North-western Sea Research Articles

Search for the Bonhomme Richard Using Computer Modeling and Submarine Technologies

The Ocean Technology Foundation and Naval Historical Center have been searching for the remains of the Bonhomme Richard, which sank in the western North Sea as a casualty of the American Revolution. Historical information about the ship's final resting place is lacking, but its activities up until the sinking are well documented. The results of many years of historical research have been incorporated into computer modeling programs, and a Geographic Information System (GIS) map was created to document all known information on shipwreck locations, seabed geology, and other pertinent information to enable the most effective survey. A recent survey expedition utilized the U.S. Navy's nuclear research submarine NR-1 to search nearly 400 square nautical miles of the North Sea. This paper focuses on the technological tools used in the search for the Bonhomme Richard: computer modeling, GIS, and submarine technologies. It also discusses the benefits and drawbacks of using a submarine to conduct marine archaeological surveys. The expedition yielded insights into the strengths and limitations of computerized drift modeling, especially when used to reconcile empiric environmental data with conflicting eyewitness accounts.

The North Sea benthic system: a 36 year time-series

Since 1971 the macro-benthic infauna at Station P, 18.5 km off the Northumberland coast (central western North Sea), have been sampled by grabbing each January/February. The data series now includes over 260 taxa from 173 genera. The most abundant taxa are Heteromastus, Levinsinia and Priospio which between them account for nearly 45% of the individuals recorded while the top 10 ranked taxa between them include almost 70% of the individuals recorded. Both total abundance and genera richness have varied through the 36 year series, particularly during the late 1980s–early 1990s but there was no trend and values in the 2000s are similar to those at the start of the series. However, MDS ordination of the entire genera abundance series shows a trend in composition of the macrobenthos through time. There is evidence that the changes in composition were driven by fishing impacts, but also influenced by the trend in climate warming and altered fluxes of phytoplankton to the benthos. Given that the dominant taxa have not changed and the total abundance and richness are similar this implies a turnover and redistribution of individuals across many taxa and raises the possibility of shifts in the ecological functioning of the system.

Unambiguous identification of pectenotoxin-1 and distribution of pectenotoxins in plankton from the North Sea

Lipophilic phycotoxins in size-fractionated plankton net tows (20 μm mesh-size) were measured on-board during a month-long oceanographic cruise in North Sea coastal waters. Tandem mass spectrometry coupled to liquid chromatography (LC–MS/MS) was employed for the detection and quantification of a broad spectrum of known and putative phycotoxins. For pectenotoxins (PTXs) the following ion masses ([M + NH 4] +) were monitored: m/ z 876 for PTX-2, m/ z 892 for PTX-11 and PTX-13, and m/ z 874 for PTX-12 and PTX-14. The PTX levels in net plankton were highest along the Danish north coast, but levels over 50 ng per net tow were also detected on the southern Scottish East coast and in the northern Skagerrak. Abundance of PTXs was highly correlated with the occurrence of the marine dinoflagellate Dinophysis spp. Whereas in the eastern North Sea PTX-2 was the most abundant PTX, in the western North Sea PTX-1 was the major component, but it was also present in lower proportions in the Norwegian and Danish waters than in the western North Sea. Isobaric PTX-11 was absent or only detected at trace levels throughout the entire cruise, and PTX-13 and PTX-14 were not detected at all. The identity of PTX-1 was confirmed by comparison of retention time and mass spectrum of the North Sea phytoplankton sample to PTX-1 previously isolated from shellfish. Statistical analysis showed the best correlation between the occurrence of PTX-1 and Dinophysis acuminata cell concentration. Nevertheless, we could not rule out the possibility of metabolic transformations of PTXs by organisms that have grazed upon Dinophysis. Such biotransformations could conceivably occur in heterotrophic dinoflagellates or ciliates, or even via oxidation in copepod fecal pellets. In any case, this study confirmed the presence of PTX-1 in the plankton and is the first definitive report of this toxin in the North Sea.

Observing change in a North Sea benthic system: A 33 year time series

Since 1972 the macro-benthic infauna at station M1, 10.5 km off the Northumberland coast (central western North Sea), have been sampled by grabbing each March and September. The data series now includes over 500 taxa from 327 genera. During the 1970s the system showed a regular alternation of high and low abundance years and this was interpreted as evidence of density dependence, when this broke down in the 1980s winter temperature appeared to be involved. After 20 years of data collection analysis of the time series, showed that variability had increased and that there was a very strong link to phytoplankton production in the overlying water. The latest analyses show that this relationship has now also disappeared. The number of genera represented in the system has increased over time while total productivity has not altered significantly. Multivariate ordinations also show changes through time with breakpoints occurring in the early 1980s and early 1990s. The coastal benthos of this region shows decadal scale and longer term changes in biological composition and ecological function. The system is certainly influenced by climatic variation, environmental conditions (winter temperature) and carbon flux to the benthos. Over the 33 year time series none of these appears to have a dominant effect, rather different factors seem to dominate at different times. The extent to which this is due to a biological ‘system memory’ imposed by good recruitments of long lived taxa would warrant further study.

Composition of the genus Leptosagitta of the family Sagittidae (Chaetognatha) with descriptions of four new species from coastal waters of the Northwestern Sea of Japan

Keys for the identification of the presently known species of the genus Leptosagitta (fam. Sagittidae) are presented. Four new species of this genus found in shallow waters of Vostok Bay, Amursky Bay (Peter the Great Bay), and Kievka Bay (all of the Sea of Japan) are described in detail: L. kiyashkoi sp. n., L. latyshevi sp. n., L. magna sp. n., and L. pauca sp. n.

Variability of sea surface temperature in the Japan Sea and its relationship to the wind-curl field

The variability of sea surface temperature (SST) in the Japan Sea is investigated using the complex EOF analysis of daily data produced at Tohoku University, Japan (New Generation SST; 2002–2006). The relationship with the wind field is investigated from the daily NCEP/NCAR reanalysis data with a 1° spatial resolution. Anomalies in the SST (SSTAs) are calculated by subtracting the basin-average annual variation estimated as a leading mode of temperature. The leading mode of an SSTA represents a adjustment to the annual mean variation, most significant in December in the zone of subtropical waters entering the sea through the Korean Strait and in the northwestern sea, over which a cyclonic wind curl develops in the cold period. The semiannual variability mode is identified, which is characterized by the largest temperature increase (decrease) in the western branch of the subarctic front (in the Tatar Strait), which lags by two months behind the semiannual changes in wind curl over the sea. An episodic SSTA movement is detected in the northern part of the sea, which moves from east to west along the western branch of the Tsushima Warm Current with a speed corresponding in magnitude to an advective scale.

Toxicity, morphology and distribution of Pseudo-nitzschia calliantha, P. multistriata and P. multiseries (Bacillariophyta) from the northwestern Sea of Japan

Abstract Toxicity, morphology and distribution patterns of three bloom-forming species of the diatom genus Pseudo-nitzschia (potential producers of the neurotoxin domoic acid and causative organisms of amnesic shellfish poisoning) from Peter the Great Bay in the northwestern Sea of Japan are presented. Pseudo-nitzschia calliantha, P. multistriata and P. multiseries bloomed in Peter the Great Bay in the fall, with abundances exceeding 106 cells l-1. This is the first report of toxicity in P. multiseries from Russian waters. Domoic acid was found in stationary-phase (days 20–35) cultures of P. multiseries isolated from Peter the Great Bay at concentrations varying between 180 and 5390 ng ml-1 or 2 to 21 pg cell-1, which is in the range reported for other isolates of P. multiseries. The Russian isolate had an increasing ability to produce domoic acid over time in culture rather than the usual trend of decreasing toxicity. No domoic acid was detected (<2 ng ml-1) in cultures of P. calliantha and P. multistriata from the same locality. The Russian isolate of P. multiseries produced gametes when mated with the Canadian strains of the opposite mating type, but they never developed into zygotes, auxospores or large initial cells. This suggests that there might be “cryptic” species within P. multiseries. However, a comparison of molecular and morphometric data between the Russian and Canadian strains showed that they indeed belong to the same species.

New species of arrowworms of the genus Aidanosagitta (Chaetognatha) from the northwestern part of the Sea of Japan

This paper provides identification keys for all known species of the genus Aidanosagitta of the World Ocean. Detailed descriptions and original drawings are presented for four new species of Aidanosagitta, namely, A. subulata sp. n., A. candida sp. n., A. oblonga sp. n., and A. acinacis sp. n. inhabiting Peter the Great Bay and adjacent waters of the northwestern Sea of Japan.

Application of habitat suitability modelling to tracking data of marine animals as a means of analyzing their feeding habitats

This paper investigates the potential for using quantitative applications of statistical models of habitat suitability based on marine animal tracking data to identify key feeding areas. Presence-only models like Ecological Niche Factor Analysis (ENFA) may be applicable to resolve habitat gradients and potentially project habitat characteristics of tracked animals over large areas of ocean. We tested ENFA on tracking data of the northern gannet ( Morus bassanus) obtained from the colony at Bass Rock, western North Sea in 2003. A total of 217 diving events were selected for model development. The ecological variables of the model were calibrated by using oceanographic structures with documented influences on seabird distribution, derived from satellite and bathymetric data. The model parameters were estimates of habitat marginality and specialisation computed by comparing the distribution of the gannet in the multivariate oceanographic space encompassed by the recorded logger data with the whole set of cells in the study area. Marginality was identified by differences to the global mean and specialization was identified by the ratio of species variance to global variance. A habitat suitability index was computed on the basis of the marginality factors and the first four specialisation factors by allocating values to all grid cells in the study area, which were proportional to the distance between their position and the position of the species optimum in the factorial space. Although gannets were using a large sector of the North Sea for feeding, ENFA estimated high habitat suitability scores within a relatively small coherent zone corresponding to a hydrographic frontal area, located east of the colony. The model was evaluated by using Jack-knife cross-validation and by comparison of the predicted core feeding area with results from historic field surveys. We discuss the limitations and potentials for applying habitat suitability models to tracking data in the marine environment, and conclude that the inclusion of hydrodynamic variables seems to be the biggest constraint. Overcoming this constraint, ENFA provides a promising method for achieving improved models of the distribution of marine species with high research and conservation priority. Due to the better coverage of entire feeding ranges, the limited influence of historic factors and the lack of bias from sampling design, marine animal tracking may provide better data than at-sea surveys for habitat suitability modelling.

Mirabilicoxa kussakini sp. nov., a new species of Desmosomatidae (Crustacea, Isopoda, Asellota) from the Sea of Japan

Mirabilicoxa kussakini sp. nov. is described from the bathyal of the northwestern Sea of Japan. This is the first record of the genus Mirabilicoxa Hessler, 1970 in the Sea of Japan. The new species is most similar to M. similis (Hansen, 1916), M. plana Hessler, 1970 and M. minuta Hessler, 1970 from the Northwest Atlantic. It differs from them in having a more elongated body (4.1-4.5 times as long as wide) and antenna 1 with the terminal article 5 shorter than article 4.

Gorgonians (Anthozoa: Octocorallia) of the northwestern Sea of Japan

Three species of gorgonians (Primnoa pacifica, Calcigorgia japonica, and Thouarella superba) are reported as new records for the northwestern Sea of Japan; one of them (Calcigorgia japonica sp. n.) has been described as a new species. Variations of colony morphology in some species are described; the taxonomical value of specific characters is discussed. The geographical range of Primnoa pacifica in the northwestern Pacific is shown to be wider than was considered earlier. Variations of sclerite morphology (number of marginal plates, presence of additional basal plates, and number of marginal spines on the basal plate) are regarded as intracolonial or intraspecific variability. The distribution range of Thouarella superba described earlier from the Aleutian Islands (Nutting, 1912) was shown to extend into the low-boreal part of the boreal Pacific. An examined specimen of Paragorgia sp. differed from all known species and appeared similar only to P. regalis Nutting, 1912 reported from the eastern coast of Japan. The most distinctive characters of Calcigorgia japonica sp. n. were the shape of polyp, with a thin lower part looking like folded podia (in fixed specimens) and the presence of two types of clubs scattered among the sclerites of the polyp.

Mesozoic–Cenozoic exhumation events in the eastern North Sea Basin: a multi‐disciplinary study based on palaeothermal, palaeoburial, stratigraphic and seismic data

ABSTRACTFour Mesozoic–Cenozoic palaeothermal episodes related to deeper burial and subsequent exhumation and one reflecting climate change during the Eocene have been identified in a study of new apatite fission‐track analysis (AFTA®) and vitrinite reflectance data in eight Danish wells. The study combined thermal‐history reconstruction with exhumation studies based on palaeoburial data (sonic velocities) and stratigraphic and seismic data. Mid‐Jurassic exhumation (ca. 175 Ma) was caused by regional doming of the North Sea area, broadly contemporaneous with deep exhumation in Scandinavia. A palaeogeothermal gradient of 45 °C km−1 at that time may be related to a mantle plume rising before rifting in the North Sea. Mid‐Cretaceous exhumation affecting the Sorgenfrei–Tornquist Zone is probably related to late Albian tectonic movements (ca. 100 Ma). The Sole Pit axis in the southern North Sea experienced similar inversion and this suggests a plate‐scale response along crustal weakness zones across NW Europe. Mid‐Cenozoic exhumation affected the eastern North Sea Basin and the onset of this event correlates with a latest Oligocene unconformity (ca. 24 Ma), which indicates a major Scandinavian uplift phase. The deeper burial that caused the late Oligocene thermal event recognized in the AFTA data reflect progradation of lower Oligocene wedges derived from the uplifting Scandinavian landmass. The onset of Scandinavian uplift is represented by an earliest Oligocene unconformity (ca. 33 Ma). Late Neogene exhumation affected the eastern (and western) North Sea Basin including Scandinavia. The sedimentation pattern in the central North Sea Basin shows that this phase began in the early Pliocene (ca. 4 Ma), in good agreement with the AFTA data. These three phases of Cenozoic uplift of Scandinavia also affected the NE Atlantic margin, whereas an intra‐Miocene unconformity (ca. 15 Ma) on the NE Atlantic margin reflects tectonic movements of only minor amplitude in that area. The study demonstrates that only by considering episodic exhumation as an inherent aspect of the sedimentary record can the tectonic evolution be accurately reconstructed.

Spatial and temporal variations in parasite prevalence and infracommunity structure in herring (Clupea harengusL.) caught to the west of the British Isles and in the North and Baltic Seas: implications for fisheries science

Herring Clupea harengus L. viscera were examined for endoparasitic infections as part of a multidisciplinary stock identification project (WESTHER, EU Contract no. Q5RS-2002-01 056) which applied a range of stock discrimination techniques to the same individual fishes to obtain comparable results for multivariate analysis. Spawning and non-spawning adults, and juvenile herring were caught, over 3 years, by commercial and research vessels from numerous locations to the west of the UK and Ireland, along with control samples of spawning fish from the eastern Baltic Sea, and juveniles from sites in the eastern and western North Sea, and the north of Norway. The metacercariae of two renicolid digeneans (Cercaria pythionike and Cercaria doricha), one larval nematode (Anisakis simplex s.s.) and one larval cestode (Lacistorhynchus tenuis) were selected as tag species. Results were compared with those from herring collected between 1973 and 1982, which suggested remarkable stability in the parasite fauna of herring in the study area. These species were used to compare the parasite infracommunities of spawning herring. A significant variation in infracommunity structure was observed between different spawning grounds. These results suggest that the parasite fauna of herring are spatially variable but remain temporally stable in both the short and long term. Significant differences in prevalence and abundance of infections and comparisons of parasite infracommunity enabled the separation of putative herring stocks west of the British Isles. Distinctive patterns of parasite infection in two different spawning groups off the north coast of Scotland suggest that this area is occupied by two spawning populations, one recruiting from the west of Scotland, the other from outside this area, and most likely from the eastern North Sea. The distribution patterns of L. tenuis, C. doricha and C. pythionike suggest the potential for fish that spawn in three distinct International Council for the Exploration of the Seas (ICES) management units to be present in mixed aggregations found over the Malin Shelf, with significant implications for management in this area.

Extreme value analysis of decadal variations in storm surge elevations

We use a novel statistical approach to analyse changes in the occurrence and severity of storm surge events in the southern and central North Sea over the period 1955–2000, using 1) output from a numerical storm surge model and 2) in situ data on surge levels at sites for which sufficiently long observational records are available. The methodology provides a robust diagnostic tool for assessing the ability of models to reproduce the observed characteristics of storm surges, in a fashion that properly accounts both for variability within a single long run of the model and for recording error in observational data on sea levels. The model re-analysis data show strong positive trends in the frequency and severity of storm surge events at locations in the north-eastern North Sea, whilst trends at locations in the southern and western North Sea appear to be dominated by decadal variability. Trends in in situ data for sites along the North Sea coast are fairly synchronous with corresponding trends in the model re-analysis data, with the most serious discrepancies attributable to known problems in the observational record.

A new species of Oscarella (Demospongiae: Plakinidae) from the Western Sea of Japan

Oscarella malakhovi sp. nov. is described from the waters of Peter the Great Bay (northwestern Sea of Japan, Russia) at depths between 0.4–4 m from a rocky coast. This is the first record of the genus Oscarella from the North-Western Pacific. The new species is characterized by its pinky-beige to yellow color, undulating appearance, lumpy, microlobate surface, soft, slimy consistency, two particular kinds of cells with inclusions (vacuolar and granular cells), and of two kinds of endobiont bacteria. The new species of Oscarella is clearly different in cell, endobiotic bacteria content, and external morphology from all previously described species of Oscarella.

Finding of new species of finless Sagittids (Sagittidae: Chaetognatha) in the northwestern Sea of Japan

Diagnosis of a new genus Abosagitta gen. n. and detailed descriptions and drawings of four new species, as well as keys for the identification of genera of Sagittidae, are given. The new species differ from species of other genera of Sagittidae by lacking lateral fins on the trunk. Instead of two pairs of lateral fins, these species have saclike gelatinous structures. These structures were previously found only in the species of Eukrohniidae (see [2, 4]). The presence of saclike gelatinous structures instead of fins is probably a plesiomorphic feature, which is retained only in some species.

Vertical distribution of hydroids in wharf fouling in the Northwestern Sea of Japan

The features of the vertical distribution of hydroids on various types of wharves in the northwest part of the Sea of Japan were studied. It was shown that the highest values of biomass of the common species of hydroids Obelia longissima and Bougainvillia ramosa were at wharf sites below the zone of varying submergence up to a depth of 1 m. The spatial variability of hydroid abundance is discussed in relation to the local specifics of their environment and the character of formation and the structure of the fouling community.

Benthic responses to organic enrichment and climatic events in the western North Sea

Macrofaunal assemblages inhabiting stable offshore muddy sand substrata responded predictably to the effects of mild organic enrichment arising from sewage-sludge disposal off the north-east coast of England (western North Sea). At the disposal site, densities were elevated up to two-fold, but classical ‘indicator’ species were only marginally enhanced and there was no evidence of a significant waste-induced change in assemblage structure. The response following cessation of disposal was equally predictable, with a decline in densities to ‘reference’ levels some three years later. However, physical manifestations of disposal, including tomato pips and non-biodegradable artefacts, were still evident after this time.Changes in diversity at selected monitoring stations tended to track each other over time and the employment of treatment/reference ratios and limit values for acceptable change provided a useful model for the simplified expression of trends. Predictions concerning the limited scale and intensity of the effects of sewage-sludge disposal appear to have been met, indicating that the management option of sea disposal was, at the time, an environmentally acceptable one.Temporal trends in the benthic fauna were also correlated with winter values of the North Atlantic Oscillation Index for the preceding year. The densities and variety of species tended to be lower in response to warmer winters characterized by westerly airflows which were commonly encountered in the 1990s. Finally, the increasing importance of extended time-series data for the investigation of man-made impacts on the marine environment is highlighted, along with the accompanying requirement for continuity and quality assurance of sampling programmes.

The genus Chaetoceros (Bacillariophyta) from Peter the Great Bay, Sea of Japan

Several studies in the Sea of Japan have dealt with the taxonomy, morphology and ecology of Chaetoceros species. In this study, a total of 33 Chaetoceros taxa was recorded between 1991 and 2004 from the phytoplankton of Peter the Great Bay, in the northwestern part of the Sea of Japan. This investigation was based on light and electron microscopy. Chaetoceros minimus is a new record for the Pacific Ocean, C. compressus var. hirtisetus is a new record for the seas of Russia, and C. socialis f. radians is a new record for the northwestern Sea of Japan. Diagnostic descriptions, illustrations and distribution are provided for all 33 Chaetoceros taxa from the study area.

Remains of Clidastes Cope, 1868, an unexpected mosasaur in the upper Campanian of NW Germany

AbstractThe mosasaurine Clidastes sp. is recognised from cranial and post-cranial remains collected at four localities in NW Germany. Cranial material was found in pelagic turbiditic marls which crop out near the village of Beckum, while post-cranial skeletal elements were collected from sandy limestones exposed near the villages of Schöppingen, Coesfeld and Billerbeck. In stratigraphic order, the units producing these specimens of Clidastes are the Coesfeld, Baumberge and Beckum formations of late Campanian (Late Cretaceous) age. The cranial material comprises the anterior part of a skull and a single isolated tooth, while post-cranial bones comprise a few isolated vertebrae and a partial skeleton including forelimb bones and an articulated vertebral column. Clidastes is known to date from the western North Sea Basin (England), southern Sweden, as well as from North America (Western Interior Seaway and Gulf Coast).