It's My Ocean

How Does the Ocean Affect a Thunderstorm?

terrapin7795 — Sat, 29 Sep 2012 20:18:30 +0000

The ocean’s effect on thunderstorms and their formation is a fascinating local effect, especially if you happen to live at the shore and experience this phenomenon. Sometimes the ocean helps to build mere a thundershower into a full-fledged supercell, and sometimes the ocean causes a supercell coming from the west to quickly collapse at the coast. To understand this effect, one must understand how sea and land breezes work. During the daytime, the land heats up, and as a result, warm air rises and an artificial low is created at the surface. Over water, an artificial high is formed due to the cooler air. In response, the air sinks over the ocean. This causes air to rush from over the water (high pressure) to over the land (low pressure), creating what is known as a sea breeze. At night, the roles reverse. The air over the ocean is now warmer than the air over the land. The land quickly lose heat after the sun goes down and the air above cools as well. The ocean, however, is better able to retain its heat after the sun sets. This causes the low surface pressure to shift over the ocean during the night and the high surface pressure to move over the land. As a result, a small temperature gradient between the ocean surface and the nearby land causes the wind to blow from the land to the ocean, creating a land breeze. Based on what I’ve explained and the diagram below, one could conclude that a land breeze would tend to knock down an existing thunderstorm since upper level winds are blowing against the movement of the storm, acting as sheer.

Sea Breeze (Left) vs. Land Breeze (Right)

During the day, when the warm air is lifted, the denser marine air can under-run the warm air residing over the land. This is called convergence, and it occurs during the passage of a sea breeze front (SBF), which is the leading edge of the marine air. When the warm air is lifted, it can cause a band of clouds to form along the frontal boundary that may help initiate afternoon thunderstorms.

Diagram of how a sea breeze front creates a thunderstorm

During the night, however, land breezes can help to bring drier air from further inland. This in turn lowers CAPE values along the coast and leaves thunderstorms with little or no energy to work with.

Sources:

http://www.nc-climate.ncsu.edu/edu/k12/.breezes

http://www.atmos.ucla.edu/~fovell/ASres/sbfhcr/sbfhcr.html

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Aquaculture and Its Environmental Effects

noahbressman — Thu, 30 Aug 2012 15:32:46 +0000

Essentially fish and shellfish farming, the aquaculture industry has been thriving, but it is very misunderstood by the public. To help satisfy the growing population’s growing hunger, the aquaculture industry has been growing exponentially, and is expected to continue to grow. While this industry has the potential to sustainably feed the world, it also has adverse effects on the environment. In this paper, I will summarize the findings of a research article, discussing the general positive and negative effects of aquaculture on the world’s fish supplies

Due to the decline of wild fisheries around the world, aquaculture has been able to grow rapidly. While many believe that aquaculture reduces pressure on fisheries, this may not necessarily be the case, depending on the species farmed and the methods used to farm them. Mollusks, which include mussels, clams, and oysters, can easily be sustainably farmed. As many mollusks are fairly sessile and do no swim around, they require minimal space and can be farmed on the seabed or on man-made structures suspended in the water column. Most farmed species of mollusks are filter-feeders, so they rely on natural food sources, like plankton and organic particles suspended in the water (Naylor et al, 2000). These species produce very little waste, and can actually clean coastal waterways through their filter-feeding.

Fish and crustacean farming vary in sustainability, depending on species and methods used to farm them. Herbivorous and omnivorous (animals that eat both plants and animals) species are often fed more sustainable diets and have better waste management than carnivorous species. Many herbivores and omnivores, like carp, tilapia, and catfish, are either farmed without the use of formulated foods or are fed foods that use vegetable products as substitutes for fish proteins and oils, which are used in feed for carnivorous species. Feeds for carnivorous species contain high levels of fish meal, which come from wild caught fish. Some species even require up to 5 kg of fish as feed to produce 1 kg of fish to be consumed by humans. However, some aquaculturists argue that this 5:1 ratio is more efficient than if the fish were raised in the wild, where only about 10% of the energy derived from food is converted into mass (Naylor et al, 2000). This argument fails to look at the end result of the feeding, though. While aquaculture may be twice as efficient at producing fish biomass as the ocean, the end result of aquaculture lies on our dinner plates, and not in the oceans. Aquaculture uses fish from the wild to feed fish in captivity, while the oceans used fish from the wild to feed other fish from the wild. The biomass shifts from the wild to captivity, resulting in diminished wild fish populations, putting more pressure on fisheries. Using wild fish as feed also takes away food from not just wild carnivorous fish, but other animals like seals, whales, and birds, putting pressure on their populations as well. Furthermore, the wild fish species used to feed farmed fish could instead be used to feed people. Species often used for feed, like mackerel, anchovy, and sardines, could be consumed directly by people, instead of unsustainably being fed to farmed fish (Naylor et al, 2000).

Seed is another fish farming issue regarding sustainability. In aquaculture, seed refers to larval fish and shellfish. Seed can be obtained from hatcheries, but is much more often taken from the wild (Naylor et al, 2000). In developing nations, fish farms may take wild seed over fishery-raised seed because it’s cheaper or the nation lacks sufficient hatcheries. Other reasons for using wild seed include the fact that some species, like tuna, cannot be raised in hatcheries, so seed must be collected from the wild. The process of collecting wild seed also results in large amounts of by-catch, which is killed and discarded. “In India and Bangladesh, up to 160 fish and shrimp fry are discarded for every fry of the giant tiger shrimp, Penaeus monodon, collected to stock shrimp ponds.” (Naylor et al, 2000) This method of collecting seed is very unsustainable, and by killing so many fry as by-catch, fisheries suffer.

Many land-locked aquaculture operations for farming freshwater species, like catfish, tilapia, and carp, use man-made ponds to raise fish. Because these systems are contained, waste can easily be managed. In the farming of marine and diadromous fish (fish that migrate between saltwater and freshwater), fish are usually contained in floating net cages. The high densities of fish in the cages produce lots of waste, and because the systems are open, the waste flows directly into the ocean. The waste from these systems can have great effects on plankton and the biodiversity near the cages. Hundreds of thousands of hectares of mangrove forests and coastal wetlands have been converted to pools to farm shrimp. These habitats provide many ecosystem services, including coastal protection, flood control, water treatment, and nursery habitats (Naylor et al, 2000). By converting these habitats into shrimp farming pools, all the services are lost, not to mention the lives of all the organisms that used to live in those habitats.

In many aquaculture operations, the species being farmed may not be native to the area, or may be genetically different to the native populations. Many fish also escape from fish farms each year, leading to invasive species. Atlantic salmon, Salmo salar, are farmed on both coasts of the US. In the Atlantic, farm-raised salmon often have different genetics than wild salmon. When they escape, they breed and hybridize with the wild fish, which are genetically adapted for their specific habitat and spawning grounds. The hybrid offspring are not well suited to their habitat, and may die before reproducing. Even with salmon escaping into the wild, a net loss of salmon results from hybridization. On the Pacific coast, Atlantic salmon are an invasive species, resulting from salmon escaping from fish farms. These salmon compete with native salmon species, causing the native salmon populations to suffer. The high densities that these salmon and other aquaculture species are raised under also lead to epidemics, particularly sea lice and fungal epidemics. In both the native and non-native ranges where these fish farms exist, the epidemics can spread to the wild and wreak havoc on populations of native species (Naylor et al, 2000).

Aquaculture operations have the potential to satisfy the world’s growing appetite for seafood, but changes need to be made for aquaculture to be sustainable. Integrated aquaculture operations can yield higher output, while producing less waste. Mollusks and red algae are found to grow extremely well near fish cages. If incorporated into fish farms, these species can not only yield higher productivity, but they can remove waste from the cages, mitigating adverse effects of waste on the surrounding environment. A shift from carnivorous fish species to herbivorous fish species and mollusks would put less pressure on wild fish populations and fisheries for feed. Higher standards could also be put into action to control over population of organisms, resulting in fewer epidemics and less waste (Naylor et al, 2000). Aquaculture currently has many flaws, but with some improvements, it can be a sustainable and important source of food for the future.

Here is an entertaining video on the future of aquaculture, showing how sustainable fish farms can be integrated into ecosystems and make the fish taste better:

http://www.youtube.com/watch?v=4EUAMe2ixCI

Works Cited

Naylor, Rosamond L., Rebecca J. Goldburg, Jurgenne H. Primavera, Nils Kautsky, Malcolm C. M. Beveridge, Jason Clay, Carl Folke, Jane Lubchenco, Harold Mooney, and Max Troell. “Effects of Aquaculture on World Fish Supplies.” Nature 405 (2000): 1017-024. Print.

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Sustainability and the Need for a Copernicus Moment

Bruce Monger — Mon, 05 Mar 2012 20:43:07 +0000

A friend of mine posted a video on her Facebook page yesterday that I noticed was one I used last fall semester in my oceanography class when I talk about issues of sustainability. It is a Coldplay song done by Willie Nelson that gets at the heart of what I think needs to happen in the world. Folks tell me that you cannot scare people into doing the right thing and become more sustainably oriented. I agree whole-heartedly. I think what has to happen is people need to be shown a new vision of the future where life is much better than what they have right now – where they turn to a more sustainable lifestyle. A related saying is that Martin Luther King Jr.’s most famous speech was not I Have a Nightmare, but rather I Have a Dream. This music video gets to this point nicely. Hope you enjoy the music.

…
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For a more academic take on the issue of sustainability and the need for change, I highly recommend you listen to this second clip containing a very insightful discussion by Dr. Paul Raskin from the Yale School of Forestry and Environmental Studies. Late in his discussion Prof. Raskin discusses the need for nations to come together and have a “Copernicus Moment“. The Copernicus Moment analogy brings up two important points. First, many people today wrongly think that humans are exempt from the law of nature and that we can continue to abuse nature forever and nothing bad will ever happen to humans because we are not a part of nature. Back in Copernicus’s day people thought the earth was the center of the universe and everything in the sky revolved around the earth for our pleasure/benefit. It was as if everyone thought that earth (i.e., humanity) was exempt from the rest of the universe and that the universe was there just for humans who sat at its center. Copernicus (with Galileo later) changed that and made people realize that earth is not the center of the universe, but rather just an ordinary rock revolving around an ordinary star in an ordinary galaxy. So, we now need to take things one step further and see that we are not special organisms on earth that are exempt from all other organisms, but that we are only one part of the WHOLE living system of organisms and we need to care for the WHOLE system for our own sake – and for our own survival. Second, I think Prof. Raskin’s use of the term Copernicus Moment was also meant to convey a note of hope. Today is seems like an almost impossible task to get all the people on the planet onboard with the idea that we need to start living more sustainable lives. However, the same sort of thing must have seemed equally impossible when Copernicus attempted to get everyone onboard with the idea that the earth was not the center of the universe! So…. if Copernicus (and others) could do it, it seems reasonable to expect that someone today (and others – including YOU) can accomplish the same thing and get all of humanity to see that humans as just one single part of a much-much bigger living SYSTEM of organisms. Anyway, I think Prof. Raskin can say it much better than me. Here is the clip.

UPDATE: For a nice interview with Juliet Schor (the author of True Wealth) on this same issue of re-imagining a better way of living in this world by changing our culture of consumption, click HERE.

— Bruce

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Expected Impacts of Climate Change on New York By the End of this Century

Bruce Monger — Thu, 17 Nov 2011 14:54:02 +0000

The comprehensive report (600 pages) released yesterday by the New York State Energy Research and Development Authority should open the eyes of some of the students in my oceanography class – many of whom grew up in New York City. The report basically says that New York – and especially New York City – can expect to grow dramatically more vulnerable to flooding and heat waves by the end of the century due to climate change. New York City subway tunnels are particularly vulnerable to flooding due to the combined effects of sea level rise and storm surge. Here are some links to a few news articles about the report’s conclusions…

Cornell Chronicle Article
New York Times Article
Wall Street Journal Article

And Here is Link to the Full Report: FULL_REPORT

This figure is from the Wall Street Journal Article linked above. It show New York City regions vulnerable to flooding by the combined effects of sea level rise and storm surge.

Factory Ships and Overfishing

Bruce Monger — Tue, 04 Oct 2011 13:34:18 +0000

At the start of my lecture on overfishing in the oceanography class that I teach, I emphasize that the good old days of small “mom and pop” family fishing efforts has given way to global factory fishing methods. Collectively these factory fishing methods have taken 90% of the top predator fish from the global ocean (e.g., tuna, billfish and swordfish) – SEE HERE (subscription required) or HERE (press release) and now threaten 75% of all the major fisheries on earth SEE HERE.

The producers of the video intended to show how cool modern technology can make fishing so much more efficient than in the past, but I watched with a sinking feeling of disgust and horror. If you have some time, take a look….

You might want to hurry, I doubt this video will stay around for very long since it is not exactly the best PR for a company to show off how efficiently it can vacuum up all of MY fish! UPDATE (11/10/2011): See I told you… They pulled the video!

—Bruce

Project AWARE: An Ocean Conservation Organization Making a Difference

Bruce Monger — Thu, 30 Jun 2011 13:20:56 +0000

Julie Szabo asked if I would post a short article on my blog to let folks know about Project Aware – an ocean conservation group devoted to organizing divers to help clean up marine debris from my/our ocean. This group is currently promoting a “Global Scavenger Hunt” to encourage divers from around the world play the game and in the process help clean up my/our ocean through their “Dive Against Debris” program. Any diver who logs debris data using Project AWARE’s new online submission form is automatically entered into the scavenger hunt contest.

I deeply admire all of the people in this group for their willingness to devote some of their personal time to make a better ocean and a better planet!!! Here is a short (1 minute) video clip describing the Project AWARE program.

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Great Story About Sustainable Fish Farming

Bruce Monger — Fri, 20 May 2011 12:24:16 +0000

A former student sent this youtube link to me this morning that describes a great story about sustainable fish farming. It is a remarkable story and example of changing the way we do things for the better!! I especially liked the point made toward the end of the presentation that the current business models of big agra companies of ”feeding more people more cheaply” is really, when you get right down to it, “a liquidation sale” i.e., we are selling off our environment on the cheap today and at some point it will all be gone. And from that perspective, humanity needs a change of view on how to feed the world and this fish story offers a hopeful new possibility.

—Bruce

Story of the Bluefin Tuna – Nice Video

Encounter Between an Orca whale and a Great White Shark

Bruce Monger — Sun, 15 May 2011 14:05:34 +0000

Here is a pretty cool video of an encounter between an Orca whale and a Great White Shark…

Have a look.

—Bruce

Affects of cyanide poisioning on reefs

Carl Greiner — Wed, 27 Apr 2011 18:39:53 +0000

This is a common practice used to collect fish for the marine aquarium trade around the world. Pretty messed up. Check out the youtube video.

—Carl

http://www.youtube.com/watch?v=Y9yPRl8KY4U

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Story of the Bluefin Tuna – Nice Video

Bruce Monger — Tue, 15 Mar 2011 17:37:56 +0000

I came across this nice video HERE. It was produced by How to Save the Bluefin. It touches on almost all the main points I mention in my oceanography class: 1) Huge decline in abundance since the 50s. 2) Corporate fishing methods that have decimated the fishery. Government subsidies that add insult to injury – you are paying through your taxes to keep this whole thing going! 4) Greed and Corruption. 5) Singling out Japan and the Mitsubishi Corporation as key elements to the over-exploitation problem. Have a look at the video and definitely make your voice heard.

It doesn’t do anyone any good if you just read something and move on to the next page. These are YOUR fish! They are not the fisherman’s personal fish. They are not Japan’s personal fish! They are not the Mitsubishi Corporation’s personal fish! They are YOUR fish and these other folks are taking YOUR stuff! You have every right to tell them to stop taking your stuff! You have every right to say that they are YOUR fish and YOU don’t want them taken! Don’t be a quiet sheep and sit idly by while others take your stuff!