RIG: Broadening Participation of Deaf and Hard-of-Hearing Scientists Through Laboratory Studies of a Harmful Algal Species

美国水生生态系统磷(P)和氮(N)负荷的增加与栖息地变化、生物多样性减少、缺氧增加和有害藻类水华有关，这些都是富营养化的症状。直到最近，淡水生态系统还没有被认为受到氮负荷增加的影响，因为这些水域被认为是磷有限的，因为供应氮的固氮蓝藻普遍存在。然而，人为氮负荷的增加正在引起富营养化表现的变化，其中之一可能是有毒蓝藻水华的增殖增加。然而，直接研究氮的数量和形态对这些生物的生长和毒性的生理作用的研究相对较少。尤其是铜绿微囊藻的患病率正在增加。与许多藻类不同的是，它不固定氮，因此在淡水生态系统中氮含量较高的情况下，它可能特别容易繁殖，并利用氮的生物地球化学有效性。该项目将使用实验室连续培养系统来研究铜绿微囊藻的生长和氮生理，方法是：(1)比较在无机N(NO3-和NH4+)或有机N(尿素)来源上生长的差异，N同化和毒素(微囊藻毒素)的产生随着N：P比的递增，(2)通过测定氮素吸收动力学和两种氮同化酶(硝酸还原酶和尿素酶)来研究不同氮源的竞争能力。这个项目旨在吸引和激发聋哑人或重听人的学生，他们传统上很少有机会在本科水平上获得有意义的研究经验。首席研究人员是一位初学聋人的女科学家，她和她的聋人和重听本科生将研究几种蓝藻物种铜绿微囊藻在生长速度、N同化和毒素产生方面的差异。一些实验将在马里兰大学环境科学中心的Horn Point实验室进行，在那里这些学生将有机会与从事营养循环和藻类动力学其他方面工作的教职员工和研究生互动。该项目的一个组成部分是在加拉德特大学举办一系列环境科学讲座，对这一代表不足的群体--聋人和重听人--进行关于营养物质污染、富营养化和气候变化等环境问题的教育。这项研究将为聋哑人和听力障碍的本科生提供一个动手项目，该项目将导致更大规模的实地研究，重点关注增加氮负荷对有毒蓝藻水华的频率和程度的影响。这些机会应该为他们攻读环境科学研究生院奠定基础。

Increases in both phosphorus (P) and nitrogen (N) loading to aquatic ecosystems in the United States have been linked to habitat changes, decreases in biodiversity, increases in hypoxia and harmful algal blooms which are all symptoms of eutrophication. Until recently, freshwater ecosystems were not considered to be impacted by increases in N loading because these waters are considered to be P limited and because there is a prevalence of N2-fixing cyanobacteria that supply N. However, increasing anthropogenic N loading is causing changes in the expression of eutrophication, one of which may be an increase in the proliferation of toxic cyanobacterial blooms. Yet, there have been relatively few studies that have directly addressed the physiology of N quantity and form on growth and toxicity of these organisms. The prevalence of Microcystis aeruginosa, in particular, is increasing. Unlike many cynaobacteria, it does not fix N, and thus may be uniquely poised to proliferate with high N loading into freshwater ecosystems and to take advantage of the altered biogeochemical availability of N. This project will use laboratory continuous culture systems to study the growth and N physiology of Microcystis aeruginosa by (1) comparing differences in rates of growth, N assimilation, and toxin (microcystin) production when grown on inorganic N (NO3- and NH4+) or organic N (urea) sources over an increasing gradient of N:P ratios, and (2) investigating competitive ability for different N sources by examining kinetics of N uptake and two N assimilation enzymes (NO3- reductase and urease). This project is designed to engage and excite students who are deaf or hard-of-hearing who have traditionally had few opportunities for meaningful research experiences at the undergraduate level. The principal investigator, a beginning deaf female scientist, and her deaf and hard-of-hearing undergraduate students, will examine differences in rates of growth, N assimilation, and toxin production in several strains of the cyanobacterial species, Microcystis aeruginosa. Some experiments will be conducted at Horn Point Laboratory, University of Maryland Center for Environmental Science, where these students will have opportunities to interact with faculty and graduate students working on other aspects of nutrient cycling and algal dynamics. An integral part of the project will be an environmental science lecture series at Gallaudet University, educating this under-represented group, the deaf and hard-of-hearing, about environmental issues including nutrient pollution, eutrophication and climate change. This study will provide deaf and hard-of-hearing undergraduate students with a hands-on project that will serve to lead to larger field studies focusing on the impact of increased N loading on the frequency and magnitude of toxic cyanobacterial blooms. These opportunities should provide them the foundation for graduate school in the environmental sciences.