Relationships between biodiversity and ecosystem functioning proxies strengthen when approaching chemosynthetic deep-sea methane seeps

As biodiversity loss accelerates globally, understanding environmental influence over biodiversity–ecosystem functioning (BEF) relationships becomes crucial for ecosystem management. Theory suggests that resource supply affects the shape of BEF relationships, but this awaits detailed investigation in marine ecosystems. Here, we use deep-sea chemosynthetic methane seeps and surrounding sediments as natural laboratories in which to contrast relationships between BEF proxies along with a gradient of trophic resource availability (higher resource methane seep, to lower resource photosynthetically fuelled deep-sea habitats). We determined sediment fauna taxonomic and functional trait biodiversity, and quantified bioturbation potential (BPc), calcification degree, standing stock and density as ecosystem functioning proxies. Relationships were strongly unimodal in chemosynthetic seep habitats, but were undetectable in transitional ‘chemotone’ habitats and photosynthetically dependent deep-sea habitats. In seep habitats, ecosystem functioning proxies peaked below maximum biodiversity, perhaps suggesting that a small number of specialized species are important in shaping this relationship. This suggests that absolute biodiversity is not a good metric of ecosystem ‘value’ at methane seeps, and that these deep-sea environments may require special management to maintain ecosystem functioning under human disturbance. We promote further investigation of BEF relationships in non-traditional resource environments and emphasize that deep-sea conservation should consider ‘functioning hotspots' alongside biodiversity hotspots.

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Exponential Decline of Deep-Sea Ecosystem Functioning Linked to Benthic Biodiversity Loss

Current Biology ◽

10.1016/j.cub.2007.11.056 ◽

2008 ◽

Vol 18 (1) ◽

pp. 1-8 ◽

Cited By ~ 322

Author(s):

Roberto Danovaro ◽

Cristina Gambi ◽

Antonio Dell'Anno ◽

Cinzia Corinaldesi ◽

Simonetta Fraschetti ◽

...

Keyword(s):

Deep Sea ◽

Ecosystem Functioning ◽

Biodiversity Loss ◽

Exponential Decline

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The results of biodiversity-ecosystem functioning experiments are realistic

10.1101/725812 ◽

2019 ◽

Author(s):

Malte Jochum ◽

Markus Fischer ◽

Forest Isbell ◽

Christiane Roscher ◽

Fons van der Plas ◽

...

Keyword(s):

Plant Communities ◽

Real World ◽

Ecosystem Functioning ◽

Biological Diversity ◽

Large Body ◽

Biodiversity Loss ◽

Functional Trait ◽

Ecosystem Functions ◽

The Real ◽

Full Dataset

SummaryA large body of research shows that biodiversity loss can reduce ecosystem functioning, thus providing support for the conservation of biological diversity1–4. Much of the evidence for this relationship is drawn from biodiversity-ecosystem functioning experiments (hereafter: biodiversity experiments), in which biodiversity loss is simulated by randomly assembling communities of varying species diversity, and ecosystem functions are measured5–9. This random assembly has led some ecologists to question the relevance of biodiversity experiments to real-world ecosystems, where community assembly may often be non-random and influenced by external drivers, such as climate or land-use intensification10–18. Despite these repeated criticisms, there has been no comprehensive, quantitative assessment of how experimental and real-world plant communities really differ, and whether these differences invalidate the experimental results. Here, we compare data from two of the largest and longest-running grassland biodiversity experiments globally (Jena Experiment, Germany; BioDIV, USA) to related real-world grassland plant communities in terms of their taxonomic, functional, and phylogenetic diversity and functional-trait composition. We found that plant communities of biodiversity experiments have greater variance in these compositional features than their real-world counterparts, covering almost all of the variation of the real-world communities (82-96%) while also containing community types that are not currently observed in the real world. We then re-analysed a subset of experimental data that included only ecologically-realistic communities, i.e. those comparable to real-world communities. For ten out of twelve biodiversity-ecosystem functioning relationships, biodiversity effects did not differ significantly between the full dataset of biodiversity experiments and the ecologically-realistic subset of experimental communities. This demonstrates that the results of biodiversity experiments are largely insensitive to the inclusion/exclusion of unrealistic communities. By bridging the gap between experimental and real-world studies, these results demonstrate the validity of inferences from biodiversity experiments, a key step in translating their results into specific recommendations for real-world biodiversity management.

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Faculty Opinions recommendation of Exponential decline of deep-sea ecosystem functioning linked to benthic biodiversity loss.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1097973.556116 ◽

2008 ◽

Author(s):

Boris Worm

Keyword(s):

Deep Sea ◽

Ecosystem Functioning ◽

Biodiversity Loss ◽

Exponential Decline

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Disentangling the effect of body size and phylogenetic distances on zooplankton top-down control of algae

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2016.0487 ◽

2016 ◽

Vol 283 (1828) ◽

pp. 20160487 ◽

Cited By ~ 22

Author(s):

Andros T. Gianuca ◽

Jelena H. Pantel ◽

Luc De Meester

Keyword(s):

Body Size ◽

Ecosystem Functioning ◽

Phylogenetic Signal ◽

Niche Partitioning ◽

Biodiversity Loss ◽

Taxonomic Diversity ◽

Functional Trait ◽

Ecosystem Functions ◽

Top Down ◽

Niche Differences

A negative consequence of biodiversity loss is reduced rates of ecosystem functions. Phylogenetic-based biodiversity indices have been claimed to provide more accurate predictions of ecosystem functioning than species diversity alone. This approach assumes that the most relevant traits for ecosystem functioning present a phylogenetic signal. Yet, traits-mediating niche partitioning and resource uptake efficiency in animals can be labile. To assess the relative power of a key trait (body size) and phylogeny to predict zooplankton top-down control on phytoplankton, we manipulated trait and phylogenetic distances independently in microcosms while holding species richness constant. We found that body size provided strong predictions of top-down control. In contrast, phylogeny was a poor predictor of grazing rates. Size-related grazing efficiency asymmetry was mechanistically more important than niche differences in mediating ecosystem function in our experimental settings. Our study demonstrates a strong link between a single functional trait (i.e. body size) in zooplankton and trophic interactions, and urges for a cautionary use of phylogenetic information and taxonomic diversity as substitutes for trait information to predict and understand ecosystem functions.

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Faculty Opinions recommendation of Extracellular DNA plays a key role in deep-sea ecosystem functioning.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1028479.337197 ◽

2005 ◽

Author(s):

Bernard Riegl

Keyword(s):

Deep Sea ◽

Ecosystem Functioning ◽

Extracellular Dna

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Faculty Opinions recommendation of Virus decomposition provides an important contribution to benthic deep-sea ecosystem functioning.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.725424620.793506189 ◽

2015 ◽

Author(s):

Kevin Lafferty

Keyword(s):

Deep Sea ◽

Ecosystem Functioning

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Functional trait responses to sediment deposition reduce macrofauna-mediated ecosystem functioning in an estuarine mudflat

Biogeosciences ◽

10.5194/bg-15-2587-2018 ◽

2018 ◽

Vol 15 (9) ◽

pp. 2587-2599 ◽

Cited By ~ 9

Author(s):

Sebastiaan Mestdagh ◽

Leila Bagaço ◽

Ulrike Braeckman ◽

Tom Ysebaert ◽

Bart De Smet ◽

...

Keyword(s):

Oxygen Consumption ◽

Ecosystem Functioning ◽

River Estuary ◽

Functional Trait ◽

Sediment Deposition ◽

Sediment Chemistry ◽

Sediment Layer ◽

Sediment Reworking ◽

Macrobenthic Communities ◽

The Impact

Abstract. Human activities, among which dredging and land use change in river basins, are altering estuarine ecosystems. These activities may result in changes in sedimentary processes, affecting biodiversity of sediment macrofauna. As macrofauna controls sediment chemistry and fluxes of energy and matter between water column and sediment, changes in the structure of macrobenthic communities could affect the functioning of an entire ecosystem. We assessed the impact of sediment deposition on intertidal macrobenthic communities and on rates of an important ecosystem function, i.e. sediment community oxygen consumption (SCOC). An experiment was performed with undisturbed sediment samples from the Scheldt river estuary (SW Netherlands). The samples were subjected to four sedimentation regimes: one control and three with a deposited sediment layer of 1, 2 or 5 cm. Oxygen consumption was measured during incubation at ambient temperature. Luminophores applied at the surface, and a seawater–bromide mixture, served as tracers for bioturbation and bio-irrigation, respectively. After incubation, the macrofauna was extracted, identified, and counted and then classified into functional groups based on motility and sediment reworking capacity. Total macrofaunal densities dropped already under the thinnest deposits. The most affected fauna were surficial and low-motility animals, occurring at high densities in the control. Their mortality resulted in a drop in SCOC, which decreased steadily with increasing deposit thickness, while bio-irrigation and bioturbation activity showed increases in the lower sediment deposition regimes but decreases in the more extreme treatments. The initial increased activity likely counteracted the effects of the drop in low-motility, surficial fauna densities, resulting in a steady rather than sudden fall in oxygen consumption. We conclude that the functional identity in terms of motility and sediment reworking can be crucial in our understanding of the regulation of ecosystem functioning and the impact of habitat alterations such as sediment deposition.

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