How should I go about choosing my topic?
Begin by reading the explanations below. Examples of each are provided below!
- Division Essay: find a topic that people might tend to underestimate or over-simplify. In other words, choose something that the average person might not know much about, and therefore can't really understand how complex or interesting that topic really is. Your job in the essay will be to break your topic down into meaningful and important categories.
- Classification Essay: think about the categories we place things in everyday and the characteristics of those categories. The topic you choose should allow you to argue that something has been misplaced.
How should I organize this essay?
As you write, keep these guidelines in mind:
- Your thesis statement and introduction will need to explain why these divisions/ classifications should matter to your reader.
- Your thesis statement and introduction MUST define or explain the category you plan to discuss (i.e. A sport is a competitive, physical activity therefore cheerleading should be considered a sport.)
- You should organize your body paragraphs so that each division or category has it's own paragraph or section. (i.e. cardio exercise is paragraph 1 and weightlifting is paragraph 2, etc.)
Division Essay Examples
If you want to lose weight, simply saying that you're going to "exercise" everyday may not be the most effective way to do so. Exercising is more complex than many people realize--attaining your goals will involve understanding how different types of exercise can help you achieve your goals.
Types of Exercise
- cardio: burns calories and strengthens your heart (running, using an elliptical or stair-stepping machine, etc.)
- weight lifting: tones muscles, increases physical strength, burns fat (using weights or weighted machines)
- recreational/sports: depending on the sport, can provide both cardio and toning benefits (cycling, tennis, kayaking)
We could also narrow this topic down a bit further and write about the important differences between different types of cycling.
Types of Cycling: stationary (exercise) biking, road biking, mountain biking, recreational biking
Classification Essay Examples
To write this type of essay, we'll need to think about things that should or should not be placed in a particular category.Example: Batman (that's our topic!) is not a superhero (category people place him in), but is simply a local vigilante (category he belongs in).
Ask yourself: Why do I think that...?
- Does not possess super powers (powers most humans don't possess).
- Chooses to be a hero, rather than being "chosen" by others/other forces.
Example: Cheerleading (That's our topic!) should be considered a sport (It belongs in the category, "sports").
Ask yourself: Why do I think that...?
- cheerleaders go to "practice" and must be in good physical shape
- cheerleaders work together toward a common goal
- cheerleaders must "try out" for their squad and often compete against other squads
Eutrophication, manifested by severe algae blooms, is globally the most pervasive water quality challenge [1,2,3]. It perturbs ecosystem services of the aquatic systems and decreases biodiversity [3,4,5]. The total amount of phytoplankton in a sample is a good biological indicator of the trophic state since algae are ubiquitous, abundant and respond quickly to environmental changes in the ecosystem [6,7,8,9]. But the total amount of algal provides little information regarding the processes governing their spatial and temporal distribution. In order to understand the conceptual mechanisms governing eutrophication there is a need for qualitative information of phytoplankton community structures.
River reservoirs, being both a river and a reservoir, are commonly used for water supply, flood control, irrigation as well as hydroelectric power generation [10,11]. These dammed rivers are generally characterized by great lengths, slow water flow velocity and thus long hydraulic residence time [12,13]. Their dams impose a substantial influence on sediment transport, thermal conditions and chemical cycling, and hence have strong impact on water quality and the aquatic ecosystems in the river . Wang et al found that 21.4% of 14 river reservoirs in the Yangtze basin were eutrophic .
Hai River in Tianjin city is a typical river reservoir in northern China. Physical and chemical characteristics of its water quality has been documented by several studies, but there is a scarcity in systematic studies of its phytoplankton composition [16,17,18,19].
In this paper, a time series of environmental and phytoplankton variables have been studied. Temporal and spatial differences in phytoplankton composition, abundance, and diversity and their relations with environmental conditions are assessed. The objective of this study is to improve the knowledge basis for early warning systems for algal blooms as well as strategies for remediation of eutrophication in similar types of river reservoirs.
2. Materials and Methods
2.1. Study Area
Hai River reservoir (Figure 1) winds 72 kilometers through the urbanized area of Tianjin city, draining a catchment area of 2066 km2 before it feeds into the Bohai Sea . It is an important reservoir as it serves several functions including flood control, water supply, irrigation, and recreation. It thus exerts a great influence on the economic and cultural development of Tianjin megacity. In recent years the water flow of Hai River has become practically stagnant due to reduced water influx and gate-dam constructions. Moreover, Hai River suffered severe eutrophication due to diffuse losses of nutrients from intensive agriculture and industry, as well as leaks in sewage system from a dense urban population, in the watershed [19,20,21].
Water samples from Hai River (Figure 1) were collected at a depth of 20–30 cm from 10 sampling sites, including two main tributaries (S1 & 2), junction (S3), and along Hai River (S4–10). Sampling was conducted in 2015 at weekly intervals between May and August, and monthly during the period from September to November.
Water Temperature (WT), pH, Dissolved Oxygen (DO), Oxidation Reduction Potential (ORP), and Conductivity (Cond) were measured in situ with a multi-parameter sonde (YSI Inc.©, Yellow Springs, OH, USA). Chemical Oxygen Demand (COD), Total Nitrogen (TN), Ammonia Nitrogen (NH3-N), Nitrite (NO2-N), Nitrate (NO3-N), Total Phosphorus (TP), Phosphate (PO4-P), Suspended Solids (SS), Salinity (SAL), and Chlorophyll a (Chl a) were analyzed by standard methods issued by the Chinese State Enviroemntal Protection Administration .
For taxonomic identification and algal cell numbers, a polyethylene bottle was filled with 1000 L sample and fixed immediately with 5‰ Lugol solution. After sedimentation for 48 h, the bulk of water was decanted off, leaving 20–30 mL of sedimented algae which was collected for analysis [23,24]. Counting was performed using microscopy (Algacount S300 (Hangzhou Xunshu Technology Co., Ltd., Hangzhou, China)).
Data from the sample sites S1–10 were grouped into three sections and averaged, with sites 1–3, 4–7, and 8–10 belonging to the upper, middle and lower reaches of the streams, respectively. Data from weekly samples from May to August were averaged to monthly values.
2.4. Species Distribution and Diversity
2.5. Statistical Analysis
Spatial and temporal variation in the composition of phytoplankton species was assessed by analysis of variance (ANOVA) using SPSS 19. Differences were considered significant at p ≤ 0.05 (95% confidence level).
Canonical correspondence analysis (CCA) (Canoco for Windows 4.5 software) [28,29] was used to examine empirical relationships between environmental factors and phytoplankton species. All measured environmental parameters (Section 2.3) except Chl a were included in the analysis after log10(x + 1) transformation (except pH). Phytoplankton species that were included in the CCA satisfied the following two criteria [30,31]: (1) the chosen species appeared more than 3 times among all sampling sites; (2) the relative population density of this species exceeded 1% in at least one sampling site.