Low growth resilience of subarctic rhodoliths (Lithothamnion glaciale) to coastal eutrophication

2020 ◽  
Vol 642 ◽  
pp. 117-132 ◽  
Author(s):  
D Bélanger ◽  
P Gagnon
Keyword(s):  
Renewable Resources ◽  
Prolonged Exposure ◽  
Slow Growth ◽  
Cold Water ◽  
Coralline Algae ◽  
Nutrient Concentrations ◽  
Crustose Coralline Algae ◽  
Coastal Marine ◽  
Coastal Marine Ecosystems

Eutrophication is one of the most important drivers of change in coastal marine ecosystems worldwide. Given their slow growth, rhodoliths and the biodiverse communities they support are regarded as non-renewable resources threatened by human activity. Consequences of nutrient enrichment on growth and calcification in crustose coralline algae are equivocal, and even more so in cold-water rhodoliths. We paired a 183 d laboratory mesocosm experiment with a 193 d field experiment on Newfoundland (Canada) rhodoliths (Lithothamnion glaciale) to test the hypothesis that nutrient (nitrate, ammonia, and phosphate) enrichment and biofouling reduce rhodolith growth. Rhodoliths in the laboratory were exposed to 1 of 3 nutrient concentrations (ambient, intermediate, or high) and either of 2 levels of manual cleaning (cleaned or uncleaned) to control biofouling. We exposed rhodoliths in the field to 1 of 2 nutrient concentrations (ambient or elevated). Eutrophication in the laboratory did not affect biofouling; however, manual cleaning reduced biofouling by ~4 times relative to uncleaned rhodoliths. Rhodoliths grew 2 times slower at elevated than ambient nutrient concentrations, and ~27% more in cleaned than uncleaned rhodoliths at all concentrations. Rhodoliths in the field also grew significantly slower under elevated than ambient phosphate concentrations, but only during the first 6 wk, indicating some capacity for long-term recovery. We conclude that despite some growth resilience to low and infrequent increases in nutrient concentrations, subarctic L. glaciale rhodoliths cannot cope with prolonged exposure to modest eutrophication.

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 Ocean acidification affects competition for space: projections of community structure using cellular automata

2016 ◽  
Vol 283 (1826) ◽  
pp. 20152561 ◽  
Author(s):  
Sophie J. McCoy ◽  
Stefano Allesina ◽  
Catherine A. Pfister
Keyword(s):  
Ocean Acidification ◽  
Competitive Interactions ◽  
Coralline Algae ◽  
Change Scenario ◽  
Crustose Coralline Algae ◽  
Field Surveys ◽  
Competition For Space ◽  
Coastal Marine ◽  
Ecological Changes

Historical ecological datasets from a coastal marine community of crustose coralline algae (CCA) enabled the documentation of ecological changes in this community over 30 years in the Northeast Pacific. Data on competitive interactions obtained from field surveys showed concordance between the 1980s and 2013, yet also revealed a reduction in how strongly species interact. Here, we extend these empirical findings with a cellular automaton model to forecast ecological dynamics. Our model suggests the emergence of a new dominant competitor in a global change scenario, with a reduced role of herbivory pressure, or trophic control, in regulating competition among CCA. Ocean acidification, due to its energetic demands, may now instead play this role in mediating competitive interactions and thereby promote species diversity within this guild.

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

Coral Reefs ◽  
2021 ◽  
Author(s):  
Alexandra Ramírez-Viaña ◽  
Guillermo Diaz-Pulido ◽  
Rocío García-Urueña
Keyword(s):  
Coralline Algae ◽  
Crustose Coralline Algae

scholarly journals Bacterial Communities and Enzymatic Activities in Sediments of Long-Term Fish and Crab Aquaculture Ponds

2021 ◽  
Vol 9 (3) ◽  
pp. 501
Author(s):  
Zhimin Zhang ◽  
Qinghui Deng ◽  
Lingling Wan ◽  
Xiuyun Cao ◽  
Yiyong Zhou ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Enzymatic Activities ◽  
Nutrient Concentrations ◽  
Biological Processes ◽  
Farming Practices ◽  
Mitten Crab ◽  
Aquaculture Ponds ◽  
Pond Sediments ◽  
Sediment Ph

Aquaculture is among the most important and fastest growing agriculture sectors worldwide; however, it generates environmental impacts by introducing nutrient accumulations in ponds, which are possibly different and further result in complex biological processes in the sediments based on diverse farming practices. In this study, we investigated the effects of long-term farming practices of representative aquatic animals dominated by grass carp (GC, Ctenopharyngodon idella) or Chinese mitten crab (CMC, Eriocheir sinensis) on the bacterial community and enzyme activity of sediments from more than 15 years of aquaculture ponds, and the differences associated with sediment properties were explored in the two farming practices. Compared to CMC ponds, GC ponds had lower contents of TC, TN, and TP in sediments, and similar trends for sediment pH and moisture content. Sediment bacterial communities were significantly different between GC and CMC ponds, with higher bacterial richness and diversity in GC ponds. The bacterial communities among the pond sediments were closely associated with sediment pH, TC, and TN. Additionally, the results showed profoundly lower activities of β-1,4-glucosidase, leucine aminopeptidase, and phosphatase in the sediments of GC ponds than CMC ponds. Pearson’s correlation analysis further revealed strong positive correlations between the hydrolytic enzyme activities and nutrient concentrations among the aquaculture ponds, indicating microbial enzyme regulation response to sediment nutrient dynamics. Our study herein reveals that farming practices of fish and crab differently affect bacterial communities and enzymatic activities in pond sediments, suggesting nutrient-driven sediment biological processes in aquaculture ponds for different farming practices.

scholarly journals Impact of Prolonged Exposure of Eleven Years to Hot Seawater on the Degradation of a Thermoset Composite

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2154
Author(s):  
Amir Hussain Idrisi ◽  
Abdel-Hamid I. Mourad ◽  
Muhammad M. Sherif
Keyword(s):  
Exposure Time ◽  
Prolonged Exposure ◽  
Mechanical Performance ◽  
Matrix Cracking ◽  
Pull Out ◽  
Strength Based ◽  
Different Temperatures ◽  
River Line ◽  
Composite Samples

This paper presents a long-term experimental investigation of E-glass/epoxy composites’ durability exposed to seawater at different temperatures. The thermoset composite samples were exposed to 23 °C, 45 °C and 65 °C seawater for a prolonged exposure time of 11 years. The mechanical performance as a function of exposure time was evaluated and a strength-based technique was used to assess the durability of the composites. The experimental results revealed that the tensile strength of E-glass/epoxy composite was reduced by 8.2%, 29.7%, and 54.4% after immersion in seawater for 11 years at 23 °C, 45 °C, and 65 °C, respectively. The prolonged immersion in seawater resulted in the plasticization and swelling in the composite. This accelerated the rate of debonding between the fibers and matrix. The failure analysis was conducted to investigate the failure mode of the samples. SEM micrographs illustrated a correlation between the fiber/matrix debonding, potholing, fiber pull-out, river line marks and matrix cracking with deterioration in the tensile characteristics of the thermoset composite.

scholarly journals Onset and Resolution of Key Adverse Events in Valbenazine-Treated Patients with Tardive Dyskinesia: Pooled Analyses from Two Long-Term Clinical Trials

CNS Spectrums ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 151-151
Author(s):  
Stephen R. Marder ◽  
Jean-Pierre Lindenmayer ◽  
Chirag Shah ◽  
Tara Carmack ◽  
Angel S. Angelov ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Adverse Events ◽  
Tardive Dyskinesia ◽  
Suicidal Behavior ◽  
Prolonged Exposure ◽  
First Occurrence ◽  
Balance Disorder ◽  
Clinical Interest ◽  
Post Hoc

AbstractObjectiveTardive dyskinesia (TD) is a persistent and potentially disabling movement disorder associated with prolonged exposure to antipsychotics and other dopamine receptor blocking agents. Long-term safety of the approved TD medication, valbenazine, was demonstrated in 2 clinical trials (KINECT 3 [NCT02274558], KINECT 4 [NCT02405091]). Data from these trials were analyzed post hoc to evaluate the onset and resolution of adverse events (AEs).MethodsParticipants in KINECT 3 and KINECT 4 received up to 48 weeks of once-daily valbenazine (40 or 80 mg). Data from these studies were pooled and analyzed to assess the incidence, time to first occurrence, and resolution for the following AEs of potential clinical interest: akathisia, balance disorder, dizziness, parkinsonism, somnolence/sedation, suicidal behavior/ideation, and tremor.ResultsIn the pooled population (N=314), all AEs of potential clinical interest occurred in <10% of participants, with somnolence (9.6%), suicidal behavior/ideation (6.4%), and dizziness (5.7%) being the most common AEs. Mean time to first occurrence ranged from 36 days (akathisia [n=9]) to 224 days (parkinsonism [n=2]). By end of study (or last study visit), resolution of AEs was as follows: 100% (suicidal ideation/behavior, parkinsonism); >85% (somnolence/sedation, dizziness); >70% (akathisia, balance disorder, tremor).ConclusionsIn long-term clinical trials, the incidence of AEs of potential clinical interest was low (<10%) and most were resolved by end of treatment (>70–100%). All patients taking valbenazine should be routinely monitored for AEs, particularly those that may exacerbate the motor symptoms associated with TD.FundingNeurocrine Biosciences, Inc.

Synergistic effects of diuron and sedimentation on photosynthesis and survival of crustose coralline algae

2005 ◽  
Vol 51 (1-4) ◽  
pp. 415-427 ◽  
Author(s):  
Lindsay Harrington ◽  
Katharina Fabricius ◽  
Geoff Eaglesham ◽  
Andrew Negri
Keyword(s):  
Synergistic Effects ◽  
Coralline Algae ◽  
Crustose Coralline Algae

Nutrient cycling differs between cropped soils with century-old and recently pyrolyzed biochar

2021 ◽  
Author(s):  
Victor Burgeon ◽  
Julien Fouché ◽  
Sarah Garré ◽  
Ramin Heidarian-Dehkordi ◽  
Gilles Colinet ◽  
...  
Keyword(s):  
Nutrient Cycling ◽  
Soil Solution ◽  
Nutrient Dynamics ◽  
Chemical Properties ◽  
Crop Productivity ◽  
Nutrient Concentrations ◽  
Soil Productivity ◽  
Long Term Effects ◽  
Mitigation And Adaptation

&lt;p&gt;The amendment of biochar to soils is often considered for its potential as a climate change mitigation and adaptation tool through agriculture. Its presence in tropical agroecosystems has been reported to positively impact soil productivity whilst successfully storing C on the short&amp;#8201;and long-term. In temperate systems, recent research showed limited to no effect on productivity following recent biochar addition to soils. Its long-term effects on productivity and nutrient cycling have, however, been overlooked yet are essential before the use of biochar can be generalized.&lt;/p&gt;&lt;p&gt;Our study was set up in a conventionally cropped field, containing relict charcoal kiln sites used as a model for century old biochar (CoBC, ~220 years old). These sites were compared to soils amended with recently pyrolyzed biochar (YBC) and biochar free soils (REF) to study nutrient dynamics in the soil-water-plant system. Our research focused on soil chemical properties, crop nutrient uptake and soil solution nutrient concentrations. Crop plant samples were collected over three consecutive land occupations (chicory, winter wheat and a cover crop) and soil solutions gathered through the use of suctions cups inserted in different horizons of the studied Luvisol throughout the field.&lt;/p&gt;&lt;p&gt;Our results showed that YBC mainly influenced the soil solution composition whereas CoBC mainly impacted the total and plant available soil nutrient content. In soils with YBC, our results showed lower nitrate and potassium concentrations in subsoil horizons, suggesting a decreased leaching, and higher phosphate concentrations in topsoil horizons. With time and the oxidation of biochar particles, our results reported higher total soil N, available K and Ca in the topsoil horizon when compared to REF, whereas available P was significantly smaller. Although significant changes occurred in terms of plant available nutrient contents and soil solution nutrient concentrations, this did not transcend in variations in crop productivity between soils for neither of the studied crops. Overall, our study highlights that young or aged biochar behave as two distinct products in terms of nutrient cycling in soils. As such the sustainability of these soils differ and their management must therefore evolve with time.&lt;/p&gt;

Effect of 3D printer enabled surface morphology and composition on coral growth in artificial reefs

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ilse Valenzuela Matus ◽  
Jorge Lino Alves ◽  
Joaquim Góis ◽  
Augusto Barata da Rocha ◽  
Rui Neto ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Chemical Composition ◽  
Chemical Elements ◽  
Three Dimensional ◽  
Coral Growth ◽  
Coralline Algae ◽  
Textured Surface ◽  
Crustose Coralline Algae ◽  
Statistical Parameters ◽  
Content Type

Purpose The purpose of this paper is to prove and qualify the influence of textured surface substrates morphology and chemical composition on the growth and propagation of transplanted corals. Use additive manufacturing and silicone moulds for converting three-dimensional samples into limestone mortar with white Portland cement substrates for coral growth. Design/methodology/approach Tiles samples were designed and printed with different geometries and textures inspired by nature marine environment. Commercial coral frag tiles were analysed through scanning electron microscopy (SEM) to identify the main chemical elements. Raw materials and coral species were selected. New base substrates were manufactured and deployed into a closed-circuit aquarium to monitor the coral weekly evolution process and analyse the results obtained. Findings Experimental results provided positive statistical parameters for future implementation tests, concluding that the intensity of textured surface, interfered favourably in the coralline algae biofilm growth. The chemical composition and design of the substrates were determinant factors for successful coral propagation. Recesses and cavities mimic the natural rocks aspect and promoted the presence and interaction of other species that favour the richness of the ecosystem. Originality/value Additive manufacturing provided an innovative method of production for ecology restoration areas, allowing rapid prototyping of substrates with high complexity morphologies, a critical and fundamental attribute to guarantee coral growth and Crustose Coralline Algae. The result of this study showed the feasibility of this approach using three-dimensional printing technologies.

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