Bio-optical evidence for increasing Phaeocystis dominance in the Barents Sea.

Increasing contributions of prymnesiophytes such as Phaeocystis pouchetii and Emiliania huxleyi to Barents Sea (BS) phytoplankton production have been suggested based on in situ observations of phytoplankton community composition, but the scattered and discontinuous nature of these records confounds simple inference of community change or its relationship to salient environmental variables. However, provided that meaningful assessments of phytoplankton community composition can be inferred based on their optical characteristics, ocean-colour records offer a potential means to develop a synthesis between sporadic in situ observations. Existing remote-sensing algorithms to retrieve phytoplankton functional types based on chlorophyll-a (chl-a) concentration or indices of pigment packaging may, however, fail to distinguish Phaeocystis from other blooms of phytoplankton with high pigment packaging, such as diatoms. We develop a novel algorithm to distinguish major phytoplankton functional types in the BS and apply it to the MODIS-Aqua ocean-colour record, to study changes in the composition of BS phytoplankton blooms in July, between 2002 and 2018, creating time series of the spatial distribution and intensity of coccolithophore, diatom and Phaeocystis blooms. We confirm a north-eastward expansion in coccolithophore bloom distribution, identified in previous studies, and suggest an inferred increase in chl-a concentrations, reported by previous researchers, may be partly explained by increasing frequencies of Phaeocystis blooms. This article is part of the theme issue 'The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning'.

Microplastics and synthetic particles ingested by deep-sea amphipods in six of the deepest marine ecosystems on Earth.

While there is now an established recognition of microplastic pollution in the oceans, and the detrimental effects this may have on marine animals, the ocean depth at which such contamination is ingested by organisms has still not been established. Here, we detect the presence of ingested microplastics in the hindguts of Lysianassoidea amphipod populations, in six deep ocean trenches from around the Pacific Rim (Japan, Izu-Bonin, Mariana, Kermadec, New Hebrides and the Peru-Chile trenches), at depths ranging from 7000 m to 10 890 m. This illustrates that microplastic contaminants occur in the very deepest reaches of the oceans. Over 72% of individuals examined (65 of 90) contained at least one microparticle. The number of microparticles ingested per individual across all trenches ranged from 1 to 8. The mean and standard error of microparticles varied per trench, from 0.9 ± 0.4 (New Hebrides Trench) to 3.3 ± 0.7 (Mariana Trench). A subsample of microfibres and fragments analysed using FTIR were found to be a collection of plastic and synthetic materials (Nylon, polyethylene, polyamide, polyvinyl alcohol, polyvinylchloride, often with inorganic filler material), semi-synthetic (rayon and lyocell) and natural fibre (ramie). Notwithstanding, this study reports the deepest record of microplastic ingestion, indicating that anthropogenic debris is bioavailable to organisms at some of the deepest locations in the Earth's oceans.

The Yang-Monti ileovesicostomy: a problematic channel?

OBJECTIVE: To compare the differences in the quality of Mitrofanoff channels created using appendix and re-tubularized small bowel (the Yang-Monti ileovesicostomy). Patients and methods The case-notes were reviewed retrospectively for all patients who underwent a Mitrofanoff procedure using either appendix or small bowel, over a 5-year period from June 1994 to July 1999. RESULTS: In all, 92 patients underwent 94 Mitrofanoff procedures; the appendix was used in 69 and small bowel in 25. The underlying diagnoses were exstrophy-epispadias complex (38), neuropathic bladder (21), anorectal malformations and cloacal anomalies (15), posterior urethral valves (nine) and miscellaneous (nine). The mean (range) age at operation was 9.2 (1.1-18.3) years. The mean (range) follow-up for the appendix group was 37 (6.7-65) months and for the Monti group 25 (6-66) months. Catheterization problems occurred in 18 (27%) patients from the appendix group; two needed an adjustment of technique, six dilatation and 10 revision. Stomal stenosis occurred in 10 (15%) patients, bladder level stenosis in four (6%) and conduit necrosis in two. Catheterization problems were reported in 15 (60%) patients from the Monti group; five needed revision, three dilatation and seven are being managed conservatively. The incidences of stomal stenosis (four, 16%) and bladder level stenosis (two, 8%) were comparable with the appendix group. In addition, two patients had distal channel (sub-stomal) stenosis and two had mid-channel stenosis. The problem unique to the Yang-Monti channel was a pouch-like dilatation in seven patients (28%), all of whom presented with catheterization problems; five are being managed conservatively and two have needed pouch resection. Stomal prolapse occurred in five (7%) patients in the appendix group, but in none of the Monti group. CONCLUSIONS: The appendix is the conduit of choice for a Mitrofanoff procedure. Re-tubularized small bowel conduits have a considerably higher incidence of catheterization problems. Anatomical factors may contribute to the unique incidence of pouch formation.