Environmental research has been shifting toward a new normal in which a primary focus is to capture change that may be accelerating. In this study, we collected particulate samples in the northern San Francisco Bay Estuary (SFBE) in the fall of 2011 through the spring of 2012 in order to assess vascular plant contributions across both time and space and to compare our findings with a similar set of samples from 1990 to 1992. Across the ∼20-year span, we detected (1) decreasing C:N_a ratios (averages ± SD of 12.5 ± 2.5 vs. 8.8 ± 1.4, significant t-test with p < 0.0001); (2) distinct shifts in chlorophyll vs. salinity, with higher chlorophyll concentrations shifting toward freshwater; and (3) greater relative proportions of vascular plant carbon that also appears less degraded (as indicated by lignin measurements) shifting from freshwater toward higher salinities. Lignin compositional data (syringyl:vanillyl and cinnamyl:vanillyl) suggest that increased lignin content in the more saline samples could be derived from wetland materials, while a two-endmember mixing model indicates that a significant portion of the particulate organic carbon (POC) in the western sites (50–60% as an upper bound, 13–15% as a lower bound) could be wetland-derived. This has potential implications for the lower food web, given recent work that demonstrates selective feeding by copepods on wetland detrital material in the northern SFBE. The latter has ramifications for proposed wetland restoration within the SFBE and Sacramento River/San Joaquin River Delta system, namely, that restored wetlands could confer important benefits toward the food web. Equally important is to prioritize continued monitoring of particulate organic matter cycling in the SFBE system to make sure that changing conditions are accounted for in any management decision.

环境研究已朝着新常态发展，该新常态的主要重点是捕捉可能正在加速的变化。在这项研究中，我们于2011年秋季至2012年春季收集了旧金山湾北部河口（SFBE）的颗粒样本，以便评估在时间和空间上对维管束的贡献，并将我们的发现与一组类似的结果进行比较。从1990年到1992年的样本。在大约20年的时间里，我们检测到（1）C：N _a比率下降（平均值±SD为12.5±2.5对8.8±1.4，显着Ť-测试 p<0.0001）; （2）叶绿素相对盐度的明显变化，其中较高的叶绿素浓度向淡水移动；（3）维管植物碳的相对比例也越来越大，从淡水向较高盐度的转化也表现出较少的降解（木质素测量表明）。木质素成分数据（丁香基：香草基和肉桂基：香草基）表明，更多盐样品中木质素含量的增加可能来自湿地材料，而两端混合模型表明，木质素中很大一部分有机碳（POC）西部站点（上限为50-60％，下限为13-15％）可能是湿地衍生的。这对食物网降低有潜在的影响，鉴于最近的工作表明co足类动物对北部SFBE北部的湿地碎屑物质有选择性的觅食。后者对SFBE和萨克拉曼多河/圣华金河三角洲系统内拟议的湿地恢复产生了影响，即恢复湿地可为食物网带来重要利益。同样重要的是，要优先监控SFBE系统中颗粒有机物循环的持续性，以确保在任何管理决策中都考虑到变化的条件。