Benthic chamber geochemical data obtained with an in situ benthic lander from the R/V Savannah at sampling stations across the Louisiana shelf and slope in the Northern Gulf of Mexico during four cruise between July 2021 and July 2022

This data set reports benthic flux measurements of dissolved inorganic carbon (DIC), orthophosphate (SPO43-), ammonium (NH4+), total alkalinity (TA), carbon isotopic fractionation of DIC (13-C-DIC), dissolved manganese (Mnd), dissolved calcium (Cad), nitrate (NO3-), and excess bromide (Br-) injected in the chamber as chemical tracer. In summer 2021, benthic flux data were obtained from benthic chamber deployments at eleven different stations on the Louisiana Shelf and slope in the Northern Gulf of Mexico during July 15-27, 2021 using two different benthic landers. These stations span two transects, one from the middle of the shelf offshore from Cocodrie, LA to the mouth of the Mississippi River North West Pass, and another from North West Pass of the Mississippi River mouth to the south, across the slope. A single station (St. 15) was also sampled on the eastern side of the second transect in the transition from the shelf break to the mid-slope. All benthic chamber samples were processed within an hour after collection. In fall 2021, benthic flux data were obtained from benthic chamber deployments at ten different stations on the Louisiana Shelf and slope in the Northern Gulf of Mexico between October 25 and November 10, 2021 using two different benthic landers. These stations span two transects, one from the middle of the shelf offshore from Cocodrie, LA to the mouth of the Mississippi River South West Pass, and another from South West Pass of the Mississippi River mouth to the south, across the slope. Two stations (St. 15 and St. 12) were also sampled on a second transect from the shelf break to the slope southeast of the Bird’s Foot. In spring 2022, benthic flux data were obtained from benthic chamber deployments at ten different stations on the Louisiana Shelf and slope in the Northern Gulf of Mexico during April 9-20, 2021 using two different benthic landers. These stations span two transects, one from the middle of the shelf offshore from Cocodrie, LA to the mouth of the Mississippi River South West Pass, and another from South West Pass of the Mississippi River mouth to the south, across the slope. Two stations (St. 15 and St. 12) were also sampled on a second transect from the shelf break to the slope southeast of the Bird’s Foot. In summer 2022, benthic flux data were obtained from benthic chamber deployments at eleven different stations on the Louisiana Shelf and slope in the Northern Gulf of Mexico in July 9 -23, 2022 using two different benthic landers. These stations span two transects, one from the middle of the shelf offshore from Cocodrie, LA to the mouth of the Mississippi River South West Pass, and another from South West Pass of the Mississippi River mouth to the south, across the slope. Two stations (St. 15 and St. 12) were also sampled on a second transect from the shelf break to the slope southeast of the Bird’s Foot. Samples were immediately filtered through 0.22-micrometer (µm) PSE syringe filters and either analyzed immediately onboard (SPO43-), preserved acidified with hydrochloric acid at 4 degrees Celsius (Cad, Mnd), frozen (NH4+, NO3-, Br-), or preserved at 4 degrees Celsius after addition of HgCl2 (TA) until analysis. In addition, samples for DIC, TA, and carbon isotopic analyses were preserved in glass bottles, whereas other samples were preserved in polypropylene containers. DIC and TA were analyzed by Gran titration (Gran, 1952) using temperature-controlled closed cells (Dickson et al. 2007), orthophosphate and ammonium by spectrophotometry (Murphy and Riley, 1962; Strickland and Parsons, 1972), the carbon isotopic signature by isotope ratio mass spectrometry (Wang et al, 2018), Mnd and Cad by ICP-MS (Magette et al., 2025 In review), and NO3- and Br- by high performance liquid chromatography (HPLC) (Beckler et al., 2014). In summer 2022, benthic chamber and pore water DIC and TA samples were analyzed by cavity ring-down spectrometry (CRDS, Picarro G2131-i) with an automatic CO2 extraction system (Apollo SciTech AS-D1) and open-cell potentiometric titrations, respectively (Ferreira et al., 2025).本数据集收录了溶解无机碳（dissolved inorganic carbon, DIC）、正磷酸盐（SPO43-）、铵态氮（NH4+）、总碱度（total alkalinity, TA）、溶解无机碳碳同位素分馏（¹³C-DIC）、溶解态锰（Mnd）、溶解态钙（Cad）、硝酸盐（NO3-），以及以化学示踪剂形式注入培养舱的过剩溴化物（Br-）的底栖通量（benthic flux）实测数据。 2021年夏季，2021年7月15日至27日，研究团队使用两台不同的底栖着陆器（benthic landers），在墨西哥湾北部路易斯安那陆架与陆坡的11个站位开展底栖培养舱（benthic chamber）部署作业，获取底栖通量数据。这些站位覆盖两条断面：一条从路易斯安那州科科德里（Cocodrie, LA）近海的陆架中部延伸至密西西比河西北航道（Mississippi River North West Pass）河口，另一条从密西西比河西北航道河口向南横跨陆坡。此外，在第二条断面从陆架坡折向陆坡中段过渡的东侧区域，还对1个站位（St.15）进行了采样。所有底栖培养舱样品均在采集后1小时内完成前处理。 2021年秋季，2021年10月25日至11月10日，研究团队使用两台不同的底栖着陆器（benthic landers），在墨西哥湾北部路易斯安那陆架与陆坡的10个站位开展底栖培养舱（benthic chamber）部署作业，获取底栖通量数据。这些站位覆盖两条断面：一条从路易斯安那州科科德里（Cocodrie, LA）近海的陆架中部延伸至密西西比河西南航道（Mississippi River South West Pass）河口，另一条从密西西比河西南航道河口向南横跨陆坡。此外，在从陆架坡折向“鸟足状三角洲（Bird’s Foot）”东南侧陆坡延伸的第二条断面上，还对2个站位（St.15与St.12）进行了采样。 2022年春季，2021年4月9日至20日，研究团队使用两台不同的底栖着陆器（benthic landers），在墨西哥湾北部路易斯安那陆架与陆坡的10个站位开展底栖培养舱（benthic chamber）部署作业，获取底栖通量数据。这些站位覆盖两条断面：一条从路易斯安那州科科德里（Cocodrie, LA）近海的陆架中部延伸至密西西比河西南航道（Mississippi River South West Pass）河口，另一条从密西西比河西南航道河口向南横跨陆坡。此外，在从陆架坡折向“鸟足状三角洲（Bird’s Foot）”东南侧陆坡延伸的第二条断面上，还对2个站位（St.15与St.12）进行了采样。 2022年夏季，2022年7月9日至23日，研究团队使用两台不同的底栖着陆器（benthic landers），在墨西哥湾北部路易斯安那陆架与陆坡的11个站位开展底栖培养舱（benthic chamber）部署作业，获取底栖通量数据。这些站位覆盖两条断面：一条从路易斯安那州科科德里（Cocodrie, LA）近海的陆架中部延伸至密西西比河西南航道（Mississippi River South West Pass）河口，另一条从密西西比河西南航道河口向南横跨陆坡。此外，在从陆架坡折向“鸟足状三角洲（Bird’s Foot）”东南侧陆坡延伸的第二条断面上，还对2个站位（St.15与St.12）进行了采样。 样品均通过0.22微米（μm）PSE注射器式滤器即刻过滤，随后根据待测组分差异采取不同保存与分析方案：正磷酸盐（SPO43-）即刻在船上完成分析；溶解态钙（Cad）与溶解态锰（Mnd）采用盐酸酸化后于4摄氏度下保存；铵态氮（NH4+）、硝酸盐（NO3-）与溴化物（Br-）采用冷冻保存；总碱度（TA）则在加入氯化汞（HgCl2）后于4摄氏度下保存，直至后续分析。此外，用于溶解无机碳、总碱度及碳同位素分析的样品保存于玻璃瓶中，其余样品保存于聚丙烯容器中。溶解无机碳与总碱度采用Gran滴定法（Gran, 1952）结合控温密闭池进行分析（Dickson et al. 2007）；正磷酸盐与铵态氮采用分光光度法测定（Murphy and Riley, 1962; Strickland and Parsons, 1972）；碳同位素特征采用同位素比值质谱法（isotope ratio mass spectrometry）分析（Wang et al, 2018）；溶解态锰与钙采用电感耦合等离子体质谱法（inductively coupled plasma mass spectrometry, ICP-MS）测定（Magette et al., 2025 In review）；硝酸盐与溴化物采用高效液相色谱（high performance liquid chromatography, HPLC）分析（Beckler et al., 2014）。2022年夏季的底栖培养舱及孔隙水溶解无机碳、总碱度样品，分别采用腔环衰减光谱法（cavity ring-down spectrometry, CRDS, Picarro G2131-i）结合自动二氧化碳萃取系统（Apollo SciTech AS-D1），以及开放式池电位滴定法进行分析（Ferreira et al., 2025）。