Carbonate-Sediment Production by Parrot Fish and Sea Urchins on Caribbean Reefs1

1977 ◽  
pp. 281-288 ◽  
Keyword(s):  
Sea Urchins ◽  
Carbonate Sediment ◽  
Sediment Production ◽  
Parrot Fish

A comparative analysis of the organic and inorganic carbon content of Halimeda and Penicillus (Chlorophyta, Bryopsidales) in a coastal subtropical lagoon

2019 ◽  
Vol 62 (4) ◽  
pp. 323-326
Author(s):  
Danielle Catherine Hatt ◽  
Ligia Collado-Vides
Keyword(s):  
Coastal Waters ◽  
Inorganic Carbon ◽  
Carbonate Sediment ◽  
Term Study ◽  
Sediment Production ◽  
Long Term Study ◽  
Organic And Inorganic Carbon ◽  
Maximum Contribution ◽  
Subtropical Lagoon

Abstract Standing stocks of the calcifying algae, Halimeda and Penicillus, have remained stable over the 10 years surveyed (2007–2017) in Florida Bay (USA), a subtropical lagoon. The maximum contribution of calcium carbonate (CaCO3; 779.75 g m−2) was lower compared to tropical lagoons. Halimeda was more abundant and had higher inorganic:organic carbon ratios compared to Penicillus. The abundance of Penicillus varied across the surveyed sites, Sprigger Bank, Bob Allen Keys, and Duck Key, while its inorganic:organic carbon ratios did not vary significantly. Our long-term study provides a critical baseline that can help understand fluctuations in carbonate sediment production by calcareous algae in subtropical coastal waters.

scholarly journals From platform top to adjacent deep sea: New source-to-sink insights into carbonate sediment production and transfer in the SW Indian Ocean (Glorieuses archipelago)

2020 ◽  
Vol 423 ◽  
pp. 106144
Author(s):  
Stéphan J. Jorry ◽  
Gwenael Jouet ◽  
Evan N. Edinger ◽  
Samuel Toucanne ◽  
John W. Counts ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Deep Sea ◽  
Carbonate Sediment ◽  
Sediment Production ◽  
Source To Sink ◽  
Sw Indian Ocean

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 CO2 released by carbonate sediment production in some coastal areas may offset the benefits of seagrass “Blue Carbon” storage

2017 ◽  
Vol 63 (1) ◽  
pp. 160-172 ◽  
Author(s):  
Jason L. Howard ◽  
Joel C. Creed ◽  
Mariana V. P. Aguiar ◽  
James W. Fourqurean
Keyword(s):  
Carbon Storage ◽  
Coastal Areas ◽  
Blue Carbon ◽  
Carbonate Sediment ◽  
Sediment Production

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

Fate of sperm membrane in fertilized ova

1993 ◽  
Vol 51 ◽  
pp. 40-41
Author(s):  
Frank J. Longo
Keyword(s):  
Electron Microscopy ◽  
Electrical Activity ◽  
Sea Urchins ◽  
Morphological Changes ◽  
Integrated System ◽  
Electrophysiological Recording ◽  
Experimental Conditions ◽  
The Status ◽  
Sperm Membrane ◽  
Temporal And Spatial

Measurement of the egg's electrical activity, the fertilization potential or the activation current (in voltage clamped eggs), provides a means of detecting the earliest perceivable response of the egg to the fertilizing sperm. By using the electrical physiological record as a “real time” indicator of the instant of electrical continuity between the gametes, eggs can be inseminated with sperm at lower, more physiological densities, thereby assuring that only one sperm interacts with the egg. Integrating techniques of intracellular electrophysiological recording, video-imaging, and electron microscopy, we are able to identify the fertilizing sperm precisely and correlate the status of gamete organelles with the first indication (fertilization potential/activation current) of the egg's response to the attached sperm. Hence, this integrated system provides improved temporal and spatial resolution of morphological changes at the site of gamete interaction, under a variety of experimental conditions. Using these integrated techniques, we have investigated when sperm-egg plasma membrane fusion occurs in sea urchins with respect to the onset of the egg's change in electrical activity.

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