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Zhang Y, Xiao Z, Wei Z, Long L. Increased light intensity enhances photosynthesis and biochemical components of red macroalga of commercial importance, Kappaphycus alvarezii, in response to ocean acidification. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 208:108465. [PMID: 38422577 DOI: 10.1016/j.plaphy.2024.108465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 02/22/2024] [Indexed: 03/02/2024]
Abstract
The concentration of atmospheric carbon dioxide (CO2) has increased drastically over the past several decades, resulting in the pH of the ocean decreasing by 0.44 ± 0.005 units, known as ocean acidification (OA). The Kappaphycus alvarezii (Rhodophyta, Solieriaceae), is a commercially and ecologically important red macroalga with significant CO2 absorption potential from seawater. The K. alvarezii also experienced light variations from self-shading and varied cultivation depths. Thus, the aim of present study was to investigate the effects of two pCO2 levels (450 and 1200 ppmv) and three light intensities (50, 100, and 150 μmol photons·m-2·s-1) on photosynthesis and the biochemical components in K. alvarezii. The results of the present study showed that a light intensity of 50 μmol photons·m-2·s-1 was optimal for K. alvarezii photosynthesis with 0.663 ± 0.030 of Fv/Fm and 0.672 ± 0.025 of Fv'/Fm'. Phycoerythrin contents at two pCO2 levels decreased significantly with an increase in light intensity by 57.14-87.76%, while phycocyanin contents only decreased from 0.0069 ± 0.001 mg g-1 FW to 0.0047 ± 0.001 mg g-1 FW with an increase in light intensity at 1200 ppmv of pCO2. Moreover, moderate increases in light intensity and pCO2 had certain positive effects on the physiological performance of K. alvarezii, specifically in terms of increasing soluble carbohydrate production. Although OA and high light levels promoted total organic carbon accumulation (21.730 ± 0.205% DW) in K. alvarezii, they had a negative impact on total nitrogen accumulation (0.600 ± 0.017% DW).
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Affiliation(s)
- Yating Zhang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, PR China; Guangdong Provincial Observation and Research Station for Coastal Upwelling Ecosystem, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Shantou, 515041, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Zhiliang Xiao
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, PR China; Key Laboratory of Tropical Marine Biotechnology of Hainan Province, Sanya Institute of Oceanology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Sanya, 572000, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Zhangliang Wei
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, PR China; Guangdong Provincial Observation and Research Station for Coastal Upwelling Ecosystem, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Shantou, 515041, PR China; Key Laboratory of Tropical Marine Biotechnology of Hainan Province, Sanya Institute of Oceanology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Sanya, 572000, PR China.
| | - Lijuan Long
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, PR China; Guangdong Provincial Observation and Research Station for Coastal Upwelling Ecosystem, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Shantou, 515041, PR China; Key Laboratory of Tropical Marine Biotechnology of Hainan Province, Sanya Institute of Oceanology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Sanya, 572000, PR China.
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Seto M, Harvey BP, Wada S, Agostini S. Potential ecosystem regime shift resulting from elevated CO2 and inhibition of macroalgal recruitment by turf algae. THEOR ECOL-NETH 2023. [DOI: 10.1007/s12080-022-00550-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Vinuganesh A, Kumar A, Prakash S, Korany SM, Alsherif EA, Selim S, AbdElgawad H. Evaluation of growth, primary productivity, nutritional composition, redox state, and antimicrobial activity of red seaweeds Gracilaria debilis and Gracilaria foliifera under pCO 2-induced seawater acidification. MARINE POLLUTION BULLETIN 2022; 185:114296. [PMID: 36343546 DOI: 10.1016/j.marpolbul.2022.114296] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 10/01/2022] [Accepted: 10/20/2022] [Indexed: 06/16/2023]
Abstract
The genus Gracilaria is an economically important group of seaweeds as several species are utilized for various products such as agar, used in medicines, human diets, and poultry feed. Hence, it is imperative to understand their response to predicted ocean acidification conditions. In the present work, we have evaluated the response of Gracilaria foliifera and Gracilaria debilis to carbon dioxide (pCO2) induced seawater acidification (pH 7.7) for two weeks in a controlled laboratory conditions. As a response variable, we have measured growth, productivity, redox state, primary and secondary metabolites, and mineral compositions. We found a general increase in the daily growth rate, primary productivity, and tissue chemical composition (such as pigments, soluble and insoluble sugars, amino acids, and fatty acids), but a decrease in the mineral contents under the acidified condition. Under acidification, there was a decrease in malondialdehyde. However, there were no significant changes in the total antioxidant capacity and a majority of enzymatic and non-enzymatic antioxidants, except for an increase in tocopherols, ascorbate and glutathione-s-transferase in G. foliifera. These results indicate that elevated pCO2 will benefit the growth of the studied species. No sign of oxidative stress markers indicating the acclimatory response of these seaweeds towards lowered pH conditions. Besides, we also found increased antimicrobial activities of acidified samples against several of the tested food pathogens. Based on these observations, we suggest that Gracilaria spp. will be benefitted from the predicted future acidified ocean.
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Affiliation(s)
- A Vinuganesh
- Cente for Climate Change Studies, Sathyabama Institute of Science and Technology, Rajiv Gandhi Salai, Chennai-600119, Tamil Nadu, India
| | - Amit Kumar
- Cente for Climate Change Studies, Sathyabama Institute of Science and Technology, Rajiv Gandhi Salai, Chennai-600119, Tamil Nadu, India; Sathyabama Marine Research Station, Sallimalai Street, Rameswaram, Tamil Nadu, India.
| | - S Prakash
- Cente for Climate Change Studies, Sathyabama Institute of Science and Technology, Rajiv Gandhi Salai, Chennai-600119, Tamil Nadu, India; Sathyabama Marine Research Station, Sallimalai Street, Rameswaram, Tamil Nadu, India
| | - Shereen Magdy Korany
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia
| | - Emad A Alsherif
- Biology Department, College of Science and Arts at Khulis, University of Jeddah, Jeddah 21959, Saudi Arabia; Botany and Microbiology Department, Faculty of Science, Beni-Suef University, Beni-Suef 62521, Egypt
| | - Samy Selim
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Sakaka 72388, Saudi Arabia
| | - Hamada AbdElgawad
- Botany and Microbiology Department, Faculty of Science, Beni-Suef University, Beni-Suef 62521, Egypt
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Sanchez-Arcos C, Paris D, Mazzella V, Mutalipassi M, Costantini M, Buia MC, von Elert E, Cutignano A, Zupo V. Responses of the Macroalga Ulva prolifera Müller to Ocean Acidification Revealed by Complementary NMR- and MS-Based Omics Approaches. Mar Drugs 2022; 20:md20120743. [PMID: 36547890 PMCID: PMC9783899 DOI: 10.3390/md20120743] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 11/21/2022] [Accepted: 11/23/2022] [Indexed: 11/29/2022] Open
Abstract
Ocean acidification (OA) is a dramatic perturbation of seawater environments due to increasing anthropogenic emissions of CO2. Several studies indicated that OA frequently induces marine biota stress and a reduction of biodiversity. Here, we adopted the macroalga Ulva prolifera as a model and applied a complementary multi-omics approach to investigate the metabolic profiles under normal and acidified conditions. Our results show that U. prolifera grows at higher rates in acidified environments. Consistently, we observed lower sucrose and phosphocreatine concentrations in response to a higher demand of energy for growth and a higher availability of essential amino acids, likely related to increased protein biosynthesis. In addition, pathways leading to signaling and deterrent compounds appeared perturbed. Finally, a remarkable shift was observed here for the first time in the fatty acid composition of triglycerides, with a decrease in the relative abundance of PUFAs towards an appreciable increase of palmitic acid, thus suggesting a remodeling in lipid biosynthesis. Overall, our studies revealed modulation of several biosynthetic pathways under OA conditions in which, besides the possible effects on the marine ecosystem, the metabolic changes of the alga should be taken into account considering its potential nutraceutical applications.
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Affiliation(s)
- Carlos Sanchez-Arcos
- Institute for Zoology, Cologne Biocenter University of Cologne, 50674 Köln, Germany
| | - Debora Paris
- Consiglio Nazionale delle Ricerche (CNR), Istituto di Chimica Biomolecolare (ICB), 80078 Pozzuoli, Italy
| | - Valerio Mazzella
- Department of Integrative Marine Ecology, Stazione Zoologica Anton Dohrn, Ischia Marine Center, 80077 Ischia, Italy
| | - Mirko Mutalipassi
- Department of Integrative Marine Ecology, Stazione Zoologica Anton Dohrn, Calabria Marine Centre, 87071 Amendolara, Italy
| | - Maria Costantini
- Department of Ecosustainable Marine Biotechnology, Stazione Zoologica Anton Dohrn, 80121 Napoli, Italy
| | - Maria Cristina Buia
- Department of Integrative Marine Ecology, Stazione Zoologica Anton Dohrn, Ischia Marine Center, 80077 Ischia, Italy
| | - Eric von Elert
- Institute for Zoology, Cologne Biocenter University of Cologne, 50674 Köln, Germany
| | - Adele Cutignano
- Consiglio Nazionale delle Ricerche (CNR), Istituto di Chimica Biomolecolare (ICB), 80078 Pozzuoli, Italy
- Department of Ecosustainable Marine Biotechnology, Stazione Zoologica Anton Dohrn, 80121 Napoli, Italy
- Correspondence: (A.C.); (V.Z.); Tel.: +39-081-8675313 (A.C.); +39-081-5833503 (V.Z.)
| | - Valerio Zupo
- Department of Ecosustainable Marine Biotechnology, Stazione Zoologica Anton Dohrn, 80077 Ischia, Italy
- Correspondence: (A.C.); (V.Z.); Tel.: +39-081-8675313 (A.C.); +39-081-5833503 (V.Z.)
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Young CS, Lee CS, Sylvers LH, Venkatesan AK, Gobler CJ. The invasive red seaweed, Dasysiphonia japonica, forms harmful algal blooms: Mortality in early life stage fish and bivalves and identification of putative toxins. HARMFUL ALGAE 2022; 118:102294. [PMID: 36195420 DOI: 10.1016/j.hal.2022.102294] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 07/25/2022] [Accepted: 07/28/2022] [Indexed: 06/16/2023]
Abstract
In recent decades, the rate of introduction of non-indigenous macroalgae has increased. While invasive seaweeds often outcompete native species for substrata, their direct effects on marine life are rarely described. Here, we describe 'red water' events caused by the decay of blooms of the invasive red seaweed, Dasysiphonia japonica, in Great South Bay, NY, USA, and the ability of water from such events to induce rapid and significant mortality in larval and juvenile fish (Menidia beryllina, Menidia menidia, and Cyprinodon variegatus) and larval bivalves (Mercenaria mercenaria and Crassostrea virginica). All species studied experienced significant (p<0.05) reductions in survival when exposed to macroalgae in a state of decay, seawater in which the alga was previously decayed, or both. Both bivalve species experienced 50-60% increases in mortality when exposed to decaying D. japonica for ∼ one week, despite normoxic conditions. Among fish, significant increases (40-80%) in mortality were observed after 24 h exposure to decayed D. japonica and one-week exposures caused, on average, 90% mortality in larval M. beryllina, 50% mortality in juvenile (∼3 cm) M. menidia, and 50% mortality in larval C. variegatus. All fish and bivalve mortality occurred under normoxic conditions (dissolved oxygen (DO) >7 mg L-1) and low ammonium levels (< 20 µM), with the exception of C. variegatus, which expired under conditions of decayed D. japonica coupled with reduced DO caused by the alga. Screening of water with decayed D. japonica using liquid chromatography-mass spectrometry revealed compounds with mass-to-charge ratios matching caulerpin, a known algal toxin that causes fish and shellfish mortality, and several other putative toxicants at elevated levels. Collectively, the high levels of mortality (50-90%) of larval and juvenile fish and bivalves exposed to decaying D. japonica under normoxic conditions coupled with the observation of 'red water' events in estuaries collectively indicate the red seaweed, D. japonica, can create harmful algal blooms (HABs).
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Affiliation(s)
- Craig S Young
- School of Marine and Atmospheric Sciences, Stony Brook University, Southampton, NY 11968, USA
| | - Cheng-Shiuan Lee
- New York State Center for Clean Water Technology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Laine H Sylvers
- School of Marine and Atmospheric Sciences, Stony Brook University, Southampton, NY 11968, USA
| | - Arjun K Venkatesan
- New York State Center for Clean Water Technology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Christopher J Gobler
- School of Marine and Atmospheric Sciences, Stony Brook University, Southampton, NY 11968, USA.
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Societal importance of Antarctic negative feedbacks on climate change: blue carbon gains from sea ice, ice shelf and glacier losses. Naturwissenschaften 2021; 108:43. [PMID: 34491425 PMCID: PMC8423686 DOI: 10.1007/s00114-021-01748-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/26/2021] [Accepted: 08/09/2021] [Indexed: 11/29/2022]
Abstract
Diminishing prospects for environmental preservation under climate change are intensifying efforts to boost capture, storage and sequestration (long-term burial) of carbon. However, as Earth’s biological carbon sinks also shrink, remediation has become a key part of the narrative for terrestrial ecosystems. In contrast, blue carbon on polar continental shelves have stronger pathways to sequestration and have increased with climate-forced marine ice losses—becoming the largest known natural negative feedback on climate change. Here we explore the size and complex dynamics of blue carbon gains with spatiotemporal changes in sea ice (60–100 MtCyear−1), ice shelves (4–40 MtCyear−1 = giant iceberg generation) and glacier retreat (< 1 MtCyear−1). Estimates suggest that, amongst these, reduced duration of seasonal sea ice is most important. Decreasing sea ice extent drives longer (not necessarily larger biomass) smaller cell-sized phytoplankton blooms, increasing growth of many primary consumers and benthic carbon storage—where sequestration chances are maximal. However, sea ice losses also create positive feedbacks in shallow waters through increased iceberg movement and scouring of benthos. Unlike loss of sea ice, which enhances existing sinks, ice shelf losses generate brand new carbon sinks both where giant icebergs were, and in their wake. These also generate small positive feedbacks from scouring, minimised by repeat scouring at biodiversity hotspots. Blue carbon change from glacier retreat has been least well quantified, and although emerging fjords are small areas, they have high storage-sequestration conversion efficiencies, whilst blue carbon in polar waters faces many diverse and complex stressors. The identity of these are known (e.g. fishing, warming, ocean acidification, non-indigenous species and plastic pollution) but not their magnitude of impact. In order to mediate multiple stressors, research should focus on wider verification of blue carbon gains, projecting future change, and the broader environmental and economic benefits to safeguard blue carbon ecosystems through law.
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Barakat KM, El-Sayed HS, Khairy HM, El-Sheikh MA, Al-Rashed SA, Arif IA, Elshobary ME. Effects of ocean acidification on the growth and biochemical composition of a green alga ( Ulva fasciata) and its associated microbiota. Saudi J Biol Sci 2021; 28:5106-5114. [PMID: 34466088 PMCID: PMC8381011 DOI: 10.1016/j.sjbs.2021.05.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 02/08/2023] Open
Abstract
In marine ecosystems, fluctuations in surface-seawater carbon dioxide (CO2), significantly influence the whole metabolism of marine algae, especially during the early stages of macroalgal development. In this study, the response of the green alga Ulva fasciata for elevating ocean acidification was investigated using four levels of pCO2 ~ 280, 550, 750 and 1050 µatm. Maximum growth rate (6.6% day-1), protein (32.43 %DW) and pigment (2.9 mg/g) accumulation were observed at pCO2-550 with an increase of ~2-fold compared to control. On the other hand, lipid and carbohydrate contents recorded their maximum production (4.23 and 46.96 %DW, respectively) at pCO2-750 while control showed 3.70 and 42.37 %DW, respectively. SDS-PAGE showed the presence of unique bands in response to pCO2, especially at 550 µatm. Dominant associated bacteria was shifted from Halomonas hydrothermalis of control to Vibrio toranzoniae at pCO2-1050. These findings suggest that ocean acidification at 550 µatm might impose noticeable effects on growth, protein, pigments, and protein profile of U. fasciata, which could be a good source for fish farming. While, pCO2-750 was recommended for energetic purpose, due to its high lipid and carbohydrate contents.
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Affiliation(s)
| | - Heba S. El-Sayed
- National Institute of Oceanography and Fisheries (NOIF), Cairo, Egypt
| | - Hanan M. Khairy
- National Institute of Oceanography and Fisheries (NOIF), Cairo, Egypt
- Corresponding authors at: National Institute of Oceanography and Fisheries, NIOF, 11516, Egypt (H.M. Khairy). Botany Department, Faculty of Science, Tanta University, 31527, Tanta, Egypt (M.E. Elshobary).
| | - Mohamed A. El-Sheikh
- Botany & Microbiology Department, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Sarah A. Al-Rashed
- Botany & Microbiology Department, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Ibrahim A. Arif
- Botany & Microbiology Department, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Mostafa E. Elshobary
- Botany Department, Faculty of Science, Tanta University, 31527, Tanta, Egypt
- Corresponding authors at: National Institute of Oceanography and Fisheries, NIOF, 11516, Egypt (H.M. Khairy). Botany Department, Faculty of Science, Tanta University, 31527, Tanta, Egypt (M.E. Elshobary).
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Sylvers PH, Gobler CJ. Mitigation of harmful algal blooms caused by Alexandrium catenella and reduction in saxitoxin accumulation in bivalves using cultivable seaweeds. HARMFUL ALGAE 2021; 105:102056. [PMID: 34303515 DOI: 10.1016/j.hal.2021.102056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 05/16/2021] [Accepted: 05/18/2021] [Indexed: 06/13/2023]
Abstract
Alexandrium catenella is a harmful algal bloom (HAB)-forming dinoflagellate that causes significant damage to the cultivation and harvest of shellfish due to its synthesis of paralytic shellfish toxins. To evaluate the potential for macroalgae aquaculture to mitigate A. catenella blooms, we determined the effects of three cultivable macroalgae - Saccharina latissima (sugar kelp), Chondrus crispus (Irish moss), and Ulva spp. - on A. catenella in culture- and field-based experiments. Co-culture growth assays of A. catenella exposed to environmentally realistic concentrations of each macroalgae showed that all species except low levels of C. crispus caused cell lysis and significant reductions in A. catenella densities relative to control treatments of 17-74% in 2-3 days and 42-96% in ~one week (p<0.05 for all assays). In a toxin accumulation experiment, S. latissima significantly lessened (p<0.05) saxitoxin (STX) accumulation in blue mussels (Mytilus edulis), keeping levels (71.80±1.98 µg STX 100 g-1) below US closure limits (80 µg STX 100 g-1) compared to the untreated control (93.47±8.11 µg STX 100 g-1). Bottle incubations of field-collected, bloom populations of A. catenella experienced significant reductions in cell densities of up to 95% when exposed to aquaculture concentrations of all three macroalgae (p<0.005 for all). The stocking of aquacultured S. latissima within mesocosms containing a bloom population of A. catenella (initial density: 3.2 × 104 cells L-1) reduced the population of A. catenella by 73% over 48 h (p<0.005) while Ulva addition caused a 54% reduction in A. catenella over 96 h (p<0.01). Among the three seaweeds, their ordered ability to inhibit A. catenella was S. latissima > Ulva spp. > C. crispus. Seaweeds' primary anti-A. catenella activity were allelopathic, while nutrient competition, pH elevation, and macroalgae-attached bacteria may have played a contributory role in some experiments. Collectively, these results suggest that the integration of macroalgae with shellfish-centric aquaculture establishments should be considered as a non-invasive, environmentally friendly, and potentially profit-generating measure to mitigate A. catenella-caused damage to the shellfish aquaculture industry.
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Affiliation(s)
- Peter H Sylvers
- School of Marine and Atmospheric Sciences, Stony Brook University, Southampton NY, United States
| | - Christopher J Gobler
- School of Marine and Atmospheric Sciences, Stony Brook University, Southampton NY, United States.
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Coastal ocean acidification and nitrogen loading facilitate invasions of the non-indigenous red macroalga, Dasysiphonia japonica. Biol Invasions 2021. [DOI: 10.1007/s10530-020-02445-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
AbstractCoastal ecosystems are prone to multiple anthropogenic and natural stressors including eutrophication, acidification, and invasive species. While the growth of some macroalgae can be promoted by excessive nutrient loading and/or elevated pCO2, responses differ among species and ecosystems. Native to the western Pacific Ocean, the filamentous, turf-forming rhodophyte, Dasysiphonia japonica, appeared in estuaries of the northeastern Atlantic Ocean during the 1980s and the northwestern Atlantic Ocean during the late 2000s. Here, we report on the southernmost expansion of the D. japonica in North America and the effects of elevated nutrients and elevated pCO2 on the growth of D. japonica over an annual cycle in Long Island, New York, USA. Growth limitation of the macroalga varied seasonally. During winter and spring, when water temperatures were < 15 °C, growth was significantly enhanced by elevated pCO2 (p < 0.05). During summer and fall, when the water temperature was 15–24 °C, growth was significantly higher under elevated nutrient treatments (p < 0.05). When temperatures reached 28 °C, the macroalga grew poorly and was unaffected by nutrients or pCO2. The δ13C content of regional populations of D. japonica was −30‰, indicating the macroalga is an obligate CO2-user. This result, coupled with significantly increased growth under elevated pCO2 when temperatures were < 15 °C, indicates this macroalga is carbon-limited during colder months, when in situ pCO2 was significantly lower in Long Island estuaries compared to warmer months when estuaries are enriched in metabolically derived CO2. The δ15N content of this macroalga (9‰) indicated it utilized wastewater-derived N and its N limitation during warmer months coincided with lower concentrations of dissolved inorganic N in the water column. Given the stimulatory effect of nutrients on this macroalga and that eutrophication can promote seasonally elevated pCO2, this study suggests that eutrophic estuaries subject to peak annual temperatures < 28 °C may be particularly vulnerable to future invasions of D. japonica as ocean acidification intensifies. Conversely, nutrient reductions would serve as a management approach that would make coastal regions more resilient to invasions by this macroalga.
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Kinnby A, White JCB, Toth GB, Pavia H. Ocean acidification decreases grazing pressure but alters morphological structure in a dominant coastal seaweed. PLoS One 2021; 16:e0245017. [PMID: 33508019 PMCID: PMC7842949 DOI: 10.1371/journal.pone.0245017] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Accepted: 12/18/2020] [Indexed: 11/20/2022] Open
Abstract
Ocean acidification driven by anthropogenic climate change is causing a global decrease in pH, which is projected to be 0.4 units lower in coastal shallow waters by the year 2100. Previous studies have shown that seaweeds grown under such conditions may alter their growth and photosynthetic capacity. It is not clear how such alterations might impact interactions between seaweed and herbivores, e.g. through changes in feeding rates, nutritional value, or defense levels. Changes in seaweeds are particularly important for coastal food webs, as they are key primary producers and often habitat-forming species. We cultured the habitat-forming brown seaweed Fucus vesiculosus for 30 days in projected future pCO2 (1100 μatm) with genetically identical controls in ambient pCO2 (400 μatm). Thereafter the macroalgae were exposed to grazing by Littorina littorea, acclimated to the relevant pCO2-treatment. We found increased growth (measured as surface area increase), decreased tissue strength in a tensile strength test, and decreased chemical defense (phlorotannins) levels in seaweeds exposed to high pCO2-levels. The herbivores exposed to elevated pCO2-levels showed improved condition index, decreased consumption, but no significant change in feeding preference. Fucoid seaweeds such as F. vesiculosus play important ecological roles in coastal habitats and are often foundation species, with a key role for ecosystem structure and function. The change in surface area and associated decrease in breaking force, as demonstrated by our results, indicate that F. vesiculosus grown under elevated levels of pCO2 may acquire an altered morphology and reduced tissue strength. This, together with increased wave energy in coastal ecosystems due to climate change, could have detrimental effects by reducing both habitat and food availability for herbivores.
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Affiliation(s)
- Alexandra Kinnby
- Tjärnö Marine Laboratory, Department of Marine Sciences, University of Gothenburg, Strömstad, Sweden
| | - Joel C. B. White
- Tjärnö Marine Laboratory, Department of Marine Sciences, University of Gothenburg, Strömstad, Sweden
| | - Gunilla B. Toth
- Tjärnö Marine Laboratory, Department of Marine Sciences, University of Gothenburg, Strömstad, Sweden
| | - Henrik Pavia
- Tjärnö Marine Laboratory, Department of Marine Sciences, University of Gothenburg, Strömstad, Sweden
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Narvarte BCV, Nelson WA, Roleda MY. Inorganic carbon utilization of tropical calcifying macroalgae and the impacts of intensive mariculture-derived coastal acidification on the physiological performance of the rhodolith Sporolithon sp. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 266:115344. [PMID: 32829170 DOI: 10.1016/j.envpol.2020.115344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 07/10/2020] [Accepted: 07/28/2020] [Indexed: 06/11/2023]
Abstract
Fish farming in coastal areas has become an important source of food to support the world's increasing population. However, intensive and unregulated mariculture activities have contributed to changing seawater carbonate chemistry through the production of high levels of respiratory CO2. This additional CO2, i.e. in addition to atmospheric inputs, intensifies the effects of global ocean acidification resulting in localized extreme low pH levels. Marine calcifying macroalgae are susceptible to such changes due to their CaCO3 skeleton. Their physiological response to CO2-driven acidification is dependent on their carbon physiology. In this study, we used the pH drift experiment to determine the capability of 9 calcifying macroalgae to use one or more inorganic carbon (Ci) species. From the 9 species, we selected the rhodolith Sporolithon sp. as a model organism to investigate the long-term effects of extreme low pH on the physiology and biochemistry of calcifying macroalgae. Samples were incubated under two pH treatments (pH 7.9 = ambient and pH 7.5 = extreme acidification) in a temperature-controlled (26 ± 0.02 °C) room provided with saturating light intensity (98.3 ± 2.50 μmol photons m-2 s-1). After the experimental treatment period (40 d), growth rate, calcification rate, nutrient uptake rate, organic content, skeletal CO3-2, pigments, and tissue C, N and P of Sporolithon samples were compared. The pH drift experiment revealed species-specific Ci use mechanisms, even between congenerics, among tropical calcifying macroalgae. Furthermore, long-term extreme low pH significantly reduced the growth rate, calcification rate and skeletal CO3-2 content by 79%, 66% and 18%, respectively. On the other hand, nutrient uptake rates, organic matter, pigments and tissue C, N and P were not affected by the low pH treatments. Our results suggest that the rhodolith Sporolithon sp. is susceptible to the negative effects of extreme low pH resulting from intensive mariculture-driven coastal acidification.
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Affiliation(s)
- Bienson Ceasar V Narvarte
- The Marine Science Institute, University of the Philippines, Diliman 1101, Quezon City, Philippines.
| | - Wendy A Nelson
- National Institute of Water & Atmospheric Research Ltd (NIWA), 301 Evans Bay Parade, Greta Point, Wellington, New Zealand
| | - Michael Y Roleda
- The Marine Science Institute, University of the Philippines, Diliman 1101, Quezon City, Philippines
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12
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Raven JA, Gobler CJ, Hansen PJ. Dynamic CO 2 and pH levels in coastal, estuarine, and inland waters: Theoretical and observed effects on harmful algal blooms. HARMFUL ALGAE 2020; 91:101594. [PMID: 32057340 DOI: 10.1016/j.hal.2019.03.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 03/08/2019] [Indexed: 06/10/2023]
Abstract
Rising concentrations of atmospheric CO2 results in higher equilibrium concentrations of dissolved CO2 in natural waters, with corresponding increases in hydrogen ion and bicarbonate concentrations and decreases in hydroxyl ion and carbonate concentrations. Superimposed on these climate change effects is the dynamic nature of carbon cycling in coastal zones, which can lead to seasonal and diel changes in pH and CO2 concentrations that can exceed changes expected for open ocean ecosystems by the end of the century. Among harmful algae, i.e. some species and/or strains of Cyanobacteria, Dinophyceae, Prymnesiophyceae, Bacillariophyceae, and Ulvophyceae, the occurrence of a CO2 concentrating mechanisms (CCMs) is the most frequent mechanism of inorganic carbon acquisition in natural waters in equilibrium with the present atmosphere (400 μmol CO2 mol-1 total gas), with varying phenotypic modification of the CCM. No data on CCMs are available for Raphidophyceae or the brown tide Pelagophyceae. Several HAB species and/or strains respond to increased CO2 concentrations with increases in growth rate and/or cellular toxin content, however, others are unaffected. Beyond the effects of altered C concentrations and speciation on HABs, changes in pH in natural waters are likely to have profound effects on algal physiology. This review outlines the implications of changes in inorganic cycling for HABs in coastal zones, and reviews the knowns and unknowns with regard to how HABs can be expected to ocean acidification. We further point to the large regions of uncertainty with regard to this evolving field.
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Affiliation(s)
- John A Raven
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK; Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, 2007, Australia; School of Biological Science, University of Western Australia, Crawley, WA, 6009, Australia.
| | - Christopher J Gobler
- School of Marine and Atmospheric Sciences, Stony Brook University, Southampton NY, 11968, USA.
| | - Per Juel Hansen
- University of Copenhagen, Marine Biological Section, Strandpromenaden 5, DK 3000 Helsingør, Denmark
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13
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Yue F, Gao G, Ma J, Wu H, Li X, Xu J. Future CO 2-induced seawater acidification mediates the physiological performance of a green alga Ulva linza in different photoperiods. PeerJ 2019; 7:e7048. [PMID: 31198646 PMCID: PMC6555391 DOI: 10.7717/peerj.7048] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 04/30/2019] [Indexed: 11/20/2022] Open
Abstract
Photoperiods have an important impact on macroalgae living in the intertidal zone. Ocean acidification also influences the physiology of macroalgae. However, little is known about the interaction between ocean acidification and photoperiod on macroalgae. In this study, a green alga Ulva linza was cultured under three different photoperiods (L: D = 8:16, 12:12, 16:8) and two different CO2 levels (LC, 400 ppm; HC, 1,000 ppm) to investigate their responses. The results showed that relative growth rate of U. linza increased with extended light periods under LC but decreased at HC when exposed to the longest light period of 16 h compared to 12 h. Higher CO2 levels enhanced the relative growth rate at a L: D of 8:16, had no effect at 12:12 but reduced RGR at 16:8. At LC, the L: D of 16:8 significantly stimulated maximum quantum yield (Yield). Higher CO2 levels enhanced Yield at L: D of 12:12 and 8:16, had negative effect at 16:8. Non-photochemical quenching (NPQ) increased with increasing light period. High CO2 levels did not affect respiration rate during shorter light periods but enhanced it at a light period of 16 h. Longer light periods had negative effects on Chl a and Chl b content, and high CO2 level also inhibited the synthesis of these pigments. Our data demonstrate the interactive effects of CO2 and photoperiod on the physiological characteristics of the green tide macroalga Ulva linza and indicate that future ocean acidification may hinder the stimulatory effect of long light periods on growth of Ulva species.
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Affiliation(s)
- Furong Yue
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Huaihai Institute of Technology, Lianyungang, China
| | - Guang Gao
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Huaihai Institute of Technology, Lianyungang, China
| | - Jing Ma
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Huaihai Institute of Technology, Lianyungang, China
| | - Hailong Wu
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Huaihai Institute of Technology, Lianyungang, China
| | - Xinshu Li
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Huaihai Institute of Technology, Lianyungang, China
| | - Juntian Xu
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Huaihai Institute of Technology, Lianyungang, China.,Co-Innovation Center of Jiangsu Marine Bio-industry Technology, HuaiHai Institute of Technology, Lianyungang, China.,Jiangsu Key Laboratory of Marine Biotechnology, Huaihai Institute of Technology, Lianyungang, China
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14
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Gao G, Fu Q, Beardall J, Wu M, Xu J. Combination of ocean acidification and warming enhances the competitive advantage of Skeletonema costatum over a green tide alga, Ulva linza. HARMFUL ALGAE 2019; 85:101698. [PMID: 31810528 DOI: 10.1016/j.hal.2019.101698] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Revised: 10/22/2019] [Accepted: 10/23/2019] [Indexed: 06/10/2023]
Abstract
Red tide and green tide are two common algal blooms that frequently occur in many areas in the global oceans. The algae causing red tide and green tide often interact with each other in costal ecosystems. However, little is known on how future CO2-induced ocean acidification combined with temperature variation would affect the interaction of red and green tides. In this study, we cultured the red tide alga Skeletonema costatum and the green tide alga Ulva linza under ambient (400 ppm) and future CO2 (1000 ppm) levels and three temperatures (12, 18, 24 °C) in both monoculture and coculture systems. Coculture did not affect the growth rate of U. linza but significantly decreased it for S. costatum. Elevated CO2 relieved the inhibitory effect of U. linza on the growth of S. costatum, particularly for higher temperatures. At elevated CO2, higher temperature increased the growth rate of S. costatum but reduced it for U. linza. Coculture with U. linza reduced the net photosynthetic rate of S. costatum, which was relieved by elevated CO2. This pattern was also found in Chl a content, indicating that U. linza may inhibit growth of S. costatum via harming pigment synthesis and thus photosynthesis. In monoculture, higher temperature did not affect respiration rate of S. costatum but increased it in U. linza. Coculture did not affect respiration of U. linza but stimulated it for S. costatum, which was a signal of responding to biotic and/abiotic stress. The increased growth of S. costatum at higher temperature and decreased inhibition of U. linza on S. costatum at elevated CO2 suggest that red tides may have more advantages over green tides in future warmer and CO2-enriched oceans.
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Affiliation(s)
- Guang Gao
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang, 222005, China; State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361005, China
| | - Qianqian Fu
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang, 222005, China
| | - John Beardall
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Min Wu
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang, 222005, China
| | - Juntian Xu
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang, 222005, China; Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Lianyungang 222005, China; Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang 222005, China.
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15
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Aires T, Muyzer G, Serrão EA, Engelen AH. Seaweed Loads Cause Stronger Bacterial Community Shifts in Coastal Lagoon Sediments Than Nutrient Loads. Front Microbiol 2019; 9:3283. [PMID: 30687271 PMCID: PMC6333863 DOI: 10.3389/fmicb.2018.03283] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 12/17/2018] [Indexed: 11/23/2022] Open
Abstract
The input of nutrients from anthropogenic sources is the leading cause of coastal eutrophication and is usually coupled with algal/seaweed blooms. Effects may be magnified in semi-enclosed systems, such as highly productive coastal lagoon ecosystems. Eutrophication and seaweed blooms can lead to ecosystem disruption. Previous studies have considered only one of these factors, disregarding possible interactive effects and the effect of the blooming species' identity on sediment bacterial communities. We tested the effect of experimental nutrient loading and two common blooming seaweeds (Ulva rigida and Gracilaria vermiculophylla) in coastal lagoon sediments, on the structure of bacterial communities (using 16S rRNA amplicon sequencing) and corresponding putative functional potential (using PiCRUSt). At the Operational Taxonomic Unit (OTU) level, the addition of nutrients reduced bacterial community α-diversity and decreased the abundance of sulfate reducers (Desulfobacterales) compared to sulfur oxidizers/denitrifiers (Chromatiales and Campylobacterales), whereas this was not the case at the order level. Seaweed addition did not change bacterial α-diversity and the effect on community structure depended on the taxonomic level considered. The addition of Gracilaria increased the abundance of orders and OTUs involved in sulfate reduction and organic matter decomposition (Desulfobacterales, Bacteroidales, and Clostridiales, respectively), an effect which was also detected when only Ulva was added. Nutrients and the seaweeds combined only interacted for Ulva and nutrients, which increased known sulfide oxidizers and denitrifiers (order Campylobacterales). Seaweed enrichment affected putative functional profiles; a stronger increase of sulfur cycling KEGG pathways was assigned to nutrient-disturbed sediments, particularly with the seaweeds and especially Ulva. In contrast, nitrogen and sulfur cycle pathways showed a higher abundance of genes related to dissimilatory nitrate reduction to ammonium (DNRA) in Ulva+nutrients treatments. However, the other seaweed treatments increased the nitrogen fixation genes. Thiosulfate reduction, performed by sulfate-reducing bacteria, increased in seaweed treatments except when Ulva was combined with nutrients. In conclusion, the in situ addition of nutrients and the seaweeds to intertidal sediments affected the bacterial communities differently and independently. The predicted functional profile suggests a shift in relative abundances of putative pathways for nitrogen and sulfur cycles, in line with the taxonomic changes of the bacterial communities.
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Affiliation(s)
- Tânia Aires
- Centro de Ciências do Mar (CCMAR), Centro de Investigação Marinha e Ambiental (CIMAR), Universidade do Algarve, Faro, Portugal
| | - Gerard Muyzer
- Microbial Systems Ecology, Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, Netherlands
| | - Ester A. Serrão
- Centro de Ciências do Mar (CCMAR), Centro de Investigação Marinha e Ambiental (CIMAR), Universidade do Algarve, Faro, Portugal
| | - Aschwin H. Engelen
- Centro de Ciências do Mar (CCMAR), Centro de Investigação Marinha e Ambiental (CIMAR), Universidade do Algarve, Faro, Portugal
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16
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Williamson CE, Neale PJ, Hylander S, Rose KC, Figueroa FL, Robinson SA, Häder DP, Wängberg SÅ, Worrest RC. The interactive effects of stratospheric ozone depletion, UV radiation, and climate change on aquatic ecosystems. Photochem Photobiol Sci 2019; 18:717-746. [DOI: 10.1039/c8pp90062k] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Summary of current knowledge about effects of UV radiation in inland and oceanic waters related to stratospheric ozone depletion and climate change.
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Affiliation(s)
| | | | - Samuel Hylander
- Centre for Ecology and Evolution in Microbial model Systems
- Linnaeus Univ
- Kalmar
- Sweden
| | - Kevin C. Rose
- Department of Biological Sciences
- Rensselaer Polytechnic Institute
- Troy
- USA
| | | | - Sharon A. Robinson
- Centre for Sustainable Ecosystem Solutions
- School of Earth
- Atmosphere and Life Sciences and Global Challenges Program
- University of Wollongong
- Australia
| | - Donat-P. Häder
- Department of Biology
- Friedrich-Alexander Universität
- Möhrendorf
- Germany
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17
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Zweng RC, Koch MS, Bowes G. The role of irradiance and C-use strategies in tropical macroalgae photosynthetic response to ocean acidification. Sci Rep 2018; 8:9479. [PMID: 29930306 PMCID: PMC6013460 DOI: 10.1038/s41598-018-27333-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 05/27/2018] [Indexed: 12/02/2022] Open
Abstract
Fleshy macroalgae may increase photosynthesis with greater CO2 availability under ocean acidification (OA) and outcompete calcifying macroalgae important for tropical reef accretion. Macroalgae use energy-dependent carbon concentrating mechanisms (CCMs) to take up HCO3-, the dominant inorganic carbon for marine photosynthesis, but carbon-use strategies may depend on the pCO2, pH and irradiance. We examined photosynthesis in eight tropical macroalgae across a range of irradiances (0-1200 μmol photon m-2 s-1), pH levels (7.5-8.5) and CO2 concentrations (3-43 μmol kg-1). Species-specific CCM strategies were assessed using inhibitors and δ13C isotope signatures. Our results indicate that the log of irradiance is a predictor of the photosynthetic response to elevated pCO2 (R2 > 0.95). All species utilized HCO3-, exhibited diverse C-use pathways and demonstrated facultative HCO3- use. All fleshy species had positive photosynthetic responses to OA, in contrast to a split amongst calcifiers. We suggest that shifts in photosynthetically-driven tropical macroalgal changes due to OA will most likely occur in moderate to high-irradiance environments when CCMs are ineffective at meeting the C-demands of photosynthesis. Further, facultative use of HCO3- allows greater access to CO2 for photosynthesis under OA conditions, particularly amongst fleshy macroalgae, which could contribute to enhance fleshy species dominance over calcifiers.
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Affiliation(s)
- Regina C Zweng
- Biological Sciences Department, Aquatic Plant Ecology Lab, Florida Atlantic University, 777 Glades Rd, Boca Raton, FL, 33431, USA
- Department of Ecology and Evolutionary Biology, University of California, 618 Charles E Young Dr S, Los Angeles, CA, 90095, USA
| | - Marguerite S Koch
- Biological Sciences Department, Aquatic Plant Ecology Lab, Florida Atlantic University, 777 Glades Rd, Boca Raton, FL, 33431, USA.
| | - George Bowes
- Department of Biology University of Florida, 220 Bartram Hall, Gainesville, FL, 32611, USA
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18
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Hughes BB, Lummis SC, Anderson SC, Kroeker KJ. Unexpected resilience of a seagrass system exposed to global stressors. GLOBAL CHANGE BIOLOGY 2018; 24:224-234. [PMID: 28752587 DOI: 10.1111/gcb.13854] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 07/13/2017] [Indexed: 06/07/2023]
Abstract
Despite a growing interest in identifying tipping points in response to environmental change, our understanding of the ecological mechanisms underlying nonlinear ecosystem dynamics is limited. Ecosystems governed by strong species interactions can provide important insight into how nonlinear relationships between organisms and their environment propagate through ecosystems, and the potential for environmentally mediated species interactions to drive or protect against sudden ecosystem shifts. Here, we experimentally determine the functional relationships (i.e., the shapes of the relationships between predictor and response variables) of a seagrass assemblage with well-defined species interactions to ocean acidification (enrichment of CO2 ) in isolation and in combination with nutrient loading. We demonstrate that the effect of ocean acidification on grazer biomass (Phyllaplysia taylori and Idotea resecata) was quadratic, with the peak of grazer biomass at mid-pH levels. Algal grazing was negatively affected by nutrients, potentially due to low grazer affinity for macroalgae (Ulva intestinalis), as recruitment of both macroalgae and diatoms were favored in elevated nutrient conditions. This led to an exponential increase in macroalgal and epiphyte biomass with ocean acidification, regardless of nutrient concentration. When left unchecked, algae can cause declines in seagrass productivity and persistence through shading and competition. Despite quadratic and exponential functional relationships to stressors that could cause a nonlinear decrease in seagrass biomass, productivity of our model seagrass-the eelgrass (Zostera marina)- remained highly resilient to increasing acidification. These results suggest that important species interactions governing ecosystem dynamics may shift with environmental change, and ecosystem state may be decoupled from ecological responses at lower levels of organization.
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Affiliation(s)
- Brent B Hughes
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
- Division of Marine Science and Conservation, Nicholas School of the Environment, Duke University, Beaufort, NC, USA
| | - Sarah C Lummis
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Sean C Anderson
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA, USA
| | - Kristy J Kroeker
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
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19
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Growth, ammonium metabolism, and photosynthetic properties of Ulva australis (Chlorophyta) under decreasing pH and ammonium enrichment. PLoS One 2017; 12:e0188389. [PMID: 29176815 PMCID: PMC5703455 DOI: 10.1371/journal.pone.0188389] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 11/06/2017] [Indexed: 11/21/2022] Open
Abstract
The responses of macroalgae to ocean acidification could be altered by availability of macronutrients, such as ammonium (NH4+). This study determined how the opportunistic macroalga, Ulva australis responded to simultaneous changes in decreasing pH and NH4+ enrichment. This was investigated in a week-long growth experiment across a range of predicted future pHs with ambient and enriched NH4+ treatments followed by measurements of relative growth rates (RGR), NH4+ uptake rates and pools, total chlorophyll, and tissue carbon and nitrogen content. Rapid light curves (RLCs) were used to measure the maximum relative electron transport rate (rETRmax) and maximum quantum yield of photosystem II (PSII) photochemistry (Fv/Fm). Photosynthetic capacity was derived from the RLCs and included the efficiency of light harvesting (α), slope of photoinhibition (β), and the light saturation point (Ek). The results showed that NH4+ enrichment did not modify the effects of pH on RGRs, NH4+ uptake rates and pools, total chlorophyll, rETRmax, α, β, Fv/Fm, tissue C and N, and the C:N ratio. However, Ek was differentially affected by pH under different NH4+ treatments. Ek increased with decreasing pH in the ambient NH4+ treatment, but not in the enriched NH4+ treatment. NH4+ enrichment increased RGRs, NH4+ pools, total chlorophyll, rETRmax, α, β, Fv/Fm, and tissue N, and decreased NH4+ uptake rates and the C:N ratio. Decreased pH increased total chlorophyll content, rETRmax, Fv/Fm, and tissue N content, and decreased the C:N ratio. Therefore, the results indicate that U. australis growth is increased with NH4+ enrichment and not with decreasing pH. While decreasing pH influenced the carbon and nitrogen metabolisms of U. australis, it did not result in changes in growth.
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20
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Bertagnolli AD, Padilla CC, Glass JB, Thamdrup B, Stewart FJ. Metabolic potential and
in situ
activity of marine Marinimicrobia bacteria in an anoxic water column. Environ Microbiol 2017; 19:4392-4416. [DOI: 10.1111/1462-2920.13879] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Revised: 07/17/2017] [Accepted: 07/26/2017] [Indexed: 11/29/2022]
Affiliation(s)
| | - Cory C. Padilla
- School of Biological SciencesGeorgia Institute of TechnologyAtlanta GA USA
| | - Jennifer B. Glass
- School of Earth and Atmospheric SciencesGeorgia Institute of TechnologyAtlanta GA USA
| | - Bo Thamdrup
- Department of Biology and Nordic Center for Earth Evolution (NordCEE)University of Southern DenmarkOdense Denmark
| | - Frank J. Stewart
- School of Biological SciencesGeorgia Institute of TechnologyAtlanta GA USA
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21
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Xu D, Schaum CE, Lin F, Sun K, Munroe JR, Zhang XW, Fan X, Teng LH, Wang YT, Zhuang ZM, Ye N. Acclimation of bloom-forming and perennial seaweeds to elevated pCO 2 conserved across levels of environmental complexity. GLOBAL CHANGE BIOLOGY 2017; 23:4828-4839. [PMID: 28346724 DOI: 10.1111/gcb.13701] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 03/16/2017] [Accepted: 03/17/2017] [Indexed: 05/23/2023]
Abstract
Macroalgae contribute approximately 15% of the primary productivity in coastal marine ecosystems, fix up to 27.4 Tg of carbon per year, and provide important structural components for life in coastal waters. Despite this ecological and commercial importance, direct measurements and comparisons of the short-term responses to elevated pCO2 in seaweeds with different life-history strategies are scarce. Here, we cultured several seaweed species (bloom forming/nonbloom forming/perennial/annual) in the laboratory, in tanks in an indoor mesocosm facility, and in coastal mesocosms under pCO2 levels ranging from 400 to 2,000 μatm. We find that, across all scales of the experimental setup, ephemeral species of the genus Ulva increase their photosynthesis and growth rates in response to elevated pCO2 the most, whereas longer-lived perennial species show a smaller increase or a decrease. These differences in short-term growth and photosynthesis rates are likely to give bloom-forming green seaweeds a competitive advantage in mixed communities, and our results thus suggest that coastal seaweed assemblages in eutrophic waters may undergo an initial shift toward communities dominated by bloom-forming, short-lived seaweeds.
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Affiliation(s)
- Dong Xu
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
- Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | | | - Fan Lin
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Ke Sun
- First Institute of Oceanography, State Oceanic Administration, Qingdao, China
- Laboratory for Regional Oceanography and Numerical Modeling, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - James R Munroe
- Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Xiao W Zhang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Xiao Fan
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Lin H Teng
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Yi T Wang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Zhi M Zhuang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Naihao Ye
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
- Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
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22
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Ober GT, Thornber CS. Divergent responses in growth and nutritional quality of coastal macroalgae to the combination of increased pCO 2 and nutrients. MARINE ENVIRONMENTAL RESEARCH 2017; 131:69-79. [PMID: 28943069 DOI: 10.1016/j.marenvres.2017.09.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 08/29/2017] [Accepted: 09/09/2017] [Indexed: 06/07/2023]
Abstract
Coastal ecosystems are subjected to global and local environmental stressors, including increased atmospheric carbon dioxide (CO2) (and subsequent ocean acidification) and nutrient loading. Here, we tested how two common macroalgal species in the Northwest Atlantic (Ulva spp. and Fucus vesiculosus Linneaus) respond to the combination of increased CO2 and nutrient loading. We utilized two levels of pCO2 with two levels of nutrients in a full factorial design, testing the growth rates and tissue quality of Ulva and Fucus grown for 21 days in monoculture and biculture. We found that the opportunistic, fast-growing Ulva exhibited increased growth rates under high pCO2 and high nutrients, with growth rates increasing three-fold above Ulva grown in ambient pCO2 and ambient nutrients. By contrast, Fucus growth rates were not impacted by either environmental factor. Both species exhibited a decline in carbon to nitrogen ratios (C:N) with elevated nutrients, but pCO2 concentration did not alter tissue quality in either species. Species grown in biculture exhibited similar growth rates to those in monoculture conditions, but Fucus C:N increased significantly when grown with Ulva, indicating an effect of the presence of Ulva on Fucus. Our results suggest that the combination of ocean acidification and nutrients will enhance abundance of opportunistic algal species in coastal systems and will likely drive macroalgal community shifts, based on species-specific responses to future conditions.
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Affiliation(s)
- Gordon T Ober
- WM Keck Sciences, Claremont McKenna College, Claremont, CA 91711, USA.
| | - Carol S Thornber
- Biological and Environmental Sciences, University of Rhode Island, Kingston, RI 02881, USA
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Klein SG, Pitt KA, Nitschke MR, Goyen S, Welsh DT, Suggett DJ, Carroll AR. Symbiodinium mitigate the combined effects of hypoxia and acidification on a noncalcifying cnidarian. GLOBAL CHANGE BIOLOGY 2017; 23:3690-3703. [PMID: 28390081 DOI: 10.1111/gcb.13718] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 03/28/2017] [Accepted: 04/02/2017] [Indexed: 05/23/2023]
Abstract
Anthropogenic nutrient inputs enhance microbial respiration within many coastal ecosystems, driving concurrent hypoxia and acidification. During photosynthesis, Symbiodinium spp., the microalgal endosymbionts of cnidarians and other marine phyla, produce O2 and assimilate CO2 and thus potentially mitigate the exposure of the host to these stresses. However, such a role for Symbiodinium remains untested for noncalcifying cnidarians. We therefore contrasted the fitness of symbiotic and aposymbiotic polyps of a model host jellyfish (Cassiopea sp.) under reduced O2 (~2.09 mg/L) and pH (~ 7.63) scenarios in a full-factorial experiment. Host fitness was characterized as asexual reproduction and their ability to regulate internal pH and Symbiodinium performance characterized by maximum photochemical efficiency, chla content and cell density. Acidification alone resulted in 58% more asexual reproduction of symbiotic polyps than aposymbiotic polyps (and enhanced Symbiodinium cell density) suggesting Cassiopea sp. fitness was enhanced by CO2 -stimulated Symbiodinium photosynthetic activity. Indeed, greater CO2 drawdown (elevated pH) was observed within host tissues of symbiotic polyps under acidification regardless of O2 conditions. Hypoxia alone produced 22% fewer polyps than ambient conditions regardless of acidification and symbiont status, suggesting Symbiodinium photosynthetic activity did not mitigate its effects. Combined hypoxia and acidification, however, produced similar numbers of symbiotic polyps compared with aposymbiotic kept under ambient conditions, demonstrating that the presence of Symbiodinium was key for mitigating the combined effects of hypoxia and acidification on asexual reproduction. We hypothesize that this mitigation occurred because of reduced photorespiration under elevated CO2 conditions where increased net O2 production ameliorates oxygen debt. We show that Symbiodinium play an important role in facilitating enhanced fitness of Cassiopea sp. polyps, and perhaps also other noncalcifying cnidarian hosts, to the ubiquitous effects of ocean acidification. Importantly we highlight that symbiotic, noncalcifying cnidarians may be particularly advantaged in productive coastal waters that are subject to simultaneous hypoxia and acidification.
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Affiliation(s)
- Shannon G Klein
- Australian Rivers Institute - Coasts and Estuaries, Griffith School of Environment, Griffith University, Gold Coast, Qld, Australia
- Red Sea Research Center (RSRC), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Kylie A Pitt
- Australian Rivers Institute - Coasts and Estuaries, Griffith School of Environment, Griffith University, Gold Coast, Qld, Australia
| | - Matthew R Nitschke
- Climate Change Cluster (C3), University of Technology Sydney, Sydney, NSW, Australia
| | - Samantha Goyen
- Climate Change Cluster (C3), University of Technology Sydney, Sydney, NSW, Australia
| | - David T Welsh
- Environmental Futures Research Institute, Griffith School of Environment, Griffith University, Gold Coast, Qld, Australia
| | - David J Suggett
- Climate Change Cluster (C3), University of Technology Sydney, Sydney, NSW, Australia
| | - Anthony R Carroll
- Environmental Futures Research Institute, Griffith School of Environment, Griffith University, Gold Coast, Qld, Australia
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Young CS, Gobler CJ. The organizing effects of elevated CO 2 on competition among estuarine primary producers. Sci Rep 2017; 7:7667. [PMID: 28794479 PMCID: PMC5550435 DOI: 10.1038/s41598-017-08178-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 07/10/2017] [Indexed: 11/23/2022] Open
Abstract
Fossil fuel combustion, eutrophication, and upwelling introduce excess CO2 into coastal zones. The extent to which marine autotrophs may benefit from elevated CO2 will be a function of their carbon limitation and, among other factors, competition with other primary producers. Here, we report on experiments performed with North Atlantic species of Ulva and Gracilaria grown in situ or exposed to ambient (~400 µatm) and elevated pCO2 (~2500 µatm) and/or subjected to competition with each other and/or with natural plankton assemblages. Elevated pCO2 significantly increased the growth rates of Gracilaria and Ulva and yielded significant declines in tissue δ13C, suggesting that increased growth was associated with increased CO2 use relative to HCO3-. Gracilaria growth was unaffected by competition with plankton or Ulva, while Ulva experienced significantly reduced growth when competing with Gracilaria or plankton. Dinoflagellates experienced significantly increased growth when exposed to elevated pCO2 but significantly slower growth when competing with Gracilaria. Elevated carbon-to-nitrogen ratios among macroalgae suggested that competition for nitrogen also shaped interactions among autotrophs, particularly Ulva. While some estuarine autotrophs benefit from elevated pCO2, the benefit can change when direct competition with other primary producers is considered with Gracilaria outcompeting Ulva and dinoflagellates outcompeting diatoms under elevated pCO2.
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Affiliation(s)
- Craig S Young
- Stony Brook University, School of Marine and Atmospheric Sciences, Southampton, NY, 11968, USA
| | - Christopher J Gobler
- Stony Brook University, School of Marine and Atmospheric Sciences, Southampton, NY, 11968, USA.
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