The morphometric acclimation to depth explains the long-term resilience of the seagrass Cymodocea nodosa in a shallow tidal lagoon

Dissolved organic carbon (DOC) plays an essential role in the global marine carbon cycle, with coastal vegetated communities as important DOC producers. However, the ultimate fate of this DOC remains still largely unknown due to the lack of knowledge about its chemical composition and lability. Furthermore, global change could alter both DOC fluxes and its bioavailability, affecting the carbon sequestration capacity of coastal vegetated communities. This study explores, in two contrasting seasons (winter and summer), the effects of an in situ simulated marine heatwave on carbon metabolism and DOC fluxes produced by seagrass (Cymodocea nodosa) and macroalgae (Caulerpa prolifera) communities. In addition, the fluorescent characteristics and biodegradability of the dissolved organic matter released directly by the communities under such conditions are evaluated. Under marine heatwave conditions, a significant increase in net community production (NCP) in C. nodosa and a shift to negative DOC fluxes in C. prolifera were observed. In control treatments, the seagrass‐dominated community produced a substantial amount of labile (between 44% and 58%) and recalcitrant DOC (between 42% and 56%), while C. prolifera community produced mainly recalcitrant DOC (between 64% and 87%). Therefore, this research revealed that temperature is an important factor determining the NCP in benthic communities and the chemical structure and bioavailability of DOC produced by these communities, since both communities tended to produce more humic‐like and less bioavailable DOC with increasing temperature.

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“…In the water column, nutrient peaks usually occur in winter, with values up to 1.4 μ mol L −1

{NO}_{2}^{-}

, 12 μ mol L −1

{NO}_{3}^{-}

, 25 μ mol L −1

{NH}_{4}^{+}

, and 1.5 μ mol L −1

{PO}_{4}^{3 -}

(Tovar et al 2000). For detailed information of the study area, see previous descriptions in Jiménez‐Ramos et al (2021) and Peralta et al (2021).…”

Section: Methodsmentioning

confidence: 99%

“…4 , and 1.5 μmol L À1 PO 3À 4 (Tovar et al 2000). For detailed information of the study area, see previous descriptions in Jiménez-Ramos et al (2021) and Peralta et al (2021).…”

Section: Study Areamentioning

confidence: 98%

Effect of marine heat waves on carbon metabolism, optical characterization, and bioavailability of dissolved organic carbon in coastal vegetated communities

Egea

Jiménez–Ramos

Romera‐Castillo

et al. 2022

Limnology & Oceanography

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“…The net productivity, respiration, and metabolic balance of S. isoetifolium plants displayed large variability (up to two-fold) among the sites studied. Large intraspecific plasticity has been attributed to the metabolism of seagrasses, as well as other physiological and morphological traits, associated with environmental drivers (Olivéet al, 2013;Enrıquez et al, 2019;Peralta et al, 2021). Differences in the metabolic balance of plants found at the different sites likely reflected the exposure to different environmental conditions.…”

Section: Metabolic Balance In the Lagoon Compartments 421 Seagrass Me...mentioning

confidence: 99%

Contribution of the seagrass Syringodium isoetifolium to the metabolic functioning of a tropical reef lagoon

Olivé

García‐Robledo²,

Silva³

et al. 2022

Front. Mar. Sci.

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Seagrasses are gaining attention thanks to their metabolism and potential major role as carbon sinks, with further implications as nature-based solutions against climate change. Despite their recognized importance and the growing number of studies published, there is still a striking paucity of information on seagrass metabolism and contribution to biogeochemical cycles for some seagrass species and ocean areas. In this study we assessed the metabolic balance and nutrient cycling contribution of seagrasses to the benthic compartment of a tropical reef lagoon in Reunion Island, providing original information on a barely studied seagrass species (Syringodium isoetifolium) and a poorly studied ocean region (West Indian Ocean). We measured the net productivity, respiration and the metabolic balance in different components of the lagoon benthic compartment (i.e. seagrass, sediment, and benthic community) and the water-sediment nutrient benthic fluxes at differently impacted sites within the lagoon. The biogeochemical environmental variability, including inorganic and organic indicators of anthropogenic contamination, was also assessed at each site.Large spatial variability was detected in the metabolic balance of each benthic component assessed, also associated with the natural and/or anthropic-driven environmental variability found in the lagoon. The seagrass S. isoetifolium was net autotrophic across the lagoon and contributed to the lagoon benthic metabolism with net plant productivity exceeding by one order of magnitude the plant respiration. The lowest seagrass metabolism was detected at the impacted site. The metabolic balance of the sediment was heterotrophic but the high productivity of S. isoetifolium contributed to reducing the heterotrophy of the whole benthic community. The lagoon-wide benthic metabolic balance was slightly heterotrophic, but the associated uncertainty ranged from autotrophy to heterotrophy. Nutrient concentrations in the lagoon were low and the benthic community capacity for nutrient retention (uptake) and removal (denitrification and anammox) indicated potential for buffering moderate nutrient inputs into the lagoon. Organic contaminants of emerging concern (CECs) were low but detectable in the lagoon, especially in highly frequented beach areas, arising as an environmental quality indicator of interest.

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“…Cymodocea nodosa is a dioecious seagrass occurring throughout the Mediterranean Sea and in the eastern Atlantic Ocean from Portugal to Senegal [ 29 , 30 ]. It lives in open waters on sandy and muddy substrates, but it can also colonize coastal lagoons, tolerating natural salinity fluctuations [ 29 , 30 , 31 , 32 ]. Little is known about C. nodosa ’s epiphytic bacterial communities [ 25 , 33 , 34 ].…”

Section: Introductionmentioning

confidence: 99%

A Tight Interaction between the Native Seagrass Cymodocea nodosa and the Exotic Halophila stipulacea in the Aegean Sea Highlights Seagrass Holobiont Variations

Conte

Apostolaki

Vizzini

2023

Plants

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Seagrasses harbour bacterial communities with which they constitute a functional unit called holobiont that responds as a whole to environmental changes. Epiphytic bacterial communities rapidly respond to both biotic and abiotic factors, potentially contributing to the host fitness. The Lessepsian migrant Halophila stipulacea has a high phenotypical plasticity and harbours a highly diverse epiphytic bacterial community, which could support its invasiveness in the Mediterranean Sea. The current study aimed to evaluate the Halophila/Cymodocea competition in the Aegean Sea by analysing each of the two seagrasses in a zone where these intermingled, as well as in their monospecific zones, at two depths. Differences in holobionts were evaluated using seagrass descriptors (morphometric, biochemical, elemental, and isotopic composition) to assess host changes, and 16S rRNA gene to identify bacterial community structure and composition. An Indicator Species Index was used to identify bacteria significantly associated with each host. In mixed meadows, native C. nodosa was shown to be affected by the presence of exotic H. stipulacea, in terms of both plant descriptors and bacterial communities, while H. stipulacea remained almost unchanged. This study provided evidence of the competitive advantage of H. stipulacea on C. nodosa in the Aegean Sea and suggests the possible use of associated bacterial communities as a descriptor of native seagrass sustainability.

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The morphometric acclimation to depth explains the long-term resilience of the seagrass Cymodocea nodosa in a shallow tidal lagoon

Cited by 24 publications

References 56 publications

Effect of marine heat waves on carbon metabolism, optical characterization, and bioavailability of dissolved organic carbon in coastal vegetated communities

Effect of marine heat waves on carbon metabolism, optical characterization, and bioavailability of dissolved organic carbon in coastal vegetated communities

Contribution of the seagrass Syringodium isoetifolium to the metabolic functioning of a tropical reef lagoon

A Tight Interaction between the Native Seagrass Cymodocea nodosa and the Exotic Halophila stipulacea in the Aegean Sea Highlights Seagrass Holobiont Variations

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