Sediment trap-derived particulate matter fluxes in the oligotrophic subtropical gyre of the South Indian Ocean

Harms, Natalie; Lahajnar, Niko; Gaye, Birgit; Rixen, Tim; Schwarz-Schampera, Ulrich; Emeis, Kay-Christian

doi:10.1016/j.dsr2.2020.104924

Cited by 22 publications

(14 citation statements)

References 72 publications

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“…The spreading ridges of the Indian Ocean and their hydrothermal ecosystems (Figure 1) are unique but have less known vent ecosystems than those in the Atlantic and Pacific mid-ocean ridges in terms of their spreading rate (Müller et al, 2008;Beaulieu, 2015), mineral composition (German et al, 2016), and carbon input from the surface (Harms et al, 2021). Indian Ocean spreading ridge vent ecosystems have been hypothesized to serve as a corridor of connectivity between Atlantic and Pacific vent fauna (Ramirez-Llodra et al, 2007;Bachraty et al, 2009;Moalic et al, 2012;Rogers et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Structure and Connectivity of Hydrothermal Vent Communities Along the Mid-Ocean Ridges in the West Indian Ocean: A Review

Perez

Sun

et al. 2021

Front. Mar. Sci.

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To date, 13 biologically active hydrothermal vent (HTV) fields have been described on the West Indian Ocean ridges. Knowledge of benthic communities of these vent ecosystems serves as scientific bases for assessing the resilience of these ecosystems under the global effort to strike an elegant balance between future deep-sea mining and biodiversity conservation. This review aims to summarize our up-to-date knowledge of the benthic community structure and connectivity of these Indian vents and to identify knowledge gaps and key research questions to be prioritized in order to assess the resilience of these communities. The HTVs in the West Indian Ocean are home to many unique invertebrate species such as the remarkable scaly-foot snail. While distinct in composition, the macrofaunal communities of the Indian HTVs share many characteristics with those of other HTVs, including high endemism, strong zonation at the local scale, and a simple food web structure. Furthermore, Indian vent benthic communities are mosaic compositions of Atlantic, Pacific, and Antarctic HTV fauna possibly owning to multiple waves of past colonization. Phylogeographic studies have shed new light into these migratory routes. Current animal connectivity across vent fields appears to be highly influenced by distance and topological barriers. However, contrasting differences in gene flow have been documented across species. Thus, a better understanding of the reproductive biology of the Indian vent animals and the structure of their population at the local scale is crucial for conservation purposes. In addition, increased effort should be given to characterizing the vents’ missing diversity (at both the meio and micro-scale) and elucidating the functional ecology of these vents.

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Section: Introductionmentioning

confidence: 99%

Structure and Connectivity of Hydrothermal Vent Communities Along the Mid-Ocean Ridges in the West Indian Ocean: A Review

Perez

Sun

et al. 2021

Front. Mar. Sci.

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“…Hence, several synchronizing factors may co-exist in vents and other deep-sea ecosystems, even within the same family of animals. For example, our results here demonstrate that R. exoculata and R. kairei exhibit seasonality decoupled from surface seasonality, but as the study areas have relatively low surface primary productivity and export of particulate organic carbon (POC) to the deep [41], [42] it is also possible that a higher POC export may begin to interfere with this pattern. Taken together -primary surface production may be the key synchronising cue for some deep-sea species as demonstrated in bathymodiolin mussels and vent crabs [24], [25], but our results underscore that reproductive cycles and seasonality at the deep is not as simple as it was thought to be.…”

Section: The Intriguing Reproductive Cycles Of Rimicaris Shrimpsmentioning

confidence: 70%

“…Such pattern was unexpected given their distribution in different hemispheres, at vent fields with opposite latitudes (figure 1). Reproductive periodicity in deep-sea animals has often been related to seasonal variations in surface photosynthetic production [26]- [28], and Rimicaris shrimps from the two hemispheres are expected to experience opposite trends in terms of surface primary production along the year [41], [42], driving opposite reproductive timing. Although our dataset for R. kairei is more limited than for R. exoculata, these sister species thus appear to share same periodic brooding cycle, regardless of local seasonal variations in surface photosynthetic productivity.…”

Section: The Intriguing Reproductive Cycles Of Rimicaris Shrimpsmentioning

confidence: 99%

“…Taken together, these recent findings suggest a seasonal reproductive cycle possibly linked to surface primary production, as shown in vent crabs, bathymodiolin mussels and some other alvinocaridid shrimps (Dixon et al 2006, Copley and Young 2006, Tyler et al 2007). However, the low primary productivity of oligotrophic surface waters and the overall low export to the deep-sea compartment within the region where these shrimps have been collected (-3500 m depth) (Pabortsava et al 2017, Harms et al 2021) challenges the possibility of such a link.…”

Section: Introductionmentioning

confidence: 99%

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Reproduction in deep-sea vent shrimps is shaped by diet and phylogeny, with rhythms unlinked to surface production

Methou

Chen

Watanabe

et al. 2021

Preprint

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Variations in reproductive patterns according to feeding strategies or food supply have been recognized in many animals from various ecosystems. Despite an unusual trophic structure, these relationships remain largely under-studied in chemosynthetic ecosystems. Here, we use Rimicaris shrimps as a study case to explore relations between reproduction, diets and food supply in these environments. For that, we compiled data on presence of reproductive individuals from the past 35 years and compared reproductive outputs of three shrimps differing by their diets and regions. We report distinct reproductive patterns between Rimicaris species according to their trophic regime regardless of variations related to body size. Besides, we observed a reproductive period mostly between January and early April whatever the region. Intriguingly, this periodicity does not correspond to seasonal variations with presence of ovigerous females during either boreal winter or austral summer. These observations contrast with the long-standing paradigm in deep-sea species for which periodic reproductive patterns have always been attributed to seasonal variations of photosynthetic production sinking from surface. Our results suggest the presence of intrinsic basis for biological rhythms in the deep sea, and bring to light the importance of having year-round observations in order to understand life history of vent animals.

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“…In the Arabian Sea sediment trap, SPM and surface sediment samples were taken in the deep ocean and on the continental slope, including a core within the oxygen minimum zone at water depths of 775 m (Gaye et al, 2013a, b;Rixen et al, 2014;Gaye-Haake et al, 2005;Suthhof et al, 2000Suthhof et al, , 2001. In the Indian Ocean Subtropical Gyre sediment trap, SPM and water samples were taken (Harms et al, 2019(Harms et al, , 2021, and samples from the equatorial North Pacific and eastern South Pacific are comprised of bottom water, pore water, and sediment core samples (Paul et al, 2018).…”

Section: Samplingmentioning

confidence: 99%

What can we learn from amino acids about oceanic organic matter cycling and degradation?

et al. 2022

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Abstract. Amino acids (AAs) mainly bound in proteins are major constituents of living biomass and non-living organic material in the oceanic particulate and dissolved organic matter pool. Uptake and cycling by heterotrophic organisms lead to characteristic changes in AA composition so that AA-based biogeochemical indicators are often used to elucidate processes of organic matter cycling and degradation. We analyzed particulate AA in a large sample set collected in various oceanic regions covering sinking and suspended particles in the water column, sediment samples, and dissolved AA from water column and pore water samples. The aim of this study was to test and improve the use of AA-derived biogeochemical indicators as proxies for organic matter sources and degradation and to better understand particle dynamics and interaction between the dissolved and particulate organic matter pools. A principal component analysis (PCA) of all data delineates diverging AA compositions of sinking and suspended particles with increasing water depth. A new sinking particle and sediment degradation indicator (SDI) allows a fine-tuned classification of sinking particles and sediments with respect to the intensity of degradation, which is associated with changes of stable isotopic ratios of nitrogen (δ15N). This new indicator is furthermore sensitive to sedimentary redox conditions and can be used to detect past anoxic early diagenesis. A second indicator emerges from the AA spectra of suspended particulate matter (SPM) in the epipelagic and that of the meso- and bathypelagic ocean and is a residence time indicator (RTI). The characteristic changes in AA patterns from shallow to deep SPM are recapitulated in the AA spectra of the dissolved organic matter (DOM) pool, so that deep SPM is more similar to DOM than to any of the other organic matter pools. This implies that there is equilibration between finely dispersed SPM and DOM in the deep sea, which may be driven by microbial activity combined with annealing and fragmentation of gels. As these processes strongly depend on physico-chemical conditions in the deep ocean, changes in quality and degradability of DOM may strongly affect the relatively large pool of suspended and dissolved AA in the ocean that amounts to 15 Pg amino acid carbon (AAC) and 89 ± 29 Pg AAC, respectively.

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Sediment trap-derived particulate matter fluxes in the oligotrophic subtropical gyre of the South Indian Ocean

Cited by 22 publications

References 72 publications

Structure and Connectivity of Hydrothermal Vent Communities Along the Mid-Ocean Ridges in the West Indian Ocean: A Review

Structure and Connectivity of Hydrothermal Vent Communities Along the Mid-Ocean Ridges in the West Indian Ocean: A Review

Reproduction in deep-sea vent shrimps is shaped by diet and phylogeny, with rhythms unlinked to surface production

What can we learn from amino acids about oceanic organic matter cycling and degradation?

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