scholarly journals Intraspecific Abundance–Occupancy–Patchiness Relations in the Intertidal Benthic Macrofauna of a Cool-Temperate North Sea Mudflat

2021 ◽  
Author(s):  
R. S. K. Barnes
Keyword(s):  
North Sea ◽  
Wadden Sea ◽  
Benthic Macrofauna ◽  
Lower Latitude ◽  
Intertidal Mudflat ◽  
Spatial Variables ◽  
Cool Temperate ◽  
Local Abundance ◽  
First Time ◽  
Intraspecific Relationships

AbstractThe macroecological variable of patchiness (Lloyd’s Ip index of patchiness, P) has recently been shown to be related inter- and intraspecifically to those of abundance (numbers m−2, A), and occupancy (% occurrence in samples, O) in lower latitude seagrass macrofaunas. For the first time in higher latitudes, intraspecific relationships between three spatial variables were investigated in the intertidal mudflat macrobenthos of the Scolt Head barrier island, southern North Sea (53° N, 01° E). Sampling was conducted between early July and late September 2009–2013 using 710-µm mesh for sample processing. Strong positive interspecific A-O and negative interspecific P-O and P-A relationships were present. Two of the most numerous and widespread assemblage components, however, occurred with effectively constant occupancy (Peringia ulvae, 100%, and Tubificoides benedii, 93%) across the whole 20-ha locality and therefore could not show intraspecific relationships of occupancy with other macroecological metrics. These two apart, only one other dominant species failed to show a significant positive intraspecific A-O relationship; no species showed significant P-A relations of any form; and only two showed the negative P-O ones that have been described elsewhere. The intraspecific A-O patterns appear to contrast with those of an earlier study at another North Sea locality (the Dutch Wadden Sea), although differences are more apparent than real, but the Scolt Head fauna showed fewer intraspecific P-O and P-A relations than those characterising similar circumstances in the two lower-latitude localities previously investigated. Neither developmental mode nor variation in local abundance appears to influence these patterns. A-O-P relations therefore seem widespread but may be subject to latitudinal modification.

Offshore Claims and Problems in the North Sea

1965 ◽  
Vol 59 (3) ◽  
pp. 505-522 ◽  
Author(s):  
Richard Young
Keyword(s):  
North Sea ◽  
Large Scale ◽  
Geneva Convention ◽  
Legal Principles ◽  
The North ◽  
Legal Problems ◽  
The North Sea ◽  
The Subject ◽  
First Time ◽  
Economic Considerations

The possible presence of very large petroleum and natural gas reserves in the area beneath the North Sea is currently the subject of intense investigation. If confirmed, as seems likely in at least some localities, this occurrence will raise legal problems of considerable interest and complexity. For the North Sea is not merely an oilfield covered by water: for centuries it has been one of the world's major fishery regions and the avenue to and from the world's busiest seaports. Thus all three of the present principal uses of the sea—fishing, navigation, and the exploitation of submarine resources—promise to meet for the first time on a large scale in an area where all are of major importance. The process of reconciling the various interests at stake will provide the first thoroughgoing test of the adequacy and acceptability of the general principles laid down in the 1958 Geneva Convention on the Continental Shelf and should add greatly to the practice and precedents available in this developing branch of the law. In the present article an attempt is made to review some of the geographical and economic considerations involved in the North Sea situation, to note some of the technical and legal developments that have already taken place, and to consider these elements in the light of the various interests and legal principles concerned.

scholarly journals Monitoring juvenile stocks of flatfish in the Wadden Sea and the coastal areas of the southeastern North Sea

1989 ◽  
Vol 43 (3-4) ◽  
pp. 461-477 ◽  
Author(s):  
F. A. Beek ◽  
A. D. Rijnsdorp ◽  
R. Clerck
Keyword(s):  
North Sea ◽  
Wadden Sea ◽  
Coastal Areas

scholarly journals Inventory and comparison of abundance of parasitic copepods on fish hosts in the western Wadden Sea (North Sea) between 1968 and 2010

2013 ◽  
Vol 94 (3) ◽  
pp. 547-555 ◽  
Author(s):  
Wouter Koch ◽  
Peter Boer ◽  
Johannes IJ. Witte ◽  
Henk W. Van der Veer ◽  
David W. Thieltges
Keyword(s):  
North Sea ◽  
Wadden Sea ◽  
Temporal Stability ◽  
Parasite Fauna ◽  
Fixed Number ◽  
Fish Host ◽  
Host Size ◽  
Negative Effects ◽  
Parasitic Copepods ◽  
Fish Hosts

A conspicuous part of the parasite fauna of marine fish are ectoparasites, which attach mainly to the fins or gills. The abundant copepods have received much interest due to their negative effects on hosts. However, for many localities the copepod fauna of fish is still poorly known, and we know little about their temporal stability as long-term observations are largely absent. Our study provides the first inventory of ectoparasitic copepods on fish from the western Wadden Sea (North Sea) based on field data from 1968 and 2010 and additional unpublished notes. In total, 47 copepod parasite species have been recorded on 52 fish host species to date. For two copepod species parasitizing the European flounder (Platichthys flesus), a quantitative comparison of infection levels between 1968 and 2010 was possible. Whereas Acanthochondria cornuta did not show a change in the relationship between host size and infection levels, Lepeophtheirus pectoralis shifted towards the infection of smaller hosts, with higher infection levels in 2010 compared to 1968. These differences probably reflect the biology of the species and the observed decrease in abundance and size of flounders during the last decades. The skin-infecting L. pectoralis can probably compensate for dwindling host abundance by infecting smaller fish and increasing its abundance per given host size. In contrast, the gill cavity inhabiting A. cornuta probably faces a spatial constraint (fixed number of gill arches), thus limiting its abundance and setting a minimum for the host size necessary for infections.

scholarly journals Phylogenetic and Ecological Signals in the Wood of Spathelioideae (Rutaceae)

IAWA Journal ◽  
2012 ◽  
Vol 33 (4) ◽  
pp. 337-353 ◽  
Author(s):  
Marc S. Appelhans ◽  
Bertie Joan van Heuven ◽  
Frederic Lens ◽  
Pieter Baas
Keyword(s):  
Molecular Phylogeny ◽  
Adaptive Evolution ◽  
Vessel Wall ◽  
Wood Anatomy ◽  
Mediterranean Climate ◽  
Cool Temperate ◽  
Hydraulic Safety ◽  
Anatomical Information ◽  
First Time

Subfamily Spathelioideae of Rutaceae constitutes a well-supported early branching clade of eight small woody genera that were formerly assigned to five different Sapindalean/Rutalean families. This study brings together detailed wood anatomical information on all eight genera (for four the wood anatomy is described for the first time in detail). Wood anatomy strongly supports the inclusion of all Spathelioid genera in Rutaceae and underpins the molecular phylogeny with a set of interesting apomorphies at different nodes of the cladogram. The wood anatomy of Cneorum tricoccon with its semi-ring porosity, dendritic vessel pattern, vascular tracheids and helical vessel wall thickenings stands out in Spathelioideae. This wood anatomical syndrome is hypothesized to be due to adaptive evolution for hydraulic safety and efficiency of this species in a typical Mediterranean climate, where similar syndromes have evolved in many unrelated clades of woody dicots. In at least six unrelated genera of Rutaceae outside Spathelioideae from Mediterranean or cool temperate and montane climates, the syndrome has also evolved in presumably parallel, adaptive evolution.

Tools to evaluate seafloor integrity: comparison of multi-device acoustic seafloor classifications for benthic macrofauna-driven patterns in the German Bight, southern North Sea

2016 ◽  
Vol 37 (2) ◽  
pp. 93-109 ◽  
Author(s):  
Peter Holler ◽  
Edith Markert ◽  
Alexander Bartholomä ◽  
Ruggero Capperucci ◽  
H. Christian Hass ◽  
...  
Keyword(s):  
North Sea ◽  
German Bight ◽  
Benthic Macrofauna ◽  
Southern North Sea

scholarly journals Living and dead foraminiferal assemblage from the supratidal sand Japsand, North Frisian Wadden Sea: distributional patterns and controlling factors

2021 ◽  
Vol 75 (1) ◽  
Author(s):  
Sarina Schmidt ◽  
Joachim Schönfeld
Keyword(s):  
North Sea ◽  
Wadden Sea ◽  
Distribution Patterns ◽  
Abundant Species ◽  
Foraminiferal Assemblage ◽  
The North ◽  
Key Species ◽  
Reproduction Season ◽  
The Dead ◽  
Reproductive Cycles

AbstractSupratidal sands are vitally important for coastal defence in the German Wadden Sea. They are less affected by human activities than other areas as they are located far off the mainland shore, touristical and commercial activities are generally prohibited. Therefore, supratidal sands are of high ecological interest. Nevertheless, the faunal inventory and distribution pattern of microorganisms on these sands were studied very little. The composition of living and dead foraminiferal assemblages was therefore investigated along a transect from the supratidal sand Japsand up to Hallig Hooge. Both assemblages were dominated by calcareous foraminifera of which Ammonia batava was the most abundant species. Elphidium selseyense and Elphidium williamsoni were also common in the living assemblage, but Elphidium williamsoni was comparably rare in the dead assemblage. The high proportions of Ammonia batava and Elphidium selseyense in the living assemblage arose from the reproduction season that differed between species. While Ammonia batava and Elphidium selseyense just finished their reproductive cycles, Elphidium williamsoni was just about to start. This was also confirmed by the size distribution patterns of the different species. The dead assemblage revealed 20 species that were not found in the living assemblage of which some were reworked from older sediments (e.g., Bucella frigida) and some were transported via tidal currents from other areas in the North Sea (e.g., Jadammina macrescens). The living foraminiferal faunas depicted close linkages between the open North Sea and the mainland. Key species revealing exchange between distant populations were Haynesina germanica, Ammonia batava and different Elphidium species. All these species share an opportunistic behaviour and are able to inhabit a variety of different environments; hence, they well may cope with changing environmental conditions. The benthic foraminiferal association from Japsand revealed that transport mechanisms via tides and currents play a major ecological role and strongly influence the faunal composition at this site.

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