原文網址：https://le.ac.uk/news/2022/may/anthropocene-berlin
萊斯特大學的研究人員正在尋找「金釘子」(golden
spike)來正式定義人類當下所處的地質時代——也等同於承認人類對地球造成了衝擊。星期三的一場國際會議中，他們發表分析結果有了重大進展。
舊金山灣區採到的黑龍江河藍蛤，以及金門大橋一景。圖片來源：Stephen Himson
星期三在柏林世界文化宮舉行的研討會「發掘當下」(Unearthing
the Present)之中，萊斯特大學的教授Jens
Zinke、Mark
Williams、Jan
Zalasiewicz以及博士後研究員Stephen
Himson公布了幾個候選者作為用來定義人類世(Anthropocene)的唯一參考點。
「人類世」是指人類的衝擊已經驅使地球的狀態邁入一個新的地質時代，也就是新的「世」。這項提議在過去十年對地質研究領域來說是最有影響力的想法之一，而萊斯特大學的研究人員在相關分析中扮演了領導腳色。
在人類世的研究中，尋找金釘子是關鍵性的概念——挑選世上某個地方為唯一的參考點，當作人類世開始的標記。金釘子最後有可能讓人類世正式被定義成地質年代表上的一份子。
研究人員關注的焦點為二十世紀中期，此時的「大加速」(Great
Acceleration)在地球歷史上是個重大的轉變，像是化石燃料大量燃燒並影響了氣候；人為製造的放射性元素(如：鈽)、塑膠碎屑和其他汙染物散播到全球各地；還有地球的生態系出現了迅速且劇烈的變遷。
目前某些研究團隊正在詳細分析全球各處的十幾個候選地點，從南極鑽出的冰芯、波蘭的泥炭沼，到深埋在義大利阿爾卑斯山底下的石筍都包括在內。
萊斯特大學的團隊研究了其中兩個候選地點：第一個是澳洲弗林德斯礁(Flinders
Reef)的一株活珊瑚，由地理、地質與環境學院的教授Zinke主持的團隊分析了它的年生長輪。第二個則是舊金山灣區的泥層，由同一學院的Stephen
Himson及Williams教授主持的團隊進行研究。這些泥層含有最近入侵灣區的許多種生物所留下的遺體，形成了一種生物時計。
候選地點的完整名單如下：
l 日本九州的別府灣(海洋沉積物)
l 加拿大安大略省的克勞福德湖(湖底泥層)
l 義大利的埃內斯托洞(洞穴沉積物)
l 澳洲珊瑚海的弗林德斯礁(珊瑚)
l 波羅的海的哥特蘭海盆(海洋沉積物)
l 南極半島的帕默冰芯(冰層)
l 美國加州的舊金山河口(海洋沉積物)
l 中國吉林省的西海龍王湖(湖底泥層)
l 波蘭的斯涅日卡沼澤(泥炭層)
l 奧地利的維也納博物館挖掘場址(城市土壤)
l 墨西哥灣的西部花園岩礁(珊瑚)
上述研究結果在這場柏林的研討會首度揭曉，並開始討論這些地點當中何者對於全球變遷可能記錄得最為完整且精確，而有資格被選來代表人類世的起始時間。
對於人類世的研究來說這些結果的發表是一大進展，或許還能以此為開端，使得人類世被眾人公認為地球歷史上一個新的階段。
在柏林這場為期五天的活動當中，科學家也會舉辦公開論壇與藝術家、學者、社運人士、一般大眾進行交流；並且透過網路上發表的一系列文章描述人類造成的各類衝擊，以及同時開幕的展覽《地球編目》(Earth Indices)來達成交流目的。這些活動將會提供獨特的觀點來看待人類如何透過地質方法，為自己的母星建立檔案庫的過程。
Zinke教授的研究主題是探討熱帶海洋的大型珊瑚以及沉積物檔案，作為環境變遷的記錄而具有的功能。他說：「在人類對於熱帶海洋的衝擊這方面，珊瑚提供了解析度最高的檔案。它們在數個世紀持續往上長的過程當中將此記錄下來。」
「弗林德斯礁的大型珊瑚提供了從17世紀開始，超過300年環境變遷的連續記錄。其中的資訊讓我們瞭解在偏遠的珊瑚礁，人類活動如何改變它們的環境。」
「1950年代開始核武測試不久之後，弗林德斯珊瑚礁的放射性碳紀錄在1959到1963年之間出現了一道明顯的高峰。這是象徵人類世開始的獨特訊號。」
「燃燒化石燃料也在珊瑚的骨骼留下了明顯的訊號，它們的碳同位素組成大概在1850年開始下降。珊瑚讓我們知道海水表層吸收了化石燃料中較輕的碳。」
Williams教授的研究主題為生物由人類誘發的改變，以及人類創造的環境如何對地球自然生態系脆弱的平衡造成影響。他說：「舊金山河口的生態系因為遠從日本引進的生物而變得完全不同。」
「有時候新來的物種可以完全宰制引入它們的生態系，它們的殼體會累積在最近的化石紀錄當中，而留下人類對地球造成衝擊的明顯地質訊號。」
「雖然舊金山河口受到了非常大量的研究，但是同樣由外來物種留下的模式，在我們的星球上正變得越來越常見。」
萊斯特大學的研究團隊也協助編寫了關於他們發現的專文〈人類世的生物與古生物訊號〉，由「人類世課程」發表。
Environment scientists close in on
‘golden spike’ to define Anthropocene
Leicester researchers searching for a
‘golden spike’ to formally define humanity’s current geological period – and
acknowledge human impact on our planet – have announced a major step in their
analysis at an international conference today (Wednesday).
University of Leicester Professors Jens Zinke, Mark
Williams and Jan Zalasiewicz and PhD researcher Stephen Himson presented
multiple candidates for unique reference points to define the Anthropocene at
Haus der Kulturen der Welt’s ‘Unearthing the Present’ conference in Berlin on
Wednesday.
The Anthropocene – the suggestions that human impact
has driven Earth into the conditions of a new geological period or ‘epoch’ –
has been one of the most influential concepts of the last decade in geological
research, with Leicester researchers playing a leading role in its analysis.
Search for a ‘golden spike’ is a key concept in
Anthropocene study, which would provide a unique reference point – chosen
somewhere in the world – to mark the beginning of the Anthropocene, that might
ultimately allow it to be formally defined as part of the Geological Time
Scale.
Researchers’ attention is focussed on the mid-20th
century, a transformational ‘Great Acceleration’ in our planet’s history that
included massive burning of fossil fuels and its climate effects, the worldwide
spread of human-made radioactive elements such as plutonium and of plastic debris
and other pollutants, as well as rapid and dramatic changes to Earth’s
ecosystems.
Currently, research teams are making detailed studies
of a dozen potential sites around the globe, ranging from a core of Antarctic
snow and ice, to a peat bog in Poland, to a stalagmite deep underground in the
Italian Alps.
Among the candidate sites are two being studied by
University of Leicester teams: a living coral on Australia’s Flinders Reef, the
annual growth layers of which are being analysed by a team led by Professor
Zinke of the School of Geography, Geology and the Environment; and the mud
layers of San Francisco Bay, studied by a team led by Stephen Himson and
Professor Williams within the same School, which contain a biological
chronometer in the form of the remains of many recently invasive organisms in
the Bay.
The full list of candidate sites includes:
l Beppu
Bay (marine sediments), Kyushu Island, Japan
l Crawford
Lake (lake muds), Ontario, Canada
l Ernesto
Cave (cave deposits), Italy
l Flinders
Reef (coral), Coral Sea, Australia
l Gotland
Basin (marine sediments), Baltic Sea
l Palmer
Ice Core (ice sheet), Antarctic Peninsula
l San
Francisco Estuary (marine sediments), California, USA
l Searsville
Reservoir (lake muds), California, USA
l Sihailongwan
Lake (lake muds), Jilin province, China
l Śnieżka
Bog (peat layers), Poland
l Vienna
Museum Excavation (urban soil), Austria
l West
Flower Garden Bank (coral), Gulf of Mexico
Results of these studies were unveiled for the first
time at the meeting in Berlin, to begin the discussion of which of these sites
might have the most precise and complete record of Earth’s global changes, to
allow it to represent the Anthropocene’s chosen beginning.
Announcement of these results are a major new
development in study of the Anthropocene, and the potential springboard to its
acceptance as a universally acknowledged new phase in our planet’s history.
Over the five days of the Berlin event the scientists
will also interact with artists, scholars, activists and the public in open
discussion forums, via a series of online essays on various kinds of human
impact, and by the opening of an exhibition, Earth Indices. This will provide unique insights into the processes
of developing a geological archive of humans’ home planet.
Professor Zinke, whose research examines the role of
massive corals and sedimentary archives from tropical oceans as recorders of
environmental change, said: “Coral provide the highest resolution archive of
anthropogenic impacts on the tropical oceans and they do that over several
centuries of continuous upward growth.”
“Massive corals at Flinders Reef provided a
continuous record of environmental change for more than 300 years, starting in
1710, giving us information how anthropogenic activity has modified the
environment in remote coral reefs.”
“The Flinders Reef corals recorded a clear spike in
radiocarbon between 1959 and 1963 short after the nuclear bomb testing began in
the 1950s. This is a unique signature of the Anthropocene.”
“The burning of fossil fuels has left a clear
signature in the coral skeleton in their isotopic composition of Carbon which
started to decline around 1850. The coral show us that light carbon from fossil
fuel burning has been taken up by the surface oceans.”
Professor Williams, whose work focuses on
human-induced changes to life and how human-built environments affect the
delicate balance of natural ecosystems on our planet, said: “The ecosystem of
the San Francisco Estuary has been wholly changed by organisms introduced from
as far afield as Japan.
“Sometimes the new arrivals completely dominate their
adopted ecologies, their shells accumulating in the recent fossil record and
leaving a clear geological signature of human impacts on the planet.
“Although San Francisco Estuary is very well studied,
the same patterns, from introduced species, are becoming widespread on our
planet.”
The Leicester research team have also contributed to
a feature on their findings, ‘Biological and Palaeontological signatures of the
Anthropocene’, published by Anthropocene
Curriculum.
引用自：University of Leicester. "Environment scientists close
in on 'golden spike' to define Anthropocene."
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