[언론] 언론 > 외국인의 시선으로 바라본 갯벌 by Gebby Keny
안녕하세요, 오늘은 저희 해양저서생태학연구실에서 조금 특별한 손님을 모셔볼까 합니다. 바로 미국 텍사스주에 위치한 Rice University에서 현재 인류학 박사과정 중에 있는 Gebby Keny 라는 학생입니다. 작년 7월 서울대에서 개최된 YES 2018에 참가한 Gebby 학생은 대한민국 갯벌과 이와 관련된 문화, 사람들에게 큰 매력을 느껴, 저희 Benthos 연구실에 요청을 하여 잠시동안 함께 갯벌 현장조사를 나갔었습니다. 이후 미국으로 돌아간 Gebby 학생은 대한민국 갯벌과 관련된 역사적 배경, 문화 그리고 어업에 종사하시는 분들에 관한 보고서와 논문을 작성하였었습니다. 그리고 마침내 올해 7월 Gebby 학생은 또 한차례 한국의 갯벌취재를 위해 저희 Benthos 연구실을 방문하였습니다. 이와 관련하여 Gebby 학생은 올해 또 어떠한 시선으로 저희에게 새로운 관점을 보여주게 될지 궁금해집니다. 아래는 작년 Gebby 학생이 서해 증도 갯벌과 남해 순천만 갯벌을 다녀온후 기행문을 함께 첨부하였습니다. 앞으로도 갯벌에 대한 Gebby 학생의 기행문을 기대해 주세요!
In 1997 the provision was made at the United Nations Convention on Climate Change to include biological carbon sinks as a form of carbon offset for national carbon emission totals. This shift in climate policy marshalled a reconceptualization of forests, oceans, and soils as potential variables within national carbon emission calculations. In South Korea, efforts to calculate the amount of carbon stored within the country’s most abundant biological carbon sink, inter-tidal mud, have encountered considerable scientific uncertainty due in large part to both the material properties of this unique carbon sink and the habits of organisms living within it. From the perspective of Blue Carbon storage, perhaps the most significant feature of inter-tidal mud is the size of its constitutive particles. Due to the largely flat expanses of coastline that extend out from the mouths of South Korea’s major westward rivers, the sediment that these rivers bring into the Yellow Sea is held in suspension in shallow waters for a longer period of time. This allows smaller sediment particles to gather in shallow sea beds before being swept out to sea.
As was explained to me by scientists from the Benthos Lab at Seoul National University, inter-tidal mud along South Korea’s western coastline is a lot more like oatmeal instead of cereal. Because cereal is composed of large contents, its structural integrity is more easily compromised after it is penetrated. When you dig your spoon into a bowl of cereal, for instance, a temporary hole forms, but when you remove your spoon this hole instantly caves in on itself. This is due to the size of its constitutive parts and the structural bonds these parts are able to sustain when damp. With oatmeal, however, a hole that is dug will likely sustain its form for some time. This, again, is due to the size of oatmeal’s constitutive contents and the amount of water and or milk one might have added. In inter-tidal mud, a “Goldilocks” threshold of varying dampness coupled with the vast distribution of small sediment particles creates a similar phenomenon. Indeed, when one goes walking out into a mudflat, one trick for finding a safe path back to shore involves simply retracing the 2-to-4-foot-deep foot holes often left in one’s wake. The capacity of inter-tidal mud to sustain its structural form in this way is also essential to the survival of a wide array of other organisms who live and die within intertidal mudflats. Most notably, crabs and bivalves of varying types can burrow holes up to one meter-deep in search of food and shelter. This is referred to as bioturbation and is a variable of significant concern for scientists studying Blue Carbon. Formally referring to the “reworking of soils and sediments by plants and animals,” bioturbation in the context of Blue Carbon is significant largely due to the oatmeal effect produced by the particle size of mudflat sediment. When benthic macro-organisms burrow holes into sediment, the structure of these holes is sustained for a considerable amount of time. During this period of time, a fundamentally anaerobic environment is temporarily made aerobic due to the penetrating column of air made possible by the open hole left by a burrowing macro-organism. Due to this shift in environmental conditions, bacteria that would otherwise not be able to exist in this area are able to feed on micro particles of organic matter and, crucially, produce carbon dioxide which then freely floats into the atmosphere.
Accounting for the amount of carbon dioxide released through such processes is something scientists at the Benthos Lab are actively struggling with in their attempts to quantify Blue Carbon storage totals in mudflats. When asked about how his lab goes about tracking the population and activity of organisms who have the capacity to produce bioturbation, the principal investigator of the Benthos Lab described the challenge as follows: “Ecology isn’t like chemistry. It’s more subjective. Two methods can produce two different results about the same thing and there is no way to tell who is more right…It’s about time and space variation throughout the food chain…these varying temporal and spatial scales need to be accounted for.”
The tasks set out for us that hot summer day in 2018 were many and varied, though each contributed in some way to the lab’s ongoing study of Blue Carbon. Blue Carbon refers to the process through which vegetated habitats in the ocean capture carbon, often in the form of biomass, by sequestering and fixing carbon from various sources within sediment. Investigating this phenomenon was precisely what me and my fellow benthic ecology research team had set out to do that hot summer day. This blog post details some of the insights we learned from this field trip nearly one year later...
Mudflats Are Like Oatmeal?
By Gebby Keny
In 1997 the provision was made at the United Nations Convention on Climate Change to include biological carbon sinks as a form of carbon offset for national carbon emission totals. This shift in climate policy marshalled a reconceptualization of forests, oceans, and soils as potential variables within national carbon emission calculations. In South Korea, efforts to calculate the amount of carbon stored within the country’s most abundant biological carbon sink, inter-tidal mud, have encountered considerable scientific uncertainty due in large part to both the material properties of this unique carbon sink and the habits of organisms living within it. From the perspective of Blue Carbon storage, perhaps the most significant feature of inter-tidal mud is the size of its constitutive particles. Due to the largely flat expanses of coastline that extend out from the mouths of South Korea’s major westward rivers, the sediment that these rivers bring into the Yellow Sea is held in suspension in shallow waters for a longer period of time. This allows smaller sediment particles to gather in shallow sea beds before being swept out to sea.
As was explained to me by scientists from the Benthos Lab at Seoul National University, inter-tidal mud along South Korea’s western coastline is a lot more like oatmeal instead of cereal. Because cereal is composed of large contents, its structural integrity is more easily compromised after it is penetrated. When you dig your spoon into a bowl of cereal, for instance, a temporary hole forms, but when you remove your spoon this hole instantly caves in on itself. This is due to the size of its constitutive parts and the structural bonds these parts are able to sustain when damp. With oatmeal, however, a hole that is dug will likely sustain its form for some time. This, again, is due to the size of oatmeal’s constitutive contents and the amount of water and or milk one might have added. In inter-tidal mud, a “Goldilocks” threshold of varying dampness coupled with the vast distribution of small sediment particles creates a similar phenomenon. Indeed, when one goes walking out into a mudflat, one trick for finding a safe path back to shore involves simply retracing the 2-to-4-foot-deep foot holes often left in one’s wake. The capacity of inter-tidal mud to sustain its structural form in this way is also essential to the survival of a wide array of other organisms who live and die within intertidal mudflats. Most notably, crabs and bivalves of varying types can burrow holes up to one meter-deep in search of food and shelter. This is referred to as bioturbation and is a variable of significant concern for scientists studying Blue Carbon. Formally referring to the “reworking of soils and sediments by plants and animals,” bioturbation in the context of Blue Carbon is significant largely due to the oatmeal effect produced by the particle size of mudflat sediment. When benthic macro-organisms burrow holes into sediment, the structure of these holes is sustained for a considerable amount of time. During this period of time, a fundamentally anaerobic environment is temporarily made aerobic due to the penetrating column of air made possible by the open hole left by a burrowing macro-organism. Due to this shift in environmental conditions, bacteria that would otherwise not be able to exist in this area are able to feed on micro particles of organic matter and, crucially, produce carbon dioxide which then freely floats into the atmosphere.
Accounting for the amount of carbon dioxide released through such processes is something scientists at the Benthos Lab are actively struggling with in their attempts to quantify Blue Carbon storage totals in mudflats. When asked about how his lab goes about tracking the population and activity of organisms who have the capacity to produce bioturbation, the principal investigator of the Benthos Lab described the challenge as follows: “Ecology isn’t like chemistry. It’s more subjective. Two methods can produce two different results about the same thing and there is no way to tell who is more right…It’s about time and space variation throughout the food chain…these varying temporal and spatial scales need to be accounted for.”
From Field Trips to Lab Results: What Did We Learn One Year Later?
By Gebby Keny
“The trick is to step with your right foot before your left foot touches the ground.” Offered with a knowing smile and scalding hot bowl of blended mudskipper soup on one of the hottest summer days in South Korea’s recorded history this seasoned mudflat fisherman’s advice would prove vital as me and my fellow researchers from Seoul National University’s Benthos Lab ventured out from the shore’s predictably stable ground and into a place I had only just learned to pronounce: getbol.
The tasks set out for us that hot summer day in 2018 were many and varied, though each contributed in some way to the lab’s ongoing study of Blue Carbon. Blue Carbon refers to the process through which vegetated habitats in the ocean capture carbon, often in the form of biomass, by sequestering and fixing carbon from various sources within sediment. Investigating this phenomenon was precisely what me and my fellow benthic ecology research team had set out to do that hot summer day. This blog post details some of the insights we learned from this field trip nearly one year later...
