Introduction

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Introduction
Many members of Vibrio species ecologically interact with other organisms that may affect humans. Two species in particular, //Vibrio vulnificus// and //Vibrio// parahaemolyticus, have devastating effects on humans as they can cause gastroenteritis or even death (Oliver et al., 2001). Naturally, it is in our interests to determine the factors that affect abundance and distribution of the two species. Upon studying potential parameters that may produce significant results to their abundance, we can then use such measures to better regulate public health with regards to these infectious species.

General Vibrio Species
 First, I must briefly discuss vibrio species in general in order to make a deductive transition from general requirements of survival into specific ranges for the two species.

Taxonomy
65 different species of the genus Vibrio inhabit ubiquitously in the ocean (Oliver et al., 1982). Their environment ranges from freshwater (ie. 0% salinity) to saline waters, and from shallow waters to deep waters as seen on Figure 1 (Oliver et al., 1982). They belong to the kingdom Bacteria, the Proteobacteria phylum, the Gamma Proteobacteria class, the Vibrionales order, and finally the Vibrionaceae family (Oliver et al., 1982).

Physiology
Most vibrio species are gram negative, rod-shaped chemo-organotrophs (Pfeffer et al., 2003). They are usually 1 µm in width and 2~3 µm in length (Chan et al., 1986). Their physiology, however, changes depending on the environment. They are able to change surface to volume size in order to adapt to the environment: when the environment is rich in nutrients, their surface area to volume decreases. On the other hand, they increases the surface area to volume ratio in order to scavange for as much nutrients as possible in nutrient-limiting environments (Pfeffer et al., 2003). In general, they are very versatile that some representatives of the Vibrios can withstand the pressure at deep waters, some can live symbiotically with other organisms like molluscs and fish, whereas other species can withstand little to no salinity; hence, the reason why vibrios are found virtually everywhere in the ocean.

Environment
Given the kind of environment required for vibrio species to survive, the real question is what kind of environment they thrive in the best. As expected, multiple factors produce different environments and thus the the factors that affect distribution of vibrio species are multifactorial. Like a symphony orchestra, vibrio species require different instruments (factors) to perform well. Some "instruments" are often overlooked and may not seem to contribute much to the overall abundance and distribution; ultimately however, significant or not, every instrument must play at optimal level for success. On average, vibrios require 2~3% of salinity for optimal growth (Kaspar et al., 1993). As mentioned, some species like //V.cholerae, V. mimicus, and V. navarrensis// have adapted to live in freshwater environment (Chan et al., 1986). Most vibrio species require water temperatures above 15°C (Kaspar et al., 1993). Moreover, other factors like number of total bacteria present in the water column, pH, dissolved oxygen level, turbidity, nutrient levels, and depth do have the potential to produce different abundance levels (Olver et al., 1982).

Introduction
//Vibrio vulnificus// are most well known for human diseases like wound infection, gastrointestinal disease, and septicemia. It is the most lethal species of vibrios and causes 50% mortality when infected (Kumamoto et al., 1998). Unlike vibrio species in general, //Vibrio vulnificus// are obligate halophiles and require at least 0.5% of salinity level for growth (Oliver et al., 1983)