source was different. In the underwater bathing area was more related to food packages (couscous, rice). On the other hand, litter on the exposed beach was associated with beach use (single-use plastic such as plastic cups). The brand audit identified 21 companies, whereby most brands were Brazilian and food-related. Regarding interactions with the biota, the litter in the bathing area had more bio-fouling (87.73 %) than the litter collected on the exposed beach (10.00 %). Information about bathing area litter can be useful to draw different management strategies. Due to the differences in litter types and behavior between the two sites, the same mitigation strategies might not be equally efficient.

Understanding the interactions between cephalopods and marine litter: A research evaluation with identification of gaps and future perspectives.

Litter is known to negatively affect numerous marine organisms, but the extent of such impacts is not well known for several groups, including cephalopods. Considering the ecological, behavioral and economic importance of these animals, we reviewed the types of interactions between cephalopods and litter in the scientific literature, to evaluate impacts and knowledge gaps. We found 30 papers, which included records of microplastic ingestion and the transfer of synthetic microfibers along the food web. The largest number of records involved litter use as shelter, and the common octopus was the most frequent species. At first sight, litter use as shelter could appear to be a potential positive effect, but it is necessary to clarify the implications of this choice and its long-term consequences. Regarding ingestion and trophic transfer, further research is needed to elucidate its occurrence and impacts on cephalopods and their predators, including humans.

In an octopus's garden in the shade: Underwater image analysis of litter use by benthic octopuses.

Benthic octopuses have been widely documented in artificial shelters for decades, and this use is apparently increasing. Despite any possible positive effects, the use of litter as shelter could have negative implications. In this work, we aimed to elucidate the interactions of octopuses with marine litter, identifying types of interactions and affected species and regions. To achieve this, we obtained 261 underwater images from 'citizen science' records, and identified 8 genera and 24 species of benthic octopuses interacting with litter. Glass objects were present in 41.6% of interactions, and plastic in 24.7%. Asia presented the highest number of images, and most records were from 2018 to 2021. Citizen science provided important evidence on octopus/marine litter interactions, highlighting its value and the need for more investigations on the subject. This information is fundamental to help prevent and mitigate the impacts of litter on octopuses, and identify knowledge gaps that require attention.

Spatio-temporal characterization of litter at a touristic sandy beach in South Brazil.

Litter is an ecological, economic, and social problem that impacts marine environments around the world. To create prevention and mitigation measures to solve this issue, it is necessary to understand the amounts and sources of this type of pollution. Cassino Beach is an extensive sandy beach located in South Brazil (∼220 km in length) that presents multiple uses, such as touristic, portuary and fishery activities. In order to evaluate the spatial and seasonal variation of litter amounts, types and sources at Cassino Beach, litter (>2.5 cm) was collected over 27 months at two urban and two non-urban sites. At each site, the litter present in three 200 m2 areas was sampled and evaluated. A total of 19,457 items were collected, mostly composed by plastic (∼88%). Paper, metal, and cloth items were also present, but in low amounts. Fragments and cigarette butts were the major types of plastic litter, with abundances of 28.4% and 17.0%, respectively. Urban sites presented higher amounts of litter, with those related to beach use being more common, emphasizing the contribution of beachgoers to litter input at these sites. During the summer season, when beach use increases, the highest total litter concentration was found. Undefined and/or beach use-related sources were dominant in all sites and seasons. Mapping the predominant materials, types and potential sources of litter creates important baseline data that can contribute not only to beach monitoring, but also to the development of litter reduction strategies.

Physiological damages of Sargassum cymosum and Hypnea pseudomusciformis exposed to trace metals from mining tailing.

The damages of Mariana's mining mud in the physiology of the brown algae Sargassum cymosum and its main epiphytic, the red algae Hypnea pseudomusciformis, were evaluated by controlled essays. Seaweeds were exposed to presence or absence of mud, isolated or in biological association, for 5 and 15 days. Measured parameters were growth rates, biochemical descriptors, and the chemical investigation of concentration and metal profile of the mud dissolved in seawater. Results showed that the highest values for metals were Al > Fe > Mn > Zn in both exposure periods. The mud also affected the growth rate with lethality in both isolated and associative treatments with H. pseudomusciformis after 15 days. According to our redundancy analysis (RDA), the profile and concentration of all metallic elements can induce different physiological responses of the organisms. We were able to observe a higher physiological adaptive ability of S. cymosum against the long-term presence of metals by the synthesis of phenolic compounds, while the deviation of metabolic routes in H. pseudomusciformis can be addressed as the main responsible for its lethality. Moreover, the presence of Hypnea in associative treatments reduces Sargassum's detoxification ability. The present results reinforce the importance of biological interaction studies in a context of physiological resilience against mining mud pollution and mutual influences of species over the individual ability to avoid oxidative stress.

Ecophysiological implications of UV radiation in the interspecific interaction of Pyropia acanthophora and Grateloupia turuturu (Rhodophyta).

Radiation, both photosynthetic active radiation (PAR, l = 400-700 nm) and Ultraviolet (UVR, l = 280-400 nm) is one of the key factors regulating algal distribution in aquatic environments. Pyropia acanthophora and Grateloupia turuturu have been found over upper rocky shore areas in Southern Brazil, occupying the same niche space. The first species is native and the second one is exotic and considered a potential invader of South Atlantic. The aim of the present study was to evaluate the effects of radiation on physiological responses of both species and infer mechanisms that allow their niche competition in the environment. Samples were cultured in the following conditions: associated or separated, and with an addition of PAR, PAR + UVA (PA) and PAR + UVA + UVB (PAB), totalizing six factorial treatments during 5 days of exposure. Photosynthetic responses of Fv/Fm and ETR were daily evaluated. At the beginning and at the end of the experiment, samples were analyzed for pigment content (chlorophyll a and phycobiliproteins), and mycosporine-like amino acids (MAAs), while oxygen evolution was evaluated at the end of the experiment. As the main results, G. turuturu died when cultivated in PAB conditions. P. acanthophora presented higher amounts of chlorophyll a than G. turuturu during the whole experiment. Phycoerythrin and Fv/Fm remained constant in P. acanthophora but diminished for G. turuturu in UV treatments. ETR was higher for samples that were cultivated in associative treatment. The presence of G. turuturu in the same flask enhanced MAA synthesis in P. acanthophora, regardless of radiation condition. In addition, UV radiation can be a factor controlling species distribution and could counteract the spreading of invasive species, like G. turuturu, allowing P. acanthophora survival in upper rocky shore zones of the natural ecological distribution area.