Influence of a Sargassum forest on the spatial distribution of water flow

Abstract

The influence of a Sargassum forest on the spatial distribution of water flow generated by waves and tidal currents was investigated. Water flow was measured horizontally and vertically by using plaster balls at a Sargassum forest in Saiki Bay facing the Bungo Channel, on the Pacific Coast of Kyushu Island, Japan, from 7 to 9 March 1989 during the luxuriant growth season of Sargassum species. Plaster balls were deployed at several depths at stations placed with horizontal scales of 10–100 m. Wet weight loss of plaster balls immersed in the field for 50 h was converted to the speed of steady flow (named intensity of water motion) that brought the equivalent loss in a tank experiment. The results clarified that the spatial distribution of water flow showed good correlation with that of the standing crop of Sargassum forest, and that the intensity of water motion was appreciably diminished in the Sargassum forest. We also discuss ecological implications of the reduction in water flow within the Sargassum forest for the growth and settlement of Sargassum species.

Insights into the species diversity of the genus Sargassum (Phaeophyceae) in the Mediterranean Sea, with a focus on a pre-viously unnoticed taxon from Algeria

“…Sargassum species can form extensive marine forests that are major components of the underwater seascape and coastal ecosystems (Komatsu & Murakami, 1994;Yatsuya et al, 2007;Komatsu et al, 2014;Boudouresque et al, 2016). In some regions, Sargassum species are undergoing a very severe decline due to overgrazing by herbivores (a cascading effect of overfishing), invasive species such as the herbivorous teleosts Siganus spp., habitat destruction, trawling and net fishing, eutrophication and an increase in water turbidity (Thibaut et al, 2005;Airoldi & Beck, 2007;Tsiamis et al, 2013a;Bianchi et al, 2014;Vergés et al, 2014;Thibaut et al, 2015Thibaut et al, , 2016Gatti et al, 2017).…”

Estimation of kelp forest, Laminaria spp., distributions in coastal waters of the Shiretoko Peninsula, Hokkaido, Japan, using echosounder and geostatistical analysis

“…5). Structurally complex kelp forests provide fish and phytal animals with suitable refuges from advection and predators and also attracts a variety of other fauna [29][30][31][32][33]. The horizontal and vertical structure of the eastern side probably enhances the diversity of fauna and ecological relationships.…”

Sargassum horneri C. Agardh space capacity estimation reveals that thallus surface area varies with wet weight

“…S . horneri beds adjust water temperature [ 11 – 13 ], pH [ 14 ], dissolved oxygen content [ 15 ], downward illumination [ 15 ], and water flow [ 13 ] of the surroundings. S .…”