Impact of Super Typhoon ‘Hinnamnor’ on Density of Kelp Forest and Associated Benthic Communities in Jeju Island, Republic of Korea

Abstract

This study was carried out to determine the levels of resistance and resilience of kelp forests to large-scale physical disturbances. Our study site, Seongsan, Jeju Island, was impacted by super typhoon ‘Hinnamnor’. Before the typhoon, Seongsan had shown high ecosystem stability. Our results indicated that the ecological stability of a kelp forest facing a severe typhoon is strongly linked to the prevailing environmental conditions. Although typhoon impact resulted in a significant loss of brown macroalgae canopy, Ecklonia cava remained dominant within the kelp forest community. Resistance and resilience levels strongly depended on water temperature and movement and presence of turf-forming algae. Hence, hydrodynamic and biological factors strongly influence the overall stability of a kelp forest. We also report the first occurrences of a scleractinian coral species (i.e., Montipora millepora) at Seongsan, which became visible after canopy loss following the typhoon. Our findings provide valuable ecological information about the benthic community of kelp-dominated ecosystems and are essential to mitigate the impacts of expected climate change-driven rises in seawater temperature and the frequency of super typhoons.

Environmental impact on marginal coastal benthic communities within the Jeju Island, South Korea temperate transition zone

“…For instance, the decrease in canopy-forming algae and high-latitude hard corals at SS and BM, respectively, can be attributed mainly to, in the absence of other extreme events, destruction by super typhoon Hinnamnor, which reached Jeju Island in September 2022. Lee K.-T. et al (2023) reported a 42% loss of E. cava at 10 m and 34% at 15 m in September 2022 compared to May 2022 at SS, which is coherent with our results. This decline in canopy density has led to an artificial increase in the percentage cover of underlying species in November, such as rhodophytes Plocamium sp.…”

“…Water motion is key in promoting and aiding kelp forest growth by dislodging grazers (Denny and Gaylord, 1996) and increasing nutrient availability and uptake (Hurd et al, 1996;Nishihara and Terada, 2010). E. cava is well-equipped to handle these physical disturbances due to its finger-like holdfasts and large thalli, which help to attach itself firmly to the substrate (Kang et al, 2011;Kang and Kim, 2012;Lee K.-T. et al, 2023). Therefore, climate change-related events, such as the intensification of the KWC (i.e., increased SST and oligotrophy) (Wu et al, 2012;Kim et al, 2022a), could promote the expansion of high-latitude hard coral communities along the southern coastline towards east and west, while driving a decline in eastern temperate kelp forests.…”

“…In fact, Jeju Island lies between two climatic zones with alternating influence depending on the season: the "polar dry" in winter and "tropical/subtropical moist" (due to a short monsoon) in summer (Shimabukuro et al, 2023). Additionally, Jeju Island is frequently affected by typhoons (Park et al, 2006;Lee K.-T. et al, 2023). Over the past half a century, the coastal waters of Jeju, and the Korean mainland in general, have recorded a rise in annual sea surface temperature (SST) by +1.23°C, 2.5 times the global average (Belkin, 2009;Wu et al, 2012;Hobday and Pecl, 2014 ;Han and Lee, 2020;Tang et al, 2020).…”

Ingestion of fishing gear and Anisakis sp. infection in a beached Indo-Pacific finless porpoise (Neophocaena phocaenoides) in the Jeju Island, Republic of Korea: findings from post-mortem computed tomography and necropsy

“…The number of cases of this species beached and discovered on the shores of Jeju Island has gradually increased in recent years. Rising sea temperatures and the tropicalization of oceans, which are attributed to global warming, are anticipated to bring significant changes to marine environments worldwide [ 50 , 51 ], including the seas surrounding Jeju Island, the southern coast, and Ulleung Island in South Korea [ 52 – 54 ]. These changes are likely to have profound effects on the habitats of N. phocaenoides throughout its range.…”

Assessment of Sessile Benthic Communities in Jeju Island, Republic of Korea, Using Autonomous Reef Monitoring Structures (ARMS)

“…Rising seawater temperatures have considerably affected coastal benthic communities in the Seogwipo area, resulting in observable changes [10,13]. Specifically, seawater temperatures on the southern coast of Jeju Island are warmer than those on the northern and eastern coasts [10,23]. From 1981 to 2020, the average annual sea surface temperature (SST) recorded in Seogwipo was 18.7 ± 0.7 • C, exhibiting a seasonal range characterized by a minimum monthly average of 14.4 ± 0.8 • C in March and a maximum monthly average of 24.6 ± 1.4 • C in August [10].…”