Seasonality and interannual variability of the European Slope Current from 20 years of altimeter data compared with in situ measurements

The European Slope Current (SC) is a major section of the warm poleward flow from the Atlantic to the Arctic, which also moderates the exchange of heat, salt, nutrients and carbon between the deep ocean and the European shelf seas. The mean structure of the geostrophic flow, seasonality, interannual variability and long-term trend of SC are appraised with an unprecedented continuous 20-year satellite altimeter dataset. Comparisons with long term in situ data showed a maximum correlation of r2=0.51 between altimeter and Acoustic Doppler Current Profilers (ADCP), with similar results for drogued buoy data. Mean geostrophic currents were appraised more comprehensively than previous attempts, and the paths of 4 branches of the North Atlantic Current (NAC) and positions of 5 eddies in the region were derived quantitatively. A consistent seasonal cycle in the flow of the SC was found at all 8 sections along the European shelf slope, with maximum poleward flow in the winter and minimum in the summer. The seasonal difference in the altimetry current speed amounted to ~8-10 cm s-1 at the northern sections, but only ~5 cm s-1 on the Bay of Biscay slopes. This extended altimeter dataset indicates significant regional and seasonal variations, and has revealed new insights into the interannual variability of the SC. It is shown that there is a peak poleward flow at most positions along a ~2000 km stretch of the continental slope from Portugal to Scotland during 1995-1997, but this did not clearly relate to the extreme negative North Atlantic Oscillation (NAO) in the winter of 1995-1996. The speed of the SC exhibited a long term decreasing trend of ~1% per year. By contrast the NAC showed no significant trend over the 20-year period. Major changes in the NAC occurred three times, and these changes followed decreases in the NAO index.

Nanoplankton and picoplankton in the Western English Channel: abundance and seasonality from 2007–2013

The nano- and picoplankton community at Station L4 in the Western English Channel was studied between 2007 and 2013 by flow cytometry to quantify abundance and investigate seasonal cycles within these communities. Nanoplankton included both photosynthetic and heterotrophic eukaryotic single-celled organisms while the picoplankton included picoeukaryote phytoplankton, Synechococcus sp. cyanobacteria and heterotrophic bacteria. A Box–Jenkins Transfer Function climatology analysis of surface data revealed that Synechococcus sp., cryptophytes, and heterotrophic flagellates had bimodal annual cycles. Nanoeukaryotes and both high and low nucleic acid-containing bacteria (HNA and LNA, respectively) groups exhibited unimodal annual cycles. Phaeocystis sp., whilst having clearly defined abundance maxima in spring was not detectable the rest of the year. Coccolithophores exhibited a weak seasonal cycle, with abundance peaks in spring and autumn. Picoeukaryotes did not exhibit a discernable seasonal cycle at the surface. Timings of maximum group abundance varied through the year. Phaeocystis sp. and heterotrophic flagellates peaked in April/May. Nanoeukaryotes and HNA bacteria peaked in June/July and had relatively high abundance throughout the summer. Synechococcus sp., cryptophytes and LNA bacteria all peaked from mid to late September. The transfer function model techniques used represent a useful means of identifying repeating annual cycles in time series data with the added ability to detect trends and harmonic terms at different time scales from months to decades.

Birth, life and death of a cyclonic eddy in the Southern Ocean

The ACC is a climatically relevant frontal structure of global importance that regularly develops instabilities which grow into meanders that eventually evolve into long-lived cyclonic eddies. These eddies exhibit sustain primary productivity that can last several months fuelled by local resupply of nutrients. During April-May 2015 we conducted an intensive field experiment in the Southern Ocean (SMILES) where we sampled and tracked an ACC meander as it developed into an eddy and later vanished some 90 days later. The meander and later eddy physical characteristics were observed with a combination of high resolution hydrography, ADCP and turbulence observations in addition to surface and depth resolved biogeochemical observations of nutrients and phytoplankton. The life and death of the eddy was subsequently tracked through ARGO, BIO-ARGO and remote sensing.

Birth technology competence: a concept analysis

Aim. To identify birth technology competencies used by midwives to support women during the birthing process and to explore the concept of birth technology competence in midwifery practice in order to inform both education and practice. Objective. To define attributes of birth technology competence. Method. The Chinn and Kramer framework for concept analysis was used to examine sources including popular and professional literature, government reports and statutory regulation. The model allows for the exploration of three areas of experience, which interact to form the meaning of an idea or concept – feelings, values and attitudes associated with the concept, the symbolic label for the concept and the concept itself. Results. Exploration of the literature led to the development of exemplar cases that illuminate tentative attributes of the concept, contained within three domains – interpersonal skills, professional knowledge and clinical proficiency. Implications. Following testing in midwifery practice to ensure its transferability into the clinical context, the theoretical perspective developed here will provide a basis to inform education and practice in relation to the use of technology.

Virgin birth in a hammerhead shark.

Parthenogenesis has been documented in all major jawed vertebrate lineages except mammals and cartilaginous fishes (Class Chondrichthyes: sharks, batoids, chimeras). Reports of captive female sharks giving birth despite being held in the extended absence of males have generally been ascribed to prior matings coupled with long-term sperm storage by the females. Here we provide the first genetic evidence for chondrichthyan parthenogenesis, involving a hammerhead shark. This finding also broadens the known occurrence of a specific type of asexual development (automictic parthenogenesis) among vertebrates, extending recently raised concerns about the potential negative effect of this type of facultative parthenogenesis on the genetic diversity of threatened vertebrate species.