scholarly journals Seasonal shifts in the competitive ability of macroalgae influence the outcomes of coral–algal competition

2020 ◽  
Vol 7 (12) ◽  
pp. 201797
Author(s):  
Kristen T. Brown ◽  
Dorothea Bender-Champ ◽  
Ove Hoegh-Guldberg ◽  
Sophie Dove
Keyword(s):  
Coral Reef ◽  
Competitive Ability ◽  
Benthic Communities ◽  
Coralline Algae ◽  
Crustose Coralline Algae ◽  
Chemical Mechanisms ◽  
Chemical Defences ◽  
Natural Processes ◽  
Coral Reef Ecosystems ◽  
Algal Competition

Understanding the effects of natural processes on coral–algal competition is an important step in identifying the role of macroalgae in perturbed coral reef ecosystems. However, studies investigating coral–algal interactions are often conducted in response to a disturbance, and rarely incorporate seasonal variability. Here, naturally occurring coral–algal interactions were assessed in situ four times a year over 2 years across eight sites spanning diverse benthic communities. In over 6500 recorded coral–algal interactions, cyanobacteria and turf algae were found to be the most damaging regardless of season, resulting in visible damage to coral in greater than 95% of interactions. Macroalgae that primarily compete using chemical mechanisms were found to be more damaging than those that compete using physical mechanisms (e.g. abrasion), with both groups demonstrating decreased competitive ability in summer. While crustose coralline algae were the least damaging to competing coral, during summer, it became three times more competitive. Our results demonstrate that the competitive ability of macroalgae and the outcomes of coral–algal competition can fluctuate in seasonal cycles that may be related to biomass, production of chemical defences and/or physical toughness. The results of this study have important implications for understanding the trajectory and resilience of coral reef ecosystems into the future.

scholarly journals Changes in coral reef communities across a natural gradient in seawater pH

2015 ◽  
Vol 1 (5) ◽  
pp. e1500328 ◽  
Author(s):  
Hannah C. Barkley ◽  
Anne L. Cohen ◽  
Yimnang Golbuu ◽  
Victoria R. Starczak ◽  
Thomas M. DeCarlo ◽  
...  
Keyword(s):  
Coral Reef ◽  
Ocean Acidification ◽  
Benthic Communities ◽  
Coral Community ◽  
Low Ph ◽  
Coralline Algae ◽  
Negative Effects ◽  
Skeletal Density ◽  
Coral Communities ◽  
Coral Reef Ecosystems

Ocean acidification threatens the survival of coral reef ecosystems worldwide. The negative effects of ocean acidification observed in many laboratory experiments have been seen in studies of naturally low-pH reefs, with little evidence to date for adaptation. Recently, we reported initial data suggesting that low-pH coral communities of the Palau Rock Islands appear healthy despite the extreme conditions in which they live. Here, we build on that observation with a comprehensive statistical analysis of benthic communities across Palau’s natural acidification gradient. Our analysis revealed a shift in coral community composition but no impact of acidification on coral richness, coralline algae abundance, macroalgae cover, coral calcification, or skeletal density. However, coral bioerosion increased 11-fold as pH decreased from the barrier reefs to the Rock Island bays. Indeed, a comparison of the naturally low-pH coral reef systems studied so far revealed increased bioerosion to be the only consistent feature among them, as responses varied across other indices of ecosystem health. Our results imply that whereas community responses may vary, escalation of coral reef bioerosion and acceleration of a shift from net accreting to net eroding reef structures will likely be a global signature of ocean acidification.

scholarly journals Community assessment of crustose calcifying red algae as coral recruitment substrates

2021 ◽  
Author(s):  
Mari E. Deinhart ◽  
Matthew S. Mills ◽  
Tom Schils
Keyword(s):  
Dna Sequences ◽  
Red Algae ◽  
Taxonomic Diversity ◽  
Coralline Algae ◽  
Crustose Coralline Algae ◽  
Coral Recruitment ◽  
Successful Recruitment ◽  
Ecological Roles ◽  
Coral Reef Ecosystems ◽  
Species Specific

AbstractSuccessful recruitment of invertebrate larvae to reef substrates is essential to the health of tropical coral reef ecosystems and their capacity to recover from disturbances. Crustose calcifying red algae (CCRA) have been identified as important recruitment substrates for scleractinian corals. As such, CCRA as a whole or subgroups (e.g., crustose coralline algae, CCA) are often used at the functional group level in experimental, ecological, and monitoring studies. Species of CCRA, however, differ in their ecological roles and their value as coral recruitment substrates. Here, we (1) investigate the species richness and community composition of CCRA on experimental coral recruitment tiles, and (2) assess if there is a recruitment preference of the coral Acropora surculosa for any of these CCRA species. 27 species of two orders of CCRA (Corallinales and Peyssonneliales) were identified from the recruit tiles. None of the DNA sequences of these species matched released sequences in GenBank or sequences of CCRA collected from natural reef systems in Guam. The similarity in CCRA communities between the recruitment tiles was high. Two species of CCRA were significantly preferred as recruitment substrates over the other CCRA species. Both of these species belonged to the subfamily of the Lithophylloideae. These two species are closely related to Pacific species that have been referred to as Titanoderma -but probably have to be assigned to another genus- and many of the latter have been attributed to be preferred coral recruitment substrates. Of all CCRA, Lithophylloideae sp. 1 had the highest benthic cover on the recruitment tiles and was the most preferred recruitment substrate. These findings highlight the high taxonomic diversity of CCRA communities and provide insight into species-specific ecological roles of CCRA that are often overlooked.

Recent density decline in wild-collected subarctic crustose coralline algae reveals climate change signature

Geology ◽  
2019 ◽  
Vol 48 (3) ◽  
pp. 226-230 ◽  
Author(s):  
P.T.W. Chan ◽  
J. Halfar ◽  
W.H. Adey ◽  
P.A. Lebednik ◽  
R. Steneck ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Benthic Communities ◽  
Crustose Coralline Alga ◽  
Coralline Algae ◽  
Co2 Uptake ◽  
Strong Correlations ◽  
Crustose Coralline Algae ◽  
Skeletal Density ◽  
Surface Ocean

Abstract Warming surface ocean temperatures combined with the continued diffusion of atmospheric CO2 into seawater have been shown to have detrimental impacts on calcareous marine organisms in tropical and temperate localities. However, greater oceanic CO2 uptake in higher latitudes may present a higher oceanic acidification risk to carbonate organisms residing in Arctic and subarctic habitats. This is especially true for crustose coralline algae that build their skeletons using high-Mg calcite, which is among the least stable and most soluble of the carbonate minerals. Here we present a century-long annually resolved growth, density, and calcification rate record from the crustose coralline alga Clathromorphum nereostratum, a dominant calcifier in Pacific Arctic and subarctic benthic communities. Specimens were collected from the Aleutian Islands, Alaska (USA), a region that has undergone a long-term decline of 0.08 ± 0.01 pH units since the late 19th century. Growth and calcification rates remain relatively stable throughout the record, but skeletal densities have declined substantially since A.D. 1983. Strong correlations to warming sea-surface temperatures indicate that temperature stress may play a significant role in influencing the ability of corallines to calcify. Decreasing algal skeletal density may offset the benefits of continued growth and calcification due to a weakening in structural integrity, which could have detrimental consequences for the diverse reef-like communities associated with algal structures in mid-to-high latitudes.

scholarly journals Sponge community (Porifera) in coral reef ecosystem in Sabang, Aceh Province, Indonesia

2021 ◽  
Vol 22 (6) ◽  
Author(s):  
Elsa Dianita Aulia ◽  
Tri Aryono Hadi ◽  
Rizkie Satria Utama
Keyword(s):  
Coral Reef ◽  
Benthic Communities ◽  
Stable State ◽  
Morphological Characters ◽  
Coral Reef Ecosystem ◽  
Significant Relationships ◽  
Lack Of Information ◽  
Aceh Province ◽  
Coral Reef Ecosystems ◽  
Reef Ecosystem

Abstract. Aulia ED, Hadi TA, Utama RS. 2021. Sponge community (Porifera) in coral reef ecosystem in Sabang, Aceh Province, Indonesia. Biodiversitas 22: 3394-3402. Sponges are one of the most influential benthic organisms in coral reef ecosystems. Many studies about sponge communities have been carried out globally, from tropical to temperate regions. In Indonesia, however, sponge communities have not been adequately observed, especially their diversity and interaction with habitats. Sabang, a developing city located in the northwest of Indonesia, has a lack of information about benthic communities and no reports about sponges. This study investigated the sponge community (species richness, coverage, and morphological characters) and the interactions, both within sponges and with corals and substrates, in Sabang. The study found that the sponge richness (species and morphology) and coverage are categorized as poor, having only 24 species with seven morphologies, and coverage of 1.79 ± 1.03% (SE). The interaction analyses showed significant relationships occur among sponge variables but not between sponges and corals, nor between sponges and their substrates. These results could be attributed to the hydrodynamic-related stresses in Sabang, which are likely influenced by exposure to the open ocean, a condition that is less favorable to diversity and interaction. It is necessary to regularly monitor the condition of benthic communities in Sabang in order to better understand their stable state and detect any change over time.

scholarly journals Facultative scavenging feeding habits in Acanthurus chirurgus (Bloch, 1787) (Acanthuriformes: Acanthuridae)

2020 ◽  
Vol 8 ◽  
Author(s):  
Benjamín Delgado-Pech ◽  
Antonio Almazán-Becerril ◽  
Jorge Peniche-Pérez ◽  
José Adán Caballero-Vázquez
Keyword(s):  
Coral Reef ◽  
Feeding Habits ◽  
Benthic Communities ◽  
Animal Tissues ◽  
The Past ◽  
Fish Flesh ◽  
Routine Monitoring ◽  
Mexican Caribbean ◽  
The Family ◽  
Coral Reef Ecosystems

The family Acanthuridae is a key component of coral reef ecosystems as it controls macroalgae biomass buildup. During routine monitoring of benthic communities in the Mexican Caribbean, we observed unusual behaviour of a group of Acanthurus chirurgus, which were feeding on a tuna head left on site by travel tour personnel. This phenomenon has been documented in other herbivorous fish species, especially in places where tourism is a major coastal activity. Although many Acanthurus seek additional sources of protein by feeding on detritus, it is unusual for them to feed directly on fish flesh. Acanthurus chirurgus will incorporate proteins from animal tissues whenever the opportunity arises. Such opportunities occurred rarely in the past, but have become more frequent recently, related to increasing tourism activities where flesh is used as bait to attract the surrounding fauna.

scholarly journals Re-evaluating the health of coral reef communities: baselines and evidence for human impacts across the central Pacific

2016 ◽  
Vol 283 (1822) ◽  
pp. 20151985 ◽  
Author(s):  
Jennifer E. Smith ◽  
Rusty Brainard ◽  
Amanda Carter ◽  
Saray Grillo ◽  
Clinton Edwards ◽  
...  
Keyword(s):  
Coral Reef ◽  
Human Impacts ◽  
Phase Shifts ◽  
Coralline Algae ◽  
Human Populations ◽  
Limited Information ◽  
Crustose Coralline Algae ◽  
Central Pacific ◽  
Reef Communities ◽  
Coral Reef Communities

Numerous studies have documented declines in the abundance of reef-building corals over the last several decades and in some but not all cases, phase shifts to dominance by macroalgae have occurred. These assessments, however, often ignore the remainder of the benthos and thus provide limited information on the present-day structure and function of coral reef communities. Here, using an unprecedentedly large dataset collected within the last 10 years across 56 islands spanning five archipelagos in the central Pacific, we examine how benthic reef communities differ in the presence and absence of human populations. Using islands as replicates, we examine whether benthic community structure is associated with human habitation within and among archipelagos and across latitude. While there was no evidence for coral to macroalgal phase shifts across our dataset we did find that the majority of reefs on inhabited islands were dominated by fleshy non-reef-building organisms (turf algae, fleshy macroalgae and non-calcifying invertebrates). By contrast, benthic communities from uninhabited islands were more variable but in general supported more calcifiers and active reef builders (stony corals and crustose coralline algae). Our results suggest that cumulative human impacts across the central Pacific may be causing a reduction in the abundance of reef builders resulting in island scale phase shifts to dominance by fleshy organisms.

scholarly journals DISTRIBUITION OF CRUSTOSE CORALLINE ALGAE (CORALLINALES, RHODOPHYTA) IN THE ABROLHOS REEFS, BAHIA, BRAZIL

Rodriguésia ◽  
2007 ◽  
Vol 58 (4) ◽  
pp. 941-947 ◽  
Author(s):  
Frederico Tapajós de Souza Tâmega ◽  
Marcia A. O. Figueiredo
Keyword(s):  
Coral Reef ◽  
Scuba Diving ◽  
Coralline Algae ◽  
Light Limitation ◽  
Filamentous Algae ◽  
Benthic Organisms ◽  
Growth Forms ◽  
Crustose Coralline Algae ◽  
Herbivore Pressure ◽  
Sessile Organisms

ABSTRACT The crustose coralline algae have an important structural role in coral reef crests, as observed for some Atlantic reefs. In this work the distribution and abundance of crustose coralline algae and their relation to other benthic reef organisms were described for the Abrolhos Archipelago. The quantification of sessile organisms was made by SCUBA diving along replicated transect lines in different habitats and sites. Anovas were performed to test differences on algae abundance among sites and habitats. Coralline crusts did not show significant differences on abundance among sites (Anova, p>0,05), neither other benthic organisms (Anovas, p=0,634 invertebrates, p=0,767 filamentous algae, p=0,581 foliose algae, p=0,070 leathery algae and p=0,616 non calcareous crusts). Invertebrates and filamentous algae were the most abundant organisms on all sites and most habitats, contrasting with the low cover of coralline algae. In sheltered sites and on reef base it was observed a trend for an increase of fleshy foliose algae and leathery algae, contrasting with wave exposed sites. The distribution of coralline growth forms was characterized by a higher abundance of flat in relation to branched thalli. Branched coralline crusts are apparently more abundant within cryptic reef areas, not necessarily because of light limitation, but probably due to less herbivore pressure.

scholarly journals Crustose Coralline Algae and a Cnidarian Neuropeptide Trigger Larval Settlement in Two Coral Reef Sponges

PLoS ONE ◽  
2012 ◽  
Vol 7 (1) ◽  
pp. e30386 ◽  
Author(s):  
Steve Whalan ◽  
Nicole S. Webster ◽  
Andrew P. Negri
Keyword(s):  
Coral Reef ◽  
Larval Settlement ◽  
Coralline Algae ◽  
Crustose Coralline Algae
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