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 Effects of terrestrial runoff on the coral communities in Santiago Bay, Colima, Mexican Pacific Coast

2016 ◽  
Vol 64 (3) ◽  
Author(s):  
Marco Agustín Liñán-Cabello ◽  
Aramis Olivos-Ortiz ◽  
Sonia Quijano-Scheggia ◽  
Daniela Muñiz Anguiano ◽  
María Luisa Reséndiz-Flores ◽  
...  
Keyword(s):  
Coral Reef ◽  
Pacific Coast ◽  
Geographical Location ◽  
Coral Community ◽  
Negative Effects ◽  
Mexican Pacific ◽  
The Status ◽  
Coral Communities ◽  
Coral Reef Ecosystems ◽  
Coral Health

Coral reef ecosystems are under stress of different origins, from factors including sedimentation, fragmentation, overfishing, and tourism, depending on their geographical location, depth, and proximity to recreation areas. In this study of Juluapan Lagoon, we examined the relationship between various water-quality attributes and the status indicators of the coral community at La Boquita reef. During 2011 (12 months of sampling), six monitoring stations in the Juluapan lagoon were established in order to observe the gradient of the distribution of the physicochemical parameters: three stations on the upper part, or BI, (S4 to S6) and three more in the lower part, or BII, (S1 to S3). A control station (CS) was located in the coral reef close to the lagoon channel, and where dissolved inorganic nutrients and cellular carbon content were determined. Additionally, we considered the monitoring of three of the eight largest coral structures/headlands of this community: the first was the station closest to the channel communicating with Juluapan lagoon (C1), the second was in the intermediate region with respect to that lagoon (C2), and the third was farthest from the channel (C3). Three line intercept transects (LIT) 30 m in length and perpendicular to the coast provenance were established in each station, and the parameters indicative of the status of corals were evaluated in an area of 60 m2 on each transect (180 m2 by the station). Turbidity, evidence of fishing, signs of settling, algal coverage, abundance of fish, rate of sediment, and coral health records (as for CoralWach chart) were determined in situ and from digital photographs and videos. Considering various community status indicators used in the reef area, we could recognize a state of general deterioration, which was reflected in the loss of 17 % of coral coverage. The main anthropogenic disturbances in adjacent areas to La Boquita reef included wastewater discharges into the lagoon, tourist developments in the coastal zone, deforestation and erosion resulting from inappropriate development, and the runoff of nutrients from agricultural lands nearby the lagoon. All these significantly contributed to the nutrient-enriched waters of the lagoon, especially in summer, with negative effects on the coral community. Continued exposure to these factors, coupled with the lack of control over other anthropogenic components, has promoted the maintenance of a chronic stress state in the studied coral community. Our findings highlight the need for the development of appropriate coastal management and conservation policies for the coral reefs of the Mexican Pacific Coast.

scholarly journals The Probability of an Unrecoverable Coral Community in Dongsha Atoll Marine National Park Due to Recurrent Disturbances

2020 ◽  
Vol 12 (21) ◽  
pp. 9052
Author(s):  
Yu-Rong Cheng ◽  
Chi-Hsiang Chin ◽  
Ding-Fa Lin ◽  
Chao-Kang Wang
Keyword(s):  
Coral Reef ◽  
National Park ◽  
Anthropogenic Impacts ◽  
Sustainable Use ◽  
Coral Community ◽  
Functional Ecology ◽  
The Past ◽  
Coral Communities ◽  
Coral Reef Ecosystems ◽  
Dongsha Atoll

In recent decades, coral reefs worldwide have been impacted annually by climate change and anthropogenic impacts. Marine parks are utilized to protect coral reef ecosystems and to ensure it is in sustainable use. In the present study, a 15-year change in coverage and composition of a hard coral community at Dongsha Atoll Marine National Park (DAMNP) was examined from 2005 to 2019. The reef has experienced several disturbances, including 11 typhoons and six coral bleaching events. A 34.39% decline in coral coverage had been recorded over the past 15 years in response to multiple and recurrent natural disturbances. The coral communities and functional ecology of the Dongsha Atoll changed during this period. The average dissimilarities in coral communities ranged from 55.38 to 59.02%. The dramatic decrease in the abundance of branching corals in addition to a slight increase in massive and encrusting corals suggest the habitat has simplified. The degraded coral reef communities represent a low resilience ecosystem, even though the DAMNP has been established. Without effective management, the coral reef ecosystem of the Dongsha Atoll may not persist due to repeated impacts from recurrent disturbances.

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 Ocean acidification accelerates dissolution of experimental coral reef communities

2015 ◽  
Vol 12 (2) ◽  
pp. 365-372 ◽  
Author(s):  
S. Comeau ◽  
R. C. Carpenter ◽  
C. A. Lantz ◽  
P. J. Edmunds
Keyword(s):  
Coral Reef ◽  
Ocean Acidification ◽  
Benthic Communities ◽  
French Polynesia ◽  
High Pco2 ◽  
Back Reef ◽  
Percentage Cover ◽  
Tropical Coral ◽  
Reef Communities ◽  
Coral Reef Communities

Abstract. Ocean acidification (OA) poses a severe threat to tropical coral reefs, yet much of what is know about these effects comes from individual corals and algae incubated in isolation under high pCO2. Studies of similar effects on coral reef communities are scarce. To investigate the response of coral reef communities to OA, we used large outdoor flumes in which communities composed of calcified algae, corals, and sediment were combined to match the percentage cover of benthic communities in the shallow back reef of Moorea, French Polynesia. Reef communities in the flumes were exposed to ambient (~ 400 μatm) and high pCO2 (~ 1300 μatm) for 8 weeks, and calcification rates measured for the constructed communities including the sediments. Community calcification was reduced by 59% under high pCO2, with sediment dissolution explaining ~ 50% of this decrease; net calcification of corals and calcified algae remained positive but was reduced by 29% under elevated pCO2. These results show that, despite the capacity of coral reef calcifiers to maintain positive net accretion of calcium carbonate under OA conditions, reef communities might transition to net dissolution as pCO2 increases, particularly at night, due to enhanced sediment dissolution.

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 Rapid multi-generational acclimation of coralline algal reproductive structures to ocean acidification

2021 ◽  
Vol 288 (1950) ◽  
Author(s):  
B. Moore ◽  
S. Comeau ◽  
M. Bekaert ◽  
A. Cossais ◽  
A. Purdy ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Growth Rates ◽  
Natural Habitat ◽  
Algal Growth ◽  
Coralline Algae ◽  
Reproductive Structures ◽  
Highly Sensitive ◽  
Negative Effect ◽  
Coral Reef Ecosystems

The future of coral reef ecosystems is under threat because vital reef-accreting species such as coralline algae are highly susceptible to ocean acidification. Although ocean acidification is known to reduce coralline algal growth rates, its direct effects on the development of coralline algal reproductive structures (conceptacles) is largely unknown. Furthermore, the long-term, multi-generational response of coralline algae to ocean acidification is extremely understudied. Here, we investigate how mean pH, pH variability and the pH regime experienced in their natural habitat affect coralline algal conceptacle abundance and size across six generations of exposure. We show that second-generation coralline algae exposed to ocean acidification treatments had conceptacle abundances 60% lower than those kept in present-day conditions, suggesting that conceptacle development is initially highly sensitive to ocean acidification. However, this negative effect of ocean acidification on conceptacle abundance disappears after three generations of exposure. Moreover, we show that this transgenerational acclimation of conceptacle development is not facilitated by a trade-off with reduced investment in growth, as higher conceptacle abundances are associated with crusts with faster growth rates. These results indicate that the potential reproductive output of coralline algae may be sustained under future ocean acidification.

scholarly journals Forever young... Colonization pattern of epibionts on Posidonia oceanica artificial leaves in relation to ocean acidification

2015 ◽  
Author(s):  
Maria Cristina Gambi ◽  
Emanuela Di Meglio ◽  
Luigia Donnarumma
Keyword(s):  
Ocean Acidification ◽  
Posidonia Oceanica ◽  
Progressive Increase ◽  
Low Ph ◽  
Coralline Algae ◽  
Short Exposure ◽  
Marine Biota ◽  
Short Exposure Time ◽  
Colonization Pattern ◽  
Ph Conditions

Ocean acidification (OA) is today considered one of the most pervasive stressors for marine biota at the level of species, communities and ecosystems. Naturally acidified systems, such as the CO2 vents, represent suitable laboratories to study the effects of OA on benthic organisms. An analysis of the colonization pattern of epibionts settled on artificial leaves (mimics) of Posidonia oceanica in relation to ocean acidification at the shallow CO2 vents off the island of Ischia, is here presented. Mimics of Posidonia oceanica artificial leaves (dark green flexible PVC stripes 1 cm wide x 36 cm long) were placed from September 2009 to September 2010 along a gradient of OA of the Ischia vent’s system at six stations (3 on the south and 3 on the north side of the study area), located at extreme low pH (mean pH 7.5), low pH (7.8), and control, normal pH conditions (8.12). Six artificial leaves per station were collected every three months and analysed for taxa identification and estimates of coverage (algae and sessile clonal invertebrates) and number of individuals (not clonal taxa). Patterns of colonization in control stations showed a progressive increase in time in coverage values of many organisms, mainly calcifying forms as coralline algae, which represent the dominant taxon, spirorbids and bryozoans. Colonization of artificial leaves located in low pH stations followed a similar temporal pattern as control conditions, but with lower coverage and higher patchiness of calcareous forms at 12 months of colonization. Epibionts in extreme low pH conditions were dominated by filamentous green/brown algae, with the occurrence of a few coralline algae, spirorbids and bryozoans, especially in the early months of colonization (3 and 6 months). Colonization at 9 and 12 months showed the disappearance of even these rare calcareous organisms and occurrence only of filamentous turf and fleshy algae, with a very simplified epibiont assemblage, remaining at an early, young colonization stage. These results indicate a strong selection of calcareous forms and the lack of successional stages in extreme low pH conditions, while the few calcifiers settled at short exposure time (3-6 months) do not seem to survive at longer exposure to critical values of OA.

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 Ecological Aspects of the Distribution of Reef Corals in the Netherlands Antilles

1975 ◽  
Vol 45 (2) ◽  
pp. 181-190 ◽  
Author(s):  
Rolf P. M. Bak
Keyword(s):  
Coral Reef ◽  
Growth Form ◽  
Coral Species ◽  
Water Movement ◽  
General Pattern ◽  
Coral Community ◽  
Salinity Range ◽  
Acropora Palmata ◽  
Deep Reef ◽  
Coral Communities

The vertical and horizontal patterns of the distribution of corals and coral reefs (to a depth of 90 m) are discussed in relation to the environmental factors: geomorphology of the bottom, available substrate, light, turbidity, sedimentation, water movement and temperature. There is a general pattern which is comparable to other well-developed Caribbean reefs. However, as in other areas variations are found, e.g. the depth and growth form of Acropora palmata will depend on the degree of exposure to water movement. There are strong correlations between the environmental variables and the occurrence of coral species and their growth form, the species composition of coral communities and the character of the coral reef. In some cases the relationship is not that obvious. The absence of Agaricia species at certain points along the coast of Aruba and the dominance of Sargassum on the deep bottom at some places along the windward coast of Curaçao is not yet explained. The relative importance of the different factors in an environmental setting is shown by a comparison of reef communities and reef habitats with a coral community of a muddy, shallow inland bay. The community of the bay consists, apart from the hardier coral species, of corals which are characteristic of the deep reef: Scolymia lacera, S. cubensis and Helioseris cucullata. These corals are adapted to sedimentation and low light intensities and are apparently able to withstand a temperature and salinity range much broader than that of their deep reef habitat. The paucity of corals and coral reef development around the islands of the Windward Group (deeper habitat included) can generally be explained by the morphology of the sea floor, the lack of suitable substrate and the effect of hurricanes. The exposed coasts of Saba and St. Eustatius, being virtually unexplored, may have richer coral growth. A new list of species of the Scleractinia of the Leeward and Windward groups, consisting of 57 species, is included.

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