Contribution of cryptogamic covers to the global cycles of carbon and nitrogen

Elbert, Wolfgang; Weber, Bettina; Burrows, Susannah M.; Steinkamp, Jörg; Büdel, Burkhard; Andreae, Meinrat O.; Pöschl, Ulrich

doi:10.1038/ngeo1486

Cited by 809 publications

(699 citation statements)

References 26 publications

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“…7). Although algae are thought to affect the net uptake of carbon in some terrestrial ecosystems 23 , the contribution of these soil-inhabiting algae to the carbon cycle in Neotropical rainforests is unknown. Only 131 OTUs were assigned to the Oomycota.…”

Section: Resultsmentioning

confidence: 99%

Parasites dominate hyperdiverse soil protist communities in Neotropical rainforests

et al. 2017

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High animal and plant richness in tropical rainforest communities has long intrigued naturalists. It is unknown if similar hyperdiversity patterns are reflected at the microbial scale with unicellular eukaryotes (protists). Here we show, using environmental metabarcoding of soil samples and a phylogeny-aware cleaning step, that protist communities in Neotropical rainforests are hyperdiverse and dominated by the parasitic Apicomplexa, which infect arthropods and other animals. These host-specific parasites potentially contribute to the high animal diversity in the forests by reducing population growth in a density-dependent manner. By contrast, too few operational taxonomic units (OTUs) of Oomycota were found to broadly drive high tropical tree diversity in a host-specific manner under the Janzen-Connell model. Extremely high OTU diversity and high heterogeneity between samples within the same forests suggest that protists, not arthropods, are the most diverse eukaryotes in tropical rainforests. Our data show that protists play a large role in tropical terrestrial ecosystems long viewed as being dominated by macroorganisms.S ince the works of early naturalists such as von Humboldt and Bonpland 1 , we have known that animal and plant communities in tropical rainforests are exceedingly species rich. For example, one hectare can contain more than 400 tree species 2 and one tree can harbour more than 40 ant species 3 . This hyperdiversity of trees has been partially explained by the Janzen-Connell model 4,5 , which hypothesizes that host-specific predators and parasites reduce plant population growth in a density-dependent manner 6,7 . Sampling up in the tree canopies and below on the ground has further led to the view that arthropods are the most diverse eukaryotes in tropical rainforests 8,9 .The focus on eukaryotic macroorganisms in these studies is primarily because they are familiar and readily observable to us. We do not know whether the less familiar and less readily observable protists-microbial eukaryotes that are not animals, plants or fungi 10 -inhabiting these same ecosystems exhibit similar diversity patterns. To evaluate if macroorganismic diversity patterns are reflected at the microbial scale with protists, we conducted an environmental DNA metabarcoding study by sampling soils in 279 locations in a variety of lowland Neotropical forest types in La Selva Biological Station, Costa Rica, Barro Colorado Island, Panama and Tiputini Biodiversity Station, Ecuador. This metabarcoding approach has the power to uncover known and new taxa on a massive scale 11 . By amplifying DNA extracted from the soils with broadly targeted primers for the V4 region of 18S rRNA and sequencing it using the Illumina MiSeq platform, we were able to detect most eukaryotic lineages, and assess the diversity and relative dominance of free-living and parasitic lineages.

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Section: Resultsmentioning

confidence: 99%

Parasites dominate hyperdiverse soil protist communities in Neotropical rainforests

et al. 2017

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“…BSCs are considered as ecosystem engineers (Pointing and Belnap, 2012) in terms of soil stabilisation (Belnap et al, 2003a), carbon fixation and nitrogen budgets (Elbert et al, 2012). At climatically extreme terrestrial sites, they may be the only photoautotrophic primary producers (Warren-Rhodes et al, 2006;Colesie et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Habitat stress initiates changes in composition, CO2 gas exchange and C-allocation as life traits in biological soil crusts

et al. 2014

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Biological soil crusts (BSC) are the dominant functional vegetation unit in some of the harshest habitats in the world. We assessed BSC response to stress through changes in biotic composition, CO 2 gas exchange and carbon allocation in three lichen-dominated BSC from habitats with different stress levels, two more extreme sites in Antarctica and one moderate site in Germany. Maximal net photosynthesis (NP) was identical, whereas the water content to achieve maximal NP was substantially lower in the Antarctic sites, this apparently being achieved by changes in biomass allocation. Optimal NP temperatures reflected local climate. The Antarctic BSC allocated fixed carbon (tracked using 14 CO 2 ) mostly to the alcohol soluble pool (low-molecular weight sugars, sugar alcohols), which has an important role in desiccation and freezing resistance and antioxidant protection. In contrast, BSC at the moderate site showed greater carbon allocation into the polysaccharide pool, indicating a tendency towards growth. The results indicate that the BSC of the more stressed Antarctic sites emphasise survival rather than growth. Changes in BSC are adaptive and at multiple levels and we identify benefits and risks attached to changing life traits, as well as describing the ecophysiological mechanisms that underlie them.

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“…) y en suelos (Belnap y Lange, 2001). Las cubiertas criptogámicas (Cryptogamic Ground Covers o CGC; Elbert et al, 2012) han demostrado ser sistemas complejos y dinámicos que contienen varios grupos funcionales distintos de procariontes y eucariontes, desde los productores primarios hasta los descomponedores de materiales específicos y los herbívoros (Fritsch, 1922;Fletcher y Martin, 1948;Campbell, 1979;Bamforth, 1984Bamforth, , 2004Nagy et al, 2005;Tirkey y Adhikary, 2005;Chanal et al, 2006;Reddy y Garcia-Pichel, 2006;Bates y Garcia-Pichel, 2009;Neher et al, 2009;Meadow y Zabinski, 2012). Esta diversidad es variable según las condiciones ambientales locales, pero todos tienen en común la presencia de cianobacterias, con pocas excepciones (i.e.…”

Section: Funcionamiento De Los Ecosistemas Terrestres Primitivosunclassified

La vida temprana en la Tierra y los primeros ecosistemas terrestres

Beraldi-Campesi¹

2014

BSGM

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La vida temprana en la Tierra y los primeros ecosistemas terrestres 65 ResumenLos ecosistemas terrestres han sido considerados tradicionalmente como superficies dominadas por plantas, cuyos primeros registros datan del Fanerozoico temprano (< 550 Ma/millones de años). Sin embargo, la presencia de componentes biológicos mucho más antiguos que las plantas en hábitats tan distintos como suelos, turberas, estanques, lagos, arroyos y dunas, sugiere que los ecosistemas terrestres comenzaron a existir en la Tierra hace al menos 2700 Ma. Los microbios fueron abundantes hace ~3500 Ma y sin duda se adaptaron a vivir en condiciones subaéreas, en entornos intermareales y en zonas áridas y semiáridas, como lo hacen actualmente los microbios terrestres, y que tienen una enorme y rápida capacidad de adaptación a condiciones cambiantes. Todo ello está respaldado por el registro fósil. No obstante, esta evidencia es inusual e indirecta en comparación con fósiles de ambientes marinos, superficiales o profundos, y su registro ha sido poco atendido. En consecuencia, la noción de que fueron comunidades microbianas las que formaron los primeros ecosistemas terrestres no ha sido ampliamente difundido ni incorporado conceptualmente en la sociedad. Hoy conocemos un amplio registro fósil de biota marina somera y lacustre a partir de los ~3500 Ma, así como microbios colonizando ambientes costeros desde hace ~3450 Ma y evidencia indirecta de actividad biológica en paleosuelos de > 3400 Ma de edad. El tipo de ambientes, de donde proviene esta evidencia, sugiere que la vida terrestre se produjo casi en paralelo con la vida acuática en el Arqueano. Las rápidas adaptaciones observadas en microbios actuales, su excepcional tolerancia a condiciones extremas y fluctuantes, su rápida y temprana diversificación y su antiguo registro fósil, indican que los primeros ecosistemas terrestres fueron exclusivamente microbianos. Es factible que los microbios contribuyeran en la formación de los primeros suelos donde las plantas se desarrollaron más tarde. Comprender cómo la vida se diversificó y adaptó a las condiciones terrestres es fundamental para entender su impacto en los sistemas terrestres durante millones de años. Beraldi-Campesi 66 661. Introducción Definición de terrestreLos ambientes terrestres seguramente han existido a través de toda la historia geológica de la Tierra a menos que su superficie estuviera permanentemente bajo el agua, lo cual no es aceptablemente realista. La definición de 'terrestre' no es tan trivial como parece. Aunque aquí se define como un ambiente 'no acuático', la distinción entre lo marino y lo terrestre atraviesa un amplio espectro de ambientes transicionales, donde lo acuático y lo no-acuático evolucionan y superponen en el tiempo. Comúnmente se entiende que un entorno terrestre (sobre el nivel del mar), puede incluir ambientes acuáticos (lagos cubiertos o no de hielo, lagunas y humedales, turberas, ríos y arroyos, campos geotérmicos) y no-acuáticos (especialmente zonas con poca lluvia). Estos hábitats pueden experimen...

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Contribution of cryptogamic covers to the global cycles of carbon and nitrogen

Cited by 809 publications

References 26 publications

Parasites dominate hyperdiverse soil protist communities in Neotropical rainforests

Parasites dominate hyperdiverse soil protist communities in Neotropical rainforests

Habitat stress initiates changes in composition, CO2 gas exchange and C-allocation as life traits in biological soil crusts

La vida temprana en la Tierra y los primeros ecosistemas terrestres

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