一、生物學特征與生態分布
海星(Asteroidea)是棘皮動物門的代表物種,全球現存約1600種,從潮間帶到深海均有分布。其獨特的生理結構展現了5億年進化的精妙設計:
1.形態多樣性
體徑從1厘米至90厘米不等,常見五腕對稱(少數如太陽海星達40腕),腕部中空且覆蓋短棘與叉棘
體色多變,包括紅、橙、紫等,部分種類(如粒皮瘤海星)因形似動畫角色“派大星”而聞名
反口面中央具篩板,為水管系統與外界交換的通道
2.運動與感知
依靠腕腹側步帶溝內的管足(單只海星含數千個)爬行,吸盤式末端可攀附陡峭巖壁
無傳統眼睛,但腕末端具眼點感知光線,表皮光敏蛋白實現“全身感光”
3.極端環境適應
僅生存于海水環境(滲透壓與海水一致),離水1020分鐘即窒息
深海種(如“派大星”背板海星)與海綿形成專性共棲關系,適應2100米高壓環境
二、生存策略與生態影響
海星通過獨特行為在海洋生態中扮演雙重角色:
1.捕食與繁殖
食性:肉食性為主,高等種類(如長棘海星)可翻出胃部體外消化珊瑚,單日吞噬珊瑚量達自身體積的80%
繁殖:多數雌雄異體,體外受精,雌性單次產卵數百萬粒;部分種類(如指海星)可通過腕斷裂無性繁殖
2.再生能力
含大量皮膚干細胞,失去的腕或內臟可在數月內再生,甚至1/5中央盤即可重建完整個體
實驗室中,棘冠海星幼體臂芽數量與年齡呈線性關系(每21.6天新增1條腕)weibo.com/ttarticle/p/show?id=2309405169241791266988
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3.生態平衡與威脅
益處:控制貝類種群,維護底棲多樣性;其骨板結構啟發仿生材料研發
危害:過度繁殖導致珊瑚礁退化(如長棘海星暴發使大堡礁珊瑚覆蓋率下降40%)
三、人海星關系與保護
1.資源利用
東亞地區食用生殖腺(海星黃),富含EPA/DHA等活性物質
韓國學者提取皮膚脂質(含24%EPA)制成免疫調節劑,可恢復小鼠脾指數至正常水平
2.入侵物種防控
法螺是棘冠海星的天敵,但因過度捕撈瀕危,需人工增殖(如澳洲保護法螺種群)
深圳規劃(20252035)將海星納入海洋動物保護體系,強調生態平衡管理
3.研究前沿
悉尼大學建立長棘海星幼體Gompertz生長模型,預測167.5天為生長速率峰值
我國發現深海新種“派大星”背板海星,揭示共棲行為對深海底棲生態的影響
當海星在礁石間伸展腕足,這些“海洋魔術師”正以再生之力與生態破壞賽跑。從《山海經》的“何羅魚”傳說到現代免疫學研究,它們始終是自然賦予人類的雙面啟示——既是生態平衡的維護者,亦是過度繁殖的警示者。保護海星,需在科學利用與種群調控間尋找精準平衡。
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