Short-Term Spatial and Temporal Carbonate Chemistry Variability in Two Contrasting Seagrass Meadows: Implications for pH Buffering Capacities

Abstract. Ambo-Rappe R, La Nafie YA, Syafiuddin, Limbong SR, Asriani N, Handayani NT, Lisdayanti E. 2019. Short Communication: Restoration of seagrass Enhalus acoroides using a combination of generative and vegetative techniques. Biodiversitas 20: 3358-3363. Seagrass areas have been declining in extent worldwide, with associated loss in seagrass ecosystem functions and services. Seagrass restoration is important to mitigate, halt and reverse such declines and their consequences. Generative propagation has benefits in terms of genetic biodiversity, however, survival of seagrass seedlings has often been poor especially in high energy environments. Terrestrial restoration often uses shade trees to protect vulnerable seedlings. This study aimed to evaluate the feasibility of a similar approach in the marine environment, using adult plants to protect seedlings of the tropical seagrass Enhalus acoroides (L.f.) Royle. Enhalus seeds taken from a donor bed were germinated and grown into seedlings, then planted in a location with high hydrodynamic exposure at three different densities (high, medium, and low). Adult Enhalus transplants were co-planted to provide three levels of protection: fifty (high), ten (medium), and none (no protection). Results showed that high-density seedling co-planting with high protection from adult transplants had significantly (p< 0.05) higher six-month survival rate compared to the other treatments. Our results indicate that, even in high energy environments, co-planting seedlings with adult transplants may combine the advantages of generative and vegetative propagation methods, promoting greater short-term effectiveness in terms of seedlings survival and growth in the restored seagrass meadows.

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Short-term fate of seagrass and macroalgal detritus in Arenicola marina bioturbated sediments

Marine Ecology Progress Series ◽

10.3354/meps13281 ◽

2020 ◽

Vol 639 ◽

pp. 21-35

Author(s):

ACG Thomson ◽

E Kristensen ◽

T Valdemarsen ◽

CO Quintana

Keyword(s):

Zostera Marina ◽

Benthic Fauna ◽

C Sequestration ◽

Fucus Vesiculosus ◽

Short Term ◽

Arenicola Marina ◽

Seagrass Meadows ◽

Seagrass Ecosystems ◽

The Common ◽

Discrete Layer

Seagrass meadows are globally important ecosystems for carbon (C) sequestration. However, bioturbation by benthic fauna can alter the distribution, degradation and overall preservation of C in the sediment. We performed a 4 wk laboratory experiment to investigate the short-term degradation and burial of 2 major C sources in bare sediments associated with seagrass ecosystems. Eelgrass Zostera marina and macroalgal (Fucus vesiculosus) detritus were amended in sediment with and without bioturbation by the common polychaete Arenicola marina. Bioturbation did not significantly affect the loss of eelgrass detritus (>0.5 mm), but caused a rapid burial of this material as a discrete layer (55% recovery) at sediment depths ranging from 8 to 14 cm. A. marina effects on macroalgal detritus were more pronounced, resulting, in total, in an 80% loss of macroalgal detritus by microbial degradation and worm ingestion. We conclude that A. marina bioturbation effectively buries eelgrass detritus into deep anoxic sediments, but we cannot confirm that this leads to enhanced C preservation in coastal ecosystems. In contrast, A. marina bioturbation significantly increases the degradation of macroalgal tissue, and it is unlikely that this detritus is a major source for permanent C burial.

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A Unique Diel Pattern in Carbonate Chemistry in the Seagrass Meadows of Dongsha Island: The Enhancement of Metabolic Carbonate Dissolution in a Semienclosed Lagoon

Frontiers in Marine Science ◽

10.3389/fmars.2021.717685 ◽

2021 ◽

Vol 8 ◽

Author(s):

Wen-Chen Chou ◽

Lan-Feng Fan ◽

Chang-Chang Yang ◽

Ying-Hsuan Chen ◽

Chin-Chang Hung ◽

...

Keyword(s):

Total Alkalinity ◽

Carbonate Dissolution ◽

Diel Pattern ◽

Carbonate Chemistry ◽

Seagrass Meadows ◽

Diel Variations ◽

Seawater Carbonate Chemistry ◽

Aerobic And Anaerobic ◽

Organic Matter Loading ◽

Photosynthesis And Respiration

In contrast to other seagrass meadows where seawater carbonate chemistry generally shows strong diel variations with higher pH but lower partial pressure of CO2 (pCO2) during the daytime and lower pH but higher pCO2 during nighttime due to the alternation in photosynthesis and respiration, the seagrass meadows of the inner lagoon (IL) on Dongsha Island had a unique diel pattern with extremely high pH and low pCO2 across a diel cycle. We suggest that this distinct diel pattern in pH and pCO2 could be associated with the enhancement of total alkalinity (TA) production coupled to carbonate sediment dissolution in a semienclosed lagoon. The confinement of the IL may hamper water exchange and seagrass detritus export to the adjacent open ocean, which may result in higher organic matter loading to the sediments, and longer residence time of the water in the IL, accompanied by microbial respiration (both aerobic and anaerobic) that may reduce carbonate saturation level to drive carbonate dissolution and thus TA elevation, thereby forming such a unique diel pattern in carbonate chemistry. This finding further highlights the importance of considering TA production through metabolic carbonate dissolution when evaluating the potential of coastal blue carbon ecosystems to buffer ocean acidification and to absorb atmospheric CO2, in particular in a semienclosed setting.

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Effects of multiple disturbances in seagrass meadows: shading decreases resilience to grazing

Marine and Freshwater Research ◽

10.1071/mf09008 ◽

2009 ◽

Vol 60 (12) ◽

pp. 1317 ◽

Cited By ~ 23

Author(s):

Johan S. Eklöf ◽

Kathryn McMahon ◽

Paul S. Lavery

Keyword(s):

Algal Blooms ◽

Phytoplankton Blooms ◽

Short Term ◽

Field Surveys ◽

Multiple Disturbances ◽

Seagrass Meadows ◽

Management Actions ◽

Halophila Ovalis ◽

Black Swans ◽

Western Australian

Ecosystem shifts are often associated with multiple disturbances, but limited knowledge on the mechanisms involved hampers management. This study investigated how short-term shading affected the resilience of the seagrass Halophila ovalis to grazing by black swans (Cygnus atratus) – a historically dominant grazer currently recovering from hunting and habitat loss – in south-western Australian estuaries, using field surveys and a grazing-shading experiment. Black swans were heterogeneously distributed and, in a high-density site, consumed 23% of seagrass production. Seagrasses recovered rapidly from a single disturbance (i.e. short-term shading or grazing), even though shading alone halved carbohydrate content. When seagrasses were exposed to both disturbances, recovery depended on the type of grazing; where grazing was confined to leaves, leaf densities recovered within 3 weeks, but where grazing was on both leaves and rhizomes there was no recovery. Shading increased the frequency of apex initiation, as did rhizome grazing, but only if the plants had not been shaded. This indicates that shading alters the flow of energy needed to produce apices and leaves following disturbance on rhizomes. Based on the historical swan densities and continuing recurring phytoplankton blooms, management actions reintroducing swans without controlling algal blooms could have an on impact seagrass resilience and associated organisms.

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Short-term response of the coccolithophore <i>Emiliania huxleyi</i> to abrupt changes in seawater carbon dioxide concentrations

Biogeosciences Discussions ◽

10.5194/bgd-6-4739-2009 ◽

2009 ◽

Vol 6 (3) ◽

pp. 4739-4763 ◽

Cited By ~ 1

Author(s):

J. Barcelos e Ramos ◽

M. N. Müller ◽

U. Riebesell

Keyword(s):

Organic Carbon ◽

Carbon Fixation ◽

Emiliania Huxleyi ◽

Carbonate Chemistry ◽

Short Term ◽

Co2 Concentrations ◽

Lack Of Information ◽

Seawater Carbonate Chemistry ◽

Time Required ◽

Term Response

Abstract. The response of the coccolithophore Emiliania huxleyi to rising CO2 concentrations is well documented in acclimated cultures where cells are exposed to the CO2 treatments for several generations prior to the experiment. Extended acclimation times have generally been applied because of the lack of information about time required to reach a new physiological "equilibrium" (acclimation) in response to CO2-induced changes in seawater carbonate chemistry. Here we show that Emiliania huxleyi's short-term response (hours to 1 day) to increasing CO2 is similar to that obtained with acclimated cultures under comparable conditions in earlier studies. At CO2 concentrations ranging from glacial (190 μatm) to projected year 2100 (750 μatm) levels, calcification decreased and organic carbon fixation increased within 8 h after exposing the cultures to the changed CO2 conditions. This led to a decrease in the ratio of CaCO3 to organic carbon production. Our results show that Emiliania huxleyiapidly alters the rates of various essential processes in response to changes in seawater carbonate chemistry, establishing a new physiological (acclimation) "state" within a matter of hours. If this relatively rapid response applies to other phytoplankton species, it may simplify interpretation of studies with natural communities (e.g. mesocosm studies and ship-board incubations), where often it is not feasible to allow for a pre-conditioning phase before starting experimental incubations.

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Can short-term meteorological events alter subtropical estuarine macrobenthic assemblages in seagrass meadows (Patos Lagoon Estuary - Southern Brazil)?

Estuarine Coastal and Shelf Science ◽

10.1016/j.ecss.2021.107532 ◽

2021 ◽

pp. 107532

Author(s):

Dairana Misturini ◽

Leonir A. Colling

Keyword(s):

Southern Brazil ◽

Short Term ◽

Patos Lagoon ◽

Seagrass Meadows ◽

Macrobenthic Assemblages ◽

Patos Lagoon Estuary

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Short-term response of the coccolithophore <i>Emiliania huxleyi</i> to an abrupt change in seawater carbon dioxide concentrations

Biogeosciences ◽

10.5194/bg-7-177-2010 ◽

2010 ◽

Vol 7 (1) ◽

pp. 177-186 ◽

Cited By ~ 45

Author(s):

J. Barcelos e Ramos ◽

M. N. Müller ◽

U. Riebesell

Keyword(s):

Carbon Fixation ◽

Physiological State ◽

Emiliania Huxleyi ◽

Carbonate Chemistry ◽

Short Term ◽

Co2 Concentrations ◽

Carbon Dioxide Concentrations ◽

Seawater Carbonate Chemistry ◽

Induced Changes ◽

Term Response

Abstract. The response of the coccolithophore Emiliania huxleyi to rising CO2 concentrations is well documented for acclimated cultures where cells are exposed to the CO2 treatments for several generations prior to the experiment. The exact number of generations required for acclimation to CO2-induced changes in seawater carbonate chemistry, however, is unknown. Here we show that Emiliania huxleyi's short-term response (26 h) after cultures (grown at 500 μatm) were abruptly exposed to changed CO2 concentrations (~190, 410, 800 and 1500 μatm) is similar to that obtained with acclimated cultures under comparable conditions in earlier studies. Most importantly, from the lower CO2 levels (190 and 410 μatm) to 750 and 1500 μatm calcification decreased and organic carbon fixation increased within the first 8 to 14 h after exposing the cultures to changes in carbonate chemistry. This suggests that Emiliania huxleyi rapidly alters the rates of essential metabolical processes in response to changes in seawater carbonate chemistry, establishing a new physiological "state" (acclimation) within a matter of hours. If this relatively rapid response applies to other phytoplankton species, it may simplify interpretation of studies with natural communities (e.g. mesocosm studies and ship-board incubations), where often it is not feasible to allow for a pre-conditioning phase before starting experimental incubations.

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Autonomous Minisubmarine Measures Seawater Conditions

Eos ◽

10.1029/2020eo151558 ◽

2020 ◽

Vol 101 ◽

Author(s):

Terri Cook

Keyword(s):

Ocean Acidification ◽

Fisheries Management ◽

Coastal Ecosystems ◽

Carbonate Chemistry ◽

Short Term

Forecasts of carbonate chemistry in coastal ecosystems determined from seasonal robotic measurements can improve fisheries management and help mitigate short-term ocean acidification events.

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The impacts of past, present and future ocean chemistry on predatory planktonic snails

Royal Society Open Science ◽

10.1098/rsos.202265 ◽

2021 ◽

Vol 8 (8) ◽

pp. 202265

Author(s):

Deborah Wall-Palmer ◽

Lisette Mekkes ◽

Paula Ramos-Silva ◽

Linda K. Dämmer ◽

Erica Goetze ◽

...

Keyword(s):

Gene Expression ◽

Shell Thickness ◽

Shell Growth ◽

Ambient Conditions ◽

Carbonate Chemistry ◽

Short Term ◽

Ocean Chemistry ◽

Decreasing Ph ◽

Organismal Development ◽

Shell Production

The atlantid heteropods represent the only predatory, aragonite shelled zooplankton. Atlantid shell production is likely to be sensitive to ocean acidification (OA), and yet we know little about their mechanisms of calcification, or their response to changing ocean chemistry. Here, we present the first study into calcification and gene expression effects of short-term OA exposure on juvenile atlantids across three pH scenarios: mid-1960s, ambient and 2050 conditions. Calcification and gene expression indicate a distinct response to each treatment. Shell extension and shell volume were reduced from the mid-1960s to ambient conditions, suggesting that calcification is already limited in today's South Atlantic. However, shell extension increased from ambient to 2050 conditions. Genes involved in protein synthesis were consistently upregulated, whereas genes involved in organismal development were downregulated with decreasing pH. Biomineralization genes were upregulated in the mid-1960s and 2050 conditions, suggesting that any deviation from ambient carbonate chemistry causes stress, resulting in rapid shell growth. We conclude that atlantid calcification is likely to be negatively affected by future OA. However, we also found that plentiful food increased shell extension and shell thickness, and so synergistic factors are likely to impact the resilience of atlantids in an acidifying ocean.

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