Fig 4 - uploaded by Sanna Majaneva
Content may be subject to copyright.
A) Euplokamis sp. from the Arctic, HF912430 (photo G. Johnsen); B) Coiled tentacle of Euplokamis sp. from the Arctic, HF912430 (photo S. Majaneva); C) Unidentified mertensiid from the Arctic, HF912439 (photo S. Cochrane); D) Mertensia ovum from the Arctic, HF912437 (photo P. Leopold); E) Mertensia ovum with stretched tentacles/tentillas from the Arctic, not sequenced (photo P. Leopold); F) Pleurobrachia pileus from unidentified area (photo M. Decleer, WoRMS); G) Euplokamis sp. (larvae) from adjacent waters of the Baltic Sea, cultivated as adult (photo L. Granhag); H) Euplokamis sp. (adult) from adjacent waters of the Baltic Sea, HE647719 (photo S. Gotensparre); I) Mertensia ovum from the Baltic Sea, FJ668937 (photo M. Lehtiniemi); J) Unidentified mertensiid from the Arctic, not sequenced (photo S. Majaneva).
Contexts in source publication
Context 1
... both captured in the samples and observed while scuba diving, exhibited morphologies that differed from the species previously known to occur in this area (1). Large numbers of synapomorphies were present, and the main identifiable morphological differences were in the body shape, structure of the tentacles, and length of the comb rows (Fig. 4, Table ...
Context 2
... the specimens identified similar to a yet undescribed mertensiid (Plate 73 D in Mills & Haddock 2007), the body shape was oval in the tentacular plane and considerably compressed in the sagittal plane (Fig. 4C, A9 in Fig. 6, accession number ...
Context 3
... sp. (as described in Mills 1987a) had a more elongated circular body (larger length-to-width ratio) (Fig. 4A, G1 in Fig. 7, HF912430) with ctene rows constituting approximately ¾ of the total length and the few secondary tentilla on the tentacles were held tightly coiled, giving the tentacle a beaded appearance. Morphologically, M. ovum ( Fig. 4D and E, Fig. 7 [A8, F2 and B10], HF912437, HF912435, HF912434, HF912433) and P. pileus (Fig. 4F) of the same size class differ by having a different body shape (strongly compressed in the sagittal plane for M. ovum and more egg- shaped or almost spherical for P. pileus), more numerous secondary tentilla, all of which are uncoiled, and comb rows ...
Context 4
... ratio) (Fig. 4A, G1 in Fig. 7, HF912430) with ctene rows constituting approximately ¾ of the total length and the few secondary tentilla on the tentacles were held tightly coiled, giving the tentacle a beaded appearance. Morphologically, M. ovum ( Fig. 4D and E, Fig. 7 [A8, F2 and B10], HF912437, HF912435, HF912434, HF912433) and P. pileus (Fig. 4F) of the same size class differ by having a different body shape (strongly compressed in the sagittal plane for M. ovum and more egg- shaped or almost spherical for P. pileus), more numerous secondary tentilla, all of which are uncoiled, and comb rows starting near to the aboral pole and extending more than ¾ of the distance towards the ...
Context 5
... identified as Euplokamis sp. (as described in Mills 1987a) had an unpigmented and elongated (larger length-to-width ratio) body, tentacles had fewer side branches than M. ovum, which were coiled except when capturing prey, and the ctene rows constituted approximately ¾ of the total length (Fig. 4H, HE647719, HE805698, HE805699). The larval Fig. 4G and ...
Context 6
... collected typically had red dots along comb rows and large tightly-packed cilia, giving a "furry" appearance ( Fig. 4G, see detailed photos in Fig. 2 of article III) that differed from other ctenophore larvae, such as M. leidyi/Bolinopsis infundibulum and Beroe spp., or from the larvae or small- sized adult ctenophores of P. pileus/M. ovum ( Fig. 4I [FJ668937]). Quite often, individuals were severely damaged during sampling, allowing only some of their ...
Context 7
... the sampling for this thesis, specimens collected and photographed by scuba divers (or by hand using buckets) were in the best condition for species identification, even though in photographs the small detailed morphological characters usable for identification were limited (Fig. 4). This is consistent with the recommendation to use Remote Operated Vehicle (ROV) and other submersibles for the in situ identification of gelatinous zooplankton such as ctenophores (e.g. Graham et al. 2001, Båmstedt et al. 2003, Haddock 2004, Lindsay & Miyake 2007, Raskoff et al. 2010). Raskoff et al. (2010) provided a baseline for ...
Context 8
... level at higher prey density with a higher ingestion rate than reported earlier (e.g. Swanberg & Båmstedt 1991a, b), suggesting M. ovum to be an even more efficient predator than previously believed. Interestingly, neither the ingestion nor the clearance rates declined significantly when predator density was increased in the experiments (see Fig. 4 at article IV). It has been thought that tentacle feeders, such as cydippid ctenophores, should exhibit a mechanical limitation when occurring in high aggregations, thus decreasing predation efficiency (Madin 1988). However, no signs of such intraspecific interference were detected, even at predator densities of 500 ind m −3 , the ...
Context 9
... is not alone in having an effect; prey selection is dependent on the consumer's capability not just to find prey but also to attack, catch, and handle it (Holling 1959, Buskey et al. 1993, Chesney 2005, Kiørboe 2011). The fragile tentacles of the Baltic Sea M. ovum stretch only 1-2 times the total body length and possess few branching tentillae (Fig. 4I), while the tentacles of the similar-sized, larval and transitional stages of M. leidyi and larger Arctic M. ovum (Fig. 4E) may stretch several times the body length and bear several to hundreds of branching tentillae ( Reeve et al. 1978, Matsumoto 1991, Sullivan & Gifford 2004, 2007. The fragile structure of the tentacles and tentillae ...
Context 10
... to attack, catch, and handle it (Holling 1959, Buskey et al. 1993, Chesney 2005, Kiørboe 2011). The fragile tentacles of the Baltic Sea M. ovum stretch only 1-2 times the total body length and possess few branching tentillae (Fig. 4I), while the tentacles of the similar-sized, larval and transitional stages of M. leidyi and larger Arctic M. ovum (Fig. 4E) may stretch several times the body length and bear several to hundreds of branching tentillae ( Reeve et al. 1978, Matsumoto 1991, Sullivan & Gifford 2004, 2007. The fragile structure of the tentacles and tentillae can cause injuries for small-sized M. ovum when pulled by escaping copepod prey. This was observed multiple times during ...
Similar publications
The Ctenophora Mertensia ovum and Beroe cucumis, collected using both conventional sampling gear and scuba divers, were studied in the Barents Sea east of Bjørnøya and North Norway in spring 1987 and summer 1988. Among the gelatinous zooplankton, Mertensia ovum was the most consistently abundant copepod predator. Feeding experiments were conducted...
Citations
... More specific sampling techniques and detailed observations will certainly provide more records in the future. According to Majaneva (2014), without proper monitoring and accurate species identification, it is impossible to assess changes in species composition, distribution, and the ecological impact of ctenophores. ...
... Based on experimental observations, Stretch (1982) described the digestion rates and feeding strategy of V. parallelum, while Swift et al. (2009) reported the feeding behavior of T. inconstans. Ignoring spatial patterns can lead to erroneous conclusions concerning their predation impact (Majaneva, 2014). In addition, the relationship between predator size and prey size is of great importance when determining the outcome of interactions among species (Scharf et al., 2000). ...
... In addition, the relationship between predator size and prey size is of great importance when determining the outcome of interactions among species (Scharf et al., 2000). Thus, direct extrapolation from one species, or population, to another raises uncertainty when modeling basic ecological traits such as diet and foraging behavior, especially if individual size of the predators clearly differs between populations (Majaneva, 2014). ...
Ctenophores are one of the most conspicuous and frequent groups of the gelatinous zooplankton community, but their regional diversity in tropical and subtropical latitudes remains largely unknown. We provide an overview and update of the current knowledge of the diversity in Mexican seas, including ocean and coastal-neritic environments of the Gulf of Mexico, the Mexican Caribbean Sea, and the Mexican Pacific Ocean. Ctenophore records were reviewed based on the available scientific and gray literature, the Naturalista network (www.naturalista.mx), and the ctenophore species collected in the Gulf of California by the Monterey Bay Aquarium Research Institute. A total of 33 taxa (Class Nuda and Tentaculata) were found to occur in Mexican seas, of which 12 of the 33 taxa (36.4 % of the total) were recorded in the Gulf of Mexico, 7 (21.2 %) in the Mexican Caribbean Sea, 25 (75.8 %) in the Gulf of California, 11 (33.3 %) in the Eastern Tropical Pacific, and only 2 (6.1 %) are known in the Northeastern Pacific. Up to nine taxa included in our account represent first records for Mexico (i.e., Bathocyroe fosteri, Kiyohimea usagi, Lampocteis cruentiventer, Leucothea sp., Aulacoctena sp., Haeckelia beehleri, Charistephane fugiens, Bathyctena chuni, and Hormiphora californensis). Due to the lack of data on benthic ctenophores and the sparse studies on oceanic and deep-living species, it is expected that the list will grow as new surveys are performed in the deep sea. The lack of long-term studies on Mexican ctenophores have limited our capacity to draw valid conclusions on their abundance, total diversity, endemicity, and trophic ecology in Mexico.
... Map of the study sites in the Arctic Ocean (III,Figure 1) and Baltic Sea (II,Figure 1). Map of the earth courtesy ofMajaneva, (2014). ...
Sea ice, at its maximum extent, is one of the largest biomes on Earth. In addition to the polar
oceans, it covers extensive sea areas at lower latitudes such as the Baltic Sea and the Sea of
Okhotsk. During ice formation, organic and inorganic components in the parent seawater
are concentrated into saline brines within the ice, which serve as a habitat for diverse auto- and
heterotrophic organisms, including bacteria. Sea-ice bacteria are responsible for many
biogeochemical processes, such as decomposition of particulate organic matter, recycling
of dissolved organic matter and remineralization of nutrients, analogously to bacterially
driven biogeochemical processes in the water column. Since bacterial groups vary by their
metabolic traits and participation in biogeochemical processes, knowledge of the bacterial
community structure and its seasonal variation is essential for an understanding of ice
biogeochemistry.
This thesis characterises sea-ice bacterial communities during ice formation and during
the winter/spring transition phase when the community composition is poorly known.
Bacterial communities in Arctic and Baltic sea ice during the winter/spring transition were
studied and compared. In addition, the effect of the dissolved organic matter regime on
bacterial community formation was investigated in an experimental sea-ice system with
North Sea water. The main methods applied were terminal-restriction fragment length
polymorphism and/or Illumina Miseq sequencing together with bacterial production and
abundance measurements.
During the early stages of sea-ice formation, the bacterial communities were similar to
the parent water communities, suggesting that the parent water determines the initial sea-ice
bacterial community composition. After congealment of the sea ice, the bacterial communities
changed towards communities typical of sea ice in spring. During the winter/spring transition,
members of the classes Flavobacteriia (formerly Flavobacteria), Gammaproteobacteria and
Alphaproteobacteria were predominant both in Baltic and Arctic sea ice. The Baltic and
Arctic sea-ice bacterial communities were significantly different; however, a few members
of common sea-ice bacterial genera, such as Polaribacter and Shewanella, were closely
related, pointing to similar selection in ice, regardless of differences in the prevailing
environmental conditions.
In the experimental system, the bacterial communities were able to respond to altered
substrate availability immediately after ice formation. This indicates successful adaptation
of sea-ice bacteria to major shifts in temperature and salinity during ice formation. The
results of this thesis suggest that sea-ice bacterial community formation and dynamics is defined by a combination of changes in environmental conditions during sea-ice maturation
and its associated substrate availability, as well as resource competition. The sea-ice habitat
provides an example of the enormous capacity of bacteria to adapt to changing environments
and how minor members of the bacterial community can become predominant when
environmental conditions change.
During the era of biodiversity loss, a complete species census and understanding where the different species occur is of high priority. Even though this knowledge has increased tremendously, mainly with expanded use of integrated taxonomic identification, there are groups where our knowledge is very limited, both in terms of diversity and distribution. Ctenophores are such a group. Due to a lack of identification literature, damage to specimens during net sampling and sample processing, difficulties with preservation and a considerably undescribed diversity within the phylum, this group is often hard to work with. A citizen science approach was applied during a mapping campaign on ctenophore diversity along the Norwegian coast in order to have a broad geographical coverage. This was achieved by a collaboration with five diving clubs along a south-north geographical gradient that were briefly introduced to ctenophore taxonomy and ecology and sampling techniques using Whatman® FTA® Cards. The data collected by the participating divers gave a broad spatial coverage and provided information on ctenophore diversity in these regions. The use of FTA® Cards in the sampling allowed successful species and genus level identification using DNA barcodes. However, small obstacles such as accurate morphological species identification and labor-intensive issues were identified that can impede the use of large-scale citizen science approaches to map ctenophore diversity and thus recommendations for future implications that address these issues are proposed here.
Cydippid ctenophores of genus Euplokamis have been rarely reported from the north-east Atlantic in the scientific literature. The conspicuous lack of previous records is likely attributable to methodological constraints detrimental to sampling ctenophores, including the use of plankton nets and preservation of samples as well as poor identification literature and a lack of taxonomic expertise on gelatinous zooplankton. Here, we have compiled published and novel records as well as documented diver observations, of Euplokamis spp. in Norwegian waters. Despite scant earlier reports, our data suggest that the genus Euplokamis is widely distributed and relatively common along the entire Norwegian coast, including Svalbard. Euplokamis was recorded from samples taken from several hundred meters depth to surface, from fjords as well as offshore. Most of the observations reported in this study are from the period between April and July, whereas specimens have been found nearly throughout the year. Specimens from Norwegian waters were morphologically most similar to Euplokamis dunlapae, and conservative 18S rDNA sequences of some specimens had a 100% match with an E. dunlapae specimen from Friday Harbor, USA, the type locality for the species. However, the morphological and molecular variation of Euplokamis demonstrates the need for systematic global sampling of multiple individuals of many ctenophore species.
