The Manitoba Great Lakes Program

The Manitoba Great Lakes (MBGL) program is led by researchers at the Centre for Earth Observation Science (CEOS) at the University of Manitoba, and is a multi-disciplinary collaboration dedicated to conducting research and providing data for science-based decision making in the Hudson Bay Watershed.

The upper Manitoba Great Lakes (Lake Manitoba, Winnipegosis and Waterhen) include the 27th (Winnipegosis) and 32nd (Manitoba) largest lakes in the world. They are important drinking water sources for the people who live near their shores, and important recreational and fisheries resources for the region and the Province as a whole. Moreover, they help to protect Lake Winnipeg by filtering nutrients and contaminants in runoff from its western watershed. In particular, the operation of the Portage Diversion during flood events has effectively shifted significant fractions of the Assiniboine River nutrient and contaminant load from the south basin of Lake Winnipeg to the south basin of Lake Manitoba, with undocumented impacts on the latter.
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Currently, the physical, chemical, biological and geological processes in the lakes are not well understood. Therefore, we have a poor ability to predict responses to change in factors such as climate, fishing pressure, and nutrient or contaminant loading from the watershed, or to understand impacts carried downstream to Lake Winnipeg, into Hudson Bay and the arctic. For example, climate change impacts include direct lake warming, which intensifies in-lake chemical and biological processes, and increasingly intense precipitation events. It is likely that this has led to increased runoff and more frequent flooding, and hence, increasing nutrient and contaminant transport from the watershed to the lakes, but we have no data to support this speculation. In Lake Manitoba, commercial catch of the most valuable species, pickerel, has declined by more than half since the 1980s. This may be due to pike in-migration through the Portage Diversion, or to high fishing pressure; we have too little information to know the cause. Most recently, in the summer of 2021, zebra mussel larvae were discovered in Lake Manitoba; again, without better information, the impact of this invasive species is a matter of conjecture. Overall, lake management and governance are being decided without adequate scientific support.
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The MBGL program deploys moorings to measure physical and biological parameters in the lakes. Through various initiatives, including graduate programs, we also collect nutrient, biological and physical data from the MBGL lakes as well as the surrounding watersheds. Other projects include studying nutrient forcing of algal biomass and associated algal toxins. We look at water quality indicators such as chlorophyll, suspended solids and dissolved organic carbon and can use them to create visualizations such as maps of chlorophyll concentration in surface water. These methods combined with satellite data can be used for early detection of algal blooms and identify potential sites where algal toxins may occur.
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Through our multi-disciplinary research the MBGL program will provide biological and physical data to support science-based decision making in the Hudson Bay Watershed, at local, regional and hemispherical scales

马尼托巴大湖（Manitoba Great Lakes, MBGL）项目由曼尼托巴大学地球观测科学中心（Centre for Earth Observation Science, CEOS）的研究人员牵头，是一项多学科合作项目，旨在开展相关研究并提供数据，为哈德逊湾流域（Hudson Bay Watershed）的科学决策提供支撑。

马尼托巴大湖上游片区（包括马尼托巴湖、温尼伯戈西斯湖与沃特亨湖）是全球第27大（温尼伯戈西斯湖）、第32大（马尼托巴湖）湖泊群。它们是沿岸居民的重要饮用水源，同时也是所在区域乃至整个曼尼托巴省重要的休闲娱乐与渔业资源。此外，这些湖泊可通过过滤西部流域径流中的营养物质与污染物，起到保护温尼伯湖的作用。值得注意的是，洪水期间启用的波蒂奇导流工程（Portage Diversion），已将阿西尼博因河（Assiniboine River）中占比可观的营养物质与污染物负荷，从温尼伯湖南部流域转移至马尼托巴湖南部流域，但其对后者的具体影响尚未有明确记录。

当前，学界对这些湖泊的物理、化学、生物与地质过程尚缺乏充分认知。因此，我们难以预测气候变化、捕捞压力、流域营养物质与污染物负荷变化等因素带来的湖泊响应，也无法明确这些变化对下游流入温尼伯湖、哈德逊湾乃至北极地区的影响。以气候变化为例，其影响包括湖泊直接升温（加剧湖内化学与生物过程）以及愈发频发的强降水事件。这类变化大概率会导致径流增加、洪水发生频率提升，进而推动流域内营养物质与污染物向湖泊的输送量上升，但目前尚无相关数据佐证这一推测。在马尼托巴湖，极具经济价值的白斑梭鲈（pickerel）商业捕捞量自20世纪80年代以来已下滑超五成，其原因可能是白斑狗鱼通过波蒂奇导流工程入侵该湖，也可能源于过度捕捞，但目前相关信息匮乏，无法确定具体诱因。最近的一例事件是，2021年夏季科研人员在马尼托巴湖发现了斑马贻贝（zebra mussel）幼虫，由于缺乏充足的监测数据，这一入侵物种对湖泊生态的影响目前仍属推测范畴。总体而言，当前湖泊管理与治理决策的制定尚未获得足够的科学支撑。

MBGL项目通过布设锚系观测设备，对湖泊内的物理与生物参数进行监测。依托包括研究生培养项目在内的多项举措，团队同时收集马尼托巴大湖流域及其周边流域的营养物质、生物与物理数据。其他研究课题还包括藻类生物量的营养驱动机制及相关藻毒素研究。团队针对叶绿素、悬浮固体与溶解性有机碳等水质指标开展监测，并基于这些数据生成地表水中叶绿素浓度分布等可视化图谱。结合卫星数据的相关技术方法，可用于藻华的早期预警，以及藻毒素潜在高发区域的识别。

通过多学科研究，MBGL项目将提供生物与物理数据，为哈德逊湾流域在地方、区域乃至半球尺度上的科学决策提供支撑。