(Table 1) Accelerator mass spectrometer 14C age measurements on bryozoans (Celleporaria sp.), ODP Hole 182-1131B

Bryozoan reef mounds are common features in the geological record, occurring within mid-ramp, slope paleoenvironments, especially in Paleozoic carbonate successions, but until now have not been recorded from the modern ocean. Recent scientific drilling in the Great Australian Bight (Ocean Drilling Program Leg 182) has confirmed the existence of shallow subsurface bryozoan reef mounds in modern water depths of 200-350 m. These structures have as much as 65 m of synoptic relief, and occur both as single mounds and as mound complexes. They are unlithified, have a floatstone texture, and are rich in delicate branching, encrusting and/or nodular-arborescent, flat-robust branching, fenestrate, and articulated zooidal bryozoan growth forms. The muddy matrix is composed of foraminifers, serpulids, fecal pellets, irregular bioclasts, sponge spicules, and calcareous nannofossils. The 14C accelerator mass spectrometry dates of 26.6-35.1 ka indicate that the most recent mounds, the tops of which are 7-10 m below the modern seafloor, flourished during the last glacial lowstand but perished during transgressive sea-level rise. This history reflects changing oceanographic current patterns; strong upwelling during lowstands, and reduced upwelling and lowered trophic resources during highstands. Large specimens of benthic foraminifers restricted to the mounds confirm overall mesotrophic growth conditions. The mounds are similar in geometry, scale, general composition, and paleoenvironments to older structures, but lack obvious microbial influence and extensive synsedimentary cementation. Such differences reflect either short-term local conditions or long-term temporal changes in ocean chemistry and biology.苔藓虫礁丘（bryozoan reef mounds）是地质记录中十分常见的地质体，赋存于中缓坡、斜坡古环境内，尤其广泛发育于古生代碳酸盐岩序列中，但截至目前尚未在现代海洋中被发现。近期在大澳大利亚湾开展的大洋钻探计划（Ocean Drilling Program）第182航次，证实了现代水深200~350米的浅表层存在苔藓虫礁丘。这类地质体的总地形起伏可达65米，以孤立礁丘与礁丘复合体两种形态产出。它们均为未固结成岩的松散堆积，具有漂浮岩（floatstone）结构，富含多种生长形态的苔藓虫：包括纤细分枝状、包壳状、结节状树状、扁平粗壮分枝状、网孔状（fenestrate）以及铰接个员型苔藓虫。其泥质基质由有孔虫（foraminifers）、龙介虫（serpulids）、粪粒、不规则生物碎屑、海绵骨针（sponge spicules）以及钙质超微化石（calcareous nannofossils）组成。经26.6~35.1 ka的碳14加速器质谱（14C accelerator mass spectrometry）测年结果显示，这些最新形成的礁丘——其顶部位于现代海底以下7~10米处——在末次冰期低海平面期繁盛，但在海侵海平面上升过程中逐渐消亡。这一演化历史反映了海洋环流模式的变化：低海平面期存在强烈上升流，而高海平面期上升流减弱且营养供给水平降低。仅分布于礁丘中的大型底栖有孔虫标本证实，礁丘整体形成于中营养生长环境。这些现代礁丘在几何形态、规模、总体组成以及古环境背景上与古老礁丘结构相似，但缺乏明显的微生物作用以及广泛的同沉积胶结作用（synsedimentary cementation）。这类差异可能源于短期局部环境变化，或是海洋化学与生物群落的长期演化改变。