Epifauna of the Sea of Japan collected via a new epibenthic sledge equipped with camera and environmental sensor systems

Abstract:In Tanaidacea morphological identification of male individuals to the species level is complicated by two factors: the presence of multiple male stages/instars confuse the assessment of sexual stage while strong sexual dimorphism within several families ob− scures the morphological affinities of undescribed males to described females. Males of Paratanaoidea are often morphologically quite different from females and have not been discovered for most genera so far, which has led to the assumption that some tanaidaceans might have parthenogenetic reproduction or simply have undeveloped secondary sex traits. As a part of the IceAGE project (Icelandic marine Animals: Genetics and Ecology), with the support of molecular methods, the first evidence for the existence of highly dimorphic (swimming) males in four families of the superfamily Paratanaoidea (Agathotanaidae, Cryptocopidae, Akanthophoreidae, and Typhlotanaidae) is presented. This study suggests that these males might be the next instars after juvenile or preparatory males, which are morphologically similar to females. It has been assumed that "juvenile" males with a re− stricted ability for swimming (e.g., undeveloped pleopods) have matured testes, are capable of reproduction, and mate with females nearby, while swimming males can mate with dis− tant females. Our explanation of the dimorphism in Tanaidomorpha lies in the fact that males of some species (e.g., Nototanais) retain the same lifestyle or niche as the females, so secondary traits improve their ability to guard females and successfully mate. Males of other species that have moved into a regime (niche) different than that of the female have acquired complex morphological changes (e.g., Typhlotanais).

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Discovery of Swimming Males of Paratanaoidea (Tanaidacea)

Błażewicz¹,

Jennings²,

Jeskulke³

et al. 2014

“…Whenever time and weather conditions allowed replicate sampling, replicates were taken by boxcorer and epibenthic sled. We used two types of epibenthic sleds (Rothlisberg and Pearcy 1977;Brenke 2005;Brandt et al 2013), the latest version equipped with a camera system (Brandt et al 2013). …”

mentioning

confidence: 99%

Preface

Brix¹,

Meißner²,

Stransky³

et al. 2014

The Nordic Seas, i.e. the Greenland, Iceland and Norwegian Seas (GIN Seas), and the northernmost part of the North Atlantic Ocean, are characterized by sev− eral local peculiarities like submarine ridges (geographical barriers) and influence of water masses of different origin. The large Greenland−Iceland−Faeroe subma− rine ridge (GIF Ridge) has its deepest saddle depth of 840 m in the Faeroe Channel ( Fig. 1) and separates the deep Arctic and Nordic Seas from the deep North Atlan− tic Ocean. Accordingly, the ecological conditions are different between these re− gions, and there is a sharp temperature gradient across the ridge. Because of these geological and oceanographic characteristics, the marine environment around Ice− land is the confluence of three very different marine environments, namely the bo− real, subarctic and Arctic zones. The resultant intersection of these zones provides interesting possibilities for biological research. More specifically, the confluence of ridge systems and oceanographic water masses around Iceland allows an un− precedented opportunity to assess how ecology and evolution are shaped by physi− cal characteristics in marine systems.Knowledge of benthic organisms in Icelandic waters stems from the remark− able Danish Ingolf expedition (Wandel 1899) which explored waters around the Faeroe Islands, Iceland and Greenland during four months each year in 1895 and 1896. This effort was the first large−scale, scientific, benthic exploration in the region. During these expeditions a fine mesh was for the first time used in the sampling gear to separate the smaller benthic invertebrates from the sediments, leading to discovery of many small, unknown isopod, tanaidacean and cumacean species (see Hansen 1913Hansen , 1916Hansen , 1920. Outcomes from these expeditions in− cluded large monographs on various invertebrates in the series The Danish Ingolf

“…-The subset of the samples to be used for DNA extraction was sorted directly onboard the research vessels. The EBS models used (Brenke 2005;Brandt et al 2013) contain two separate samplers which are arranged on top of each other. The upper (supra) net was usually best suited because it has proven to be frequently the cleanest and thus fastest to sort.…”

Section: Methodsmentioning

confidence: 99%

“…-Samples were collected by means of epibenthic sledges (EBS) as designed by Brenke (2005) and Brandt et al (2013). Both models were equipped with thermally insulated boxes that enclose the cod ends of the nets as well as a spring−lever system that mechanically controls doors at the mouth of the sledge and allows for selectively collecting endo− and suprabenthic organisms only ( Fig.…”

Section: Methodsmentioning

confidence: 99%

Field and Laboratory Methods for DNA Studies on Deep-sea Isopod Crustaceans

Riehl¹,

Brenke²,

Brix³

et al. 2014

Field and laboratory protocols that originally led to the success of published stud− ies have previously been only briefly laid out in the methods sections of scientific publica− tions. For the sake of repeatability, we regard the details of the methodology that allowed broad−range DNA studies on deep−sea isopods too valuable to be neglected. Here, a com− prehensive summary of protocols for the retrieval of the samples, fixation on board research vessels, PCR amplification and cycle sequencing of altogether six loci (three mitochondrial and three nuclear) is provided. These were adapted from previous protocols and developed especially for asellote Isopoda from deep−sea samples but have been successfully used in some other peracarids as well. In total, about 2300 specimens of isopods, 100 amphipods and 300 tanaids were sequenced mainly for COI and 16S and partly for the other markers. Although we did not set up an experimental design, we were able to analyze amplification and sequencing success of different methods on 16S and compare success rates for COI and 16S. The primer pair 16S SF/SR was generally reliable and led to better results than univer− sal primers in all studied Janiroidea, except Munnopsidae and Dendrotionidae. The widely applied universal primers for the barcoding region of COI are problematic to use in deep−sea isopods with a success rate of 45-79% varying with family. To improve this, we recommend the development of taxon−specific primers.