Postglacial carbonate production by cold-water corals on the Norwegian Shelf and their role in the global carbonate budget

Geology ◽  
2005 ◽  
Vol 33 (7) ◽  
pp. 537 ◽  
Author(s):  
Björn Lindberg ◽  
Jürgen Mienert
Keyword(s):  
Cold Water ◽  
Carbonate Production ◽  
Carbonate Budget

scholarly journals Temperate carbonate cycling and water mass properties from intertidal to bathyal depths (Azores, N-Atlantic)

2010 ◽  
Vol 7 (3) ◽  
pp. 3297-3333 ◽  
Author(s):  
M. Wisshak ◽  
A. Form ◽  
J. Jakobsen ◽  
A. Freiwald
Keyword(s):  
Cold Water ◽  
Light Availability ◽  
Euphotic Zone ◽  
Carbonate Production ◽  
Carbonate Budget ◽  
Mass Properties ◽  
Accretion Rates ◽  
Key Factor ◽  
Temperate Carbonate ◽  
Factor Governing

Abstract. The rugged submarine topography of the Azores supports a diverse heterozoan association resulting in intense biotically-controlled carbonate production and accumulation. In order to characterise this cold-water (C) factory a 2-year experiment was carried out to study the biodiversity of hardground communities and for budgeting carbonate production and degradation along a bathymetrical transect from the intertidal to bathyal 500 m depth. Seasonal temperatures peak in September (above a thermocline) and bottom in March (stratification diminishes) with a decrease in amplitude and absolute values with depth, and with tidal-driven short-term fluctuations. Measured seawater stable isotope ratios and levels of dissolved nutrients decrease with depth, as do the calcium carbonate saturation states. The photosynthetic active radiation shows a base of the euphotic zone in ~70 m and a dysphotic limit in ~150 m depth. Bioerosion, being primarily a function of light availability for phototrophic endoliths and grazers feeding upon them, is ~10 times stronger on the illuminated upside versus the shaded underside of substrates in the photic zone, with maximum rates in the intertidal (−631 g/m2/yr). Rates rapidly decline towards deeper waters where bioerosion and carbonate accretion are slow and epibenthic/endolithic communities take years to mature. Accretion rates are highest in the lower euphotic zone (955 g/m2/yr), where the substrate is less prone to hydrodynamic force. Highest rates are found – inversely to bioerosion – on downward facing substrates, suggesting that bioerosion may be a key factor governing the preferential settlement and growth of calcareous epilithobionts on downward facing substrates. In context of a latitudinal gradient, the Azores carbonate cycling rates plot between known values from the cold-temperate Swedish Kosterfjord and the tropical Bahamas, with a total range of two orders in magnitude. Carbonate budget calculations for the bathymetrical transect yield a mean 266.9 kg of epilithic carbonate production, −54.6 kg of bioerosion, and 212.3 kg of annual net carbonate production per metre of coastline in the Azores C factory.

scholarly journals Temperate carbonate cycling and water mass properties from intertidal to bathyal depths (Azores)

2010 ◽  
Vol 7 (8) ◽  
pp. 2379-2396 ◽  
Author(s):  
M. Wisshak ◽  
A. Form ◽  
J. Jakobsen ◽  
A. Freiwald
Keyword(s):  
Cold Water ◽  
Light Availability ◽  
Euphotic Zone ◽  
Carbonate Production ◽  
Carbonate Budget ◽  
Mass Properties ◽  
Accretion Rates ◽  
Key Factor ◽  
Temperate Carbonate ◽  
Factor Governing

Abstract. The rugged submarine topography of the Azores supports a diverse heterozoan association resulting in intense biotically-controlled carbonate-production and accumulation. In order to characterise this cold-water (C) factory a 2-year experiment was carried out in the southern Faial Channel to study the biodiversity of hardground communities and for budgeting carbonate production and degradation along a bathymetrical transect from the intertidal to bathyal 500 m depth. Seasonal temperatures peak in September (above a thermocline) and bottom in March (stratification diminishes) with a decrease in amplitude and absolute values with depth, and tidal-driven short-term fluctuations. Measured seawater stable isotope ratios and levels of dissolved nutrients decrease with depth, as do the calcium carbonate saturation states. The photosynthetic active radiation shows a base of the euphotic zone in ~70 m and a dysphotic limit in ~150 m depth. Bioerosion, being primarily a function of light availability for phototrophic endoliths and grazers feeding upon them, is ~10 times stronger on the illuminated upside versus the shaded underside of substrates in the photic zone, with maximum rates in the intertidal (−631 g/m2/yr). Rates rapidly decline towards deeper waters where bioerosion and carbonate accretion are slow and epibenthic/endolithic communities take years to mature. Accretion rates are highest in the lower euphotic zone (955 g/m2/yr), where the substrate is less prone to hydrodynamic force. Highest rates are found – inversely to bioerosion – on down-facing substrates, suggesting that bioerosion may be a key factor governing the preferential settlement and growth of calcareous epilithobionts on down-facing substrates. In context of a latitudinal gradient, the Azores carbonate cycling rates plot between known values from the cold-temperate Swedish Kosterfjord and the tropical Bahamas, with a total range of two orders in magnitude. Carbonate budget calculations for the bathymetrical transect yield a mean 266.9 kg of epilithic carbonate production, −54.6 kg of bioerosion, and 212.3 kg of annual net carbonate production per metre of coastline in the Azores C factory.

Carbonate budget of a cold-water coral mound (Challenger Mound, IODP Exp. 307)

2009 ◽  
Vol 259 (1-4) ◽  
pp. 36-46 ◽  
Author(s):  
J. Titschack ◽  
M. Thierens ◽  
B. Dorschel ◽  
C. Schulbert ◽  
A. Freiwald ◽  
...  
Keyword(s):  
Cold Water ◽  
Carbonate Budget ◽  
Water Coral

The standing stock and CaCO3 contribution of Halimeda macroloba in the tropical seagrass-dominated ecosystem in Dongsha Island, the main island of Dongsha Atoll, South China Sea

2020 ◽  
pp. 1-9
Author(s):  
Jaruwan Mayakun ◽  
Chen-Pan Liao ◽  
Shao-Lun Liu
Keyword(s):  
Growth Rate ◽  
South China Sea ◽  
South China ◽  
Standing Stock ◽  
Dry Weight ◽  
Carbonate Production ◽  
China Sea ◽  
Carbonate Budget ◽  
Marine Carbonate ◽  
Dongsha Atoll

Abstract Calcareous green alga in the genus Halimeda are important contributors to the marine carbonate budget. Dongsha Island is located in the northernmost South China Sea and is a seagrass-dominated ecosystem with intermixed Halimeda macroloba patches, making it an excellent system to better examine the extent of carbonate contribution by H. macroloba in such an ecosystem. To this end, we examined the standing stock and actual CaCO3 contribution of H. macroloba in the seagrass-dominated ecosystem (herein Dongsha Island) and compared them with those in Halimeda-dominated ecosystems. The density, growth rate, calcification rate and CaCO3 content of H. macroloba at four life stages were investigated. The mean density of H. macroloba was around 8.82 ± 1.57 thalli m−2 and the estimated standing stock was 61,740 to 72,730 thalli. Thalli produced 1 to 2 new segments day−1, giving a growth rate of 0.003 ± 0.001 g dry weight thallus−1 day−1. Calculated algal biomass and annual areal production were 0.03 g m−2 and 9.66 g m−2 year−1. In each square metre of this area, H. macroloba produced 8.82 to 17.64 new segments day−1, accumulating 0.002 ± 0.001 g CaCO3 thallus−1 day−1 or around 6.44 g CaCO3 m−2 year−1. Mean CaCO3 content was 0.32 ± 0.05 g thallus−1. As expected, the growth rate and CaCO3 production of H. macroloba in Dongsha Island were lower than in other studies from Halimeda tropical ecosystems. Overall, this work provides the baseline of carbonate production of H. macroloba in Dongsha Island and relevant systems where the ecosystem is dominated by seagrasses.

Carbonate budget of a cold-water coral carbonate mound: Propeller Mound, Porcupine Seabight

2005 ◽  
Vol 96 (1) ◽  
pp. 73-83 ◽  
Author(s):  
Boris Dorschel ◽  
Dierk Hebbeln ◽  
Andres Rüggeberg ◽  
Christian Dullo
Keyword(s):  
Cold Water ◽  
Carbonate Mound ◽  
Porcupine Seabight ◽  
Carbonate Budget ◽  
Coral Carbonate ◽  
Water Coral

scholarly journals Changing dynamics of Caribbean reef carbonate budgets: emergence of reef bioeroders as critical controls on present and future reef growth potential

2014 ◽  
Vol 281 (1796) ◽  
pp. 20142018 ◽  
Author(s):  
Chris T. Perry ◽  
Gary N. Murphy ◽  
Paul S. Kench ◽  
Evan N. Edinger ◽  
Scott G. Smithers ◽  
...  
Keyword(s):  
Coral Cover ◽  
Coral Community ◽  
Growth Potential ◽  
Reef Growth ◽  
Carbonate Production ◽  
Erosion Rates ◽  
Caribbean Reef ◽  
Carbonate Budget ◽  
Coral Recovery ◽  
Fundamental Shift

Coral cover has declined rapidly on Caribbean reefs since the early 1980s, reducing carbonate production and reef growth. Using a cross-regional dataset, we show that widespread reductions in bioerosion rates—a key carbonate cycling process—have accompanied carbonate production declines. Bioerosion by parrotfish, urchins, endolithic sponges and microendoliths collectively averages 2 G (where G = kg CaCO 3 m −2 yr −1 ) (range 0.96–3.67 G). This rate is at least 75% lower than that reported from Caribbean reefs prior to their shift towards their present degraded state. Despite chronic overfishing, parrotfish are the dominant bioeroders, but erosion rates are reduced from averages of approximately 4 to 1.6 G. Urchin erosion rates have declined further and are functionally irrelevant to bioerosion on most reefs. These changes demonstrate a fundamental shift in Caribbean reef carbonate budget dynamics. To-date, reduced bioerosion rates have partially offset carbonate production declines, limiting the extent to which more widespread transitions to negative budget states have occurred. However, given the poor prognosis for coral recovery in the Caribbean and reported shifts to coral community states dominated by slower calcifying taxa, a continued transition from production to bioerosion-controlled budget states, which will increasingly threaten reef growth, is predicted.

Dynamics of carbonate sediment production by Halimeda: implications for reef carbonate budgets

2020 ◽  
Vol 639 ◽  
pp. 91-106
Author(s):  
C Castro-Sanguino ◽  
YM Bozec ◽  
PJ Mumby
Keyword(s):  
Major Contributor ◽  
Indirect Pathway ◽  
Carbonate Sediment ◽  
Carbonate Production ◽  
Sediment Production ◽  
Carbonate Budget ◽  
Shoreline Protection ◽  
Fish Herbivory ◽  
Manipulative Experiments ◽  
Gains And Losses

Reef carbonate production and sediment generation are key processes for coral reef development and shoreline protection. The calcified green alga Halimeda is a major contributor of calcareous sediments, but rates of production and herbivory upon Halimeda are driven by biotic and environmental factors. Consequently, estimating rates of calcium carbonate (CaCO3) production and transformation into sediment requires the integration of Halimeda gains and losses across habitats and seasons, which is rarely considered in carbonate budgets. Using seasonal rates of recruitment, growth, senescence and herbivory derived from observations and manipulative experiments, we developed an individual-based model to quantify the annual cycle of Halimeda carbonate and sediment production at Heron Island, Great Barrier Reef. Halimeda population dynamics were simulated both within and outside branching Acropora canopies, which provide refuge from herbivory. Shelter from herbivory allowed larger Halimeda thalli to grow, leading to higher rates of carbonate accumulation (3.9 and 0.9 kg CaCO3 m-2 yr-1 within and outside Acropora canopies, respectively) and sediment production (2.5 versus 1.0 kg CaCO3 m-2 yr-1, respectively). Overall, 37% of the annual carbonate production was transformed into sediments through senescence (84%) and fish herbivory (16%), with important variations among seasons and habitats. Our model underlines that algal rates of carbonate production are likely to be underestimated if herbivory is not integrated into the carbonate budget, and reveals an important indirect pathway by which structurally complex coral habitats contribute to reef carbonate budgets, suggesting that coral losses due to climate change may lead to further declines in reef sediment production.

scholarly journals Carbon mineralization and carbonate preservation in modern cold-water coral reef sediments on the Norwegian shelf

2008 ◽  
Vol 5 (6) ◽  
pp. 4945-4992
Author(s):  
L. M. Wehrmann ◽  
N. J. Knab ◽  
H. Pirlet ◽  
V. Unnithan ◽  
C. Wild ◽  
...  
Keyword(s):  
Coral Reefs ◽  
Sulfate Reduction ◽  
Pore Water ◽  
Iron Reduction ◽  
Cold Water ◽  
Carbon Mineralization ◽  
Reduction Rate ◽  
Carbonate Production ◽  
The Impact ◽  
Water Coral

Abstract. Cold-water coral ecosystems are considered hot-spots of biodiversity and biomass production and may be a regionally important contributor to carbonate production. The impact of these ecosystems on biogeochemical processes and carbonate preservation in associated sediments were studied at Røst Reef and Traenadjupet Reef, two modern (post-glacial) cold-water coral reefs on the Mid-Norwegian shelf. Sulfate and iron reduction as well as carbonate dissolution and precipitation were investigated by combining pore-water geochemical profiles, steady state modeling, as well as solid phase analyses and sulfate reduction rate measurements on gravity cores of up to 3.2 m length. Low extents of sulfate depletion and dissolved inorganic carbon (DIC) production, combined with sulfate reduction rates not exceeding 3 nmolS cm−3 d−1, suggested that overall anaerobic carbon mineralization in the sediments was low. These data showed that the coral fragment-bearing siliciclastic sediments were effectively decoupled from the productive pelagic ecosystem by the complex reef surface framework. Organic matter being mineralized by sulfate reduction was calculated to consist of 57% carbon bound in –CH2O– groups and 43% carbon in –CH2– groups. Methane concentrations were below 1 μM, and failed to support the hypothesis of a linkage between the distribution of cold-water coral reefs and the presence of hydrocarbon seepage. Iron reduction linked to microbial sulfate reduction buffered the pore-water carbonate system and inhibited acid driven coral skeleton dissolution. A large pool of reactive iron was available leading to the formation of iron sulfide minerals. Constant pore-water Ca2+, Mg2+ and Sr2+ concentrations in most cores and decreasing Ca2+ and Sr2+ concentrations with depth in core 23-18 GC indicated diagenetic carbonate precipitation. This was consistent with the excellent preservation of buried coral fragments.

scholarly journals Two decades of carbonate budget change on shifted coral reef assemblages: are these reefs being locked into low net budget states?

2020 ◽  
Vol 287 (1940) ◽  
pp. 20202305
Author(s):  
Ana Molina-Hernández ◽  
F. Javier González-Barrios ◽  
Chris T. Perry ◽  
Lorenzo Álvarez-Filip
Keyword(s):  
Coral Reefs ◽  
Short Term ◽  
Ecological Processes ◽  
Size Frequency Distribution ◽  
Carbonate Production ◽  
The Past ◽  
Carbonate Budget ◽  
Ecological Changes ◽  
Reef Recovery ◽  
Coral Carbonate

The ecology of coral reefs is rapidly shifting from historical baselines. One key-question is whether under these new, less favourable ecological conditions, coral reefs will be able to sustain key geo-ecological processes such as the capacity to accumulate carbonate structure. Here, we use data from 34 Caribbean reef sites to examine how the carbonate production, net erosion and net carbonate budgets, as well as the organisms underlying these processes, have changed over the past 15 years in the absence of further severe acute disturbances. We find that despite fundamental benthic ecological changes, these ecologically shifted coral assemblages have exhibited a modest but significant increase in their net carbonate budgets over the past 15 years. However, contrary to expectations this trend was driven by a decrease in erosion pressure, largely resulting from changes in the abundance and size-frequency distribution of parrotfishes, and not by an increase in rates of coral carbonate production. Although in the short term, the carbonate budgets seem to have benefitted marginally from reduced parrotfish erosion, the absence of these key substrate grazers, particularly of larger individuals, is unlikely to be conducive to reef recovery and will thus probably lock these reefs into low budget states.

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