In Situ Variability of Large Aggregates over a Fluid Mud Bed: Shear Effects, Settling Velocities and Response to Storms

威尔斯博士之前的工作已经证明，有机结合的矿物颗粒集合体在北卡罗来纳州海岸的河口水中相对常见。这些聚集体(500微米)是海洋生物的食物来源，影响化学分布，并可能是浅水垂直质量通量的主要原因。很少有工作人员能够观察到或恢复这种“海洋积雪”。Wells博士和他的合作者Luettich博士将使用他们在之前的NSF奖项中开发的技术来分析这些聚集体的现场特征。在两年的时间里，望湾角各站点的横断面将每3个月重新占用一次，垂直剖面将每3个月重新占用一年，系泊设备将在3次“东北风暴”期间留在原地。集料的照片，集料沉降速度的现场测量，以及记录系泊和系留缆索上各种水柱特性的传感器将：1)获得关于望角湾和巴登海湾大集料的大小、形状和丰度的详细信息；2)调查水流对大集料的影响；3)提供集料的沉降速度；以及4)洞察大型集合体对风暴事件和其他季节性现象的反应。

Previous work by the Dr. Wells has demonstrated that organically bound aggregates of mineral grains are relatively common to estuarine water along the N. Carolina coast. These aggregates (500 microns) are a food source for marine organisms, affect chemical distributions, and may be responsible for a substantial part of the vertical mass flux in shallow water. Few workers have been able to either observe or recover this "marine snow". Using techniques developed in their previous NSF award, Dr. Wells and his collaborator Dr. Luettich will analyze the in situ characteristics of these aggrregates. Transects of stations across Cape Lookout Bight will be re-occupied every 3 months for 2 years, vertical profiles will be re-occuppied every 3 months for 1 year, and moorings will be left in place for the duration of 3 "northeaster" storms. Photographs of aggregates, in situ measurements of aggregate settling velocities, and sensors recording a variety of water column propoerties on moorings and tethered cables will: 1) yield details about the size, shape and abundance of large aggregates in Cape Lookout Bight and Barden Inlet; 2) investigate the effect of currents on large aggregates; 3) provide settling velocities of aggregates; and 4) provide insight into the reponse of large aggregates to storm events and other seasonal phenomena.