Challenge 01: Understand and beat marine pollution
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Ocean Decade
Challenge 01:
Understand and beat marine pollution
Understand and map land and sea-based sources of pollutants and contaminants and their potential impacts on human health and ocean ecosystems and develop solutions to remove or mitigate them.
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- Composition and spatial distribution of infauna in a river estuary affected by fishpond effluentsGalope-Bacaltos, Della Grace; San Diego-McGlone, Maria Lourdes (Elsevier BV, 2002-08)Infauna, either macrofauna or meiofauna, are benthos and phytal fauna which pass through a 1.0-0.5 mm screen (Hulings and Gray, 1971). These organisms include a wide array of taxonomic groups, namely: nematodes, oligochaetes, polychaetes, copepods, and amphipods. The importance of infauna in benthic ecosystems has been investigated because they play vital roles in the ecology of the marine environment. Their diverse morphology and ability to adapt to various habitats make them important as food for large benthic organisms (McIntyre, 1964; Christensen, 1967; Tietjen, 1969; Thorson, 1971; Bretschko, 1973) and in the recirculation of nutrients (Thorson, 1966; McIntyre, 1973; Gerlach and Schrage, 1971; Mercer and Cairns, 1973).
- Elevated seawater temperatures affect embryonic and larval development in the giant clam Tridacna gigas (Cardiidae: Tridacninae)Enricuso, Odette B.; Conaco, Cecilia; Sayco, Sherry Lyn G.; Neo, Mei Lin; Cabaitan, Patrick (Oxford Academic, 2018-11-17)Giant clams are the largest bivalve molluscs and play a key role in coral reef ecosystems. Almost all species are considered endangered or vulnerable to extinction, thus requiring intervention through culturing and restocking. Although successful culture techniques have been developed, the responses of giant clam embryos and larvae to environmental factors, such as seawater temperature, are not yet fully understood. In this study, fertilization, development and survival of Tridacna gigas larvae were observed at low (28 °C), medium (30 °C) and high (33 °C) seawater temperatures. Fertilization success was not significantly different between the water temperatures tested. At 28 °C, ciliated gastrulae appeared first at 12 h postfertilization (hpf) and trochophore larvae at 24 hpf. In contrast, more rapid development was observed at 30 °C and 33 °C, with ciliated gastrulae first appearing at 9 hpf and trochophore larvae at 18 hpf. Veliger larvae were observed after 48 h at 28 °C and 30 °C. No veligers were observed at 33 °C, but a greater proportion of embryos and larvae exhibited developmental abnormalities at this temperature compared with the other treatments. Larval survival was lowest at 33 °C at the 12 and 24 h timepoints, although there was no longer a significant difference across treatments after 48 h. Furthermore, post-settlement survival of juveniles subjected to different seawater temperatures for 22 d starting at 8 d postfertilization (dpf) was lowest at 33 °C. These findings reveal that higher water temperatures promote rapid progression through early development, but result in lower overall survival as a consequence of abnormal development and reduced post-settlement survival.The authors acknowledge Julio Curiano and the staff of the Bolinao Marine Laboratory for assistance with experiments. This work was supported in part by the University of the Philippines Marine Science Institute; a grant from the National Geographic Society (ASIA-08-15) to PCC; a grant from the Department of Science and Technology Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development (QMSR-MRRD-MEC-295-1449) to PCC and CC; and a Department of Science and Technology Science Education Institute graduate scholarship to OBE. MLN acknowledges the support of the National Research Foundation Singapore for research at the St John’s Island National Marine Laboratory.
- The community composition and production of phytoplankton in fish pens of Cape Bolinao, Pangasinan: A field studyYap, Leni G.; Azanza, Rhodora V.; Talaue-McManus, Liana (Elsevier BV, 2004-11)From 1995 up to the present, fish pens proliferated in the municipal waters of Bolinao, northern Philippines. Since then, fish kills and phytoplankton blooms have been recurrent. Have fishpens altered the phytoplankton community composition and production of these waters? The phytoplankton community in Cape Bolinao, Lingayen Gulf is typical of a tropical coastal area where diatoms alternate with dinoflagellates during the dry and wet seasons. In the nutrient-rich fish pens, phytoplankton in this study showed a lower diatom/dinoflagellate ratio and unusually high phytoplankton counts of 104 cells/l and even as high as 105 cells/l. Correlations between physico-chemical parameters, phytoplankton production and community composition were made in 2001. This paper tried to explain the occurrence of a Cylindrotheca closterium bloom (105 cells/l), during the dry season of the same year and a Prorocentrum minimum bloom (4.7 × 105 cells/l), which accompanied a massive fish kill during January 2002.
- Comparison of coral growth and survival under enclosed, semi-natural conditions and in the fieldYap, Helen T.; Molina, Reverie Alvarez (Elsevier BV, 2003-07)Two closely related scleractinian coral species, Porites cylindrica and Porites rus, were transplanted to two different locations: the natural environment on the reef flat, and culture tanks on land. The use of tanks enabled the regulation of certain environmental factors, and, hence, the evaluation of specific responses of the corals to these factors. For both species, growth and survival were much better in the field than in the land-based tanks most probably due to unrestricted water circulation. Since the two species were subjected to identical experimental treatments, it was possible to distinguish inherent differences between them in terms of responses to external variables. Porites cylindrica was more susceptible than P. rus to predation by corallivores. Predators, as well as grazers, occurred in significant numbers in the field, but not in the land-based tanks. Porites rus, on the other hand, succumbed more readily to overgrowth by macroalgae which thrived in the culture tanks presumably because of significantly higher nutrient levels and the conspicuous absence of grazers. These results have broader ecological implications because of accelerated environmental changes taking place in present-day reefs due to human impact. Major examples are eutrophication and alterations in water circulation which frequently result in sub-optimal conditions for coral survival and growth.
- Intensive fish farming in the Philippines is detrimental to the reef-building coral Pocillopora damicornisVillanueva, R. D.; Yap, H. T.; Montaño, M. N. E. (Inter-Research Science Center, 2006-07-03)To determine the effects of fish farm effluent on the reef-building species Pocillopora damicornis, we exposed different life stages of the coral to a gradient of effluent concentrations. After 81 d no juvenile coral survived at the Fish Farm site or at the site receiving intermediate concentrations, and survival rates were low (<20%) at the site receiving minimal effluent concentrations and at the reference site. At the Fish Farm site, juveniles (on terracotta tiles) were completely overgrown by barnacles. Coral nubbins and mature colonies displayed similar survivorship trends along the effluent gradient, i.e. higher mortality with higher effluent concentrations. At the site of intermediate exposure, surviving nubbins had skeletal growth rates half of those from the site of minimal influence and from the reference site. The mean gross photosynthesis to respiration ratio of coral branches deployed at the fish farm was below the physiological compensatory value of 1, whereas values of about 1 were attained at the sites of diminishing effluent influence. Reduced larval output in mature colonies exposed to intermediate and minimal concentrations of fish farm effluent were observed as compared to those from the reference site. No reproductive measurements could be conducted for colonies at the Fish Farm site, due to high mortality. At the larval stage, metamorphosis was diminished both on substrates collected from, and tiles conditioned in, the Fish Farm environment, compared to those from sites of diminishing effluent influence. Hence, many aspects of coral biology are impaired by exposure to effluent from intensive fish farming.
- Microcystin production during algal bloom occurrence in Laguna de Bay, the PhilippinesBaldia, Susana F.; Conaco, Ma Cecilia G.; Nishijima, Toshitaka; IMANISHI, SUSUMU; Harada, Ken-ichi (Japanese Society of Fisheries Science, 2003-02)The amount of microcystin in Microcystis aeruginosa bloom was investigated during the rainy season of 1999 in Laguna de Bay, the Philippines. Bloom samples taken from the West Bay and East Cove stations of the lake were studied in relation to the characteristics of environmental conditions. Four types of microcystins, microcystin-LR (MC-LR), microcystin-RR (MC-RR), 6(Z)-Adda-microcystin-RR, and 3-desmethylmicrocystin-LR were identified from the natural bloom samples among which MC-LR was the most dominant type of microcystin. Production of microcystin (88.6 µg/100 mg dried cells) was highest during the first sampling week that coincided with high water transparency and high conductivity. The occurrence of a strong typhoon during the second sampling week had changed the environment drastically, which was characterized by low water transparency, high turbidity, low water temperature, and with trace amounts of MC-LR detected at the East Cove station. Thus, toxin production over time as well as the relationship between Microcystis production and toxin concentration could not be fully evaluated.
- Copper pollution exacerbates the effects of ocean acidification and warming on kelp microscopic early life stagesLeal, Pablo P.; Hurd, Catriona L.; Sander, Sylvia G.; Armstrong, Evelyn; Fernández, Pamela A.; Suhrhoff, Tim Jesper; Rolenda, Michael Y. (Nature, 2018-10-03)Ocean warming (OW), ocean acidification (OA) and their interaction with local drivers, e.g., copper pollution, may negatively affect macroalgae and their microscopic life stages. We evaluated meiospore development of the kelps Macrocystis pyrifera and Undaria pinnatifida exposed to a factorial combination of current and 2100-predicted temperature (12 and 16 °C, respectively), pH (8.16 and 7.65, respectively), and two copper levels (no-added-copper and species-specific germination Cu-EC50). Meiospore germination for both species declined by 5–18% under OA and ambient temperature/OA conditions, irrespective of copper exposure. Germling growth rate declined by >40%·day−1, and gametophyte development was inhibited under Cu-EC50 exposure, compared to the no-added-copper treatment, irrespective of pH and temperature. Following the removal of copper and 9-day recovery under respective pH and temperature treatments, germling growth rates increased by 8–18%·day−1. The exception was U. pinnatifida under OW/OA, where growth rate remained at 10%·day−1 before and after copper exposure. Copper-binding ligand concentrations were higher in copper-exposed cultures of both species, suggesting that ligands may act as a defence mechanism of kelp early life stages against copper toxicity. Our study demonstrated that copper pollution is more important than global climate drivers in controlling meiospore development in kelps as it disrupts the completion of their life cycle.
- Interannual coral Δ14C records of surface water exchange across the Luzon StraitRamos, Riovie D.; Goodkin, Nathalie F.; Druffel, Ellen R. M.; Fan, N.; Siringan, F. P. (AGU Publications, 2019-01-02)The Luzon Strait (LS) hosts the largest transport of water between the Western Pacific Ocean (WPO) and the South China Sea (SCS). The transport through the strait, dominated by the westward propagation of the Kuroshio Intrusion, influences the climate and circulation of the SCS. While numerical models have investigated the interannual variability of the transport and subsequent water exchange across the LS, a lack of long-term on-site records prevents a general consensus on the transport rates, variability, and drivers. Corals offer high-resolution, continuous histories of radiocarbon (Δ14C) content of the seawater dissolved inorganic carbon, allowing us to track changes in ocean transport and circulation through time. Seasonal and annual Δ14C samples from Houbihu, Taiwan, and Palaui, Philippines, located on either side of the strait, are compared to the Western Pacific Ocean and SCS Δ14C records to examine the spatial and temporal Δ14C variability in the region. We calculated the mean transport across the strait using a five-box mixing model and identified its potential drivers. The mean amount of water exchanged across the strait from 1970 to 1999 was 2.2 Sv, ranging from −13.4 to 16 Sv, where a positive (negative) value indicates net flow into (out of) the SCS. A weaker East Asian Winter Monsoon increases the contribution of the SCS outflow on the Kuroshio Intrusion-dominated LS, while the El Niño–Southern Oscillation primarily drives the intrusion into the SCS. These results provide support to the dominant control of El Niño–Southern Oscillation on the long-term ocean circulation variability in this region.The authors would like to thank K. Hughen and J. Ossolinski for fieldwork. Additional help in the field was also provided by J. Aggangan, J. Quevedo, R. Lloren, G. Albano, J. Perez, and A. Bolton in the Philippines and S. Murty, A. Bolton, L. Tsai, R. Tan, S. Doo, I. Suprihanto, and D. Prayudi in Taiwan. We thank S. Griffin for the Δ14C analysis. The detailed comments and suggestions of two anonymous reviewers significantly improved the original manuscript. Coral Δ14C data set and box model calculations are available in the supporting information. This research was funded by the National Research Foundation Singapore under its Singapore NRF Fellowship scheme awarded to N. F. Goodkin (National Research Fellow award NRF-RF2012-03), as administered by the Earth Observatory of Singapore and the Singapore Ministry of Education under the Research Centres of Excellence initiative and by the Ministry of Education, Singapore through its Academic Research Fund Tier 2 (Project MOE2016-T2-1-016). This work is a part of the International Atomic Energy Agency (IAEA) Coordinated Research Project K41015. This work comprises Earth Observatory of Singapore contribution 229.
- Over 30 years of HABs in the Philippines and Malaysia: What have we learned?Yñiguez, Aletta T.; Lim, Po Teen; Leaw, Chui Pin; Jipanin, Steffiana J.; Iwataki, Mitsunori; Benico, Garry; Azanza, Rhodora V. (Elsevier, 2021-02)In the Southeast Asian region, the Philippines and Malaysia are two of the most affected by Harmful Algal Blooms (HABs). Using long-term observations of HAB events, we determined if these are increasing in frequency and duration, and expanding across space in each country. Blooms of Paralytic Shellfish Toxin (PST)-producing species in the Philippines did increase in frequency and duration during the early to mid-1990s, but have stabilized since then. However, the number of sites affected by these blooms continue to expand though at a slower rate than in the 1990s. Furthermore, the type of HABs and causative species have diversified for both toxic blooms and fish kill events. In contrast, Malaysia showed no increasing trend in the frequency of toxic blooms over the past three decades since Pyrodinium bahamense was reported in 1976. However, similar to the Philippines, other PST producers such as Alexandrium minutum and Alexandrium tamiyavanichii have become a concern. No amnesic shellfish poisoning (ASP) has been confirmed in either Philippines or Malaysia thus far, while ciguatera fish poisoning cases are known from the Philippines and Malaysia but the causative organisms remain poorly studied. Since the 1990s and early 2000s, recognition of the distribution of other PST-producing species such as species of Alexandrium and Gymnodinium catenatum in Southeast Asia has grown, though there has been no significant expansion in the known distributions within the last decade. A major more recent problem in the two countries and for Southeast Asia in general are the frequent fish-killing algal blooms of various species such as Prorocentrum cordatum, Margalefidinium polykrikoides, Chattonella spp., and unarmored dinoflagellates (e.g., Karlodinium australe and Takayama sp.). These new sites affected and the increase in types of HABs and causative species could be attributed to various factors such as introduction through mariculture and eutrophication, and partly because of increased scientific awareness. These connections still need to be more concretely investigated. The link to the El Niño Southern Oscillation (ENSO) should also be better understood if we want to discern how climate change plays a role in these patterns of HAB occurrences.
- Sorption of paralytic shellfish toxins (PSTs) in algal polysaccharide gelsOlano, Dave Eldon B.; Salvador-Reyes, Lilibeth A.; Montaño, Marco Nemesio E.; Azanza, Rhodora V. (Elsevier, 2020-01)Sorption mechanics of the paralytic shellfish toxins (PSTs), saxitoxin (STX) and neo-saxitoxin (neo-STX), on algal polysaccharide gels was characterized using surface chemistry models. Refined (RC), semi-refined (SRC) carrageenan and alginate showed sorption of STX and neo-STX. The sorption of PSTs on RC, SRC and alginate was affected by contact time and in part, temperature. From surface chemistry models, alginate followed a spontaneous endothermic physical monolayer sorption of STX and neo-STX. SRC and RC favoured the concurrence of physical and chemical monolayer sorption, being endothermic for SRC and exothermic for RC.The authors acknowledge funding from the Department of Science and Technology – Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development (DOST-PCAARRD) through the research program Hazard Detection and Mitigation Tools for Opportunistic Algal Blooms in a Changing Environment. We thank A. Yñiguez, J. K. Andres and J. Mendoza for technical assistance and M. Murphy for critically reviewing the manuscript. This is MSI Contribution No. 466.