Martin R. Langer

Assessing the Contribution of Foraminiferan Protists to Global Ocean Carbonate Production

ABSTRACT. Larger symbiont‐bearing foraminifera are prominent and important producers of calcium carbonate in modern tropical environments. With an estimated production of at least 130 million tons of CaCO3 per year, they contribute almost 5% of the annual present‐day carbonate production in the worlds reef and shelf areas (0–200 m) and approximately 2.5% of the CaCO3 of all oceans. Together with non‐symbiont‐bearing smaller foraminifera, all benthic foraminifera are estimated to annually produce 200 million tons of calcium carbonate worldwide. The majority of foraminiferal calcite in modern oceans is produced by planktic foraminifera. With an estimated annual production of at least 1.2 billion tons, planktic foraminifera contribute more than 21% of the annual global ocean carbonate production. Total CaCO3 of benthic and planktic foraminifera together amounts to 1.4 billion tons of calcium carbonate per year. This accounts to almost 25% of the present‐day carbonate production of the oceans, and highlights the importance of foraminifera within the CaCO3 budget of the worlds oceans.

Biosynthesis of glycosaminoglycans in foraminifera: A review

Abstract Organic matrix deposits in the tests of benthic and planktic foraminifera contain glycosaminoglycans as a major component. They are present in organic linings, organic cements and secretion products. Following cytological, autoradiographic, and molecular cell biological studies in plants and animals, the intracellular process for glycosaminoglycan production is choreographed by ribosomes, the endoplasmatic reticulum and the Golgi complex. Synthesized proteins released from the ribosomes on the granular endoplasmic reticulum are glycosylated and sulfated in a multistage process within the Golgi compartments. The completed glycosylated proteins are shed as vesicles (secretory vesicles?) into the cytoplasm. Along microtubular strands the vesicles are transported to the cell membrane and either formed into organic linings or organic cements or are secreted. As indicated by their composition both the secretion of organic material by foraminifera as well as the production of organic linings and organic cements are caused by the same intracellular mechanism. Some aspects of the relation between macromolecular preorganization of the glycosaminoglycan-rich template and patterns of biomineralization are discussed.

Phylogenetic incongruence between dinoflagellate endosymbionts (Symbiodinium) and their host foraminifera (Sorites): small-subunit ribosomal RNA gene sequence evidence

Abstract Phototrophic dinoflagellate zooxanthellae commonly occur as endosymbionts in many planktic and certain benthic foraminifera (soritids). Many taxonomic issues and specific identities of foraminiferal dinoflagellates are not yet resolved. To assess taxonomic affinities among other dinoflagellates, we have determined the complete nucleotide sequence of the small-subunit rRNA coding region from Symbiodinium sp., an endosymbiotic dinoflagellate of the larger foraminifer Sorites orbiculus . The poly merase chain reaction was adopted for the in vitro amplification of ribosomal DNA, utilizing primers complementary to conserved regions. PCR-amplified DNA was directly sequenced and the sequence was aligned to all complete 18S-rDNA dinoflagellate sequences currently available through GenBank. Apicomplexan, ciliate, chromistacean, and rhodophycean sequences were added to infer across-kingdom phylogenetic relationships. Phylogenetic analysis of aligned nucleotide sequences produced a single most parsimonious tree (generated by the branch and bound method of PAUP). The inferred phylogeny indicates that the dinoflagellate extracted from the foraminifer Sorites orbiculus is a sister taxon to the symbiont present in the larger foraminifera Marginopora kudakajimaensis , but only distantly related to the dinoflagellate isolated from the soritid Amphisorus hemprichii . The sequence heterogeneity demonstrates a high degree of genetic diversity among Symbiodinium -like zooxanthellae and re-emphasizes that they are a variety of distinct entities. The inferred molecular phylogenetic relationships among symbiotic dinoflagellates are not congruent with the foraminiferal phylogeny based on cladistic methodology. The lack of correlation between the evolutionary history of dinoflagellate symbionts and their foraminiferal hosts argues against co-evolution. This lack of co-evolution implies that flexible recombinations among hosts and symbionts are evolutionarily favorable over permanently associated lineages, at least in these benthic foraminifera.

Predation on foraminifera by the dentaliid deep-sea scaphopod Fissidentalium megathyris

The dentaliid scaphopod Fissidentalium megathyris, collected from Pacific deep-sea sites off central California, was dissected and examined for prey items. Gut contents revealed that it takes almost exclusively benthic foraminifera, thus indicating that foraminiferal cytoplasm is an important component in the diet. Individual scaphopods contained up to 188 and averaged 33 foraminiferal specimens. On average 73.6% of ingested foraminifera tests had mechanical and/or chemical test damage. Mechanical damage was inflicted chiefly on the last three or so chambers. The mechanical manipulation of the tests by the radula alone could result in damage to the last chambers. Test destruction may result from selective chamber destruction, weaker construction of the last chambers than of the rest of the test, mechanically more vulnerable last chambers, or a combination of all three of these. The high number of ingested tests indicates that deep-sea scaphopods may exert significant predation pressure on benthic foraminifera, which may also lead to preferential destruction during taphonomic and diagenetic processes.

Climate-Driven Range Extension of Amphistegina (Protista, Foraminiferida): Models of Current and Predicted Future Ranges

Species-range expansions are a predicted and realized consequence of global climate change. Climate warming and the poleward widening of the tropical belt have induced range shifts in a variety of marine and terrestrial species. Range expansions may have broad implications on native biota and ecosystem functioning as shifting species may perturb recipient communities. Larger symbiont-bearing foraminifera constitute ubiquitous and prominent components of shallow water ecosystems, and range shifts of these important protists are likely to trigger changes in ecosystem functioning. We have used historical and newly acquired occurrence records to compute current range shifts of Amphistegina spp., a larger symbiont-bearing foraminifera, along the eastern coastline of Africa and compare them to analogous range shifts currently observed in the Mediterranean Sea. The study provides new evidence that amphisteginid foraminifera are rapidly progressing southwestward, closely approaching Port Edward (South Africa) at 31°S. To project future species distributions, we applied a species distribution model (SDM) based on ecological niche constraints of current distribution ranges. Our model indicates that further warming is likely to cause a continued range extension, and predicts dispersal along nearly the entire southeastern coast of Africa. The average rates of amphisteginid range shift were computed between 8 and 2.7 km year−1, and are projected to lead to a total southward range expansion of 267 km, or 2.4° latitude, in the year 2100. Our results corroborate findings from the fossil record that some larger symbiont-bearing foraminifera cope well with rising water temperatures and are beneficiaries of global climate change.

Molecular paleobiology of protists; amplification and direct sequencing of foraminiferal DNA

Molecular biological techniques are used to reveal or confirm phylogenies and biogeographic and ecologic histories of fossilizable organisms with great success. Using the PCR (polymerase chain reaction) technique, we have successfully amplified and sequenced ribosomal DNA (1 8S-rDNA) from benthic and planktic foraminifera. DNA is first extracted from single living specimens and DNA templates are prepared. The DNA is then amplified using PCR for single and double strands. The direct methods using primers developed for protists and fungi allow amplification of the 18S-rRNA gene, a relatively conservative gene useful in phylogenetic analyses. The amplified DNA is sequenced on acrylomide gels using the chain-terminaton method. The 18S-rDNA nucleotide sequences may then be analyzed using standard phylogenetic analytical techniques such as PAUP (Phylogenetic Analysis Using Parsimony) or PHYLIP (Phylogeny Inference Package)..

Benthic Foraminifera from the meromictic Mecherchar Jellyfish Lake, Palau (western Pacific)

Foraminifera occur in the peculiar, meromictic Jellyfish Lake on Mecherchar Island in the Palau Archipelago (Western Caroline Islands). The lake is marine, 30 m deep, and characterized by both oxic and anoxic water layers separated by a distinct chemo-and thermocline. Above 15 m, the lake is well lighted, oxic, and with normal marine salinity and temperatures. Below that, the lake is dark and anoxic with high sulfide content in the water and sediment. Sediment surface samples, collected by SCUBA from sites within both layers, contain few foraminifera. The foraminiferal fauna is characterized by a particularly low-diversity and thin-shelled assemblage and is devoid of typical diverse reef and lagoonal species commonly present in South Pacific reef complexes, including those surrounding Mecherchar Island just 100 m or so from Jellyfish Lake. A total of 15 species was recovered from surface sediments in the upper oxic zone of the lake, but no foraminifera were found in those samples collected in the deeper, anoxic water of the lake. Two species, Helenina sp. and Ammonia sp., dominate in the shallow-water lake habitats (0-10 m), while the agglutinated species Glomospira fijiensis and Rheophax scorpiurus appear to be most tolerant to decreasing oxygen conditions at the anoxic/oxic interface. The foraminiferal faunal association most closely resembles assemblages that have been described from mangrove environments of the South Pacific. The specific distribution pattern and the absence of foraminifera within the anoxic zone is consistent with findings from volcanic sulfide-rich environments. The physico-chemical properties of this stratified lake, in particular the lack of dissolved oxygen and the high concentration of hydrogen sulfide within the anoxic water layer, appear to control this particular presence/absence pattern of benthic foraminifera.

Healthcare Costs Associated with an Adequate Intake of Sugars, Salt and Saturated Fat in Germany: A Health Econometrical Analysis.

Non-communicable diseases (NCDs) represent not only the major driver for quality-restricted and lost life years; NCDs and their related medical treatment costs also pose a substantial economic burden on healthcare and intra-generational tax distribution systems. The main objective of this study was therefore to quantify the economic burden of unbalanced nutrition in Germany—in particular the effects of an excessive consumption of fat, salt and sugar—and to examine different reduction scenarios on this basis. In this study, the avoidable direct cost savings in the German healthcare system attributable to an adequate intake of saturated fatty acids (SFA), salt and sugar (mono- & disaccharides, MDS) were calculated. To this end, disease-specific healthcare cost data from the official Federal Health Monitoring for the years 2002–2008 and disease-related risk factors, obtained by thoroughly searching the literature, were used. A total of 22 clinical endpoints with 48 risk-outcome pairs were considered. Direct healthcare costs attributable to an unbalanced intake of fat, salt and sugar are calculated to be 16.8 billion EUR (CI95%: 6.3–24.1 billion EUR) in the year 2008, which represents 7% (CI95% 2%-10%) of the total treatment costs in Germany (254 billion EUR). This is equal to 205 EUR per person annually. The excessive consumption of sugar poses the highest burden, at 8.6 billion EUR (CI95%: 3.0–12.1); salt ranks 2nd at 5.3 billion EUR (CI95%: 3.2–7.3) and saturated fat ranks 3rd at 2.9 billion EUR (CI95%: 32 million—4.7 billion). Predicted direct healthcare cost savings by means of a balanced intake of sugars, salt and saturated fat are substantial. However, as this study solely considered direct medical treatment costs regarding an adequate consumption of fat, salt and sugars, the actual societal and economic gains, resulting both from direct and indirect cost savings, may easily exceed 16.8 billion EUR.

Tubicolous polychaetes as substrates for epizoic foraminifera

Associations of epizoic foraminifera and invertebrates are widespread and have been reported from polar to tropical and shallow to bathyal environments (Zumwalt & DeLaca, 1980). Their fossil record stretches far back into Palaeozoic times as documented by agglutinated foraminifera attached to crinoids in Silurian and Devonian reef deposits of Morocco and Gotland (Franzen, 1974). Strong preferences for filter-feeding hosts suggest that epizoic foraminifera benefit from increased nutritional resources accumulated in the immediate flow microhabitat (Langer & Long, 1994). In the course of a broader study on foraminifera/invertebrate associations, several hundred foraminifera attached to the outer wall of agglutinated tubes of various polychaetes (e.g. Sabella sp., Potamilla sp.) were collected from sediment samples dredged at 61 m depth off the University of California, Moss Landing Marine Laboratory (NW Pacific). Attached foraminifera display a remarkable mode to obtain and differentially cement grains from the host tube that previously has not been reported. Agglutinated polychaete tubes and fragments thereof may reach 2 cm or more in length and are composed of fine sand, silt and micas cemented together by secreted organic material (Fig. 1). Tubes are typically orientated vertically in the mud and project above the sediment surface into the water column. NEW OBSERVATIONS Examination of agglutinated polychaete tubes revealed that their outer walls were commonly colonized by one to three foraminiferans (Figs 1–3, tube diameter 1.5–2.0 mm). The epizoic foraminiferal fauna comprised exclusively agglutinated taxa and included the following species: Alveophragmium advenum (Cushman), Textularia abbreviata Lalicker & McCulloch, Textularia schencki . . .

Heading for new shores: projecting marine distribution ranges of selected larger foraminifera.

The distribution of modern symbiont-bearing larger foraminifera is confined to tropical and subtropical shallow water marine habitats and a narrow range of environmental variables (e.g. temperature). Most of todays taxa are restricted to tropical and subtropical regions (between 30°N and 30°S) and their minimum temperature limits are governed by the 14 to 20°C isotherms. However, during times of extensive global warming (e.g., the Eocene and Miocene), larger foraminifera have been found as far north as 50°N (North America and Central Europe) as well as towards 47°S in New Zealand. During the last century, sea surface temperatures have been rising significantly. This trend is expected to continue and climate change scenarios for 2050 suggest a further increase by 1 to 3°C. We applied Species Distribution Models to assess potential distribution range changes of three taxa of larger foraminifera under current and future climate. The studied foraminifera include Archaias angulatus, Calcarina spp., and Amphistegina spp., and represent taxa with regional, superregional and global distribution patterns. Under present environmental conditions, Amphistegina spp. shows the largest potential distribution, apparently due to its temperature tolerance. Both Archaias angulatus and Calcarina spp. display potential distributions that cover currently uninhabited regions. Under climate conditions expected for the year 2050, all taxa should display latitudinal range expansions between 1 to 2.5 degrees both north- and southward. The modeled range projections suggest that some larger foraminifera may colonize biogeographic regions that so far seemed unsuitable. Archaias angulatus and Calcarina spp. also show an increase in habitat suitability within their native occurrence ranges, suggesting that their tolerance for maximum temperatures has yet not been fully exploited and that they benefit from ocean warming. Our findings suggest an increased role of larger foraminifera as carbonate producers and reef framework builders in future oceans.