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Environment Research and Technology Development Fund S-13 Development of Coastal Management Method to Realize the Sustainable Coastal SeaEnvironment Research and Technology Development Fund S-13 Development of Coastal Management Method to Realize the Sustainable Coastal Sea

Home » Objectives » Topic 2: Development of coastal environmental management methods along the Sanriku Coast – a coast line that has a succession of open inner bays

Topic 2Development of coastal environmental management methods along the Sanriku Coast – a coast line that has a succession of open inner bays

Outline

This project will monitor the fluctuations in seaweed bed ecosystems on the Sanriku Coast to determine what human efforts are effective in restoring abundant coastal zones. Optimal aquaculture methods for oysters, scallops, wakame etc. on the Sanriku Coast will be proposed. In addition, quantitative evidence showing that the forests are the ocean’s best friend will be presented.

Topic Leader Teruhisa Komatsu (Associate Professor, Atmosphere and Ocean Research Institute, The University of Tokyo)

Subtopic (1) Monitoring of changes in coastal environments, and use of the results to develop methods for coastal sea management

Description of Research (FY 2014 – 2015 Achievements)

(1) Using satellite images, we determined the distribution of representative salt marshes and seaweed beds formed by the tsunami at locations south of Ofunato City and studied the changes in the distribution of estuaries, etc. before and after the tsunami. Continuing the research from FY 2014, we studied the relationship between growth and food in oysters and other non-fed cultivated organisms depending on the location in Shuzugawa Bay and prepared references for use in creating ecosystem models. In addition, we studied the results of an ecosystem model created by the synthesis team to determine whether it could explain the growth of oysters, etc. in Shizugawa Bay.

Description of Research (FY 2016 Plan)

(1) Using satellite images, we will study the salt marshes that are a major ecotone formed by the tsunami between the cities of Kamaishi and Miyako, as well as the distribution of seaweed beds that were affected by the tsunami and the changes in the distribution of estuaries, etc. before and after the tsunami. Using the ecosystem model created by the synthesis team, we will study the ideal placement and intake capacity of cultivating facilities for oysters and other non-fed cultivated organisms, and conduct a study to identify problems that may occur in the event of actual ideal placement and the resolution to those problems. We will also gather and study basic information on the impact of enormous breakwaters on the coastal ecosystem.

Subtopic Leader Teruhisa Komatsu (Associate Professor, Atmosphere and Ocean Research Institute, The University of Tokyo)

Subtopic (2) Determination of the mechanisms of nutrient transfer among forests, rivers and oceans

Description of Research (FY 2014 – 2015 Achievements)

(2) We studied the changes in the quantity and quality of nutrient salts brought by rivers resulting from differences in land use patterns. We also estimated the annual load flux from the rivers flowing into Shizugawa Bay, based on a consideration of seasonal differences in water quality and flow rate. In the collaboration of forest, river and ocean, we determined the sources of nutrient salts as forest soil on land, soil from cultivated fields, and substances from forests and other vegetation on land, and estimated the nutrient salt discharge potential of each source. We also monitored the distribution and cyclic processes of nutrient salts in seaweed beds and salt marshes in coastal zones. Through experiments both at site and in the laboratory, we analyzed nutrient salt circulation in relation to oysters, one of the major cultivated shellfish in the bay. Moreover, we also estimated the quantity of water and nutrient salts flowing in from outside the bay.

Description of Research (FY 2016 Plan)

(2) Focusing primarily on the dynamics of nutrient salts from inland water in the bay, we will use water sampling and existing information on seawater flow to determine the horizontal and vertical distribution throughout the seasons. At the same time, we will quantify the existing quantities of primary (basic) producers (phytoplankton, benthic microalgae, periphytic microalgae, Zostera, macroalgae) that form the foundation of the material circulation system (biological ecosystem). As much as possible, we will measure the basic speed of production in these sectors (using values from existing reference in cases in which measurement is difficult) to assess the basic production capacity of Shizugawa Bay as a whole. We will also estimate the elution of nutrient salts from seafloor sediment. In addition, we will quantify the filtration capacity and nutrient salt regeneration capacity of oysters. To verify that “forests are the lover of the oceans,” we will monitor the change in nutrient salt concentration over minute time intervals (in units ranging from hours to days) in order to quantify the nutrient salt dynamics relating to material circulation from land to rivers to marshes.

Subtopic Leader Shigeru Montani (Professor, Graduate School of Fisheries Sciences, Hokkaido University)

Subtopic (3) 1 Determination of the role of organic matter in substance transfer between forests and oceans

Description of Research (FY 2014 – 2015 Achievements)

(1) We continued studying the dynamics of the organic matter that affects the chemical state of iron in diverse types of soil such as Shizugawa Bay in Miyagi Prefecture, the rivers flowing into the bay, forests, rice paddies and so on, and gathered data throughout the year. We also began tests of the iron intake of microalgae, with the aim of determining their contribution to the primary production of iron in natural water. Specifically, we isolated the dominant microalgae strains in Shizugawa Bay and used diverse water samples obtained through field testing to cultivate these strains in the laboratory, in order to investigate the dynamics of bioavailable iron at the site. Through these studies, we were able to evaluate the effect of the chemical dynamics of iron, the water quantity conditions, and light and other environmental conditions on the iron intake of microalgae, and to collect basic information for use in determining the role of iron in primary production in Shizugawa Bay.

Description of Research (FY 2016 Plan)

We will continue to conduct microalgae iron intake tests, focusing on organic matter and physicochemical conditions, and coordinate with the results of the research conducted up to and including the previous fiscal year to determine the characteristics of iron and organic matter in Shizugawa Bay and the rivers flowing into the bay, as well as assessing the temporal and spatial fluctuations in iron and organic matter and the resulting changes in the utility of microalgae in the bay. In other words, we will conduct a quantitative assessment of the role of iron supplied from land via rivers, from the standpoint of basic production by microalgae in Shizugawa Bay.

Subtopic Leader Chihiro Yoshimura (Associate Professor, Graduate School of Science and Engineering, Tokyo Institute of Technology)

Subtopic (3) 2 Determination of the role of organic matter in material transport between forests and oceans

Description of Research (FY 2014 – 2015 Achievements)

Continuing the research from FY 2014, we continued to study the spread of organic matter coming from rivers at the estuaries of Shizugawa Bay and studied the effect of this organic matter on bioavailability and community composition. We also studied the dynamics of organic matter in oyster and other cultivation beds and the growth of cultivated organisms, as well as the distribution of organic matter that is the source of seaweed and seagrass beds, and quantified the production activity of the particulate organic matter that is produced there. We also studied the distribution of particulate organic matter in river water, open ocean water and the bay in order to build particulate organic matter models, and gathered information on the chemical composition and oxygen consumption characteristics of fatty acids, isotopes and so on.

Description of Research (FY 2016 Plan)

(3) We will continue the research conducted up to and including FY 2015 and conduct an analysis together with the data collected up to that time, and will also work to prepare an interim report on the following.
1) Assessment of the contribution of organic matter from each source (watershed, seagrass bed, phytoplankton etc.) with respect to the particulate organic matter pool in Shizugawa Bay and primary consumers, based on the results of an analysis of fatty acid composition, an analysis of carbon and nitrogen stable isotopes and so on. The role of organic matter from watersheds with respect to the growth of primary consumers and assimilated food and the like will also be assessed.
2) Based on quantitative data on the dynamics of particulate organic matter that have been collected up to now, an estimate of the flux in the dynamics of various types of organic matter needed to assess the approximate inflow and outflow of organic matter in Shizugawa Bay will be conducted.

Subtopic Leader Osamu Nishimura (Professor, Graduate School of Engineering, Tohoku University)