scholarly journals Annual phytoplankton succession results from niche-environment interaction

2020 ◽  
Author(s):  
Mariarita Caracciolo ◽  
Grégory Beaugrand ◽  
Pierre Hélaouët ◽  
Francois Gevaert ◽  
Martin Edwards ◽  
...  
Keyword(s):  
Species Level ◽  
Ecological Niches ◽  
Environment Interaction ◽  
Phytoplankton Succession ◽  
Active Radiation ◽  
The North ◽  
The North Sea ◽  
Using Data ◽  
Recurrent Patterns ◽  
Macro Nutrients

Abstract Annual plankton succession has been investigated for many decades with hypotheses ranging from abiotic to biotic mechanisms being proposed to explain these recurrent patterns. Here, using data collected by the Continuous Plankton Recorder (CPR) survey and models originating from the MacroEcological Theory on the Arrangement of Life, we investigate Annual Phytoplankton Succession (APS) in the North Sea at a species level. Our results show that this phenomenon can be predicted well by models combining photosynthetically active radiation, temperature and macro-nutrients. Our findings suggest that APS originates from the interaction between species’ ecological niches and the annual environmental fluctuations at a community level. We discuss our results in the context of traditional hypotheses formulated to explain this recurrent pattern in the marine field.

Building a Low-Manned Production Installation: Considerations for Rotating Equipment, Electrical & Automation Systems, and Digitalization

2021 ◽  
Author(s):  
Elgonda LaGrange
Keyword(s):  
Oil And Gas ◽  
Cost Savings ◽  
Decision Makers ◽  
The North ◽  
Automation Systems ◽  
The North Sea ◽  
Rotating Equipment ◽  
Using Data ◽  
Areas Of Interest ◽  
Insight Into

Abstract Nearly all oil and gas operators and engineering companies in the offshore sector today are engaged in programs to advance concepts for low-manned and/or normally unattended production installations (NUIs). When it comes to the design of these facilities, topsides rotating equipment and electrical, instrumentation, control, and telecommunications (EICT) packages represent key areas of interest for decision-makers, owing to the significant impact they can have on required manning levels. Over the past decade, the author's company has worked closely with major Operators in the U.S. and the North Sea to look at how existing technologies can be applied in these areas to safely facilitate de-manning of both brownfields and greenfields. This paper provides insight into these efforts. It also presents projected manpower and cost savings from de-manning, using data derived from both studies and real-world projects.

scholarly journals Sympatric Atlantic puffins and razorbills show contrasting responses to adverse marine conditions during winter foraging within the North Sea

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Katie St. John Glew ◽  
Sarah Wanless ◽  
Michael P. Harris ◽  
Francis Daunt ◽  
Kjell Einar Erikstad ◽  
...  
Keyword(s):  
North Sea ◽  
Environmental Conditions ◽  
Trophic Position ◽  
Survival Rates ◽  
Sympatric Species ◽  
Ecological Niches ◽  
Overwinter Survival ◽  
The North ◽  
Winter Conditions ◽  
The North Sea

Abstract Background Natural environments are dynamic systems with conditions varying across years. Higher trophic level consumers may respond to changes in the distribution and quality of available prey by moving to locate new resources or by switching diets. In order to persist, sympatric species with similar ecological niches may show contrasting foraging responses to changes in environmental conditions. However, in marine environments this assertion remains largely untested for highly mobile predators outside the breeding season because of the challenges of quantifying foraging location and trophic position under contrasting conditions. Method Differences in overwinter survival rates of two populations of North Sea seabirds (Atlantic puffins (Fratercula arctica) and razorbills (Alca torda)) indicated that environmental conditions differed between 2007/08 (low survival and thus poor conditions) and 2014/15 (higher survival, favourable conditions). We used a combination of bird-borne data loggers and stable isotope analyses to test 1) whether these sympatric species showed consistent responses with respect to foraging location and trophic position to these contrasting winter conditions during periods when body and cheek feathers were being grown (moult) and 2) whether any observed changes in moult locations and diet could be related to the abundance and distribution of potential prey species of differing energetic quality. Results Puffins and razorbills showed divergent foraging responses to contrasting winter conditions. Puffins foraging in the North Sea used broadly similar foraging locations during moult in both winters. However, puffin diet significantly differed, with a lower average trophic position in the winter characterised by lower survival rates. By contrast, razorbills’ trophic position increased in the poor survival winter and the population foraged in more distant southerly waters of the North Sea. Conclusions Populations of North Sea puffins and razorbills showed contrasting foraging responses when environmental conditions, as indicated by overwinter survival differed. Conservation of mobile predators, many of which are in sharp decline, may benefit from dynamic spatial based management approaches focusing on behavioural changes in response to changing environmental conditions, particularly during life history stages associated with increased mortality.

scholarly journals Distribution of marine, benthic, shell bearing gastropods along the Norwegian coast

2009 ◽  
Vol 28 ◽  
Author(s):  
Tore Høisæter
Keyword(s):  
Continental Slope ◽  
Main Part ◽  
Geographic Area ◽  
Species Level ◽  
Western Slope ◽  
Southern Limit ◽  
North East ◽  
The North ◽  
The North Sea ◽  
The One

Based on literature data and my extensive material from along the coast, the distribution of shell bearing marine, benthic gastropods known from Norwegian waters, is outlined. The geographic area covered goes down to c. 1200 m on the continental slope, and extends from the Swedish border<br />in the south to the Russian border in the north-east. On the slope the distribution is restricted to an area east of 0°, and south of 72° N. Neither the North Sea nor the western ‘slope’ of the Norwegian Trench are included. Systematics and nomenclature follow Clemam (Check List of European Marine Mollusca) closely. The emphasis is on the distribution of each species within the designated area, but taxonomic and nomenclaturial problems are discussed wherever considered relevant. Altogether 365 species level taxa are included, of which 326 are considered as definitely belonging to the Norwegian fauna. The rest are recorded as doubtful, either because only empty shells have been found, or their confirmed distribution falls outside the limits here defined. Of the ‘species’ included, I consider at least 18 to be undescribed, while another 16 were described from Norwegian material after Høisæter (1986) was published. The northern distributional limit is extended for 47 species, while 11 species have received a new southern limit. Sixty six species have a generic name diferent from the one used in Høisæter (1986), while 35 species have another specific name. All changes are listed in the main part of the article, and references are given to the sources for the changes. Four faunal components are recognized: a slope component, species mainly found in negative temperatures on the continental slope, between 500 and 1200 m; an Arctic component, species in Norway almost exclusively found in East Finnmark; a group of species in Norway found only or mainly on the Skagerrak coast or in Oslofjorden; and finally the main group found along most of the coast.

scholarly journals Demersal fish biodiversity: species-level indicators and trends-based targets for the Marine Strategy Framework Directive

2012 ◽  
Vol 69 (10) ◽  
pp. 1789-1801 ◽  
Author(s):  
Simon P. R. Greenstreet ◽  
Axel G. Rossberg ◽  
Clive J. Fox ◽  
William J. F. Le Quesne ◽  
Tom Blasdale ◽  
...  
Keyword(s):  
North Sea ◽  
Demersal Fish ◽  
Species Level ◽  
Marine Strategy Framework Directive ◽  
The North ◽  
Fish Biodiversity ◽  
Environmental Status ◽  
The North Sea ◽  
Good Environmental Status ◽  
Species Specific

Abstract Greenstreet, S. P. R., Rossberg, A. G., Fox, C. J., Le Quesne, W. J. F., Blasdale, T., Boulcott, P., Mitchell, I., Millar, C., and Moffat, C. F. 2012. Demersal fish biodiversity: species-level indicators and trends-based targets for the Marine Strategy Framework Directive. – ICES Journal of Marine Science, 69: 1789–1801. The maintenance of biodiversity is a fundamental theme of the Marine Strategy Framework Directive. Appropriate indicators to monitor change in biodiversity, along with associated targets representing “good environmental status” (GES), are required to be in place by July 2012. A method for selecting species-specific metrics to fulfil various specified indicator roles is proposed for demersal fish communities. Available data frequently do not extend far enough back in time to allow GES to be defined empirically. In such situations, trends-based targets offer a pragmatic solution. A method is proposed for setting indicator-level targets for the number of species-specific metrics required to meet their trends-based metric-level targets. This is based on demonstrating significant departures from the binomial distribution. The procedure is trialled using North Sea demersal fish survey data. Although fisheries management in the North Sea has improved in recent decades, management goals to stop further decline in biodiversity, and to initiate recovery, are yet to be met.

Discarding practices for commercial gadoids in the North Sea

1998 ◽  
Vol 55 (7) ◽  
pp. 1632-1644 ◽  
Author(s):  
Yorgos Stratoudakis ◽  
Robert J Fryer ◽  
Robin M Cook
Keyword(s):  
North Sea ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Melanogrammus Aeglefinus ◽  
The North ◽  
The North Sea ◽  
Merlangius Merlangus ◽  
Using Data ◽  
Species Specific ◽  
Catch Composition

Understanding fishers' discarding behaviour, and anticipating their reactions to changes in the biological or regulatory characteristics of a fishery, are important for dealing with the problem of discarding. In this paper, we investigate the discarding of haddock (Melanogrammus aeglefinus), whiting (Merlangius merlangus), and Atlantic cod (Gadus morhua) in the North Sea, using data collected by scientific observers onboard Scottish demersal vessels. We describe discarding on each trip by species-specific discard curves and explore how these curves depend on biological and regulatory variables. There are large differences in the size of discarded fish between inshore and offshore areas, with offshore-operating vessels discarding larger fish (high-grading). Increases in legal landing size correspond to immediate increases in the size of discarded fish, particularly for haddock and cod in inshore areas. In general, discarding practices for haddock and cod are similar over time and consistent across gears, whereas decisions for the lesser valued whiting are more variable and can be affected by the catch composition.

scholarly journals Weighting of acoustic- and trawl-survey indices for the assessment of North Sea herring

2003 ◽  
Vol 60 (3) ◽  
pp. 463-471 ◽  
Author(s):  
E.J Simmonds
Keyword(s):  
North Sea ◽  
Assessment Model ◽  
The Other ◽  
Trawl Survey ◽  
Acoustic Survey ◽  
Weighting Method ◽  
The North ◽  
The North Sea ◽  
Using Data ◽  
Almost All

Abstract Acoustic surveys are used in 20 stock assessments within the ICES community, and almost all as relative indices of abundance, but little has been done to explore their performance in detail. The North Sea herring acoustic survey started in 1979 and by 1984 had become an internationally-coordinated survey conducted annually in July. Along with trawl- and larvae-survey indices, it has been used to tune a catch-at-age assessment model of North Sea herring. In this article, the precision of the survey is estimated, using data at ICES statistical-rectangle level from 1989 to 2001, and bootstrap-resampling methods modified by geostatistical estimates of the spatial autocorrelation. Similar techniques are applied to the larvae, Methot and trawl surveys that provide the other data on the distribution and abundance of North Sea herring. The comparison of survey performance is also examined using the bootstrap estimates of abundance to give 1000 simulated assessments of North Sea herring using the integrated catch-at-age (ICA) method. The results of these analyses are compared and the annual acoustic survey is shown to provide the most precise estimate of relative abundance for adult North Sea herring each year. The weighting of the various indices within the assessment is investigated. A weighting method is presented that provides a more precise method for estimating the stock. The more precise assessments are compared for retrospective pattern. An assessment is proposed which provides the most precise stock estimates with the best retrospective pattern. This assessment has been reviewed and accepted by the ICES Advisory Committee on Fisheries Management. The importance of the acoustic survey and its contribution to the assessment in relation to the other indices is discussed.

Length–weight relationships of 216 North Sea benthic invertebrates and fish

2010 ◽  
Vol 90 (1) ◽  
pp. 95-104 ◽  
Author(s):  
L.A. Robinson ◽  
S.P.R. Greenstreet ◽  
H. Reiss ◽  
R. Callaway ◽  
J. Craeymeersch ◽  
...  
Keyword(s):  
North Sea ◽  
Marine Animals ◽  
Pooled Data ◽  
The North ◽  
Body Weights ◽  
Benthic Survey ◽  
The North Sea ◽  
Using Data ◽  
And Function ◽  
Number Of Individuals

Size-based analyses of marine animals are increasingly used to improve understanding of community structure and function. However, the resources required to record individual body weights for benthic animals, where the number of individuals can reach several thousand in a square metre, are often prohibitive. Here we present morphometric (length–weight) relationships for 216 benthic species from the North Sea to permit weight estimation from length measurements. These relationships were calculated using data collected over two years from 283 stations. For ten abundant and widely dispersed species we tested for significant spatial and temporal differences in morphometric relationships. Some were found, but the magnitude of differences was small in relation to the size-ranges of animals that are usually present and we recommend that the regression relationships given here, based on pooled data, are appropriate for most types of population and community analyses. Our hope is that the availability of these morphometric relationships will encourage the more frequent application of size-based analyses to benthic survey data, and so enhance understanding of the ecology of the benthic/demersal component of marine ecosystems and food webs.

scholarly journals Turbulence measurements suggest high rates of new production over the shelf edge in the north-eastern North Sea during summer

2018 ◽  
Author(s):  
Jørgen Bendtsen ◽  
Katherine Richardson
Keyword(s):  
North Sea ◽  
Vertical Mixing ◽  
Euphotic Zone ◽  
Shelf Edge ◽  
Nutrient Inputs ◽  
New Production ◽  
The North ◽  
North Eastern ◽  
The North Sea ◽  
Using Data

Abstract. New production, i.e., that driven by allochthonous nutrient inputs, is the only form of primary production that can lead to net increases in organic material and is, therefore, important for understanding energy flow in marine ecosystems. The spatial distribution of new production is generally, however, not well known. Here, using data collected in July 2016, we analyse the potential for vertical mixing to support new production in the upper layers of the north eastern portion of the North Sea. Estimated nitrate fluxes due to turbulent vertical mixing into the euphotic zone were up to 0.5–1 mmol N m−2 d−1 over the shelf-edge (f-ratios > 0.1) while values of

scholarly journals Significant taxon sampling gaps in DNA databases limit the operational use of marine macrofauna metabarcoding

2020 ◽  
Vol 50 (5) ◽  
Author(s):  
Jon Thomassen Hestetun ◽  
Einar Bye-Ingebrigtsen ◽  
R. Henrik Nilsson ◽  
Adrian G. Glover ◽  
Per-Otto Johansen ◽  
...  
Keyword(s):  
North Sea ◽  
Large Scale ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Species Level ◽  
Case Scenario ◽  
Species Identity ◽  
The North ◽  
The North Sea ◽  
Significant Effort

Abstract Significant effort is spent on monitoring of benthic ecosystems through government funding or indirectly as a cost of business, and metabarcoding of environmental DNA samples has been suggested as a possible complement or alternative to current morphological methods to assess biodiversity. In metabarcoding, a public sequence database is typically used to match barcodes to species identity, but these databases are naturally incomplete. The North Sea oil and gas industry conducts large-scale environmental monitoring programs in one of the most heavily sampled marine areas worldwide and could therefore be considered a “best-case scenario” for macrofaunal metabarcoding. As a test case, we investigated the database coverage of two common metabarcoding markers, mitochondrial COI and the ribosomal rRNA 18S gene, for a complete list of 1802 macrofauna taxa reported from the North Sea monitoring region IV. For COI, species level barcode coverage was 50.4% in GenBank and 42.4% for public sequences in BOLD. For 18S, species level coverage was 36.4% in GenBank and 27.1% in SILVA. To see whether rare species were underrepresented, we investigated the most commonly reported species as a separate dataset but found only minor coverage increases. We conclude that compared to global figures, barcode coverage is high for this area, but that a significant effort remains to fill barcode databases to levels that would make metabarcoding operational as a taxonomic tool, including for the most common macrofaunal taxa.

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