National Committee on Marine Sciences (NCMS)
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- Nitrite regeneration in the oligotrophic Atlantic OceanClark, Darren R.; Rees, Andrew P.; Ferrera, Charissa M.; Al-Moosawi, Lisa; Somerfield, Paul J.; Harris, Carolyn; Quartly, Graham D.; Goult, Stephen; Tarran, Glen; Lessin, Gennadi (Copernicus GmbH, 2022-03-07)The recycling of scarce nutrient resources in the sunlit open ocean is crucial to ecosystem function. Nitrification directs ammonium (NH4+) derived from organic matter decomposition towards the regeneration of nitrate (NO3-), an important resource for photosynthetic primary producers. However, the technical challenge of making nitrification rate measurements in oligotrophic conditions combined with the remote nature of these environments means that data availability, and the understanding that provides, is limited. This study reports nitrite (NO2-) regeneration rate (RNO2 – the first product of nitrification derived from NH4+ oxidation) over a 13 000 km transect within the photic zone of the Atlantic Ocean. These measurements, at relatively high resolution (order 300 km), permit the examination of interactions between RNO2 and environmental conditions that may warrant explicit development in model descriptions. At all locations we report measurable RNO2 with significant variability between and within Atlantic provinces. Statistical analysis indicated significant correlative structure between RNO2 and ecosystem variables, explaining ∼65 % of the data variability. Differences between sampling depths were of the same magnitude as or greater than horizontally resolved differences, identifying distinct biogeochemical niches between depth horizons. The best overall match between RNO2 and environmental variables combined chlorophyll-a concentration, light-phase duration, and silicate concentration (representing a short-term tracer of water column physical instability). On this basis we hypothesize that RNO2 is related to the short-term autotrophic production and heterotrophic decomposition of dissolved organic nitrogen (DON), which regenerates NH4+ and supports NH4+ oxidation. However, this did not explain the observation that RNO2 in the deep euphotic zone was significantly greater in the Southern Hemisphere compared to the Northern Hemisphere. We present the complimentary hypothesis that observations reflect the difference in DON concentration supplied by lateral transport into the gyre interior from the Atlantic's eastern boundary upwelling ecosystems.We thank the crew of the AMT19 cruise. MSLA data were obtained and analysed through the NERC Earth Observation Data Acquisition and Analysis Service (NEODAAS), and further data were provided by the European Space Agency's Sea Level CCI. This is contribution number 320 of the AMT program supported by UKRI through the National Capability Long-term Single Centre Science Programme, Climate Linked Atlantic Sector Science program and further from the Natural Environment Research Council funded Microbial Carbon Pump project. We would like to thank Dennis Hansell and two anonymous reviewers for constructive and insightful comments.
- Lake Sebu fish kill destroys ₱20M worth of tilapiaSarmiento, Bong S. (Philippine Daily Inquirer, Inc., 2021-01-13)At least 1,000 fish cages containing about 200,000 kilograms of tilapia were ravaged by the latest fish kill in Lake Sebu town, South Cotabato province, last week, an official said on Monday. Lake Sebu Mayor Floro Gandam said at least 250 tilapia growers would get aid from the local government to recover their losses estimated at P20 million.But officials who joined an emergency meeting which Gandam convened on Monday did not think the damage was extensive enough to place the town under a state of calamity. Christopher Ofong, the municipal information officer, said the disaster risk reduction and management office decided against recommending the declaration of state of calamity because some criteria were not met, such as the condition that the fish kill should affect at least 20 percent of the population.
- Quinta' aftermath: Deaths, fishkillLocus, Sundy Mae T.; Romero, Maria; Wakefield, Francis T. (Concept & Information Group, Inc., 2020-10-29)Bureau of Fisheries and Aquatic Resources (BFAR) Region 5, meanwhile, reported an initial 20 metric tons of tilapia valued at P2.1 million were lost. BFAR-5’s Regional Fisheries Laboratory conducted water sampling in six villages — Iraya, Ibayugan, Tambo, Cabatuan, Salvacion and Sta. Elena. Results showed low dissolved oxygen (DO), ranging from 0.18 to 4.37PPM, and very high ammonia (ranging from 7.58 to 10,679 mg/L) content in Lake Buhi. Normal and tolerable ranges of DO are below 5PPM and ammonia at only 0.050 mg/L or lower.
- ₱12.3-M tilapia lost in Taal Lake fish kill: BFAR monitoring waters off 3 lakeshore townsCinco, Maricar (Philippine Daily Inquirer, Inc., 2019-06-01)At least 150 tons or P12.3 million worth of cultured tilapia turned belly-up in fish cages in Taal Lake in Batangas province due to a low level of dissolved oxygen in the water. The Department of Environment and Natural Resources and the local government of Laurel town in Batangas continued to closely monitor the remaining fish cages after the fish kill occurred in the villages of Gulod and Buso-buso in the last two days. As of Friday, provincial environment officer, Jose Elmer Bascos, said they had yet to dispose all of the dead fish as they needed a larger area to bury them.
- Taal fish feeding resumes as water quality improvesSimeon, Louise Maureen (Philippine Star Printing Co., Inc., 2019-02-09)Fish cage operators can now resume feeding their fish stocks in Taal Lake after tests showed improvements in the quality of water. Agriculture Secretary William Dar said tests conducted by the Bureau of Fisheries and Aquatic Resources (BFAR) from Jan. 14 to 30 revealed that the level of dissolved oxygen in Taal Lake, which is essential to fish growth and survival, had already improved. BFAR Calabarzon director Sammy Malvas said Taal water quality tests also showed that the sulfide level is within normal.
- RP's first mariculture park to rise in GuimarasFernandez, Rudy A. (Philippine Star Printing Co., Inc., 2001-06-17)The country's first mariculture park has been established in Igang Bay, Nueva Valencia, Guimaras. The park was jointly set up by the government-hosted Southeast Asian Fisheries Development Center Aquaculture Department (SEAFDEC AQD), Department of Agriculture-Bureau of Fisheries and Aquatic Resources (DA-BFAR) and the provincial government of Guimaras. The facility will be launched on July 5 as one of the main activities during the celebration of SEAFDEC AQD's 28th anniversary.
- Who killed the milkfish?Cardinoza, Gabriel (Philippine Daily Inquirer, Inc., 2011-06-08)They're stubborn. These are the words of Nestor Domenden, regional director of the Bureau of Fisheries and Aquatic Resources (BFAR) when asked why fishkills have been a recurring nightmare in Bolinao and Anda towns in western Pangasinan in the last 10 years. “They (milkfish growers) know where their fishing structures should be built, but they continued to disregard it,” Domenden says. A report from the office of the provincial agriculturist in Lingayen shows that 72 of the 75 fishkill-hit cages were built in the waters off Catubig Point in Barangay Tara up to Barangay Culang in Bolinao, while the rest, mostly bamboo pens, dotted the fishing area from Barangay Mal-ong to Barangay Awag and across the Kakiputan Channel to the island village of Siapar in Anda.
- Fishkill hits cages in Taal LakeCinco, Maricar (Philippine Daily Inquirer, Inc., 2018-11-06)The local government of Agoncillo town in Batangas province will distribute tilapia fingerlings to local cage operators affected by the recent fishkill in Taal Lake. The incidence of “fish mortality,” a term preferred by local officials in referring to a smaller area where fish turn belly up, occurred at Barangay Subic Ilaya, said Agoncillo Mayor Daniel Reyes. He said 105 cages, out of 1,555 operating in the town, were affected, with about P5 million worth of mature and juvenile tilapia killed in a phenomenon called “sulfur upwelling.”