We are all connected by water. All living things need water. The earth has a remarkable system of transporting and recycling water for our use. Because we live on a planet, with a finite supply of water, we must take care of our natural resources, especially the water we use where we live. It doesn’t matter if we are a community of humans or a community of aquatic plants and animals, we all live downstream of someone or some organism that needs and uses the water. We should treat the water that we use the same way we hope the water we use was treated by others.
One of the most fun ways to use your knowledge about aquatic science is to go fishing. It’s a great way to spend time with friends and family outdoors. With over 191,000 miles of rivers, 212 major lakes, 367 miles of coastline, and 3,300 miles of bays and estuaries, Texas has many places to go fishing. Hike or take a canoe or boat to a fishing spot. Try camping near a lake. Cook what you catch and have a picnic. Fishing is a great way to learn about nature. When you go fishing for fun, you are called an angler. To be a good angler, you need patience, fishing skills, and knowledge about aquatic ecosystems.
The Gulf of Mexico is the ninth largest ocean basin in the world, covering almost 600,000 square miles. This is twice the size of Texas. At its deepest point the bottom is 2.7 miles underwater, but most of the Gulf is much shallower. About 60% of the Gulf is less than 700 feet deep. The Gulf is one of the most productive waters in the world for aquatic organisms. It provides habitat for many of our most important seafoods. The Gulf is productive in other ways, too. The Gulf holds one of the world’s largest reserves of oil and gas, leading to an extensive petroleum industry. The Gulf’s combination of ecosystem productivity, industrial importance, and accessibility has made it one of the most important waters to people on Earth as well as one of the most threatened by human actions and neglect.
Aquifers and springs have attracted humans to settle nearby where water is abundant, but careful use of water is necessary to balance the recharge of aquifers with the use by people. Aquifers and springs also provide aquatic habitats where unique species may live on the brink of extinction.
Aquatic habitats are communities in which complex interactions take place among populations and individual organisms as they compete for limited resources in an interdependent web of relationships. Within a community every species has a particular niche. A species’ niche defines how a species fits into its environment. It includes its way of getting food, the habitat it needs, and the role it performs in the community.
A species is a group of individuals sharing some common characteristics or qualities, and whose offspring also share those characteristics or qualities. All species are specially suited for the lives they lead. An adaptation is a behavioral, structural, or physiological trait that increases a species’ chance of survival in a specific environment. Every living thing has adapted to fit with where it lives. That’s what it takes for life to survive. Aquatic organisms live in water and have adaptations to do so. This chapter talks about life in water and aquatic ecosystems by fish, aquatic invertebrates, zooplankton, phytoplankton, aquatic plants, and algae in freshwater, estuaries, and the ocean, which in Texas is called the Gulf of Mexico.
Everything that happens on the land in a watershed affects the water body into which it drains. A stream, pond or wetland can only be as healthy as its watershed. How we use the land affects the health of our aquatic resources, and in turn affects us and what we do in the watershed. In a healthy watershed, water is filtered and stored, but as water runs downhill, it can pick up whatever is on the ground beginning a process of altering water quality. When it flows through cities or across fields and pastures, water picks up dirt, pollutants, and heat. These contaminants flow into a stream, wetland or lake, affecting the water you use to drink, swim, or fish.
The hydrologic cycle works like a huge water pump powered by solar energy and gravity. It is a global system, and every molecule of water on Earth travels through it. Because it is a cycle, it has no beginning or end. For three and a half billion years, the Earth’s water has been moving from streams to lakes to oceans, flowing underground, sitting high up on mountain glaciers, freezing and melting on the edges of the polar ice caps and forming clouds in the atmosphere. Average weather conditions over time is what we call climate. Texas is so large it is affected by air drawn in from the Pacific Ocean as well as the humid topical air flowing in from the Gulf of Mexico.
Water has properties that make it essential to life. And although the earth is known as “the water planet,” it has limited quantities of available freshwater. Humans need clean water to keep them healthy. Water can take three forms: liquid, solid (ice) and gas (vapor). Water exists in all three forms on Earth. Water can travel great distances. Water is called the “universal solvent” by chemists because it is very good at dissolving many different things. At this moment, the Earth has all the water it has ever had or will ever have. The hydrosphere is all the water on Earth. Compared to many countries, the US is water rich. We have 39 million surface acres of lakes and reservoirs. Agriculture is the biggest user of water. Water is the most important natural resource in Texas. Pure water is clear and transparent to light. Water may look clean but still be polluted. Pollution can also occur when too much organic matter, such as manure or human sewage, gets in the water and decays. The amounts and types of pollution in water affect water quality, which is water’s fitness for a particular use. Fish, birds, amphibians, reptiles, and all other wildlife depend on water for life. In particular, aquatic resources such as fish require abundant clean water.