Article

The Role of Sponges in High Antarctic Carbon and Silicon Cycling - a Modelling Approach.

Authors:
To read the full-text of this research, you can request a copy directly from the author.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the author.

... drastic rifts in the bottom scoured by icebergs). In the Weddell Sea, early successional stages are considered precursors toward the late slow-growing hexactinellid sponge stage (Dayton 1979, Gatti 2002, assuming that many decades or even centuries may be necessary to return to such a mature community after disturbance. However, no quantitative studies have been carried out to characterise this pattern. ...
... The demosponge Stylocordyla borealis sexually develops young complete sponges incubated in the mother's body, which settle in the close vicinity, thereby showing low dispersability (Sarà et al. 2002). Based on growth models, Gatti (2002) calculated an estimated age of 10.4 yr for a body area of 4.4 cm 2 . In R0, we found smaller individuals of S. borealis with a mean area of 1.2 cm 2 , suggesting a younger age. ...
... Gambi et al. (2000);2 Svane & Young (1989);3 Monniot & Monniot (1983); 4 Rauschert (1991); 5Kowalke et al. (2001);6 Sarà et al. (2002); 7Gatti (2002);8 Cancino et al. (2002); 9Zabala et al. (1997);10 Gambi et al. (2001); 11 López (pers. comm.); ...
Article
Full-text available
The response of an Antarctic benthic community to iceberg disturbance was investigated using underwater photographs (1 m(2) each) on the SE Weddell Sea shelf. This study: (1) characterises composition, coverage, number of patches and area of sessile benthic fauna, (2) describes faunal heterogeneity using MDS ordination and identifies 'structural taxa' of each recovery stage, and (3) analyses changes of growth-form patterns during Antarctic recovery. We observed changes in the space occupation of benthic organisms along the recolonisation stages. Uncovered sediment characterised the early stages ranging from 98 to 91% of the coverage. The later stages showed high (70.5%) and intermediate (52.5%) values of benthic coverage, where demosponges, bryozoans and ascidians exhibited a high number of patches and taxa. Several 'structural species' were identified among the stages, and information is provided on their coverage, number of patches and area. Overall, maximum areas of patches increased as recovery proceeded. Early stages were characterised by the presence of pioneer taxa, which only partly covered the bottom sediment but were locally abundant (e.g. the bryozoan Cellarinella spp. and the gorgonian Primnosis antarctica with a maximum coverage of 13 and 3%, and 51 and 30 patches m(-2), respectively). Soft bush-like bryozoans, sheet-like sabellid polychaetes, and tree-like sponges, gorgonians, bryozoans and ascidians were the first colonisers. Mound-like sponges and ascidians as well as tree-like organisms with a long lifespan and different reproductive strategies defined the late stages. We conclude by comparing the selected,structural species' and relating their life-history traits to differences in distribution in the course of Antarctic recovery.
... Even the early epifaunal colonists are relatively long-lived. For example, the lollipop sponge (Stylocordyla borealis) is considered an indicator of recent disturbance by icebergs in the Weddell Sea, with small individuals (4.4 cm 2 in body area) estimated to be about 10.4 yr (Gatti, 2002), while early colonist bryozoans are estimated to live about 30 yr (Brey et al., 1999). Maintaining sedentary and long-lived organisms in any ecosystem requires either low frequencies or spatial extents of disturbance (or a combination of the two). ...
... The sponge communities described by Dayton et al. (1974) in McMurdo Sound and by Cattaneo-Vietti et al. (2000a) in Terra Nova Bay clearly indicate areas that have escaped disturbance by icebergs for long periods. Hexactinellid sponges appear to exhibit sporadic growth (Dayton, 1979(Dayton, , 1974, and recent estimates based on the metabolic activity of sponges in the Weddell Sea indicate Rossella sponges may live on the order of 10 4 yr (Gatti, 2002). This modelling approach based on metabolic rates may not directly translate to the Ross Sea, due to its overall higher primary productivity in comparison to the Weddell Sea (142 cf 81 gCm À2 yr À1 ; Gatti, 2002). ...
... Hexactinellid sponges appear to exhibit sporadic growth (Dayton, 1979(Dayton, , 1974, and recent estimates based on the metabolic activity of sponges in the Weddell Sea indicate Rossella sponges may live on the order of 10 4 yr (Gatti, 2002). This modelling approach based on metabolic rates may not directly translate to the Ross Sea, due to its overall higher primary productivity in comparison to the Weddell Sea (142 cf 81 gCm À2 yr À1 ; Gatti, 2002). Moreover, with ages of organisms on these time scales, it is important to consider a palaeoecological perspective, as it is estimated that it was only about 6000 yr ago when the extent of the Ross Sea and adjacent ice shelf resembled today's conditions (Barrett, 1999). ...
Article
Early ecological research in McMurdo Sound revealed local spatial gradients in community structure associated with variations in anchor ice disturbance, fast ice and snow cover, and the effects of predators. Research contrasting the east and west sides of McMurdo Sound has shown major differences in benthic communities, which have been attributed to oceanographic influences on the advection of water-column productivity and the frequency of fast ice break-out. Despite these regional and local differences, coastal benthic communities in McMurdo Sound show a high level of stability, and contain a variety of large and potentially very long-lived species. In Terra Nova Bay, about half way along the Victoria Land Coast of the western Ross Sea, the coastal benthic communities provide some insightful contrasts with those in McMurdo Sound. For example, the abundance and depth distribution of dominant species such as Sterechinus neumayeri and Adamussium colbecki are markedly different from McMurdo Sound. In both locations communities dominated by large sponges are most prolific in regions that are free from iceberg disturbance of the seabed. A recent assessment of northern Victoria Land coastal benthic communities, in conjunction with multibeam imagery of the seafloor, further highlights the importance of iceberg disturbance in structuring Antarctic benthic communities. A comparative synthesis of these coastal ecological studies enables us to generate hypotheses concerning the relative importance of different environmental drivers in structuring benthic communities. Overlain on the regular latitudinal shifts in physical factors such as light regime, are regional fluctuations that are controlled by atmospheric and oceanographic circulation patterns and coastal topography/bathymetry. Change in diversity along the western coast of the Ross Sea is predicted to be influenced by three main factors (1) ice disturbance (e.g., via anchor ice and advection of supercooled water or icebergs), (2) photosynthetically available radiation (affected by ice and snow cover and water clarity), (3) the locations of polynyas and advection of planktonic production and larvae. Interactions between these factors are expected to result in non-linear changes along the latitudinal gradient. While predictions generated from these hypotheses remain to be rigorously tested, they provide indications of how benthic communities may respond to changes in production, disturbance and the stability of coastal sea ice.
... All individual terminally differentiated cell types have maximum longevity of up to one week and sponges continually replace all their terminally differentiated cells through stem cell differentiation [33][34][35]. They are hence potentially long lived/immortal [36,37]. ...
... In less advanced metazoans, sponges, cnidarians and basal bilaterians, totipotent/pluripotent stem cells are retained. These organisms can hence continually replace all senescent terminally differentiated cells and so have the potential to be long lived/immortal [36,37,47]. ...
Article
It is proposed that a primary and fundamental aspect of metazoan evolution is an ability to control and extend the longevity of individual cells. This was achieved through an intracellular oscillator, dubbed 'Life's Timekeeper', which evolved in the hypothetical ancestor of all metazoans. Slower oscillatory frequencies directed metazoan evolution towards extended longevity of individual cells, enabling generation of many specialised types of terminally differentiated cells. As the longevity of these cells was still relatively short in more primitive metazoans, stem cells, capable of differentiating into all specialised cell types, were retained in order to replace senescent cells. With increasing cell longevity, continual replacement of all senescent cells was no longer necessary. Cells such as neurons could be sustained throughout life, enabling the evolution of brains, hence, complex behaviour and intelligence. In multicellular metazoans the oscillator remains synchronised across all cells. It coordinates the timing of all cell-cell signalling systems, hence controls the timing of development and aging/senescence. In advanced metazoans, where senescent cells are not continually replaced, it controls lifespan. With regards to morphological evolution the oscillator, through alterations to developmental timing, controls change in size and shape. With regards to life history theory it functions as the key variable mediating the correlation between life history traits. This theory is compatible with a prominent role for environmental selection but, as it implicates some degree of internal mediation and direction, it is not entirely compatible with the 'modern synthesis' view of natural selection.
... About 600 species [32]. Big life span is reported with a maximum record of 15 000 years [4,42]. Minimum is not well known, but most likely these sponges live at least several years, because they live in the big depth and have slow metabolism. ...
... Probably, they can live several hundred years or even more than 1 000. Number 1550 is considered record [42,92]. However, several species are shortlived; their representative live just several months [31] or several years [165]. ...
Article
Full-text available
Animal world is one of the main sources of information on ageing and longevity. Several animal species are used to explore the evolution of ageing and to fi nd the remedies to extend human longevity. However, about a third of animal phyla, and usually less, are mentioned in the relevant reviews. We analysed the entire animal world in context of longevity studies choosing for the analysis one of its most general characteristics — the limits of variation of life spans within the main groups. We performed a systematic review of the sources on all groups of animals of the class level and meta-analysis of the values of life spans within them.
... Nevertheless, latest advances in sequencing technologies have allowed the expansion of cross-species comparative studies and investigations on so far un-investigated long-lived model organisms (Seim et al., 2014;Tian et al., 2019). Interestingly, there are still unexplored animals with extreme longevity such as several species of antarctic seasponge (such as Anoxycalyx (Scolymastra) joubini) that may live for several thousand years (Dayton, 1979;Gatti, 2002). However, a creature dwelling at the bottom of the Antarctic ocean has a vastly different environment than humans which will impact ageing in numerous ways. ...
... Drosophila melanogaster ∼15 weeks (Pletcher et al., 2002;Zou et al., 2000), Caenorhabditis elegans ∼8 weeks (Friedman and Johnson, 1988;Klass, 1977) (Nielsen et al., 2016) Leiopathes sp. ∼4000 years (Roark et al., 2009) Pinus longaeva ∼5000 years (Lanner and Connor, 2001) Anoxycalyx (Scolymastra) joubini ∼15,000 years (Dayton, 1979;Gatti, 2002) Hydra vulgaris unknown (Martínez, 1998) ...
Article
Full-text available
Ageing is arguably the most complex phenotype that occurs in humans. To understand and treat ageing as well as associated diseases, highly specialised technologies are emerging that reveal critical insight into the underlying mechanisms and provide new hope for previously untreated diseases. Herein, we describe the latest developments in cutting edge technologies applied across the field of ageing research. We cover emerging model organisms, high-throughput methodologies and machine-driven approaches. In all, this review will give you a glimpse of what will be pushing the field onwards and upwards.
... Patchy distributions are common for Antarctic sponges (Barthel and Gutt 1992;Gutt and Koltun 1995;Gatti 2002). Some species form dense populations in some areas. ...
... Antarctic benthic invertebrates have been isolated from the rest of continents for several millions of years (Dayton 1990;Thompson 1991). Isolation and stability over evolutionary time scales enable us to foresee that some Antarctic invertebrates from ancient asexual lineages (Stoeckel et al. 2006) have perpetuated well-adapted genotypes to consistently low temperatures (Clarke 1988) and temporal trophic depletion (Clarke 1988;Gatti 2002). ...
Article
Full-text available
Antarctic bottoms harbor stable, benthic communities, subjected to low temperatures. Environmental stability may promote the asexual (clonal) reproduction of sponges to maintain adapted genotypes to those particular conditions. Stylocordyla chupachups forms patchy populations across the Antarctic continental shelf. Individuals are mostly similar in size without distinct cohorts, which indicates fast growth of the new recruits. Settlement of incubated (clonal?) functional sponges may accelerate sponge growth and success at early colonization phases. To analyze the weight of clonal reproduction in the species, a genetic study was performed on three close populations using eight polymorphic microsatellite loci that were designed from massive sequencing. The three study populations showed a relatively low genetic diversity and low loci polymorphism (from 2 to 6 alleles). The estimators of genetic structure, the Analysis of the Molecular Variance (AMOVA), and the presence of private alleles indicated low but significant structure between the populations. A relatively high rate of asexual reproduction (ca. 25% of the individuals) was detected. The program MLGsim found five identical multilocus genotypes (MLGs) with an asexual origin. An excess of heterozygotes (in five out of the eight loci genotyped) was found, which suggests a positive selection mechanism for heterozygotes. The relatively high rates of asexual reproduction may be the result of adaptation to the environmental stability, while heterozygote selection would help maintain some genetic diversity in the populations. S. chupachups has been reported to be one of the first sponge species recolonizing bare areas resulting from iceberg scouring, which indicates a high species fitness and adaptation to Antarctic bottoms. Two out of the three study populations showed bottleneck, which may indicate a recent founder effect and supports the pioneer nature of this species.
... There is presently an intensive debate on the lifespans of siliceous sponges (hexactinellids or demosponges). Gatti (2002) provided experimental evidence that specimens from the Antarctic hexactinellid sponges, e.g. Rossella spp., can reach ages of 1500 to 23,000 years, whereas the demosponges Stylocordyla borealis and Cinachyra antarctica live only 150 years, or 35 years, respectively. ...
... Attempts to determine the age of the long-living sponges, e.g. Monorhaphis, by 32 Si dating technique (Ellwood et al., 2007) as well as by an indirect approach based on metabolic parameters and increase of body mass (Gatti, 2002) turned out to be not suitable. In the present study a different approach was applied which uses the intrinsic potential of biogenic silica as paleoenvironmental archives. ...
Article
Full-text available
The deep-sea sponge Monorhaphis chuni forms giant basal spicules, which can reach lengths of 3 m; they represent the largest biogenic silica structures on Earth that is formed from an individual metazoan. The spicules offer a unique opportunity to record environmental change of past oceanic and climatic conditions. A giant spicule collected in the East China Sea in a depth of 1110 m was investigated. The oxygen isotopic composition and Mg/Ca ratios determined along center-to-surface segments are used as geochemical proxies for the assessment of seawater paleotemperatures. Calculations are based on the assumption that the calculated temperature near the surface of the spicule is identical with the average ambient temperature of 4 °C. A seawater temperature of 1.9 °C is inferred for the beginning of the lifespan of the Monorhaphis specimen. The temperature increases smoothly to 2.3 °C, to be followed by sharply increased and variable temperatures up to 6–10 °C. In the outer part of the spicule, the inferred seawater temperature is about 4 °C. The lifespan of the spicule can be estimated to 11,000 ± 3000 years using the long-term trend of the inferred temperatures fitted to the seawater temperature–age relationships since the Last Glacial Maximum. Specimens of Monorhaphis therefore represents one the oldest living animals on Earth. The remarkable temperature spikes of the ambient seawater occurring 9500–3100 years B.P. are explained by discharges of hydrothermal fluids in the neighborhood of the spicule. The irregular lamellar organization of the spicule and the elevated Mn concentrations during the high-temperature growth are consistent with a hydrothermal fluid input.
... Sponges (Phylum Porifera), are diverse, sessile, benthic metazoans, occurring in marine, fresh-water and quasi-terrestrial ecosystems worldwide. In marine habitats, from coral reefs to abyssal plains, sponges play important roles in biogeochemical cycling [1], in the spatial structuring of the seafloor [2], and in benthic-pelagic coupling of nutrient transfer within ocean ecosystems [3]; sponges also participate in complex biotic interactions with diverse macrobiotic taxa (for a review see: [3]), and microbiological communities (e.g. [4]). ...
... Low temperature in invertebrates, and ectotherms/ poikilotherms in general, is associated with an overall slower life history, including a slower pace of development (Gillooly et al. 2002;Trudgill et al. 2005). Antarctic sponges such as Cinachyra antarctica (Epibenthic sponge) and Scolymastra joubini (Hexactinellid sponge) are known to have slower growth rates at lower temperatures which may contribute to their exceptional longevity; these are possibly the longest-lived animals on earth, estimated to live up to 1550 and 15,000 years old, respectively (Gatti 2002). This link between temperature and the slowing down of development of ectotherms could possibly support the 'rate of living hypothesis' Only laboratory studies specifically manipulating temperature are included. ...
Article
Full-text available
Temperature is a basic and essential property of any physical system, including living systems. Even modest variations in temperature can have profound effects on organisms, and it has long been thought that as metabolism increases at higher temperatures so should rates of ageing. Here, we review the literature on how temperature affects longevity, ageing and life history traits. From poikilotherms to homeotherms, there is a clear trend for lower temperature being associated with longer lifespans both in wild populations and in laboratory conditions. Many life-extending manipulations in rodents, such as caloric restriction, also decrease core body temperature. Nonetheless, an inverse relationship between temperature and lifespan can be obscured or reversed, especially when the range of body temperatures is small as in homeotherms. An example is observed in humans: women appear to have a slightly higher body temperature and yet live longer than men. The mechanisms involved in the relationship between temperature and longevity also appear to be less direct than once thought with neuroendocrine processes possibly mediating complex physiological responses to temperature changes. Lastly, we discuss species differences in longevity in mammals and how this relates to body temperature and argue that the low temperature of the long-lived naked mole-rat possibly contributes to its exceptional longevity.
... However, this hypothesis requires the rejection of the assumption that C. barbata s.l. grows much faster than hexactinellids (Gatti 2002), even though their absolute growth rates and differences in growth performance are not sufficiently documented. Further, a possible faster re cruitment of hexactinellids alone cannot explain the very low abundance of C. barbata s.l. ...
Article
Full-text available
Sponge spicule sea-bed cover was analysed and related to the mega- and macro-epibenthos along one video-recorded and one still image sea-bed transect in the southeastern Weddell Sea, Antarctica. The origin of the patterns of spicule mats and their associated fauna was conceptually reconstructed and interpreted to be a result of iceberg scouring as the main driver. Spicule beds were not necessarily correlated with a diverse fauna, which was shown by a comparison of sponge spicule cover and macrobenthic and megabenthic abundance and biodiversity. On the one hand, this result might reflect slow recolonisation processes, especially by the megabenthos. On the other hand, local maximum densities of adult sponges were found where spicule cover was highest. A simple numerical model revealed that biogenic silicon converted from living to dead material by iceberg scouring accounts for 0.69% of the global silicon flux to the deep sea, which originates from primary production. However, the sponge-derived silicon sequestration occurs over only 2.4 parts per thousand area of the global ocean. On the Antarctic continental shelf, flux rates of silicon that originated from primary production are similar to or twice as high as silicon sequestration due to iceberg-induced sponge mass mortality.
... В штате Пенсильвания (США) известна система связанных подземными побегами парциальных кустов черники Gaylussacia brachycera (Michx.) A. Gray возрастом предположительно до 13 000 лет (Wherry, 1972). Возраст одной гигантской антарктической губки Scolymastra joubini Topsent составляет не менее 15 000 лет (Gatti, 2002), а возраст вегетативно размножающейся генеты остролиста королевского (Lomatia tasmanica W. M. Curtis) с о. Тасмания -43 600 лет (Jordan et al. 1991;Lynch et al., 1998). ...
Conference Paper
Full-text available
Some time delay between materialization and production of any information is unavoidable, since there is always a time distance between these processes. As for the delay in materialization of genetic information, that is because the natural selection acts upon groups of living organisms on momentary basis whereas the selected information is realized in the following generations. And since the material world is always hanging, some information about the structure of current successful individuals inevitably becomes outdated by the time their next generation appears. Organisms can often only reduce their lifespan to adapt to this henomenon. But among a huge quantity of structural elements that are formed based on “outdated” information, the ones that are able to improve individual fi tness with respect to the new state of the environment will be present with high probability. Such structural features may contain elements of ‘overadaptations’ or serve as anticipatory adaptations, that has allowed some species to persist during abrupt and unpredictable changes of their environment, when they did not have enough time for gradual adaptation.
... They also have biochemical and genetic properties which make them a valuable source of chemical compounds for the pharmaceutical industry (Thakur & Mü ller 2004; Bell 2008). The slow growth rates and long-lived nature of large sponges (Hoppe 1988; Leys & Lauzon 1998; Gatti 2002; Klitgaard & Tendal 2004) makes them very vulnerable to perturbations, particularly to the mechanical impacts of bottom fishing activities when sponge grounds overlap with trawl grounds (Freese 2001; Wassenberg et al. 2002; Heifetz et al. 2009) and sponges can take decades to recover if they are removed, if ever (Jones 1992; Klitgaard & Tendal 2004). Recently, protection of deep-sea habitats has received considerable attention (Ardron et al. 2007; Hall-Spencer et al. 2009; Penney et al. 2009) and in Resolution 61/105 on sustainable fisheries the United Nations General Assembly (UNGA) called for Member States and Regional Fisheries Management Organizations (RFMOs) to take measures to protect vulnerable marine ecosystems , such as sponge grounds, in the high seas (UNGA 2006; FAO 2009). ...
Article
Full-text available
Distribution and species composition of deep-sea sponge grounds of the Flemish Cap, Flemish Pass and the Grand Banks of Newfoundland are described based on Spanish/EU bottom trawl groundfish surveys between 40 and 1500 m depth. Four areas with large catches of sponges and at least 30 different species have been identified in the study area. Geodia barretti, Geodia macandrewii, Geodia phlegraei, Stryphnus ponderosus and Stelletta normani are the main structural sponges and constitute more than 94% of the total invertebrate biomass of these grounds. The temperature and salinity observed over these bottoms ranged between 3.38 and 3.84C and between 34.85 and 34.90C respectively. The biomass of deep-water sponges per swept area was significantly higher on lightly or untrawled bottoms than in the grounds that are regularly fished. Data from trawl groundfish surveys cannot map the deep-sea sponge grounds to a precision less than the trawl distance of 1.5 nm. Nevertheless it has been used by the Northwest Atlantic Fisheries Organization (NAFO), along with additional Canadian data, to implement the 61/105 United Nations General Assembly Resolution in closing six areas to bottom fishing activities to protect the sponge grounds of the NAFO Regulatory Area.
... Reiswig, 2004;Leys et al., 2007), where these sponges are one of the most important megafaunal benthic components and make up a substantial proportion of benthic biomass since they often occur abundantly and in large individual sizes (Barthel, 1992;Cattaneo-Vietti et al., 1999;Reiswig, 2004). It has been shown that hexactinellid species, reach high individual age of several 100 years (Gatti, 2002). Moreover, hexactinellid sponges are considered to play an important structuring ecological role by providing shelter, habitat, food and nursery ground for a huge variety of associated faunal components (Konecki & Targett, 1989;Kunzmann, 1992;Barthel, 1995Barthel, , 1997. ...
Article
Full-text available
Amongst the Hexactinellida, Hexasterophora is the most important taxon in terms of number of species as well as concerning the variability in morphological characters. In this study the first comprehensive analysis of phylogenetic relations between hexactinellid families and genera of the subclass Hexasterophora based on morphological features is presented. Therefore, 157 morphological characters of the Hexasterophora were compiled into a matrix by presence/absence data. The resulting phylogenetic trees are compared with conclusions based on molecular data and classical systematics. So far, we find the main hexasterophoran taxa (Hexactinosida, Rossellidae and Euplectellidae) well established as monophyletic and in rather good correspondence with classical systematics and molecular results. Our phylogenetic trees largely support the systematic classification proposed by Schulze (1886) and Mehl (2002). However, some families (e.g. Euretidae) are not corroborated. For others (Euplectellidae), our cladistics approach is at odds with the system proposed by Tabachnick (2002a). Morphological phylogeny becomes problematic for those taxa, in which many of the diagnostic characters are either symplesiomorphic, or multiple homoplastic. Our results indicated the need for revision of the classification features used.
... Indeterminate growth does not exist in birds and mammals Indeterminate growth exists in various taxa within sponges, cnidarians, annelids, bryozoans, and tunicates (Jackson & Coates, 1986;Hughes, 1987;Vogt, 2012;Gazave et al., 2013); Direct evidence for the role of ASCs found in sponges, flatworms, cnidarians and annelids (e.g. in atokous worms). Contribution to immortal lifespan Immortality does not exist Immortality exists in cnidarians (Martínez, 1998;Schmich et al., 2007;Da nko, Kozłowski & Schaible, 2015), planarians [further associated with neoblasts (Sal o, 2006;Tan et al., 2012)] and sponges (which may live for thousands of years) (Gatti, 2002;McMurray, Blum & Pawlik, 2008); extended lifespan in bivalves, the longest lived non-colonial animals (Gruber et al., 2015). ...
Article
Full-text available
Adult stem cells (ASCs) in vertebrates and model invertebrates (e.g. Drosophila melanogaster) are typically long-lived, lineage-restricted, clonogenic and quiescent cells with somatic descendants and tissue/organ-restricted activities. Such ASCs are mostly rare, morphologically undifferentiated, and undergo asymmetric cell division. Characterized by 'stemness' gene expression, they can regulate tissue/organ homeostasis, repair and regeneration. By contrast, analysis of other animal phyla shows that ASCs emerge at different life stages, present both differentiated and undifferentiated phenotypes, and may possess amoeboid movement. Usually pluri/totipotent, they may express germ-cell markers, but often lack germ-line sequestering, and typically do not reside in discrete niches. ASCs may constitute up to 40% of animal cells, and participate in a range of biological phenomena, from whole-body regeneration, dormancy, and agametic asexual reproduction, to indeterminate growth. They are considered legitimate units of selection. Conceptualizing this divergence, we present an alternative stemness metaphor to the Waddington landscape: the 'wobbling Penrose' landscape. Here, totipotent ASCs adopt ascending/descending courses of an 'Escherian stairwell', in a lifelong totipotency pathway. ASCs may also travel along lower stemness echelons to reach fully differentiated states. However, from any starting state, cells can change their stemness status, underscoring their dynamic cellular potencies. Thus, vertebrate ASCs may reflect just one metazoan ASC archetype.
... Total production [F P(gross) ] 240 ± 40 the contribution of sponges. Silica-secreting sponges in relatively shallow, DSi-rich environments like the continental margins of the Southern Ocean (Dayton et al. 1974, Dayton 1979, Gatti 2002) and the North Pacific (Chu et al. 2011) create reefs that might serve as significant and previously overlooked silica sinks. Siliceous sponge reefs have also been described in DSi-poor environments like the Bahamas (Atlantic Ocean), the Western Mediterranean, the Hawaiian Archipelago, and the Belizean continental shelf (Maldonado et al. 2005(Maldonado et al. , 2010. ...
Article
Full-text available
Over the past few decades, we have realized that the silica cycle is strongly intertwined with other major biogeochemical cycles, like those of carbon and nitrogen, and as such is intimately related to marine primary production, the efficiency of carbon export to the deep sea, and the inventory of carbon dioxide in the atmosphere. For nearly 20 years, the marine silica budget compiled by Tréguer et al. (1995), with its exploration of reservoirs, processes, sources, and sinks in the silica cycle, has provided context and information fundamental to study of the silica cycle. Today, the budget needs revisiting to incorporate advances that have notably changed estimates of river and groundwater inputs to the ocean of dissolved silicon and easily dissolvable amorphous silica, inputs from the dissolution of terrestrial lithogenic silica in ocean margin sediments, reverse weathering removal fluxes, and outputs of biogenic silica (especially on ocean margins and in the form of nondiatomaceous biogenic silica). The resulting budget recognizes significantly higher input and output fluxes and notes that the recycling of silicon occurs mostly at the sediment-water interface and not during the sinking of silica particles through deep waters. Expected final online publication date for the Annual Review of Marine Science Volume 5 is December 05, 2012. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.
... Sponges (Phylum Porifera), are diverse, sessile, benthic metazoans , occurring in marine, fresh-water and quasi-terrestrial ecosystems worldwide. In marine habitats, from coral reefs to abyssal plains, sponges play important roles in biogeochemical cycling [1], in the spatial structuring of the seafloor [2], and in benthic-pelagic coupling of nutrient transfer within ocean ecosys- tems [3]; sponges also participate in complex biotic interactions with diverse macrobiotic taxa (for a review see: [3]), and microbiological communities (e.g. [4]). ...
Article
Full-text available
Phylum Porifera includes ∼8,500 valid species distributed world-wide in aquatic ecosystems ranging from ephemeral fresh-water bodies to coastal environments and the deep-sea. The taxonomy and systematics of sponges is complicated, and morphological identification can be both time consuming and erroneous due to phenotypic convergence and secondary losses, etc. DNA barcoding can provide sponge biologists with a simple and rapid method for the identification of samples of unknown taxonomic membership. The Sponge Barcoding Project (www.spongebarcoding.org), the first initiative to barcode a non-bilaterian metazoan phylum, aims to provide a comprehensive DNA barcode database for Phylum Porifera. ∼7,400 sponge specimens have been extracted, and amplification of the standard COI barcoding fragment has been attempted for approximately 3,300 museum samples with ∼25% mean amplification success. Based on this comprehensive sampling, we present the first report on the workflow and progress of the sponge barcoding project, and discuss some common pitfalls inherent to the barcoding of sponges. A DNA-barcoding workflow capable of processing potentially large sponge collections has been developed and is routinely used for the Sponge Barcoding Project with success. Sponge specific problems such as the frequent co-amplification of non-target organisms have been detected and potential solutions are currently under development. The initial success of this innovative project have already demonstrated considerable refinement of sponge systematics, evaluating morphometric character importance, geographic phenotypic variability, and the utility of the standard barcoding fragment for Porifera (despite its conserved evolution within this basal metazoan phylum).
... As with the CWC, sponges are slow-growing organisms. No exact ageing has been done so far, but investigations suggest that they can live for over decades or centuries (Dayton 1979;Gatti 2003). ...
Article
Full-text available
514 NINA Publications NINA Report (NINA Rapport) This is a electronic series beginning in 2005, which replaces the earlier series NINA commissioned reports and NINA project reports. This will be NINA's usual form of reporting completed research, monitoring or review work to clients. In addition, the series will include much of the institute's other reporting, for example from seminars and conferences, results of internal research and review work and literature studies, etc. NINA report may also be issued in a second language where appropri-ate. NINA Special Report (NINA Temahefte) As the name suggests, special reports deal with special subjects. Special reports are produced as required and the series ranges widely: from systematic identification keys to information on impor-tant problem areas in society. NINA special reports are usually given a popular scientific form with more weight on illustrations than a NINA report. NINA Factsheet (NINA Fakta) Factsheets have as their goal to make NINA's research results quickly and easily accessible to the general public. The are sent to the press, civil society organisations, nature management at all lev-els, politicians, and other special interests. Fact sheets give a short presentation of some of our most important research themes.
... Indeed, if animals in this group are maintained in the absence of sexual reproduction, aging is absent (discussed by Martinez and Bridge, 2012). Life times of thousands of years have been estimated in sponges (McMurray, Blum, & Pawlik, 2008), even more than 10,000 years (Gatti, 2002;Jochum, Wang, Vennemann, Sinha, & Mueller, 2012). They continually replace their somas from archeocytes, even at the rate of two thirds of their cellular compliment per day (De Goeij et al., 2009). ...
Article
The evolution of multicellular animals has been attributed to many kinds of selective advantage; here I suggest that the evolution of somatic cells to feed and protect the germline was central to the appearance of animals. This would have been driven by selection for extreme anisogamy-the evolution of sperm and egg. Evidence is adduced from the germline stem cells of simple animals (defining germline as any cell that normally produces the next generation via the sexual process) and from the control circuitry ubiquitous in animal germlines. With the soma and its elaboration came animal development, as we understand it.
... Indeterminate growth does not exist in birds and mammals Indeterminate growth exists in various taxa within sponges, cnidarians, annelids, bryozoans, and tunicates (Jackson & Coates, 1986;Hughes, 1987;Vogt, 2012;Gazave et al., 2013); Direct evidence for the role of ASCs found in sponges, flatworms, cnidarians and annelids (e.g. in atokous worms). Contribution to immortal lifespan Immortality does not exist Immortality exists in cnidarians (Martínez, 1998;Schmich et al., 2007;Da nko, Kozłowski & Schaible, 2015), planarians [further associated with neoblasts (Sal o, 2006;Tan et al., 2012)] and sponges (which may live for thousands of years) (Gatti, 2002;McMurray, Blum & Pawlik, 2008); extended lifespan in bivalves, the longest lived non-colonial animals (Gruber et al., 2015). ...
... Their high biomass and morphological diversity are believed to be important in maintaining and structuring Antarctic benthic diversity (Gutt and Schickan, 1998;Cocito, 2004;McClintock et al., 2005). The efficient filter feeding of sponges makes them important components of the nutrient cycles of many marine ecosystems (Diaz and Ward, 1997;Diaz and Rutzler, 2001), as they perform an important role in benthopelagic coupling, transferring energy, and carbon from pelagic to benthic ecosystems (Gatti, 2002). Sponges can utilize a variety of food sources, including picoplankton, such as bacteria and viruses within the water column (Hadas et al., 2009;Perea-Blázquez et al., 2013a). ...
Article
Full-text available
Seasonal measurements of the metabolic physiology of four Antarctic demosponges and their associated assemblages, maintained in a flow through aquarium facility, demonstrated one of the largest differences in seasonal strategies between species and their associated sponge communities. The sponge oxygen consumption measured here exhibited both the lowest and highest seasonal changes for any Antarctic species; metabolic rates varied from a 25% decrease to a 5.8 fold increase from winter to summer, a range which was greater than all 17 Antarctic marine species (encompassing eight phyla) previously investigated and amongst the highest recorded for any marine environment. The differences in nitrogen excretion, metabolic substrate utilization and tissue composition between species were, overall, greater than seasonal changes. The largest seasonal difference in tissue composition was an increase in CHN (Carbon, Hydrogen, and Nitrogen) content in Homaxinella balfourensis, a pioneer species in ice-scour regions, which changed growth form to a twig-like morph in winter. The considerable flexibility in seasonal and metabolic physiology across the Demospongiae likely enables these species to respond to rapid environmental change such as ice-scour, reductions in sea ice cover and ice-shelf collapse in the Polar Regions, shifting the paradigm that polar sponges always live “life in the slow lane.” Great phenotypic plasticity in physiology has been linked to differences in symbiotic community composition, and this is likely to be a key factor in the global success of sponges in all marine environments and their dominant role in many climax communities.
... These provide refuge, foraging, spawning, and nursery grounds for fish Kutti et al., 2015), and create an abundance of microhabitats for sponge-associated invertebrates (Barthel, 1992;Bett and Rice, 1992;Herrnkind et al., 1997;Freese and Wing, 2003, and references therein;Henkel and Pawlik, 2005;Amsler et al., 2009;Maldonado et al., 2015). Sponge grounds also play important roles in biogeochemical cycling and bentho-pelagic coupling (Gatti, 2002;Pile and Young, 2006;Bell, 2008;Hoffmann et al., 2009;De Goeij et al., 2013;Kutti et al., 2013). Thirdly, deep-sea sponges are thought to be vulnerable to physical disturbance and environmental change (Hogg et al., 2010). ...
Article
Mass occurrences of large sponges, or ‘sponge grounds’, are found globally in a range of oceanographic settings. Interest in these grounds is growing because of their ecological importance as hotspots of biodiversity, their role in biogeochemical cycling and bentho-pelagic coupling, the biotechnological potential of their constituent sponges, and their perceived vulnerability to physical disturbance and environmental change. Little is known about the environmental conditions required for sponges to persist and for grounds to form, and very few studies have explicitly characterised and interpreted the importance of oceanographic conditions. Here, results are presented of the first observational oceanographic campaign at a known sponge ground on the Schultz Massif Seamount (SMS; Arctic Mid-Ocean Ridge, Greenland / Norwegian Seas). The campaign consisted of water column profiling and short-term deployment of a benthic lander. It was supported by multibeam echosounder bathymetry and remotely operated vehicle video surveys. The seamount summit hosted several environmental factors potentially beneficial to sponges. It occurred within relatively nutrient-rich waters and was regularly flushed from above with slightly warmer, oxygen-enriched Norwegian Arctic Intermediate Water. It was exposed to elevated suspended particulate matter levels and oscillating currents (with diurnal tidal frequency) likely to enhance food supply and prevent smothering of the sponges by sedimentation. Elevated chlorophyll a concentration was observed in lenses above the summit, which may indicate particle retention by seamount-scale circulation patterns. High sponge density and diversity observed on the summit is likely explained by the combination of several beneficial factors, the coincidence of which at the summit arises from interaction between seamount geomorphology, hydrodynamic regime, and water column structure. Neighbouring seamounts along the mid-ocean ridge are likely to present similarly complex oceanographic settings and, as with the SMS, associated sponge ground ecosystems may therefore be sensitive to changes over a particularly broad range of abiotic factors.
... As they grow to considerable sizes (Barthel and Tendal 1994), they are important structuring elements of Antarctic shelf communities (Barthel 1992; Barthel and Gutt 1992;Gutt et al. 2013Gutt et al. , 2016Kersken et al. 2016) and provide habitat for a diverse associated fauna (Kunzmann 1996;Barthel 1997;Kersken et al. 2014). In contrast to long-held views of slow growth (e.g., Barthel and Tendal 1994;Gatti 2002), rossellid sponge populations respond dynamically to environmental changes like shifts in ice cover and productivity (Fillinger et al. 2013;Dayton et al. 2013Dayton et al. , 2016. Further impacts of climate-induced changes can be expected in the future, but as different species show different life history patterns (Dayton et al. 2013), general trends are hard to foresee. ...
Article
Full-text available
Glass sponges (Porifera, Hexactinellida) are conspicuous habitat-forming members of many Antarctic shelf communities. Despite their ecological importance, in-situ species identification remains problematic as it is traditionally based on microscopic analysis of spicules. External morphological features, in contrast, have largely been disregarded, so that different species have been mislabeled or lumped together when their identification was based on image material. In this paper, we provide a straight-forward guideline for in-situ identification of the most common rossellid sponges of the Antarctic shelf based on macroscopic characteristics. To determine diagnostic macroscopic characteristics of Anoxycalyx (Scolymastra) joubini and eight Rossella species, we combined examination of trawl-collected specimens, previous species descriptions and in-situ image material from the eastern Weddell Sea. Our study revealed that the smooth-walled species A. joubini, R. nuda and R. vanhoeffeni, previously often mixed up, can be distinguished by the form of their basal spicule tuft, their surface structure and their overall body form. The previously synonymized species R. racovitzae and R. podagrosa can be distinguished by their markedly different habitus. Based on our results, the so-called ‘R. racovitzae budding type’ in fact refers to R. podagrosa which occurs regularly in the eastern Weddell Sea. The species R. villosa, R. levis, R. fibulata and R. antarctica can be distinguished by the appearance of their conules, protruding spicules and overall body form. We conclude that macroscopic characteristics are helpful means for identification of Antarctic rossellid sponge species. This approach enables species-specific quantitative studies of Antarctic glass sponge grounds based on increasingly used non-invasive imaging technology.
... Firstly, they are involved in structuring the seafloor and stabilization of substrate, offering refuge/habitat to a wide range of infauna species, and so they participate in complex biotic interactions with diverse macrobiotic taxa, influencing turbulence, spatial competition, and predation [7][8][9][10]. Secondly, sponges are key elements of biogeochemical cycles in coral reefs [11][12][13][14], participating in benthicpelagic coupling of nutrient transfer. Indeed, they capture large amounts of food particles and other nutrients from the pelagic habitat via their capacity to pump thousands of liters per kilogram of sponge per day [7]. ...
Article
Full-text available
Xestospongia muta is among the most emblematic sponge species inhabiting coral reefs of the Caribbean Sea. Besides being the largest sponge species growing in the Caribbean, it is also known to produce secondary metabolites. This study aimed to assess the effect of depth and season on the symbiotic bacterial dynamics and major metabolite profiles of specimens of X. muta thriving in a tropical marine biome (Portobelo Bay, Panamá), which allow us to determine whether variability patterns are similar to those reported for subtropical latitudes. The bacterial assemblages were characterized using Illumina deep-sequencing and metabolomic profiles using UHPLC-DAD-ELSD from five depths (ranging 9–28 m) across two seasons (spring and autumn). Diverse symbiotic communities, representing 24 phyla with a predominance of Proteobacteria and Chloroflexi, were found. Although several thousands of OTUs were determined, most of them belong to the rare biosphere and only 23 to a core community. There was a significant difference between the structure of the microbial communities in respect to season (autumn to spring), with a further significant difference between depths only in autumn. This was partially mirrored in the metabolome profile, where the overall metabolite composition did not differ between seasons, but a significant depth gradient was observed in autumn. At the phyla level, Cyanobacteria, Firmicutes, Actinobacteria, and Spirochaete showed a mild-moderate correlation with the metabolome profile. The metabolomic profiles were mainly characterized by known brominated polyunsaturated fatty acids. This work presents findings about the composition and dynamics of the microbial assemblages of X. muta expanding and confirming current knowledge about its remarkable diversity and geographic variability as observed in this tropical marine biome.
... ) A. Gray возрастом предположительно до 13 000 лет (Wherry, 1972). Возраст одной гигантской антарктической губки Scolymastra joubini Topsent составляет не менее 15 000 лет (Gatti, 2002), а возраст вегетативно размножающейся генеты остролиста королевского (Lomatia tasmanica W. M. Curtis) с о. Тасмания -43 600 лет (Jordan et al. 1991;Lynch et al., 1998). ...
Article
Full-text available
Some time delay between materialization and production of any information is unavoidable, since there is always a time distance between these processes. As for the delay in materialization of genetic information, that is because the natural selection acts upon groups of living organisms on momentary basis whereas the selected information is realized in the following generations. And since the material world is always changing, some information about the structure of current successful individuals inevitably becomes outdated by the time their next generation appears. Organisms can often only reduce their lifespan to adapt to this phenomenon. But among a huge quantity of structural elements that are formed based on “outdated” information, the ones that are able to improve individual fi tness with respect to the new state of the environment will be present with high probability. Such structural features may contain elements of ‘overadaptations’ or serve as anticipatory adaptations, that has allowed some species to persist during abrupt and unpredictable changes of their environment, when they did not have enough time for gradual adaptation.
... Rossella species are the most abundant and biomass-rich benthic organisms in many habitats of the Antarctic shelf, covering up to 50% of the seafloor and increasing its spatial complexity (Fig. 1) by forming biogenic structures which can be used by other species (Gutt and Starmans 1998;Starmans et al. 1999;Janussen and Reiswig 2009;Dayton et al. 2013;Fillinger et al. 2013). Rossella have been also reported to structure benthic communities (Barthel 1992a, b) and to play a major role in local silicon cycling (Gatti 2002;Gutt et al. 2013). Large Rossella specimens can harbor a diverse community of invertebrates and juvenile stages of many other organisms, and serve as substratum for various taxa of other sessile invertebrates (epibionts and endobionts) (Kunzmann 1996;Barthel 1997;Gutt and Schickan 1998;Kersken et al. 2014). ...
Article
Full-text available
Hexactinellida (glass sponges) are abundant and important components of Antarctic benthic communities. However, the relationships and systematics within the common genus Rossella Carter, 1872 (Lyssacinosida: Rossellidae), are unclear and in need of revision. The species content of this genus has changed dramatically over the years depending on the criteria used by the taxonomic authority consulted. Rossella was formerly regarded as a putatively monophyletic group distributed in the Southern Ocean and the North Atlantic. However, molecular phylogenetic analyses have shown that Rossella is restricted to the Southern Ocean, where it shows a circum-Antarctic and subantarctic distribution. Herein, we provide a molecular phylogenetic analysis of the genus Rossella, based on mitochondrial (16S rDNA and COI) and nuclear (28S rDNA) markers. We corroborate the monophyly of Rossella and provide evidence supporting the existence of one species, namely Rossella antarctica Carter, 1872 and a species flock including specimens determined as Rossella racovitzae Topsent, 1901, Rossella nuda Topsent, 1901, Rossella fibulata Schulze and Kirkpatrick 1910, and Rossella levis (Kirkpatrick 1907).
... Firstly, they are involved in structuring the seafloor and stabilization of substrate, offering refuge/habitat to a wide range of infauna species, and so they participate in complex biotic interactions with diverse macrobiotic taxa, influencing turbulence, spatial competition, and predation [7][8][9][10]. Secondly, sponges are key elements of biogeochemical cycles in coral reefs [11][12][13][14], participating in benthicpelagic coupling of nutrient transfer. Indeed, they capture large amounts of food particles and other nutrients from the pelagic habitat via their capacity to pump thousands of liters per kilogram of sponge per day [7]. ...
Poster
Xestospongia muta is one of the most abundant sponge species of the coral reef communities at the Caribbean Sea. Its high ecological significance makes this species a suitable holobiont model for further understanding of the relationships between its symbiotic bacteria and the secondary metabolism it produces. The aim of our study was to identify the composition and changes of the bacterial symbiotic communities and the sponge metabolomic profiles and whether they might be related to environmental conditions such as depth or season, and also if there are correlations between the relative abundance of bacterial symbionts and the concentration of main sponge metabolites. Microbiome composition was determined using Illumina MiSeq platform (V5-V6 region of 16S rRNA gene), and metabolomic analyses were carried out by UHPLC-DAD-ELSD. We identified significant variations in the structure of the communities in relation to the season. We observed a clear increasing trend for bacterial diversity with depth. The metabolic profile evidenced shifting patterns with similarities not ascribed to depth or season and mainly composed by two predominant brominated polyunsaturated fatty acids. No statistically significant dependence was found between any OTU/metabolite pair. A X. muta core microbiome across all the specimens collected could be defined; it is composed by 23 different OTUs collectively representing between 10-25% of the total relative abundance.
... Their high biomass and morphological diversity are believed to be important in maintaining and structuring Antarctic benthic diversity ( Gutt and Schickan, 1998;Cocito, 2004;McClintock et al., 2005). The efficient filter feeding of sponges makes them important components of the nutrient cycles of many marine ecosystems ( Diaz and Ward, 1997;Diaz and Rutzler, 2001), as they perform an important role in benthopelagic coupling, transferring energy, and carbon from pelagic to benthic ecosystems ( Gatti, 2002). Sponges can utilize a variety of food sources, including picoplankton, such as bacteria and viruses within the water column ( Hadas et al., 2009;PereaBlázquez et al., 2013a). ...
Article
Full-text available
The waters of the Southern Ocean exhibit extreme seasonality in primary production, with marine life living below 0 °C for much of the year. The metabolic cold adaptation (MCA) hypothesis suggests that polar species need elevated basal metabolic rates to enable activity in such cold which should result in higher metabolic rates, or at least rates similar to temperate species. This study aimed to test whether any of the five common marine invertebrates around Adelaide Island (Western Antarctic Peninsula) displayed MCA: the suspension-feeding holothurian Heterocucumis steineni, the grazing limpet Nacella concinna, and the omnivorous brittle star, cushion star and sea-urchin Ophionotus victoriae, Odontaster validus and Sterechinus neumayeri, respectively. We also tested a second hypothesis that secondary consumers will exhibit less seasonal variation of metabolic rate than primary consumers. Routine oxygen consumption was measured in both the austral summer and winter using closed circuit respirometry techniques. Metabolic rates for all the species studied were low compared with temperate species, in a fashion consistent with expected temperature effects on biological systems and, therefore, the data do not support MCA. All the species studied showed significant seasonal differences for a standard mass animal except N. concinna. In two species N. concinna and H. steineni, size affected the seasonality of metabolism. There was no difference in seasonality of metabolism between primary and secondary consumers. Thus, for secondary consumers seasonal factors, most likely food availability and quality, vary enough to impact metabolic rates, and produce seasonal metabolic signals at all trophic levels. Other factors such as reproductive status that are linked to seasonal signals may also have contributed to the metabolic variation across trophic levels.
... On consideration of the limited knowledge of the deep-sea environment, WGDEC agreed that the sensitivity evidence should be collected at Level 4. This enabled evidence to be gathered on sensitivities for broad habitat communities such as deep-sea sponge aggregations, but ensured that assessments would not be attempted for specific deep-sea biological assemblages where evidence may be scarce. For example, knowledge of sensitivities of deep-sea sponge aggregations is fairly well recorded (Freese et al., 1999;Gatti et al., 2002;Teixidó et al., 2004;Rooper et al., 2011), but information on specific communities such as Lobose sponges is less well known ( ...
Technical Report
Full-text available
Executive summary On 15th February 2016, the joint ICES/NAFO Working Group on Deep-water Ecology (WGDEC), chaired by Neil Golding (UK) and attended by eleven members, met at ICES HQ, Copenhagen, Denmark, to consider the terms of reference (ToR) listed in Section 1. WGDEC was requested to provide all new information on the distribution of vulnerable marine ecosystems (VMEs) in the North Atlantic. A total of 487 new records, from within the NEAFC and NAFO Regulatory Areas (RA) and areas within the EEZs of member states, were submitted and appended to the ICES VME database. The new data were from a range of sources including fisheries and scientific visual seabed surveys. No recommendations were made for the modification of existing, or creation of new bottom fishing closures. WGDEC sought to refine the VME indicator weighting system developed through 2014 and 2015. In addition, WGDEC consolidated a number of approaches for the delineation of bottom fishing closures, providing some ‘guiding principles’ in order to help standardise the delineation of closures when considering a range of different data types. The new ICES VME Data Portal was launched. For the first time, users can view and download data on VME indicators and habitats used by WGDEC. Finally WGDEC contributed to a request from the European Commission’s Environment Directorate-General (DGENV) to ICES, to provide guidance on the interpretation of bottom fishing pressure maps in relation to impacts on benthic habitats and the related indicators across an EU regional scale. Specifically, WGDEC collated habitat sensitivity information for each deep-sea benthic habitat to fishing pressure, for presentation at WKFBI (ICES Workshop on Fisheries Benthic Impacts).
... On consideration of the limited knowledge of the deep-sea environment, WGDEC agreed that the sensitivity evidence should be collected at Level 4. This enabled evidence to be gathered on sensitivities for broad habitat communities such as deep-sea sponge aggregations, but ensured that assessments would not be attempted for specific deep-sea biological assemblages where evidence may be scarce. For example, knowledge of sensitivities of deep-sea sponge aggregations is fairly well recorded (Freese et al., 1999;Gatti et al., 2002;Teixidó et al., 2004;Rooper et al., 2011), but information on specific communities such as Lobose sponges is less well known ( ...
Article
Full-text available
This paper reviews studies on the hexactinellid glass sponges (Hexactinellida: Porifera) that have organic silica spicules. According to its physical properties (microdensity, Young’s modulus, and light transmission), the material of the spicules is similar to amorphous silica; however, sponge spicules are birefringent, which suggests that they have a highly ordered crystal-like nature. Mineralized remnants of siliceous spicules composed of chemically inert materials are preserved in sedimentary rocks and provide evidence of the ecological state of the ancient biosphere. Sponges occur in waters with low temperatures; therefore, they grow very slowly and live for hundreds of years. The organic silica spicules exhibit the capacity for triboluminescence. The generated light emission may be used by symbiotic bacteria on the spicule surface.
Article
Full-text available
New Hexactinellida from the deep Weddel Sea are described. This moderately diverse hexactinellid fauna includes 14 species belonging to 12 genera, of which five species and one subgenus are new to science: Periphragella antarctica n. sp., Holascus pseudostellatus n. sp., Caulophacus (Caulophacus) discohexactinus n. sp., C. (Caulodiscus) brandti n. sp., C. (Oxydiscus) weddelli n. sp., and C. (Oxydiscus) n. subgen. So far, 20 hexactinellid species have been reported from the deep Weddell Sea, 15 are known from the northern part and 10 only from here, while 10 came from the southern area, and five of these only from there. However, this apparent high “endemism” of Antarctic hexactinellid sponges is most likely the result of severe undersampling of the deep-sea fauna. We find no reason to believe that a division between an oceanic and a more continental group of species exists. The current poor database indicates that a substantial part of the deep hexactinellid fauna of the Weddell Sea is shared with other deep-sea regions, but it does not indicate a special biogeographic relationship with any other ocean.
Article
The sub-Antarctic Magellan region in southern Chile belongs to the most extensive fjord regions of the world. Coastal and marine environments are exposed to natural and anthropogenic perturbations. Research on the marine ecosystems have received some attention, however, research on the flow of energy is rather limited. To trace energy flow and resource distribution across communities is of considerable concern to current ecological studies for understanding how marine benthic ecosystems are organized, the base of which food sources they are built upon and how benthic organisms utilize resources. Heterogeneous environmental conditions along the Sub-Antarctic Magellan region, however, suggest the possibility of great heterogeneity in community structure and population dynamics. Studies of the trophic structure and energy flow are essential in this context. The aim of this thesis is to increase the knowledge of the ecological role of benthic species to communities living in the sub-Antarctic Magellan region. The main objectives of this research are (i) to investigate the trophic ecology of conspicuous species and their ecological role in the marine benthic communities of the Magellan region, (ii) to describe the trophic structure of two shallow-water benthic community types in the Strait of Magellan in order to establish baseline descriptions of trophic relationships for community structure and function, and (iii) to estimate benthic secondary production in this sub-Antarctic region as a proxy for energy flow along latitudinal gradients. The main results indicate that both local/regional environmental conditions and biological features cause clear differences in the trophic structure and energy flow patterns. This research gives valuable insight into ecological functioning of marine benthic communities present in the sub-Antarctic Magellan region and offers useful information to build food web models.
Article
Full-text available
Shallow marine benthic communities around Antarctica show high levels of endemism, gigantism, slow growth, longevity and late maturity, as well as adaptive radiations that have generated considerable biodiversity in some taxa. The deeper parts of the Southern Ocean exhibit some unique environmental features, including a very deep continental shelf and a weakly stratified water column, and are the source for much of the deep water in the world ocean. These features suggest that deep-sea faunas around the Antarctic may be related both to adjacent shelf communities and to those in other oceans. Unlike shallow-water Antarctic benthic communities, however, little is known about life in this vast deep-sea region. Here, we report new data from recent sampling expeditions in the deep Weddell Sea and adjacent areas (748-6,348 m water depth) that reveal high levels of new biodiversity; for example, 674 isopods species, of which 585 were new to science. Bathymetric and biogeographic trends varied between taxa. In groups such as the isopods and polychaetes, slope assemblages included species that have invaded from the shelf. In other taxa, the shelf and slope assemblages were more distinct. Abyssal faunas tended to have stronger links to other oceans, particularly the Atlantic, but mainly in taxa with good dispersal capabilities, such as the Foraminifera. The isopods, ostracods and nematodes, which are poor dispersers, include many species currently known only from the Southern Ocean. Our findings challenge suggestions that deep-sea diversity is depressed in the Southern Ocean and provide a basis for exploring the evolutionary significance of the varied biogeographic patterns observed in this remote environment.
Article
Full-text available
The long-term benthic disturbance experiment (BENDEX) was started on the eastern Weddell Sea shelf off Austasen (Antarctica) during ‘Polarstern’ cruise ANT XXI/2 in December 2003 to simulate the impact of grounding icebergs on the seabed and follow the steps and timescales of recovery of disturbed benthos and demersal fish communities. Here, we report the basic approach and first results for this experimental field study. By means of 11 densely-placed hauls with a modified bottom trawl, a seabed area of approximately 100×1000m was artificially scoured to inflict a similar damage to the benthic habitats as a grounding iceberg. Before the disturbance event and 11days after it, the seafloor communities were sampled (invertebrate assemblages by multibox corers, the fish fauna by trawl hauls) and comparatively analyzed. Sediment texture and chemistry was not significantly altered by the heavy disturbance inflicted by repeated trawling, whereas the fauna was negatively affected. Invertebrate benthic biomass was drastically reduced by a factor of 10, while mean abundances were only slightly reduced. Demersal fish biomass and abundance were slightly but not significantly smaller after the disturbance. Effects of disturbance became more evident in the composition of the fish fauna, with Trematomus pennelli and T. hansoni being dominant at disturbed sites, whereas Chionodraco myersi was the dominant species in trawl catches from undisturbed stations.
Article
The coexistence of species within a community generally can be explained by niche differentiation, mechanisms that control competitive displacement, and by chance. This review is an attempt to link ecological conceptual models with results from field research. A verification of different theoretically developed mechanisms shows that niche differentiation plays a major role in the Antarctic. This is particularly true if a broad niche definition is applied that includes alternating phases of competitive strength and weakness that allow populations to persist in a community. Such specific adaptation to the environment also seems to be an important mechanism among animals, which, to date, have been assumed to have broadly overlapping ecological demands. Nevertheless, disturbances due to glaciation history, ice impact, and predation, as well as a high dispersal capacity and low resource limitation contribute to the coexistence or, locally, to the reduction of potential competitors. Chance, reflecting extremely complex or otherwise indecipherable processes, also shapes diversity, e.g., during recolonization after habitat devastation due to iceberg scouring. The slow rates of ecological processes in the Antarctic benthos are shown not necessarily to reduce, but perhaps, to increase the potential for evolutionary radiation in some systematic groups. The fundamental question of how ecosystems continue to develop in the presence or absence of anthropogenic impacts can only be answered if such system-specific ecological and evolutionary mechanisms can be better identified and verified. Studies of the Antarctic benthos can contribute to a corresponding global approach if more comparable information on the life histories of representative species becomes available and if ecological models are developed to decipher complex processes, that shape biodiversity patterns.
Article
Sponges are an important part of many benthic ecosystems, but little is known of their physiology and ecology, which is alarming given the predicted rise in global environmental stress and observed increases in mortality and disease of these organisms. The overall aim of this study was to further understand the physiological processes of sponges and the influence of environmental stress on these organisms. Oxygen consumption rates were investigated, as this is an important measure of the energy required for all physiological activities. The impact of ultraviolet-B(UV-B) radiation and sedimentation on sponges were selected because their input into the marine environment has been predicted to increase in the future, yet little is known about their affect on these organisms. Oxygen consumption rates were measured from a number of temperate and tropical sponges in New Zealand and Indonesia. Variability in oxygen consumption rates was found within and between species from their respective habitats. Interestingly, oxygen consumption rates in the temperate sponges appeared to increase with the proportion of inorganic material (spicule load). Ultraviolet-B radiation, at 60microWcm-2, was found to have no affect on the oxygen consumption of model temperate and tropical sponges. Sponge oxygen consumption, however, increased with repetitive exposure to 2.5 g L-1of sediment, while rates decreased in specimens under higher levels at 8.5 and 16.5 g L-1. Explanations for differences in oxygen consumption rates were constrained by the low level of information on sponges at a species-specific level, and highlighted the needed for future bioenergetic research. The results from the UV-B and sedimentation work suggest that some sponge species may be able to tolerate increasing environmental stress with the onset of global climate change, although interactions between factors could have the potential to negatively affect these organisms.
ResearchGate has not been able to resolve any references for this publication.