Increasing turbidity in the North Sea during the 20th century due to changing wave climate

Data on Secchi disc depth (the depth at which a standard white disc lowered into the water just becomes invisible to a surface observer) show that water clarity in the North Sea declined during the 20th century, with likely consequences for marine primary production. However, the causes of this trend remain unknown. Here we analyse the hypothesis that changes in the North Sea's wave climate were largely responsible by causing an increase in the concentrations of suspended particulate matter (SPM) in the water column through the resuspension of seabed sediments. First, we analysed the broad-scale statistical relationships between SPM and bed shear stress due to waves and tides. We used hindcasts of wave and current data to construct a space–time dataset of bed shear stress between 1997 and 2017 across the northwest European Continental Shelf and compared the results with satellite-derived SPM concentrations. Bed shear stress was found to drive most of the inter-annual variation in SPM in the hydrographically mixed waters of the central and southern North Sea. We then used a long-term wave reanalysis to construct a time series of bed shear stress from 1900 to 2010. This shows that bed shear stress increased significantly across much of the shelf during this period, with increases of over 20 % in the southeastern North Sea. An increase in bed shear stress of this magnitude would have resulted in a large reduction in water clarity. Wave-driven processes are rarely included in projections of climate change impacts on marine ecosystems, but our analysis indicates that this should be reconsidered for shelf sea regions

Modelling the Whole-Ecosystem Impacts of Trawling

Trawling has been controversial since its introduction in the 17th century. In 1882 the Fishery Board for Scotland was established and assigned powers to ban beam and otter trawling where necessary to protect traditional static gear fisheries. Under these powers, large parts of the inshore waters off the east and west coasts of Scotland were closed to trawling. The Firth of Clyde remained closed until 1962. More recently, in April 2015 solicitors acting for Greenpeace obtained High Court permission for a judicial review of Defra’s alleged failure to adjust its policy on allocating annual landing quotas to reflect reforms to the CFP. It is claimed the reforms stipulate that greater preference should be given to sustainable low impact fishing methods at the expense of high-impact methods such as trawling. In Scotland, the exclusion of trawling activity from a network of marine protected areas established in July 2015 has also been highly controversial. There is no doubt that some trawl gears can be extremely destructive of fragile habitats and slowly regenerating fauna such as coral. Over expanses of mud or sand, however, it has been claimed that trawling may be a positive factor, akin to ploughing the fields in terrestrial agriculture, and enhancing the productivity of the ecosystem. There have been many scientific studies, both in the field and using mathematical modelling, of the impact of trawling on the seabed. Similarly, we know very well that harvesting of fish and shellfish, whether using trawling or static gear, has consequences for marine food webs. However, there have been few, if any, scientific studies which have put these two aspects of trawling together and then compared the seabed impacts of trawling with the consequences of harvesting. In this project we used a mathematical model to compare and contrast the whole ecosystem effects of harvesting fish and shellfish with the consequences of other aspects of trawling activity, especially the ploughing of seabed habitats. The model is not detailed to the level of individual species or exact locations. Rather it gives results at the level of a whole regional sea area, such as the North Sea or the whole of the west of Scotland. The project had three main components. First, was the extension of an existing mathematical model of a marine ecosystem to include explicit representation of the ploughing effects that different gears have on seabed habitats. Second, an analysis of a large international data set on activity, landings and catches by different fishing gears in northwest European waters, and the mapping of these onto different seabed habitats to generate inputs to the model. Finally, we carried out a series of sensitivity experiments with the model. These experiments investigated the whole ecosystem effects of seabed ploughing by different gears, using food web indicators relevant to the EU Marine Strategy Framework Directive, and compared them with the impact of one scenario for implementing a landing obligation, and the potential impacts of a reduction in overall fishing activity. For the North Sea, the results show that even if all ploughing effects were eliminated, the effects on the whole ecosystem would be equivalent to only a 1% or less change in overall harvesting rate of fish and shellfish. This is a very small effect compared to the changes in effective harvesting rate implied by the improvements in gear selectivity required to achieve the landing obligation. For the west of Scotland region, the model showed that the food web was more sensitive to the effects of ploughing by fishing gears than in the North Sea, but the effect was still small compared to the consequences of activity reduction overall. The greater sensitivity of the west of Scotland to seabed ploughing arose because the disturbance rate of muddy sediments was around 5-times higher than in the North Sea, almost entirely due to the activities of TR2 Nephrops trawling. Despite our conclusion that the regional scale food web effects of seabed ploughing are small compared to the primary consequences of harvesting fish, this is not to say that there are no effects on regional biodiversity, or significant effects at local scales on specific habitats or vulnerable species. In particular the study identifies the TR2 gear fleet as being responsible for the majority of ecosystem-wide consequences of seabed ploughing. This gear has a particularly high ploughing rate and its activity is focussed on muddy sediments where the nutrient chemistry processes are more vulnerable to ploughing than in sandy and coarser sediments

The role of TREX in gene expression and disease

TRanscription and EXport (TREX) is a conserved multisubunit complex essential for embryogenesis, organogenesis and cellular differentiation throughout life. By linking transcription, mRNA processing and export together, it exerts a physiologically vital role in the gene expression pathway. In addition, this complex prevents DNA damage and regulates the cell cycle by ensuring optimal gene expression. As the extent of TREX activity in viral infections, amyotrophic lateral sclerosis and cancer emerges, the need for a greater understanding of TREX function becomes evident. A complete elucidation of the composition, function and interactions of the complex will provide the framework for understanding the molecular basis for a variety of diseases. This review details the known composition of TREX, how it is regulated and its cellular functions with an emphasis on mammalian systems

Spatial modelling of Calanus finmarchicus and Calanus helgolandicus : parameter differences explain differences in biogeography

The North Atlantic copepods Calanus finmarchicus and C. helgolandicus are moving north in response to rising temperatures. Understanding the drivers of their relative geographic distributions is required in order to anticipate future changes. To explore this, we created a new spatially explicit stage-structured model of their populations throughout the North Atlantic. Recent advances in understanding Calanus biology, including U-shaped relationships between growth and fecundity and temperature, and a new model of diapause duration are incorporated in the model. Equations were identical for both species, but some parameters were species-specific. The model was parameterized using Continuous Plankton Recorder Survey data and tested using time series of abundance and fecundity. The geographic distributions of both species were reproduced by assuming that only known interspecific differences and a difference in the temperature influence on mortality exist. We show that differences in diapause capability are not necessary to explain why C. helgolandicus is restricted to the continental shelf. Smaller body size and higher overwinter temperatures likely make true diapause implausible for C. helgolandicus. Known differences were incapable of explaining why only C. helgolandicus exists southwest of the British Isles. Further, the fecundity of C. helgolandicus in the English Channel is much lower than we predict. We hypothesize that food quality is a key influence on the population dynamics of these species. The modeling framework presented can potentially be extended to further Calanus species

Lipid content in overwintering Calanus finmarchicus across the Subpolar Eastern North Atlantic Ocean

The boreal copepod Calanus finmarchicus accumulates lipid reserves during summer feeding in surface ocean waters, which enable it to stay at depth and survive famine during overwintering. Respiration of lipids during prolonged overwintering at ocean depths (> 1000 m in some areas) has been shown to result in a net sequestration of carbon into the deep ocean: the so-called “lipid pump.” Here, we provide a comprehensive synthesis of the geographic and vertical variations in lipid content of overwintering animals across the Subpolar Eastern North Atlantic and, on the basis of this, we revise the estimates of carbon sequestration. Wax ester content ranged from 40 to 190 μg individual −1 at > 250 m depths, with highest concentrations in the coldest ( 4°C) Irminger Sea and Rockall Basin. Our new analysis results in about 44% higher estimates of carbon sequestration at up to 11.5 g C m −2

Projected impacts of 21st century climate change on diapause in Calanus finmarchicus

Diapause plays a key role in the life cycle of high latitude zooplankton. During diapause animals avoid starving in winter by living in deep waters where metabolism is lower and met by lipid reserves. Global warming is therefore expected to shorten the maximum potential diapause duration by increasing metabolic rates and by reducing body size and lipid reserves. This will alter the phenology of zooplankton, impact higher trophic levels and disrupt biological carbon pumps. Here we project the impacts of climate change on the key North Atlantic copepod Calanus finmarchicus under IPCC RCP 8.5. Potential diapause duration is modelled in relation to body size and overwintering temperature. The projections show pronounced geographic variations. Potential diapause duration reduces by more than 30% in the Western Atlantic, whereas in the key overwintering centre of the Norwegian Sea it changes only marginally. Surface temperature rises, which reduce body size and lipid reserves, will have a similar impact to deep water changes on diapause in many regions. Because deep water warming lags that at the surface, animals in the Labrador Sea could offset warming impacts by diapausing in deeper waters. However, the ability to control diapause depth may be limited

Nominal juxtaposition in Australian languages: An LFG analysis

It is well known that Australian languages make heavy use of nominal juxtaposition in a wide variety of functions, but there is little discussion in the theoretical literature of how such juxtapositions should be analysed. We discuss a range of data from Australian languages illustrating how multiple nominals share a single grammatical function within the clause. We argue that such constructions should be treated syntactically as set-valued grammatical functions in Lexical-Functional Grammar (LFG). Sets as values for functions are well-established in LFG and are used in the representation of adjuncts, and also in the representation of coordination. In many Australian languages, coordination is expressed asyndetically, that is, by nominal juxtaposition with no overt coordinator at all. We argue that the syntactic similarity of all juxtaposed constructions (ranging from coordination through a number of more appositional relations) motivates an analysis in which they are treated similarly in the syntax, but suitably distinguished in the semantics. We show how this can be achieved within LFG, providing a unified treatment of the syntax of juxtaposition in Australian languages and showing how the interface to the semantics can be quite straightforwardly defined in the modular LFG approach. Copyright © Cambridge University Press 2009

Protective Effect of Maritime Quarantine in South Pacific Jurisdictions, 1918–19 Influenza Pandemic

We reviewed mortality data of the 1918–19 influenza pandemic for 11 South Pacific Island jurisdictions. Four of these appear to have successfully delayed or excluded the arrival of pandemic influenza by imposing strict maritime quarantine. They also experienced lower excess death rates than the other jurisdictions that did not apply quarantine measures

Real-Time Simulation of Ares I Launch Vehicle

The Ares Real-Time Environment for Modeling, Integration, and Simulation (ARTEMIS) has been developed for use by the Ares I launch vehicle System Integration Laboratory (SIL) at the Marshall Space Flight Center (MSFC). The primary purpose of the Ares SIL is to test the vehicle avionics hardware and software in a hardware-in-the-loop (HWIL) environment to certify that the integrated system is prepared for flight. ARTEMIS has been designed to be the real-time software backbone to stimulate all required Ares components through high-fidelity simulation. ARTEMIS has been designed to take full advantage of the advances in underlying computational power now available to support HWIL testing. A modular real-time design relying on a fully distributed computing architecture has been achieved. Two fundamental requirements drove ARTEMIS to pursue the use of high-fidelity simulation models in a real-time environment. First, ARTEMIS must be used to test a man-rated integrated avionics hardware and software system, thus requiring a wide variety of nominal and off-nominal simulation capabilities to certify system robustness. The second driving requirement - derived from a nationwide review of current state-of-the-art HWIL facilities - was that preserving digital model fidelity significantly reduced overall vehicle lifecycle cost by reducing testing time for certification runs and increasing flight tempo through an expanded operational envelope. These two driving requirements necessitated the use of high-fidelity models throughout the ARTEMIS simulation. The nature of the Ares mission profile imposed a variety of additional requirements on the ARTEMIS simulation. The Ares I vehicle is composed of multiple elements, including the First Stage Solid Rocket Booster (SRB), the Upper Stage powered by the J- 2X engine, the Orion Crew Exploration Vehicle (CEV) which houses the crew, the Launch Abort System (LAS), and various secondary elements that separate from the vehicle. At launch, the integrated vehicle stack is composed of these stages, and throughout the mission, various elements separate from the integrated stack and tumble back towards the earth. ARTEMIS must be capable of simulating the integrated stack through the flight as well as propagating each individual element after separation. In addition, abort sequences can lead to other unique configurations of the integrated stack as the timing and sequence of the stage separations are altered

RhoJ interacts with the GIT-PIX complex and regulates focal adhesion disassembly

RhoJ is a Rho GTPase expressed in endothelial cells and tumour cells, which regulates cell motility, invasion, endothelial tube formation and focal adhesion numbers. This study aimed to further delineate the molecular function of RhoJ. Using timelapse microscopy RhoJ was found to regulate focal adhesion disassembly; small interfering RNA (siRNA)-mediated knockdown of RhoJ increased focal adhesion disassembly time, whereas expression of an active mutant (daRhoJ) decreased it. Furthermore, daRhoJ co-precipitated with the GIT–PIX complex, a regulator of focal adhesion disassembly. An interaction between daRhoJ and GIT1 was confirmed using yeast two-hybrid experiments, and this depended on the Spa homology domain of GIT1. GIT1, GIT2, β-PIX (also known as ARHGEF7) and RhoJ all colocalised in focal adhesions and depended on each other for their recruitment to focal adhesions. Functionally, the GIT–PIX complex regulated endothelial tube formation, with knockdown of both GIT1 and GIT2, or β-PIX phenocopying RhoJ knockdown. RhoJ-knockout mice showed reduced tumour growth and diminished tumour vessel density, identifying a role for RhoJ in mediating tumour angiogenesis. These studies give new insight into the molecular function of RhoJ in regulating cell motility and tumour vessel formation