Trojan horses in the marine realm: characterizing protistan parasite ecology in coastal waters

Protists are taxonomically and metabolically diverse drivers of energy and nutrient flow in the marine environment, with recent research suggesting significant roles in global carbon cycling throughout the water column. Top-down controls on planktonic protists include grazing and parasitism, processes that both contribute to nutrient transfer and biogeochemical cycling in the global ocean. Recent global surveys of eukaryotic small subunit ribosomal RNA molecular signatures have highlighted the fact that parasites belonging to the marine alveolate order Syndiniales are both abundant and ubiquitous in coastal and open ocean environments, suggesting a major role for this taxon in marine food webs. Two coastal sites, Saanich Inlet (Vancouver Island, BC) and Salt Pond (Falmouth, MA, USA) were selected as model ecosystems to examine the impacts of Syndinian parasitism on protist communities. Data presented in this thesis combines high-resolution sampling, water chemistry (including nutrients) analyses, molecular marker gene analyses, fluorescence in situ hybridization, and modeling to address key knowledge gaps regarding syndinian ecology. Information is presented on previously undescribed putative host taxa, the prevalence of syndinian parasites and infections on different hosts in coastal waters, and a framework for modeling host-parasite interactions based on field observations.

Evaluation of Water Suitability for Sustainable Seaweed (Kappaphycus Alvarezii) Cultivation to Support Science Technopark in North Kalimantan

Tarakan dry seaweed production increased during 2012-2018 for the cultivation of Kappaphycus alvarezii with the longline planting method. This study aims to assess the quality of the waters and their suitability for seaweed cultivation on the coast of Tarakan Island. The environmental parameters of water quality measured were chlorophyll-a, water temperature, salinity, pH, DO, TDS, turbidity, nitrate, phosphate, water depth, current velocity, protection, research location, and distance between settlements. The study was conducted with in-situ and ex-situ measurements based on APHA (2012). Water samples were taken using the multi-parameter Horiba U51. chlorophyll-a was analyzed using spectrophotometric methods, nitrate levels were analyzed using SNI 06-6989.79-2011, while phosphates were analyzed using SNI 06-6989.31-2005. The suitability of the waters is divided into 4 classes, S1 (very suitable), S2 (suitable), S3 (marginally suitable), and N (not suitable). The results showed that the coast of Tarakan Island has 3 categories, namely marginally suitable (S3) 13.20%, suitable (S2) 86.50%, and very suitable (S1) 0.30%. The existing condition of the coastal waters of Tarakan Island supports the cultivation of K. alvarezii seaweed. Tarakan Island coastal existing condition as an areal support seaweed cultivation K. alvarezii with the potential to be developed land area of 33896.73 ha.

Plastic After an Extreme Storm: The Typhoon-Induced Response of Micro- and Mesoplastics in Coastal Waters

Extreme storms, such as tropical cyclones, are responsible for a significant portion of the plastic debris transported from land to sea yet little is known about the storm response of microplastics and other debris in offshore and open waters. To investigate this, we conducted floating plastic surveys in the center of Sagami Bay, Japan approximately 30 km from the coastline, before and after the passage of a typhoon. The concentrations (number of particles/km2) of micro- and mesoplastics were two orders of magnitude higher 1-day after the typhoon than the values recorded pre-typhoon and the mass (g/km2) of plastic particles (sum of micro- and mesoplastics) increased 1,300 times immediately after the storm. However, the remarkably high abundance of micro- and mesoplastics found at 1-day after the typhoon returned to the pre-typhoon levels in just 2 days. Model simulations also suggested that during an extreme storm a significant amount of micro- and mesoplastics can be rapidly swept away from coastal to open waters over a short period of time. To better estimate the annual load of plastics from land to sea it is important to consider the increase in leakages of plastic debris into the ocean associated with extreme storm events.