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基本介紹

苔(tai)蘚(xian)蟲(chong)(chong)(Bryozoa=Polyzoa)是(shi)固著生(sheng)活(huo)的群(qun)體(ti)(ti)動(dong)物(wu)(wu)。苔(tai)蘚(xian)蟲(chong)(chong)是(shi)一種(zhong)像苔(tai)蘚(xian)植(zhi)(zhi)物(wu)(wu)的動(dong)物(wu)(wu),外形很像植(zhi)(zhi)物(wu)(wu)，但具(ju)一套完整的消化器，包括口(kou)、食道、胃、腸(chang)和(he)肛(gang)門等。所以把它放(fang)在動(dong)物(wu)(wu)界內(nei)。這種(zhong)生(sheng)物(wu)(wu)常和(he)海藻伴生(sheng)在一起。個(ge)體(ti)(ti)小，不(bu)分(fen)節，具(ju)體(ti)(ti)腔(qiang)。體(ti)(ti)外分(fen)泌一層膠質，形成(cheng)群(qun)體(ti)(ti)的骨胳。蟲(chong)(chong)體(ti)(ti)前端有口(kou)，口(kou)的周圍有一冠狀物(wu)(wu)，稱“總擔(dan)”，其上(shang)生(sheng)許(xu)多(duo)觸手。消化道U字形，口(kou)和(he)肛(gang)門因而靠近。無排泄和(he)循環器官(guan)。海水(shui)、淡水(shui)均產。在地質時代種(zhong)類很多(duo)，奧陶紀即已出現(xian)，現(xian)代尚有生(sheng)存。例如羽苔(tai)蟲(chong)(chong)附著湖邊(bian)石上(shang)或植(zhi)(zhi)物(wu)(wu)上(shang)；牡丹苔(tai)蘚(xian)蟲(chong)(chong)，附著淺海巖礁上(shang)。

常見種類

變口目苔蘚蟲

硬體(ti)為(wei)鈣質，蟲管(guan)細長，斷面呈(cheng)圓形(xing)、多邊形(xing)，有間隙孔、刺孔、中心區(內帶(dai))、邊緣區(外(wai)帶(dai))，內外(wai)帶(dai)界線不清，內帶(dai)壁(bi)(bi)厚，橫板(ban)少，外(wai)帶(dai)壁(bi)(bi)薄，橫板(ban)多。蟲管(guan)壁(bi)(bi)具平行片狀結(jie)構圍(wei)繞蟲室。

隱口目苔蘚蟲

硬體(ti)為鈣質，群體(ti)呈(cheng)扇狀(zhuang)(zhuang)(zhuang)(zhuang)、漏斗狀(zhuang)(zhuang)(zhuang)(zhuang)、枝(zhi)(zhi)狀(zhuang)(zhuang)(zhuang)(zhuang)等，通常由許多(duo)平行(xing)的分枝(zhi)(zhi)構(gou)成(cheng)，有橫枝(zhi)(zhi)相(xiang)連，構(gou)成(cheng)網格狀(zhuang)(zhuang)(zhuang)(zhuang)，兩枝(zhi)(zhi)上有兩列蟲(chong)室(shi)(shi)，蟲(chong)室(shi)(shi)中(zhong)(zhong)間被一中(zhong)(zhong)棱隔開。蟲(chong)室(shi)(shi)呈(cheng)長(chang)方形、正方形或(huo)六邊(bian)形，內外(wai)帶清楚(chu)，內帶窄，外(wai)帶寬，有刺孔。單偏(pian)光鏡(jing)下(xia)呈(cheng)深棕(zong)色(se)，壁(bi)具平行(xing)片(pian)狀(zhuang)(zhuang)(zhuang)(zhuang)結構(gou)。苔蘚蟲(chong)以其群體(ti)較小，蟲(chong)管(guan)細長(chang)與珊(shan)瑚區別，并以其蟲(chong)管(guan)向外(wai)不收縮，而管(guan)壁(bi)在(zai)加厚處呈(cheng)疊錐(zhui)似(si)的平行(xing)片(pian)狀(zhuang)(zhuang)(zhuang)(zhuang)結構(gou)，有間隙(xi)孔及刺孔來(lai)區別珊(shan)瑚藻和珊(shan)瑚。絕大多(duo)數苔蘚蟲(chong)生活在(zai)淺(qian)海中(zhong)(zhong)，也有少數于(yu)淡水中(zhong)(zhong)。

生長與分布

苔(tai)蘚蟲(chong)(chong)多生活在海(hai)洋。有(you)菊皿苔(tai)蟲(chong)(chong)、白薄苔(tai)蟲(chong)(chong)和鞭須苔(tai)蟲(chong)(chong)，我國海(hai)產苔(tai)蘚蟲(chong)(chong)分(fen)布(bu)在膠州灣、浙江淺海(hai)海(hai)底，和珊瑚混生在一起。淡水(shui)產的苔(tai)蘚蟲(chong)(chong)在蘇(su)州、南京、深圳淡水(shui)水(shui)體中均有(you)。

苔蘚(xian)蟲(chong)(chong)喜歡(huan)在較清潔、富(fu)含藻(zao)類、溶解氧充足的水(shui)(shui)(shui)(shui)體中(zhong)(zhong)生(sheng)(sheng)(sheng)活(huo)，能適應各地(di)帶的溫度，廣泛分布于世界各地(di)。淡水(shui)(shui)(shui)(shui)種(zhong)在春、秋季節（25～28℃）生(sheng)(sheng)(sheng)長旺(wang)盛，水(shui)(shui)(shui)(shui)面有(you)(you)(you)很多上(shang)一年的休眠芽，遇適宜環境發育成(cheng)苔蘚(xian)蟲(chong)(chong)。微污(wu)染的水(shui)(shui)(shui)(shui)體中(zhong)(zhong)也有(you)(you)(you)苔蘚(xian)蟲(chong)(chong)。在微污(wu)染源水(shui)(shui)(shui)(shui)生(sheng)(sheng)(sheng)物(wu)預處理過程中(zhong)(zhong)如有(you)(you)(you)大量苔蘚(xian)蟲(chong)(chong)出現，會(hui)被填料攔(lan)截，附在填料上(shang)生(sheng)(sheng)(sheng)長，和鐘蟲(chong)(chong)、聚縮(suo)蟲(chong)(chong)、獨縮(suo)蟲(chong)(chong)、累枝蟲(chong)(chong)、蓋纖蟲(chong)(chong)等有(you)(you)(you)粘(zhan)性尾柄的原生(sheng)(sheng)(sheng)動(dong)物(wu)聚在一起，具(ju)有(you)(you)(you)一定(ding)的生(sheng)(sheng)(sheng)物(wu)吸附作用，并吞(tun)食水(shui)(shui)(shui)(shui)中(zhong)(zhong)微型生(sheng)(sheng)(sheng)物(wu)和有(you)(you)(you)機雜質(zhi)，對水(shui)(shui)(shui)(shui)體的凈化有(you)(you)(you)一定(ding)積極作用。但如果(guo)極度大量繁殖，會(hui)降低(di)水(shui)(shui)(shui)(shui)流(liu)速度，給工程運行造成(cheng)一定(ding)不利(li)影響(xiang)。