Understanding Physiological Vulnerability of Ulva spp.: Implication to Green Tide Blooms

Jayvee A. Saco, Najeen Arabelle M. Rula, Glen Brian I. Aguila

Rationale

     Recently, green tide blooms are becoming one of the major environmental challenges among coastal environments. This phenomenon is caused by over-proliferation of green seaweeds Ulva, Ulvaria, and other Ulvophyceae, as a response to environmental changes, especially when coastal waters become nutrient-enriched. During the Beijing Olympics in June 2008, this phenomenon almost hindered the hosting of the sailing regatta in the shores of Qingdao, Eastern China (Cohen 2008; Walker 2009; Jing 2013). As a consequence, blooms may have significant negative effect on commercial and leisure fishing, human health, tourism activities and threaten coastal biodiversity (Sanseverino et al. 2016).

     In the Philippines, green tide blooms along the beaches of Boracay became controversial and widely publicized in 2017 and has led to the suspension of tourism activities and closure of the whole Island for rehabilitation (Rodriguez 2017). Also, this phenomenon was already documented in some parts of the country such as in Mactan Island, Cebu, Central Visayas (Largo et al. 2005) and El Salvador, Misamis Oriental, Northern Mindanao (Villaluz et al. 2016). The increasing trend on tourism and other human activities, poor sewage systems, and industrialization on the coast of Batangas and nearby provinces makes the Verde Island Passage (VIP) vulnerable to eutrophication, which could promote (macro- and micro-) algal blooms. As VIP is considered as the world’s center of the center of marine shore fish biodiversity (Carpenter and Springer 2005), bloom events may threaten this ecologically and economically important key marine conservation area, which may have cascading negative effects on marine biodiversity and ecological integrity, as well as the life and livelihood of coastal populations. Understanding the complex dynamics between Ulva photosynthesis (a basic process in primary production), growth and development, and physicochemical parameters may provide insights on preventing and/or mitigating the effects of green tide blooms. Moreover, profiling the diversity, distribution, and seasonality of Ulva standing crop could provide baseline information that may be used to identify and/or predict possible areas where green tide events are likely to occur. In addition, information on standing crop are especially useful towards the development of Ulva as commodities (e.g., as food for human consumption and feed additives) or as a potential renewable source of biofuels.

Objectives

     The general objective of this study is to provide baseline information on aspects of the biology, ecology, and physiology of green tide bloom-forming Ulva species in selected coastal areas in Batangas for coastal resources management and possible cultivation.

Specific Objectives

  • It aims to assess the standing crop/biomass, distribution, and phenology of different Ulva spp. In selected coastal areas in Batangas Province,
  • characterize the productivity and other photosynthetic characteristics of the naturally growing Ulva spp., under different physicochemical parameters and,
  • examine the optimum conditions for growth and development of Ulva spp. under different physicochemical parameters

Accomplishments

  • The first Meeting for ULVA Project was conducted last July 5, 2021 regarding orientation and discussion with the Project Staffs of ULVA Project, participated online by BatStateU and UPMSI Personnel.
  • Preliminary fieldwork including sampling of Ulva seaweed samples was conducted last July 15, 2021.
  • Preliminary sampling fieldwork in Pagkilatan, Batangas City and site reconnaissance at the Shoreline of Brgy. Cuta West, Batangas City.
  • An online webinar titled “Preliminary PAM Fluorometry and Oxygen-Evolution Technique: Determination of Photosynthetic Yield (II) and P-I Curve” was conducted last July 16-17, 2021. Actual practice for the set-up and application of PAM fluorometry and oxygen-evolution technique and seaweed sample handling were also held.