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Zooplankton phenological shifts may affect energy transfer through pelagic food web and up to fisheries, but few studies have compared zooplankton phenology across a wide latitudinal range of water temperatures. We examined the phenological variations of zooplankton at four sites along a latitudinal gradient from the Bay of Biscay [Bilbao and Urdaibai (BU)], the English Channel (Plymouth; L4), and the North Sea [Stonehaven (SH)] from 1999 to 2013. Zooplankton taxa showed interannual phenological variations that were opposite in direction between the southernmost BU and the northernmost SH sites. The East Atlantic pattern was the climate teleconnection best related to zooplankton phenological variations. Among local variables , salinity at BU was best related to phenological changes at BU as opposed to those at SH. Locally, chlorophyll a was most relevant at SH and temperature at L4. While we did see some imprints of temperature in causing expected directions of phenology shifts, i.e. towards earlier appearance of spring taxa and later appearance of autumn taxa in warm years, these patterns were by no means clear-cut. The dominant role of temperature in driving phenological variation suggested by some studies seems to be obscured by biotic and climatic controls acting differently along our environmental gradient.

Zooplankton seasonality and its environmental drivers were studied at four coastal sites within the Northeast Atlantic Shelves Province (Bilbao35 (B35) and Urdaibai35 (U35) in the Bay of Biscay, Plymouth L4 (L4) in the English Channel and Stonehaven (SH) in the North Sea) using time series spanning 1999–2013. Seasonal community patterns were extracted at the level of broad zooplankton groups and copepod and cladoceran genera using redundancy analysis. Temperature was generally the environmental factor that explained most of the taxa seasonal variations at the four sites. However, between-site differences related to latitude and trophic status (i.e. from oligotrophic to mesotrophic) were observed in the seasonality of zooplankton community, mainly in the pattern of taxa that peaked in spring-summer as opposed to late autumn-winter zooplankton, which were linked primarily to differences in the seasonal pattern of phytoplankton. The percentage of taxa variations explained by environmental factors increased with latitude and trophic status likely related to the increase in the co-variation of temperature and chlorophyll a, as well as in the increase in regularity of the seasonal patterns of both temperature and chlorophyll a from south to north, and of chlorophyll a with trophic status. Cladocerans and cirripede larvae at B35 and U35, echinoderm larvae at L4 and decapod larvae at SH made the highest contribution to shape the main mode of seasonal pattern of zooplankton community, which showed a seasonal delay with latitude, as well as with the increase in trophic status.

Zooplankton abundance series (1999–2013) from the coastal sites of Bilbao 35 (B35), Urdaibai 35 (U35), Plymouth L4 (L4) and Stonehaven (SH), in the Northeast Atlantic were compared to assess differences in the magnitude of seasonal, interannual and residual scales of variability, and in patterns of seasonal and interannual variation in relation to latitudinal location and trophic status. Results showed highest seasonal variability at SH consistent with its northernmost location, highest interannual variability at U35 associated to an atypical event identified in 2012 in the Bay of Biscay, and highest residual variability at U35 and B35 likely related to lower sampling frequency and higher natural and anthropogenic stress. Interannual zooplankton variations were not coherent across sites, suggesting the dominance of local influences over large scale environmental drivers. For most taxa the seasonal pattern showed coherent differences across sites, the northward delay of the annual peak being the most common feature. The between-site seasonal differences in spring–summer zooplankton taxa were related mainly to phytoplankton biomass, in turn, related to differences in latitude or anthropogenic nutrient enrichment. The northward delay in water cooling likely accounted for between-site seasonal differences in taxa that increase in the second half of the year.

We consider the problem of deciding whether a k-colored graph can be completed to have a given property. We establish that, when k is not fixed, the completion problems for (Helly) circular-arc graphs, even (Helly) proper or (Helly) unit circular-arc graphs, are NP-complete. When k is fixed, in the case of completion to a (Helly) circular-arc graph, (Helly) proper circular-arc graph, or (Helly) unit circular-arc graph we fully classify the complexities of the problems. We also show that deciding whether a 3-colored graph can be completed to be strongly chordal can be done in O(n2) time. As a corollary of our results, the sandwich problems for Helly circular-arc graphs, Helly proper circular-arc graphs, and Helly unit circular-arc graphs are NP-complete.

This study examined the inter-relationships between kittiwake breeding success and sandeel abundance, Calanus copepods, chlorophyll and temperature. The validity of past proxies of sandeel prey (Calanus and temperature) suggested in the literature was also examined. Winter temperature was not found to be a reliable indicator of the abundance of sandeel or lower trophic levels, although the present study did support past evidence for a dependence of kittiwake breeding success on local sandeel abundance as, with the exception of two years, there was a linear relationship with log age-0 sandeel abundance. The abundance of sandeel was positively linked to the dates of predicted peak egg abundance in C. finmarchicus and C. helgolandicus. This supported earlier evidence that the match with prey timing is important to sandeel recruitment. Neither Calanus species was associated with temperature in the February to March period nor in the April–May period, which may explain the lack of a temperature effect that propagates through the trophic levels. Consequently, although kittiwake breeding success appears to show some sensitivity and specificity to changes in their prey, this responsiveness was not found to extend to the lowest trophic level (Calanus abundance) or to temperature. As such kittiwake breeding success was not a reliable indicator of climate-driven changes in the local food web.

Plankton are sensitive indicators of change and, at the base of marine food webs, they underpin important ecosystem services such as carbon sequestration and fisheries production. In the UK and the Northeast Atlantic region, change in plankton functional groups, or ‘lifeforms’, constructed based on biological traits, is the formally accepted policy indicator used to assess Good Environmental Status (GES) for pelagic habitats under the Marine Strategy Framework Directive (MSFD: 2008/56/EC). To identify changes in UK pelagic habitats, plankton lifeforms, were used from diverse UK data sets collected by different methods, including plankton sampling by nets, water bottles, integrating tube samplers, and the Continuous Plankton Recorder. A Plankton Index approach was used to identify change in plankton lifeforms. This is the first time that the pelagic plankton community has been assessed on a UK-wide scale and forms the foundation of the UK’s 2020 MSFD Assessment for pelagic habitat biodiversity and food webs. This approach revealed that some of the plankton lifeforms used in the assessment displayed spatially-variable changes during the past decade. Assessing plankton community change using a common indicator at the UK scale for the first time is a significant step towards evaluating GES for European seas. Determining GES for pelagic habitats, however, is a challenging process, with additional work required to interpret the assessment results and to identify causation of the changes observed.

The copepod Eurytemora herdmani, native to coastal waters of the north-west Atlantic and north Pacific Oceans, was discovered at a marine sampling station in the Firth of Forth, Scotland, UK. The species was present in the summer zooplankton assemblage over three successive years. Peak abundance followed peak chlorophyll a concentration in surface waters. Given that previous studies on the Firth of Forth had only found species native to Europe, a survey of the Forth estuary was undertaken in summer 2014. Eurytemora herdmani was found at sampling stations where the salinity was greater than 20, while Eurytemora affinis was found at sampling stations with lower salinity further upstream. The impact of this introduction on the native zooplankton community is not known, and will require further study. The Firth of Forth has a high level of shipping traffic, and this species may have been introduced by ships’ ballast water.

This study presents the first comparative description of the physics, nutrients and plankton communities at two Scottish monitoring sites between 2003 and 2012; Stonehaven on the east coast of Scotland and Loch Ewe on the west coast. This description provides baseline information about the diversity of the plankton community in Scottish waters to support assessment of the plankton community for the EU Marine Strategy Framework Directive. Spring time temperatures at Loch Ewe were approximately 2 °C higher and the median secchi depth was almost 1 m greater than at Stonehaven during this period. Freshwater inflow from the river Ewe may promote water column stability at Loch Ewe. These factors may account for the earlier spring bloom observed at the Loch Ewe monitoring site. The seasonality of chlorophyll ‘a’ at Loch Ewe was typical of stratified waters in temperate regions with a strong spring/autumn peak attributed to increased numbers of diatoms whilst dinoflagellates dominated during the summer. At Stonehaven highest concentrations of chlorophyll were recorded between May and June and the autumn diatom bloom was considerably less than in Loch Ewe. A higher biomass of zooplankton grazers was found at Loch Ewe than at Stonehaven. Pseudocalanus was the dominant copepod at both sites, particularly during the spring period. Zooplankton carnivores were also more abundant at Loch Ewe than at Stonehaven and were dominated by cnidarians. Considerable interannual variability was observed in cnidarian abundance and diversity at both sites. Variation in the abundance of Ceratium, Calanus finmarchicus and Calanus helgolandicus at both sites followed similar trends in other time series suggesting that the plankton communities at Stonehaven and Loch Ewe are responding to large scale environmental influences.

Recent research has focused on the development of effective online problem based learning (PBL). However, there is a need for research to examine experiences of online PBL in those new to online learning. This study used a single module blended approach to examine the student experience of online PBL in a group of postgraduates new to online learning. This employed one problem scenario for each group (four students per group) as the central component of the module. Asynchronous discussion boards were used to facilitate the learning process with other forms of delivery used as appropriate. Focus group interviews revealed that students believed online PBL developed skills related to employability and information retrieval/evaluation. Online PBL was seen as beneficial for developing ideas and critiquing information. However, the artificial nature of the discussion board space was a barrier for some students, as was anxiety about online participation in the PBL tasks.

The efficacy of caffeine ingestion in enhancing aerobic performance is well established. The evidence for caffeine's effects on resistance exercise is mixed and has not fully examined the associated psychological and psychophysiological changes. This study examined acute effects of ingesting a caffeine-containing energy drink on repetitions to failure, the rating of perceived exertion (RPE), and the readiness to invest physical effort (RTIPE) and mental effort during resistance exercise to failure. Thirteen resistance-trained men took part in this double-blind, randomized cross-over experimental study whereby they ingested a caffeinated (179 mg) energy drink or placebo solution 60 minutes before completing a bout of resistance exercise comprising bench press, deadlift, prone row, and back squat exercise to failure at an intensity of 60% 1-repetition maximum. Experimental conditions were separated by at least 48 hours. Participants completed significantly greater repetitions to failure, irrespective of exercise, in the energy drink condition (p = 0.015). Rating of perceived exertion was significantly higher in the placebo condition (p = 0.02) and was significantly higher during lower-body exercises compared with upper-body exercises irrespective of the substance ingested (p = 0.0001). Readiness to invest mental effort was greater with the energy drink condition (p = 0.04), irrespective of time. A significant time × substance interaction (p = 0.036) for RTIPE indicated that RTIPE increased for both placebo and energy drink conditions preingestion to pre-exercise, but the magnitude of increase was greater with the energy drink condition compared with placebo. This resulted in higher RTIPE postexercise for the energy drink condition. These results suggest that acute ingestion of a caffeine-containing energy drink can enhance resistance exercise performance to failure and positively enhance psychophysiological factors related to exertion in trained men.

We examined how predicted end of century ocean warming and acidification scenarios affected the incidence of apoptosis in the eggs and nauplii of the copepod Calanus helgolandicus. Offspring viability was not affected by 1000 ppm CO2-acidified seawater, whereas the effects of 2 and 4°C warming were dependent upon the batch of eggs used; warming increased viability in the second batch. This context-dependency highlights the need for cautious interpretation and application of data from individual climate-change studies.

The performance of a new mesozooplankton sampler, the U-Tow, was compared to that of the traditional WP2 net. The U-Tow significantly underestimated species abundance, but gave a very good representation of species composition and community size structure. WP2 net samples could be used to calibrate the U-Tow, allowing absolute abundance to be determined. It is recommended that the U-Tow, in its current configuration, be used in conjunction with WP2 net samples to give measures of abundance, or as a tool to identify areas of change in plankton communities.