Cold Temperate Coral Habitats

Cold-water coral habitats are constituted by a great variety of anthozoan taxa, with reefs and gardens being homes for numerous invertebrates and fish species. In the cold temperate North Atlantic, some coral habitats such as Lophelia pertusa reefs, and Primnoa/Paragorgia dominated coral gardens occur on both sides of the Atlantic over a wide latitudinal range. Other habitats, as some dominated by species of Isididae and Chrysogorgidae seem to have a more local/regional distribution. In this chapter, we describe the habitat characteristics of cold-water coral reefs, soft and hard-bottom coral gardens, and sea pen meadows with their rich associated fauna illustrated with numerous photos

Marine litter in the Nordic Seas: Distribution composition and abundance

Litter has been found in all marine environments and is accumulating in seabirds and mammals in the Nordic Seas. These ecosystems are under pressure from climatic change and fisheries while the human population is small. The marine landscapes in the area range from shallow fishing banks to deep-sea canyons. We present density, distribution and composition of litter from the first large-scale mapping of sea bed litter in arctic and subarctic waters. Litter was registered from 1778 video transects, of which 27% contained litter. The background density of litter in the Barents Sea and Norwegian Sea is 202 and 279 items/km2 respectively, and highest densities were found close to coast and in canyons. Most of the litter originated from the fishing industry and plastic was the second most common litter. Background levels were comparable to European records and areas with most littering had higher densities than in Europe.publishedVersio

Distribution and suitable habitat of the cold-water corals Lophelia pertusa, Paragorgia arborea, and Primnoa resedaeformis on the Norwegian continental shelf

Cold-water corals are habitat-forming species that are also classified as indicators of vulnerable marine ecosystems (VMEs) due to the threat of various anthropogenic impacts, e.g., fisheries and oil/mineral exploration. To best protect VMEs, knowledge of their habitat requirements and distribution is essential. However, comprehensive sampling of the deep sea is difficult due to access and cost constraints, so species distribution modeling (SDM) is often used to predict overall distributions and ecological preferences of species based on limited data. We used Maximum Entropy (Maxent) modeling to predict the probability of presence of the reef-building scleractinian Lophelia pertusa and the octocorals Paragorgia arborea and Primnoa resedaeformis using a total of 2149 coral presence points and 15 environmental predictor variables. The environmental variables used in the analysis were processed to 176 m resolution and included bathymetry, depth, geomorphometric characteristics [slope, aspect, and bathymetric position index (BPI)], oceanography (temperature, salinity, current directions, and speed), surface chlorophyll a concentration, sediment type, and marine landscape type. Comparing presence points with environmental data showed that the temperature and depth range for Lophelia was narrower compared to the gorgonians, and it occurred in shallower, warmer water. Observations showed that Lophelia had a broad, bimodal response to Broad BPI, while the predicted model indicated a more narrow response. Paragorgia tolerated the greatest range of sloping according to the model. All three species were observed with a bimodal pattern along a wide range of mean current speed, while the models indicated a high response to faster current speed. Jackknife tests showed that sediment type was an important predictor for gorgonian corals, while BPI and minimum temperature were more important for Lophelia. The spatial precision of the models could be further increased by applying environmental layers with a higher and uniform spatial resolution. The predicted distribution of corals and their relation to environmental variables provides an important background for prioritizing areas for detailed mapping surveys and will aid in the conservation efforts for these VMEs in Norwegian waters and beyond.publishedVersio

Distribution and habitat of Scalpellidae (Cirripedia: Thoracica) in the Norwegian and Barents Seas

We describe the distribution and habitats of Amigdoscalpellum hispidum, Weltnerium stroemii, Scalpellum scalpellum, Weltnerium cornutum, Catherinum striolatum, Weltnerium nymphocola and Hamatoscalpellum hamatum in the Norwegian and Barents Seas, and their morphology. These are seven of the eight scalpellid species recorded in the area. Expeditions from 2006 to 2018 of the MAREANO (Marine areal database for Norwegian waters) programme have provided a comprehensive collection of Scalpellidae that can contribute to our knowledge of their distribution. The collections were from 335 localities in 40–2300 m depth. Of the 1406 specimens collected, 1396 were collected by beam trawl and 37 were from grabs. Patchy distributions and the association of species with other organisms (e.g. hydroids and gorgonian corals) can explain the low abundance in grabs compared with beam trawls, the latter covering larger areas and mixed sediments better. Weltnerium stroemii was the most abundant species and had the largest depth and temperature range, followed by A. hispidum and W. nymphocola. Species were assigned into three geographic groups based on their depth distribution. Shelf species: W. stroemii, S. scalpellum and A. hispidum occurring mainly shallower than 400 m in water temperatures >4°C; Upper slope species: W. nymphocola, W. cornutum and H. hamatum, found mainly between 600–1000 m in temperatures from 4 to 0°C; Lower slope species: C. striolatum occurring below 1500 m in temperatures <0°C. The species C. striolatum and W. cornutum are new to the Norwegian fauna and future deep-sea exploration will probably discover further scalpellid species.publishedVersio

First description of a Lophelia pertusa reef complex in Atlantic Canada

For the first time, we describe a cold-water coral reef complex in Atlantic Canada, discovered at the shelf break, in the mouth of the Laurentian Channel. The study is based on underwater video and sidescan sonar. The reef complex covered an area of approximately 490×1300 m, at 280–400 m depth. It consisted of several small mounds (< 3 m high) where the scleractinian Lophelia pertusa occurred as live colonies, dead blocks and skeletal rubble. On the mounds, a total of 67 live colonies occurred within 14 patches at 300–320 m depth. Most of these (67%) were small (< 20 cm high). Dead coral (rubble and blocks), dominated (88% of all coral observations). Extensive signs of damage by bottom-fishing gear were observed: broken and tilted coral colonies, over-turned boulders and lost fishing gear. Fisheries observer data indicated that the reef complex was subjected to heavy otter trawling annually between 1980 and 2000. In June 2004, a 15 km2 conservation area excluding all bottom-fishing was established. Current bottom fisheries outside the closure include otter trawling for redfish and anchored longlines for halibut. Vessel monitoring system data indicate that the closure is generally respected by the fishing industry.publishedVersio

Undersøkelser av sedimentsamfunn offshore – sammenlignende kvantitativ utprøving av 0,1 m² vs. 0,25 m² van Veen grabb

På bakgrunn av mulig bruk av Mareanos faunadata som bakgrunnsreferanse ved petroleumsindustriens forurensningsovervåking rundt offshore-installasjoner på norsk sokkel, er det utført en sammenlignende kvantitativ undersøkelse av fangstegenskapene for van Veen grabb med innsamlet bunnareal på henholdsvis 0,25 m² som hittil er benyttet av Mareano, og 0,1 m² som benyttes av petroleumsindustrien grunnere enn 500 m. Undersøkelsen ble utført på fire upåvirkede lokaliteter fra 287 til 963 m dyp, der det ble samlet inn sedimentfauna fra 1,0 m2 bunnareal pr. grabbstørrelse. Det er ikke funnet entydige statistisk signifikante forskjeller i faunasammensetningen mellom de to grabbstørrelsene. For standard offshore prøvetatt bunnareal på 0,5 m2 indikerer ikkesignifikante multivariate statistiske resultater forskjeller i faunasammensetning på 32–39 % på de respektive lokalitetene, hvorav inntil 6 % utgjør forskjeller mellom liten og stor grabb (Bray-Curtis ulikhet). For kvalitativ artsfangst (antall taksa) er forskjellen mellom grabbstørrelsene ved 0,5 m² prøvetatt areal 7–10 %, der liten grabb samlet inn høyest prosentandel på tre av fire lokaliteter. Både for liten og stor grabb er antall taksa innsamlet ved 0,5 m² prøvetatt areal mindre enn 60 % av totalt antall innsamlede taksa på de respektive lokalitetene (2 m2 pr. lokalitet).publishedVersio

Gorgonophilus canadensis (Copepoda: Lamippidae) a parasite in the octocoral Paragorgia arborea – relation to host, reproduction, and morphology

The family Lamippidae (Cyclopoida) are endosymbionts mainly occurring in shallow water octocorals and records from deep-sea corals are few. Here we investigated the relationship between the lamippid Gorgonophilus canadensis Buhl-Mortensen & Mortensen, 2004 and its host the deep-sea coral Paragorgia arborea. Twenty-one specimens of G. canadensis was found inside eight gall-like structures on a P. arborea colony collected in 2010 at 318 m depth off Norway. The galls contained on average 1.6 females, 1.0 males, and 7.5 egg sacs estimated to contain 400 eggs each. Females were larger than males (4.6 mm compared to 2.0 mm). The gall volume increased with the number of egg sacs, females, and the length of females inside, the latter correlation was significant (p < 0.05). The number of egg sacs in galls was positively correlated with the abundance and length of females (p < 0.05), and by adding Canadian data from 17 galls the relation between egg sacs and numbers of females and males in galls became stronger (p < 0.01 and p < 0.05, respectively). Scanning electron microscopy revealed that this highly modified endoparasite has thoracic appendages with non-segmented flexible spines with a specialized structure at their tips through which threads are excreted. We speculate that this adaptation could relate to feeding or attachment of egg sacs inside the galls. Thread production has rarely been reported for copepods and we explore its function in the group as well as other crustaceans. The age and size of the parasite, and the introduction to and release from the host is also discussed.publishedVersio

A new species of Crinoniscus Pérez, 1900 (Crustacea: Isopoda: Crinoniscidae) parasitising the pedunculate barnacle Heteralepas newmani Buhl-Mortensen & Mifsud (Cirripedia: Heteralepadidae) with notes on its ecology and a review of the genus

The new species Crinoniscus stroembergi n. sp. belonging to the parasitic isopod family Crinoniscidae Bonnier, 1900, is described from a pedunculate barnacle host collected in the Mediterranean Sea. This is the first species of Crinoniscus Pérez, 1900 described from a host in the genus Heteralepas Pilsbry. The male cryptoniscus larva is distinguished from congeneric species by having a dorsoventrally flattened body with the posterolateral margins of the cephalon scarcely extending beyond the anterior margin of pereomere 1 (in contrast to C. cephalatus Hosie, 2008 with extended margins); articles 1 and 2 of the antennule being subequal in width and the anterodistal angle of antennule article being low and rounded; propodus of pereopods 6 and 7 having a sinuous dorsal margin that is distally narrowing and the posterior margin of the pleotelson being short and rounded. The mature females of species in Crinoniscus are of two basic forms: those with ventrolateral lobes on the pereomeres (C. alepadis (Gruvel, 1901) n. comb., and C. politosummus Hosie, 2008) and those lacking such lobes (C. cephalatus and C. stroembergi n. sp.). The mature females of C. stroembergi n. sp. can be distinguished from other species of Crininiscus based on their lacking lobes on the anterior end. The material examined includes the male and three female developmental stages of the parasite in the host, Heteralepas newmani Buhl-Mortensen & Mifsud. The mouthparts of the immature female are described and the feeding biology and effects on the host are discussed along with a review of feeding modes in species of the Cryptoniscoidea. Leponiscus alepadis is transferred to Crinoniscus; the latter genus now contains five species. A modified diagnosis of Crinoniscus is provided.publishedVersio

Predicting the Distribution of Indicator Taxa of Vulnerable Marine Ecosystems in the Arctic and Sub-arctic Waters of the Nordic Seas

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Sea pens and bamboo corals in Skagerrak and the Norwegian trench

This study presents the distribution and abundance of key species of the vulnerable marine ecosystems (VMEs) ‘Coral gardens’ and ‘Sea pen and burrowing megafauna’ in Skagerrak and the Norwegian trench. It is based on 543 bycatches from 2017–2021, and 35 ROV dives from 2016-2017. Bycatches were used to indicate distribution and relative abundance of the VME key species while ROV observations provided information on colony densities, associated fauna and damages. Four sea pen species were recorded. Funiculina quadrangularis and Kophobelemnon stelliferum were widely distributed and most abundant below 200 meters. The few records of Pennatula phosphorea were mainly from shallower than 100 meters, and the rare Balticina finmarchica primarily occurred below 200 meters. The ROV videos confirmed the pattern from the bycatches, however, colony densities were much higher, and the sea pen Virgularia mirabilis recorded in high abundances was not present in bycatches. The coral garden key species Isidella lofotensis, endemic to Norway, had a restricted area of occurrence confirmed by both methodologies. The restricted distribution makes it particularly vulnerable. Fishing activities overlap with the VMEs distribution and the observations of sea pen skeletons and the coral predatory anemone Ptychodactis patula are indicative of pressure from bottom trawl fishing.publishedVersio