Helgoland Marine Research

https://hmr.biomedcentral.com

List of Papers (Total 2,053)

Spatial and temporal variation in mercury contamination of seabirds in the North Sea

Once the moult patterns have been taken into account, feather methylmercury levels can be used to accurately measure the mercury burdens of seabirds. We used body feathers from live seabirds and from museum collections to examine geographical and temporal patterns of mercury contamination in the North Sea. This approach identifies an increase in mercury concentrations in seabirds...

Rostock zooplankton studies off West Africa

Since the beginning of the seventies, upwelling research has become increasingly popular in the path of the Canary and Benguela Current, because of economic consideration, particularly in the relation to fisheries and marine geology. Many expeditions were carried out between 1970 and 1977, including 8 cruises of the German R. V. “A. v. Humboldt” operating from Rostock...

Fate and distribution of toxic heavy metals in some marine organisms from the eastern Adriatic coast

The paper reports on levels of heavy metals in some organisms from the eastern Adriatic coast and polluted areas near a big urban centre (Split area). Surprisingly high Hg and MeHg concentrations were found in sea bream (Pagellus erythrinus) and striped mullet (Mullus barbatus) from the south-eastern part of the Adriatic. The reason for the high levels are probably geochemical...

How to overcome osmotic stress? Marine crabs conquer freshwater. New insights from modern electrophysiology

In the present article we review our findings on split lamella preparations of crab gills mounted in modified Ussing-chambers with respect to mechanistic and ecophysiological aspects. The leaky gill epithelium of shore crabs adapted to brackish water absorbs Na+ and Cl− in a coupled mode, and shows similarities to other salt-absorbing epithelia exposed to moderately diluted media...

The potential of and limitations to marine population prognosis

Following the 19th century recognition and definition of basic ecological entities, functional analysis has been the highlight of this century. The synthesis of these findings enables ecological prognosis. The population as the basic functional unit has been repeatedly treated; in the marine field, fisheries management approaches developed into multi-species population analysis...

Red List of macrofaunal benthic invertebrates of the Wadden Sea

In the Wadden Sea, in total, 93 species of macrofaunal benthic invertebrates are threatened in at least one subregion. Of these, 72 species are threatened in the entire area and are therefore placed on the trilateral Red List. 7 species are (probably) extinct in the entire Wadden Sea area. The status of 9 species of macrofaunal invertebrates is critical, 13 species are (probably...

Verbreitung von Makrozooplankton in der Grönlandsee im Spätherbst 1988 (Crustacea: Ostracoda, Hyperiidea [Amphipoda], Euphausiacea)

The horizontal and vertical distribution and the abundance of ostracods, hyperiids (amphipods) and euphausiids in the Greenland Sea along a transect parallel 74°45′N (from 15°45′E to 08°30′W) are described. The samples were taken by RV “Meteor” in late autumn of 1988. 8 species of the above named groups have been recorded in two different water masses which were touched by the...

Historical changes and inventory of macroalgae from Königshafen Bay in the northern Wadden Sea

Knowledge on the distribution, abundance and species richness of intertidal macroalgae occurring on sandy and muddy flats of the German Wadden Sea is still incomplete. We summarize published and unpublished information available on the presence of macroalgae on the tidal flats of Königshafen Bay (island of Sylt, North Sea), one of the more extensively studied areas of the Wadden...

Phytoplankton: a significant trophic source for soft corals?

Histological autoradiographs and biochemical analyses show that 14C-labelled microalgae (diatoms, chlorophytes and dinoflagellates) are used by the soft coral Dendronephthya sp. Digestion of the algae took place at the point of exit of the pharynx into the coelenteron. Ingestion and assimilation of the labelled algae depended on incubation time, cell density, and to a lesser...

Satellite observations of the effect of the “Godzilla El Niño” on the Tehuantepec upwelling system in the Mexican Pacific

During 2015–2016, a strong El Niño, the “Godzilla El Niño,” which is similar to El Niño events that occurred in 1982/1983 and 1997/1998, occurred in the Pacific Ocean. In this paper, we report on the influence of the “Godzilla El Niño” on the sea surface temperature (SST) and chlorophyll-a (Chla) concentrations in the Tehuantepec upwelling system using satellite observation data...

Dual culture of the oomycete Lagenisma coscinodisci Drebes and Coscinodiscus diatoms as a model for plankton/parasite interactions

Diatoms are thought to provide about 40% of total global photosynthesis and diatoms of the genus Coscinodiscus are an important, sometimes dominant, cosmopolitan component of the marine diatom community. The oomycete parasitoid Lagenisma coscinodisci is widespread in the northern hemisphere on its hosts in the genus Coscinodiscus. Because of its potential ecological importance...

Parasites of fish Poecilia velifera and their potential as bioindicators of wetland restoration progress

Fish harbor a high diversity of parasites that play an important role for the ecosystem. Because these parasites have different life-cycle traits, changes in their populations or communities may provide useful information related to ecosystem health. Highly stressful conditions may reduce parasite communities or populations. However, it is not a rule since host-parasite...

Uncharted biodiversity in the marine benthos: the void of the smallish with description of ten new Platyhelminth taxa from the well-studied North Sea

Most of our planet’s biodiversity is still unknown, particularly in the sea. Although around the island of Sylt in the North Sea, the small zoobenthos (meiofauna) has been studied intensively since the 1950s, repeating previous surveys revealed an unexpected wealth of new species in addition to the 330 species of free-living microturbellarians (non-parasitic Platyhelminthes...

Nudibranchs out of water: long-term temporal variations in the abundance of two Dendrodoris species under emersion

The sudden appearance and disappearance of nudibranchs in intertidal areas have puzzled researchers all over the world, giving rise to a great diversity of theories to explain it. Here we conducted a five-year survey to evaluate seasonal changes in the abundance of Dendrodoris herytra and D. grandiflora in the Sado estuary (Portugal) and to explore a possible relationship with...

First record of the non-indigenous jellyfish Blackfordia virginica (Mayer, 1910) in the Baltic Sea

Marine invasions are of increasing concern for biodiversity conservation worldwide. Gelatinous macrozooplankton contain members, which have become globally invasive, for example the ctenophore Mnemiopsis leidyi or the hydromedusae Blackfordia virginica. B. virginica is characterised by a large salinity tolerance, with a brackish-water habitat preference, and by a metagenic life...

The illusion of rarity in an epibenthic jellyfish: facts and artefacts in the distribution of Tesserogastria musculosa (Hydrozoa, Ptychogastriidae)

Epibenthic and benthopelagic medusae are rarely collected by standard benthic or pelagic sampling methods, and many species are considered uncommon and geographically restricted. Peer-reviewed scientific literature contains only two records of medusae belonging to the monotypic genus Tesserogastria Beyer, 1958 since their original description, both from the vicinity of the type...

Does rock type account for variation in mussel attachment strength? A test with Brachidontes rodriguezii in the southwestern Atlantic

Mussel attachment strength varies in space and time, frequently in association with variations in wave exposure. Yet, it remains uninvestigated whether different rock types can contribute to variation in mussel attachment. Here we compared the attachment strength of the mussel Brachidontes rodriguezii between soft and hard intertidal rock substrates that are typical of coastal...

Microscopic species make the diversity: a checklist of marine flora and fauna around the Island of Sylt in the North Sea

Based on the past 150 years of research and ongoing time-series observations we give a comprehensive overview of marine species composition around the island of Sylt in the eastern North Sea. A total of 2758 species is listed according to the categories microplankton (591 species), zooplankton (137), nekton (118), benthic microflora (158), benthic macroflora (125), benthic micro...

Variation of sperm morphology in Pacific oyster precludes its use as a species marker but enables intraspecific geo-authentification and aquatic monitoring

According to recent reports, shell morphology is unreliable for the identification of oysters because of the high phenotypic plasticity of these bivalves. Using COI DNA barcoding and sperm morphology, we reinvestigated the species validity of wild Pacific oyster Crassostrea gigas habituating the Peter the Great Bay (Sea of Japan). DNA barcoding confirmed the species validity of...

Mysterious and elaborated: the reproductive behavior of the rhomboid mojarra, Diapterus rhombeus (Cuvier, 1829), in Brazilian mangrove habitats

Many fish species have behavioral traits related to reproduction that aim to improve egg conditions and survival of early life stages. Here, we provide the first detailed description of reproductive strategies performed by the rhomboid mojarra, Diapterus rhombeus. We based this description on several mating events, which occurred in mangroves located in Todos os Santos Bay...