Fish Food in the Deep Sea: Revisiting the Role of Large Food-Falls

The carcasses of large pelagic vertebrates that sink to the seafloor represent a bounty of food to the deep-sea benthos, but natural food-falls have been rarely observed. Here were report on the first observations of three large ‘fish-falls’ on the deep-sea floor: a whale shark (Rhincodon typus) and three mobulid rays (genus Mobula). These observations come from industrial remotely operated vehicle video surveys of the seafloor on the Angola continental margin. The carcasses supported moderate communities of scavenging fish (up to 50 individuals per carcass), mostly from the family Zoarcidae, which appeared to be resident on or around the remains. Based on a global dataset of scavenging rates, we estimate that the elasmobranch carcasses provided food for mobile scavengers over extended time periods from weeks to months. No evidence of whale-fall type communities was observed on or around the carcasses, with the exception of putative sulphide-oxidising bacterial mats that outlined one of the mobulid carcasses. Using best estimates of carcass mass, we calculate that the carcasses reported here represent an average supply of carbon to the local seafloor of 0.4 mg m−2d−1, equivalent to ~4% of the normal particulate organic carbon flux. Rapid flux of high-quality labile organic carbon in fish carcasses increases the transfer efficiency of the biological pump of carbon from the surface oceans to the deep sea. We postulate that these food-falls are the result of a local concentration of large marine vertebrates, linked to the high surface primary productivity in the study area

Emotional distress among adult survivors of childhood cancer

PURPOSE: To estimate the prevalence of emotional distress in a large cohort of adult survivors of childhood cancer and evaluate the interrelationship of risk factors including cancer-related late effects. METHODS: 1,863 adult survivors of childhood cancer, median age of 32 years at follow-up, completed comprehensive medical evaluations. Clinically relevant emotional distress was assessed using the Brief Symptom Inventory-18 and was defined as T-scores ≥63. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using multivariable logistic regression models to identify risk factors for distress. Path analysis was used to examine associations among identified risk factors. RESULTS: Elevated global distress was reported by 15.1% of survivors. Cancer-related pain was associated with elevated distress (OR 8.72; 95% CI, 5.32 – 14.31). Survivors who reported moderate learning or memory problems were more likely to have elevated distress than survivors who reported no learning or memory problems (OR 3.27; 95% CI, 2.17 – 4.93). Path analysis implied that cancer-related pain has a direct effect on distress symptoms and an indirect effect through socioeconomic status and learning or memory problems. Similar results were observed for learning or memory problems. CONCLUSIONS: Childhood cancer-related morbidities including pain and learning or memory problems appear to be directly and indirectly associated with elevated distress symptoms decades after treatment. Understanding these associations may help inform intervention targets for survivors of childhood cancer experiencing symptoms of distress. IMPLICATIONS FOR CANCER SURVIVORS: A subset of long-term childhood cancer survivors experience significant emotional distress. Physical and cognitive late effects may contribute to these symptoms