Radiolaria data from a total of 133 sampling events from 1969 to 1971 in Korsfjorden close to Bergen will be prepared for publication in GBIF. The dataset includes an estimated 66 species and 8778 occurrence data points (estimate including both presence and absence data). Korsfjorden is approximately 670 meters deep and samples are collected at each 100-meter depth. The project will also include adding species illustration images and updating the radiolaria checklist dataset in GBIF. Co-funding from GBIF-Norway is 75 000 NOK. Two previous co-funded projects on Radiolaria data at NHMO has been co-funded by GBIF-Norway in 2015 and 2017.
Project report by professor emeritus Kjell Bjørklund, UiO NHM, version: 19-09-2019
Radiolarians in the Nordic Seas and the Arctic Ocean: Distribution, abundance, preparation and taxonomy
Radiolaria: Definition
Radiolaria are single-celled marine eukaryotes, also some colonial forms, existing from the Cambrian (ca. 530 million years) to Recent. Thus, radiolarians are one of the longest ranging groups of fossil microorganisms. The founders of radiolarian taxonomy were two German scientists, C.G. Ehrenberg (1795-1876) and E. Haeckel (1834-1919). Ehrenberg described more than 70 genera and 500 species, while Haeckel contributed more than 700 genera and 4,000 species. Haeckel's (1887) system is the basis of some modern taxonomic systems. One proposed by Riedel (1967) is the most commonly used: kingdom Protista, phylum Sarcomastigophora, subphylum Sarcodina, class Actinopoda, subclass Radiolaria, superorder Polycystina, and orders Spumellaria (SiO2)/Nassellaria (SiO2)/Phaeodaria (SiO2 + organic compound). In this scheme, Acantharia (SrSO4) and Heliozoa (SiO2) also are assigned to the class Actinopoda but in separate subclasses. This system is mainly based on skeletal material and general morphology, as well as internal cellular structures. New phylogenomic studies show that this Haeckelian system is artificial (not representing evolutionary relationships) and new systems based on molecular genetic data establish more natural relationships among the six supergroups of eukaryotes as proposed by Cavalier-Smith (2002, 2003). The first description of living colonial forms, such as Sphaerozoum fuscum, was made by Meyen (1834). Since then we have recorded about 2,500 high rank taxa (genera/subgenera) and 15,000 species, of which 800 to 1,000 are currently living in the oceans (Suzuki and Aita, 2011).
Taxonomic Position of Radiolaria
Today, molecular work on radiolarians is an active field of research, and the taxonomical scheme is constantly adjusted as new data are made available. Cavalier-Smith (2003) suggested the following system: kingdom Protozoa, subkingdom Biciliata, phylum Retaria, and subphylum Radiozoa, with classes Acantharea, Polycystinea, and Sticholonchea, a system
that has not stabilized and is under development. The Phaeodaria are no longer included in the general category of "Radiolaria" (previously in the phylum Retaria), but placed in phylum Cercozoa. The Radiolaria 18S rDNA phylogeny trees presented in recent publications are rather similar to each other and suggest a polyphyletic status for the polycystines but
are limited by using only the 18S gene. By contrast, Krabberød et al. (2011), using both 18S and 28S rDNA, show that Spumellaria group with Nassellaria, thus suggesting they form a natural phylogenetic group (Figure 1). 
Their data provide a more convincing monophyletic status for the polycystines (Spumellaria together with Nassellaria), as well as a close relation between Acantharea and Sticholonchea, a group given the name Spasmaria (Cavalier-Smith, 1993). In contrast, when only 18S rDNA is used, the Acantharea branch with Spumellaria. These results show that combining the 18S and 28S rDNA genes may greatly improve the resolution of the radiolarian phylogeny. For those being curious about the development of radiolarian taxonomy based on DNA studies, visit also Suzuki and Aita (2011); Suzuki and Not (20??). More about the taxonomy below (in the full project report).
Description of the purpose of this GBIF-entry.
On the basis of sediment samples recovered on the Meteor Expedition in the South Atlantic, Pratje (1951) found the abundance of radiolarians to range from zero to 5% sediment weight in the region between 5° and 60° S. He found the abundance to be essentially in accord with that of diatoms and sponge spicules, and concluded that a direct relationship exists between the biomass of the water column and the concentration of biogenous opal in the underlying sediments. The surface samples from selected gravity cores, essentially from the Lamont-Doherty Earth Observatory (Columbia University, New York), was used to present three geographical data sets as outlined by Goll and Bjørklund (1971, North Atlantic; 1974, South Atlantic), and Bjørklund et al. (1998, Nordic Seas). To collect marine deep-sea sediments are now very expensive and surface sediment samples from gravity or trigger weight core tops are not easily available. Therefore, the intention with this contribution is to present my quantitative distribution data of radiolarian skeletons in the Atlantic sector of the World Ocean, from the Antarctic continent in the south to the Arctic Ocean in the north. The gross distribution as presented herein does provide three data sets of detailed information of the number of radiolarian skeletons/g dried sediment, from the three regions mentioned above. These numbers define zoogeographical radiolarian provinces which essentially are in harmony with oceanographic fronts, submarine bathymetry and do also reflect ecological provinces and borders.
I have studied radiolarians in high northern latitudes since 1969 and my results of the radiolarian distribution in surface sediment samples are summarized herein (http://nhm2.uio.no/radiolaria/). Essentially three areas of study will be encountered herein:
1) The North Atlantic (333 samples (Red stations on map “View North Atlantic Ocean”) used in Goll and Bjørklund, 1971).
2) The South Atlantic (456 samples (Yellow stations on map “View South Atlantic Ocean”) used in Goll and Bjørklund, 1974).
3) The Nordic Seas and Arctic Ocean (479 samples (Blue stations no fauna lists, Green stations with fauna lists, in “View Norwegian Sea and Arctic Ocean”) used in Cortese et al., 2003, and Bjørklund and Kruglikova, 2003).
The cores in the papers by Goll and Bjørklund, 1971; 1974) only show the coordinates and water depth in addition to the actual number of radiolarians/g dried sediment counted and calculated. These data might be of interest for the general radiolarian student in the first attempt to locate an area where radiolarians are abundant in the sediments, and/or where they are rare/absent. As large areas in both the North and South Atlantic Ocean have areas where opal preservation is poor, the abundance numbers from the North and South Atlantic may give a good hint to areas where radiolarian numbers are high. This might be a good guideline when requesting material for radiolarian studies from the different core libraries providing sediment samples.
The cores used in the Bjørklund and Kruglikova (2003) study, and the way they are presented herein, is unique. All stations appearing in green indicate that these stations have information on the total number of species counted and the relative percent value for each species. Species information is further linked to www.Radiolaria.org, for description and picture support.
