Calcification does not necessarily protect articulated coralline algae from urchin grazing

Abstract. Coralline algae are important habitat formers found on all rocky shores. While the impact of future ocean acidification on the physiological performance of the species has been well studied, little research has focused on potential changes in structural integrity in response to climate change. A previous study using 2-D Finite Element Analysis (FEA) suggested increased vulnerability to fracture (by wave action or boring) in algae grown under high CO2 conditions. To assess how realistically 2-D simplified models represent structural performance, a series of increasingly biologically accurate 3-D FE models that represent different aspects of coralline algal growth were developed. Simplified geometric 3-D models of the genus Lithothamnion were compared to models created from computed tomography (CT) scan data of the same genus. The biologically accurate model and the simplified geometric model representing individual cells had similar average stresses and stress distributions, emphasising the importance of the cell walls in dissipating the stress throughout the structure. In contrast models without the accurate representation of the cell geometry resulted in larger stress and strain results. Our more complex 3-D model reiterated the potential of climate change to diminish the structural integrity of the organism. This suggests that under future environmental conditions the weakening of the coralline algal skeleton along with increased external pressures (wave and bioerosion) may negatively influence the ability for coralline algae to maintain a habitat able to sustain high levels of biodiversity.

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Bioerosion of reef-building crustose coralline algae by endolithic invertebrates in an upwelling-influenced reef

Coral Reefs ◽

10.1007/s00338-021-02065-2 ◽

2021 ◽

Author(s):

Alexandra Ramírez-Viaña ◽

Guillermo Diaz-Pulido ◽

Rocío García-Urueña

Keyword(s):

Coralline Algae ◽

Crustose Coralline Algae

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Coverage Increases of Porites astreoides in Grenada Determined by Shifts in Size-Frequency Distribution

Diversity ◽

10.3390/d13070288 ◽

2021 ◽

Vol 13 (7) ◽

pp. 288

Author(s):

Ryan G. Eagleson ◽

John S. Lumsden ◽

Lorenzo Álvarez-Filip ◽

Christophe M. Herbinger ◽

Ryan A. Horricks

Keyword(s):

Coral Community ◽

Scleractinian Corals ◽

Area Measurement ◽

Coralline Algae ◽

Measurement Tool ◽

Size Frequency Distribution ◽

Point Count ◽

Porites Astreoides ◽

The Mean ◽

The Caribbean

Despite coral community collapse, the mustard hill coral (Porites astreoides) is a species currently experiencing success throughout the Caribbean. The inshore reefs of Grenada were selected to study the influence of benthic factors on the abundance, size, and coverage of P. astreoides colonies. Surveys of reef communities along established 30 m transects were conducted at eight sites in 2014 and 2017 using a 0.5 m² quadrat. Coral Point Count was used to annotate the images, estimating the coverage of scleractinian corals, sponges, algae, and benthic substrates. Coverage, size, and abundance of P. astreoides colonies were quantified using the area measurement tool in ImageJ standardized against the quadrats. There were significant differences in benthic community assemblages between islands, selected sites, and between years. From 2014 to 2017 there was a significant decrease in the mean abundance of P. astreoides colonies and significant increases in mean colony size and coverage. The presence of P. astreoides colonies was significantly correlated with: rubble (−), sand (−); pavement (+); macroalgae (−); coralline algae (+); sponges (varying response); gorgonians (−); massive corals (+); and branching corals (−). P. astreoides follows similar recruitment patterns as other scleractinian corals. Observed changes in P. astreoides populations appear to indicate a recovery event following a disturbance, potentially tropical storm Chantal in 2013.

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Light Absorption in Coralline Algae (Rhodophyta): A Morphological and Functional Approach to Understanding Species Distribution in a Coral Reef Lagoon

Frontiers in Marine Science ◽

10.3389/fmars.2017.00297 ◽

2017 ◽

Vol 4 ◽

Cited By ~ 7

Author(s):

Román M. Vásquez-Elizondo ◽

Susana Enríquez

Keyword(s):

Coral Reef ◽

Species Distribution ◽

Light Absorption ◽

Functional Approach ◽

Coralline Algae ◽

Reef Lagoon ◽

Coral Reef Lagoon

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Experimental effects of kelp canopies on subtidal coralline algae

Austral Ecology ◽

10.1111/j.1442-9993.2001.01089.pp.x ◽

2001 ◽

Vol 26 (1) ◽

pp. 102-108 ◽

Cited By ~ 2

Author(s):

A. J. Melville ◽

S. D. Connell

Keyword(s):

Coralline Algae

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Growth Interruptions in Arctic Rhodoliths Correspond to Water Depth and Rhodolith Morphology

Minerals ◽

10.3390/min11050538 ◽

2021 ◽

Vol 11 (5) ◽

pp. 538

Author(s):

Moritz Schlüter ◽

Ines Pyko ◽

Max Wisshak ◽

Christian Schulbert ◽

Sebastian Teichert

Keyword(s):

Light Availability ◽

Growth Patterns ◽

Skeletal Growth ◽

Coralline Algae ◽

Ambient Light ◽

Micro Computed Tomography ◽

Svalbard Archipelago ◽

X Ray ◽

Algal Thalli ◽

Environmental Proxies

Coralline algae that form rhodoliths are widespread globally and their skeletal growth patterns have been used as (paleo-) environmental proxies in a variety of studies. However, growth interruptions (hiati) within their calcareous skeletons are regarded as problematic in this context. Here we investigated how hiati in the growth of Arctic rhodoliths from the Svalbard archipelago correspond to their environment and morphology. Using X-ray micro-computed tomography and stepwise model selections, we found that rhodoliths from deeper waters are subject to more frequent hiatus formation. In addition, rhodoliths with a higher sphericity (i.e., roundness) are less often affected by such growth interruptions. We conclude that these correlations are mainly regulated by hydrodynamics, because, in deeper waters, rhodoliths are not turned frequently enough to prevent a dieback of coralline algal thalli forming on the underside of the rhodolith. In this coherence, spheroidal rhodoliths are turned more easily, therefore shortening the amount of time between turnover events. Moreover, the incidence of light is more advantageous in shallower waters where rhodoliths exhibit a greater share of their surface to diffused ambient light, thus enabling thallus growth also on the down-facing surface of the rhodoliths. In consequence, information on the frequency of hiatus formation combined with rhodolith morphology might serve as a valuable proxy for (paleo-)environmental reconstructions in respect to light availability and the hydrodynamic regime.

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Two new species ofSyllis(Polychaeta: Syllidae) from South Africa, one of them viviparous, with remarks on larval development and vivipary

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315413001926 ◽

2014 ◽

Vol 94 (4) ◽

pp. 729-746 ◽

Cited By ~ 6

Author(s):

Carol Simon ◽

Guillermo San Martín ◽

Georgina Robinson

Keyword(s):

South Africa ◽

New Species ◽

South African ◽

The Other ◽

Coralline Algae ◽

Colour Pattern ◽

The Family ◽

Two New Species ◽

Haliotis Midae ◽

Characteristic Colour

Two new species of South African Syllidae of the genusSyllisLamarck, 1818 are described.Syllis unzimasp. nov. is characterized by having unidentate compound chaetae with long spines on margin, a characteristic colour pattern and its reproduction by vivipary. Vivipary is not common among the polychaetes, but most representatives occur in the family Syllidae Grube, 1850 (in five otherSyllisspecies, two species ofDentatisyllisPerkins, 1981 and two species ofParexogoneMesnil & Caullery, 1818).Syllis unzimasp. nov. differs from the other viviparous species in having large broods (>44 juveniles) which develop synchronously. Development of the juveniles is similar to that of free-spawningSyllisspecies, but the appearance of the first pair of eyespots and the differentiation of the pharynx and proventricle occur later inS. unzima.Syllis amicarmillarissp. nov., is characterized by having an elongated body with relatively short, fusiform dorsal cirri and the presence of one or two pseudosimple chaeta on midbody parapodia by loss of blade and enlargement of shaft.Syllis unzimasp. nov. was found in high densities on culturedHolothuria scabraJaeger, 1833 with single specimens found on a culturedCrassostrea gigasThunberg, 1793 and on coralline algae, respectively, whileS. amicarmillariswas found mainly in sediment outside an abalone farm and less frequently on culturedHaliotis midaeLinnaeus, 1758. We discuss the possible benefits of the association withH. scabratoS. unzimasp. nov.

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