Importance of suspended particulate organic matter in the diet of Nephrops norvegicus (Linnaeus, 1758)

Anthropogenic pollutants in Nephrops norvegicus (Linnaeus, 1758) from the NW Mediterranean Sea: Uptake assessment and potential impact on health

Anthropogenic pollution is considered one of the main threats to the marine environment, and there is an imperious need to assess its potential impact on ecologically and economically relevant species. This study characterises plastic ingestion and tissue levels of potentially toxic metallic elements in Nephrops norvegicus and their simultaneous levels in abiotic compartments from three locations of the Catalan coast (NW Mediterranean Sea). A multidisciplinary assessment of the health condition of N. norvegicus through condition indices, enzymatic biomarkers and histological techniques is provided, and its relationship with anthropogenic pollutant levels explored. Plastic fibres were commonly found in stomachs of N. norvegicus (85% of the individuals), with higher abundances (13 ± 21 fibres · ind^-1) in specimens captured close to Barcelona. The presence of long synthetic fibres in near-bottom waters, as well as the mirroring trends in abundance among locations for water and ingested plastics, suggest that uptake from water may be occurring potentially through suspension feeding. The spatial variability in the levels of metallic elements in N. norvegicus was poorly correlated to the variability in sediments. In any case, present levels in abdominal muscle are considered safe for human consumption. Levels of ingested plastics only showed significant, yet weak, correlations with glutathione S-transferase and catalase activities. However, no other health parameter analysed showed any trend potentially associated to anthropogenic pollutant levels. Neither the condition indices nor the histopathological assessment evidenced any signs of pathologic conditions affecting N. norvegicus. Thus, it was concluded that presently there is no evidence of a negative impact of the studied pollutants on the health condition of N. norvegicus in the studied grounds.

Spatial and temporal diet variability of Adélie (Pygoscelis adeliae) and Emperor (Aptenodytes forsteri) Penguin: a multi tissue stable isotope analysis

The Ross Sea, Antarctica, supports large populations of Emperor Penguin (Aptenodytes forsteri) and Adélie Penguin (Pygoscelis adeliae), two key meso-predators that occupy high trophic levels. Despite these species are largely studied, little is known about their diet outside the breeding period. In the present study, we investigated the intra-annual diet of Adélie and Emperor Penguins belonging to five colonies in the Ross Sea through the stable isotope analysis of different tissues (feathers and shell membranes), synthetized in different seasons, and guano that indicates recent diet. Penguin samples and prey (krill and fish) were collected during the Antarctic spring–summer. δ13C and δ15N of tissues and guano indicate spatio-temporal variation in the penguin diet. The krill consumption by Adélie Penguins was lowest in winter except in the northernmost colony, where it was always very high. It peaked in spring and remained prevalent in summer. The greatest krill contribution to Emperor Penguin’s diet occurred in summer. The relative krill and fish consumption by both species changed in relation to the prey availability, which is influenced by seasonal sea ice dynamics, and according to the penguin life cycle phases. The results highlight a strong trophic plasticity in the Adélie Penguin, whose dietary variability has been already recognized, and in the Emperor Penguin, which had not previously reported. Our findings can help understand how these species might react to resource variation due to climate change or anthropogenic overexploitation. Furthermore, data provides useful basis for future comparisons in the Ross Sea MPA and for planning conservation actions.

Geographical location and water depth are important driving factors for the differences of suspended particulate organic matter (SPOM) in lake environment across nationwide scale: Evidences from n-alkane fingerprints

Suspended particulate organic matter (SPOM) plays a connective role in global biogeochemical carbon cycles and energy flows in aquatic ecosystems. However, little is known about the occurrence and source of SPOM in lake environment and their driving factors across nationwide scale. Here, we utilize the molecular markers of n-alkanes and their fingerprints in 46 typical lakes and reservoirs with different water depths across China from both sides of the Hu Line to study this issue. Σ₂₉n-alkanes, Σ biogenic n-alkanes and Σ anthropogenic n-alkanes ranged from 104.8 to 10332 ng·L^-1, from 88.5 to 4843 ng·L^-1, and from 16.2 to 5488 ng·L^-1, respectively. Their occurrences were only associated with water depth. Then, we compared the differences of carbon-chain distribution of both biogenic and anthropogenic n-alkanes and related proxies in different lake groups. The profiles of different biogenic and anthropogenic n-alkanes posed large differences in different lake groups. Finally, linear discriminant analysis (LDA) was applied to test the possible effects of geographical location and water depth on the holistic differences of SPOM in different lakes and reservoirs across China. The results illustrated that both geographical location and water depth were important driving factors for the holistic differences of SPOM in different lakes and reservoirs across China. Intensive anthropogenic activities narrowed the differences between shallow and deep lakes in eastern China. In conclusion, this study provided new insights into the driving factor analysis of SPOM in lakes and reservoirs on large scale.