Helgoland Marine Research

https://hmr.biomedcentral.com

List of Papers (Total 2,053)

Modelling present and future global distributions of razor clams (Bivalvia: Solenidae)

Razor clams (Pharidae and Solenidae) are deep-burrowing bivalves that inhabit shallow waters of the tropical, subtropical, and temperate seas. Using ‘maximum entropy’, a species distribution modelling software, we predicted the most suitable environments for the entire family and 14 Solen species to indicate their present and future geographic distributions. Distance to land...

A non-native macroalga is less attractive for herbivores but more susceptible to light limitation and grazing stress than a comparable native species

It has been suggested that non-native species are more tolerant towards abiotic stress than ecologically comparable native species. Furthermore, non-native marine macroalgae should be under lower grazing pressure than native seaweeds, because they left their co-evolved enemies behind. As a consequence, they generally need to allocate less energy to defences and can invest more...

Description, systematics and ecology of a new tanaidacean (Crustacea, Peracarida) species from mediterranean fish farms

An undescribed species of tanaidacean belonging to the genus Hexapleomera, tribe Pancolini, Hexapleomera bultidactyla sp. nov. was found in fouling community samples from off-coast fish farms cages in the western Mediterranean Sea. The species can be distinguished from other Hexapleomera species by the presence of a ventral apophysis on the dactylus of the chela in males. Other...

Synchronism of naupliar development of Sacculina carcini Thompson, 1836 (Pancrustacea, Rhizocephala) revealed by precise monitoring

Sacculina carcini is member of a highly-specialized group of parasitic cirripeds (Rhizocephala) that use crabs (Carcinus maenas) as hosts to carry out the reproductive phase of their life cycle. We describe the naupliar development of S. carcini Thompson, 1836 from a very precise monitoring of three different broods from three specimens. Nauplii were sampled every 4 h, from the...

A new species of Cephalorhyncha Adrianov, 1999 (Kinorhyncha: Cyclorhagida) from the Aegean Coast of Turkey

Kinorhynchs are marine, microscopic ecdysozoan animals that are found throughout the world’s ocean. Cephalorhyncha flosculosa sp. nov. is described from the Aegean Coast of Turkey. Samples were collected from intertidal zones at two localities. The new species is distinguished from its congeners by having flosculi in midventral positions on segment 3–8, and by differences in its...

Four new species of Chaetodermatidae (Mollusca, Caudofoveata) from bathyal bottoms of the NW Iberian Peninsula

Caudofoveata is a class of vermiform molluscs with bilateral symmetry and circular transverse section. There are at least 135 described species of Caudofoveata. Fourteen species have been reported from the coast of the Iberian Peninsula, four of which belong to the family Chaetodermatidae. Of these four species, three are endemic to the Mediterranean Sea and one to the NW Iberian...

Basal articulation of the palps and ovigers in Antarctic Colossendeis (Pycnogonida; Colossendeidae)

Selected sea spider specimens of Antarctic Colossendeis species collected during the Italica XIX cruise and the Polarstern cruise ANT XXIII/8 were examined to provide new information about the external and internal anatomy of the basal parts of the palps and ovigers. The presence and insertion of the muscle bands, as well as the arthrodial membrane are illustrated and discussed...

Substrate preference and settlement behaviour of the megalopa of the invasive crab Percnon gibbesi (Decapoda, Percnidae) in the Mediterranean Sea

The transition from a planktonic to a benthic life is a critical phase in which sub-adults are particularly exposed to the risk of predation and dispersion into unsuitable habitats, and plays a crucial role in the distribution, structure and dynamics of marine populations. Settlement involves the selection of an adequate substrate that provides shelter and food during early life...

A reappraisal of Stegastes species occurring in the South Atlantic using morphological and molecular data

The taxonomic status of Pomacentridae species can be difficult to determine, due to the high diversity, and in some cases, poorly understood characters, such as color patterns. Although Stegastes rocasensis, endemic to the Rocas atoll and Fernando de Noronha archipelago, and S. sanctipauli, endemic to the São Pedro and São Paulo archipelago, differ in color pattern, they exhibit...

Species identification of echinoderms from the North Sea by combining morphology and molecular data

Background Taxonomic uncertainties in the morphological species identification and taxonomic revisions in individual groups are known for all echinoderm classes. These uncertainties in morphological species identification and discrimination have spawned the application of molecular genetic identification techniques. However, as the fundamental step to allow and ensure future...

Food-limited growth of larval Atlantic herring Clupea harengus recurrently observed in a coastal nursery area

Food-limited growth of larval fish, defined as growth rates lower than observed in other habitats or from laboratory experiments at a given temperature, is rarely reported in field studies. This would imply that either larval fishes are living in an environment characterized by plenty of food, that nutritional condition selective mortality (i.e., eliminating the weak) is very...

Seven new species of sponges (Porifera) from deep-sea coral mounds at Campos Basin (SW Atlantic)

Deep-sea reefs and coral banks are increasingly known as highly biodiverse ecosystems where sponges constitute a significant proportion of builders and inhabitants. Albeit smaller in dimensions, Campos Basin coral mounds also harbor a rich associated fauna, whence only 16 species of sponges had been fully identified this far. Seven new species are described here, viz. Geodia...

Epibiontic associations between apostomid ciliates Conidophrys spp. and amphipods associated with fish farms fouling in the western Mediterranean Sea

Fish farms commonly support high abundances of invertebrates, especially amphipods, associated with fouling communities developed over nets, ropes and buoys. Protozoan epibiont ciliates of the genus Conidophrys were observed on three of the most abundant amphipod species collected from ropes of a fish farm in the western Mediterranean Sea. The amphipod species were Ericthonius...

First record on the development of the larva of the basally branching nemertean species Carinina ochracea (Palaeonemertea)

Nemertea are a clade of unsegmented, vermiform, mostly marine Spiralia. While it is generally accepted that Nemertea develop via a pelagic larval stage there is considerable uncertainty about its characteristic, ancestral features. The uncertainty is mainly due to highly disparate larval types in the derived clade Neonemertea and the scarce information on the larval types of...

Effect of different protein supply on growth of three populations of a crab adapted to low energy diets

Juvenile individuals of the crab Neohelice granulata (Brachyura: Grapsoidea: Varunidae) were grown in laboratory using five artificial diets containing 3, 6, 12, 18 and 24 % of crude protein and 3 % of lipids during 7 months. Crabs belonged to three different populations. Two of them, San Antonio Oeste (SAO) and Riacho San José (RSJ) are close; they are not genetically...

Spatiotemporal variation of the bacterioplankton community in the German Bight: from estuarine to offshore regions

Marine microbial biogeography has been studied intensively; however few studies address community variation across temporal and spatial scales simultaneously so far. Here we present a yearlong study investigating the dynamics of the free-living and particle-attached bacterioplankton community across a 100 km transect in the German Bight reaching from the Elbe estuary towards the...

A new species of Austrodecus Hodgson, 1907 (Pycnogonida, Austrodecidae) from the Chilean fjords

A new species of the “glaciale” group of Austrodecus Hodgson, 1907, Austrodecus nausinoos sp. n., is described from specimens collected by “Huinay Fjordos” expeditions to the southern Chilean fjords in 2005, 2011 and 2013. Specific to the new species is the combination of the following morphological characters: six-articled ovigers, auxiliary claws, two spines on the first coxa...

Diversity of Bugulidae (Bryozoa, Cheilostomata) colonizing artificial substrates in the Madeira Archipelago (NE Atlantic Ocean)

Until very recently the Madeira Archipelago registered a total of eight Bugulidae species. In the present study we include descriptions of seven Bugulidae species, now with Scanning Electron Microscopy images, with four new records for the Archipelago: Bugulina fulva and Bugulina simplex for Madeira Island and Bugula neritina and Crisularia gracilis for the neighbouring Island of...

Growth of Mya arenaria L. at the northern edge of the range: heterogeneity of soft-shell clam growth characteristics in the White Sea

Linear growth of soft-shell clams, Mya arenaria L., was studied at six locations in the White Sea situated in the middle and low tidal zones. The main aim was to analyse the growth heterogeneity both within beds (with respect to individual growth) and between beds (with respect to group growth). Mya population was characterized by a slow growth and a long lifespan. Maximum shell...

Growth and reproductive biology of the sea star Astropecten aranciacus (Echinodermata, Asteroidea) on the continental shelf of the Catalan Sea (northwestern Mediterranean)

The growth and reproductive biology of the sea star Astropecten aranciacus was investigated on the continental shelf of the northwestern Mediterranean Sea. Sea stars were captured monthly in two bathymetric ranges (5–30 and 50–150 m) between November 2009 and October 2012. Bathymetric segregation by size in A. aranciacus was detected: small individuals inhabit shallow areas (5–30...

Response of the zooxanthellae of Palythoa caribaeorum (Cnidaria: Zoanthidea) to different environmental conditions in coastal and oceanic ecosystems of the Tropical Atlantic

The present study tested the hypothesis that endosymbionts of the zoanthid Palythoa caribaeorum show specific responses in cell density, size, and mitotic index (as proxy for cell population growth) under different environmental conditions (water depth, position within the reef and within the colony). Colony fragments were sampled at the nearshore coastal reefs of Porto de...

Some Bryozoa species recently introduced into the Azores: reproductive strategies as a proxy for further spread

In the marine environment, control of invasive species’ population levels, that is, keeping them at an abundance level which is below a density-dependent adverse effect, may be the most attainable goal for the management of introduced bryozoans. An improved understanding of reproductive strategies and life history traits is key in order to understand the spreading potential. The...

Spicular analysis of surficial sediments as a supplementary tool for studies of modern sponge communities

The method of spicular analysis that examines surficial sediments has been used to study the sponge spicule assemblage in the lagoon reef of Bocas del Toro, Panama. The method allowed to recognize some highly diagnostic spicule morphotypes that may belong to four sponge species as yet unnoticed in this area. The presence of these sponges must have been overlooked while studying...