2021 State of the Environment Report Marine Chapter – Expert Assessment – Pressure – Ocean nutrients and dissolved oxygen

2021年环境状况报告海洋章节→专家评估→压力→海洋营养物和溶解氧

• 批准号: global : 418564b1-c742-417a-909e-b88e07603756
• 金额: --
• 依托单位国家: 澳大利亚
• 资助国家: 澳大利亚
• 起止时间: 0100-11-30 至 无数据
• 项目状态: 已结题
• 来源: https://researchdata.edu.au/2021-state-environment-dissolved-oxygen/1767651
• 关键词: 2021; State; Environment; Report; Marine

The Marine chapter of the 2021 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "Pressure of Ocean nutrients and dissolved oxygen". <br /> ***A PDF of the full Expert Assessment, including figures and tables (where provided) is downloadable in the "On-line Resources" section of this record as "EXPERT ASSESSMENT 2021 - Pressure – Ocean nutrients and dissolved oxygen"***<br /> <br /> ----------------------------------------<br /> <br /> DESCRIPTION OF PRESSURE<br /> The vital physical processes supplying nutrients to the upper ocean (Figure 1) are the seasonal deepening of the surface ocean mixed layer, the upwelling and vertical mixing associated with ocean eddies, and wind-driven upwelling. In the Australian region, the first two processes dominate because wind-induced upwelling is confined to a few small areas (e.g. Bonnie Upwelling off South Australia). As the climate warms, the upper ocean will develop a stronger vertical gradient in temperature, becoming more stratified, reducing the vertical supply of nutrients to the surface ocean (Kwiatkowski et al., 2020). Climate change is also projected to modify winds, and strengthen boundary currents and increased eddy activity their vertical nutrient supply (e.g. the East Australia Current, Matear et al., 2013).<br /> Oxygen is essential to living aerobic organisms in the ocean. In the surface ocean, oxygen levels are high because air-sea exchange keeps oxygen near saturation levels. Due to aerobic respiration, the dissolved oxygen concentrations in the ocean interior decline and are lowest in the intermediate water (300 m to 1000 m) away from regions these waters exchange with the atmosphere (i.e. the Southern Ocean, Figure 2). High oxygen consumption in coastal regions can lower oxygen to a level where it can no longer support aerobic organisms leading to fish kills (Hobbs and McDonald, 2010). Solubility of oxygen is reduced in a warming ocean, and climate change is projected to lead to the expansion of areas with low oxygen (Kwiatkowski et al., 2020).<br /> With climate change warming of the ocean, marine heatwaves in Australian waters are projected to increase in frequency and intensity (Hayashida et al., 2020b).<br /> Additional pressures exist in coastal ocean regions, such as increased nutrient input (rives and estuary); which reduces oxygen with the potential for local anoxic events and increases nutrients with the increase phytoplankton blooms.<br /> <br /> DATA STREAM(S) USED IN EXPERT ASSESSMENT<br /> Data come from the CARS climatological atlas of nitrate, phosphate and oxygen (1996). Details can be found at http://www.globcolour.info/products_description.html.<br /> <br /> ----------------------------------------<br /> <br /> 2021 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details]<br /> <br /> • 2021 •<br /> Assessment grade: High impact<br /> Assessment trend: Unclear<br /> Confidence grade: Low<br /> Confidence trend: Low<br /> Comparability: Somewhat comparable (oxygen and nutrients assessed separately in 2016<br /> <br /> ----------------------------------------<br /> <br /> CHANGES SINCE 2016 SOE ASSESSMENT<br /> The seasonal climatologies are based on the latest version of CARS, which brings in additional observations collected since 2016. Additionally, dissolved oxygen and nutrient supply and cycling were previously assessed separately, but have been combined into a single ‘biogeochemistry’ assessment for 2021.

《2021年环境状况报告》的海洋章节包含了从海洋数据流中开发的多个专家模板。该元数据记录描述了“海洋营养物和溶解氧压力”专家评估。<br /> * 专家评估全文的PDF格式，包括图表（如有提供），可在本记录的“在线资源”部分下载，名称为“专家评估2021 -压力-海洋营养物和溶解氧”*<br /> <br /> ----------------------------------------<br /> <br /> 压力说明<br /> 向海洋上层提供营养物质的重要物理过程（图1）是海洋表层混合层的季节性加深、与海洋涡旋相关的上升流和垂直混合以及风驱动的上升流。在澳大利亚地区，前两个过程占主导地位，因为风引起的上升流仅限于几个小区域（例如南澳外海的Bonnie Upwelling）。随着气候变暖，上层海洋将形成更强的温度垂直梯度，变得更加分层，减少了对表层海洋的营养物垂直供应（Kwiatkowski等人，2020年）。气候变化预计也会改变风，加强边界流，增加涡流活动，增加垂直营养供应（例如，东澳大利亚海流，Matear等人，2013年）。<br /> 氧气对海洋中的有氧生物是必不可少的。在海洋表面，氧气含量很高，因为海气交换使氧气接近饱和水平。由于有氧呼吸作用，海洋内部的溶解氧浓度下降，在远离这些沃茨与大气交换的区域（即南大洋，图2）的中层水域（300米至1000米）最低。沿海地区的高耗氧量会将氧气降低到无法再支持需氧生物的水平，导致鱼类死亡（Hobbs和McDonald，2010年）。氧气的溶解度在变暖的海洋中降低，并且气候变化预计将导致低氧区域的扩大（Kwiatkowski等人，2020年）。<br /> 随着气候变化使海洋变暖，预计澳大利亚沃茨的海洋热浪的频率和强度将增加（Hayashida等人，2020年b）。<br /> 沿海海洋区域还存在其他压力，例如营养物输入增加（河流和河口）;这减少了氧气，有可能发生局部缺氧事件，并增加了营养物，浮游植物大量繁殖。<br /> <br /> 用于专家评估的数据流<br /> 数据来自汽车硝酸盐、磷酸盐和氧气气候图集（1996年）。详细信息可在http://www.globcolour.info/products_description.html上找到。<br /> <br /> ----------------------------------------<br /> <br /> 2021年国有企业评估摘要[详细信息请参见随附的专家评估]<br /> <br /> · 2021 ·<br /> 评价等级：高影响<br /> 评估趋势：不明确<br /> 置信度等级：低<br /> 信心趋势：低<br /> 可比性：具有一定的可比性（2016年分别评估了氧气和营养物质<br /> <br /> ----------------------------------------<br /> <br /> 2016年以来的变化<br /> 季节性气候是基于最新版本的汽车，它带来了自2016年以来收集的额外观测数据。 此外，溶解氧及营养物供应及循环先前是分开评估，但已合并为二零二一年的单一“生态地球化学”评估。