The World is Your…Sewer??

My Lead Science Cutie on staff (who I pay with milkshakes and bizarre postcards) has given me an excellent topic. Recently I chose to donate to a group looking to limit/control the dumping of human waste into the ocean from cruise ships. Science Cutie naturally wondered how big an impact this could have on a body of water as large as the ocean. My answer was “very” and “because eutrophication”.

Eutrophication is enrichment of an aquatic environment with nutrients. It’s natural in lakes and ponds over time, I’m sure most people reading have been around some stinky, algae filled ponds in their time and will have seen what I mean (even if you didn’t all know it at the time). Besides clouding the water and filling pond and lake bottoms with sediment, thereby reducing clarity (and light available underwater), eutrophication allows algal blooms to flourish and grow. Without enough light, they’ll start consuming oxygen. During particularly intense eutrophication, this can essentially suffocate other species.

This can radically change a habitat, but natural eutrophication is VERY slow, and though the build-up of sediment and nutrients may result in the lake or pond disappearing completely, local species have been adapting along with the changing water body. I mean, the fish and stuff are toast, but the lake/pond would have been supporting less and less of those things for a WHILE. But then there’s Unnatural eutrophication…That is, human-induced eutrophication.

Now we get to the cruise ships…

Human-induced eutrophication is a result of organic pollution, as with agriculture runoff or the dumping of human waste from ships or poorly managed sewers. Dee-lightful. Besides the aforementioned depletion of oxygen and light availability, toxic algae and bacteria can effectively poison local species. In the ocean, we are most familiar with this process as Red Tide. Toxins build up in the food chain as predators eat many things with a little toxin, then something bigger eats many of those and so on. This also impacts us because, considering we have found a away to eat almost everything in the sea, our big tasty fish dinner may have consumed enough toxic smaller fish to make it toxic to US. Yay. So now we have Red Tide warnings to let us know when and where we’ve totally messed everything up. If that’s not enough, you see large die-offs as the algal blooms suffocate or poison local species, thereby significantly reducing biodiversity.

Lead Science Cutie is correct that while you may not see the full effect of ocean eutrophication on a global scale, the ocean is composed of many ecosystems supporting a WIDE variety of life on which eutrophication can have a profound impact. Furthermore, if you dump enough waste in one area (as happens when many ships cover the same routes), it will spread. Even if we took the impact on our fishing industry out of the equation, the kinds of dieoffs that result from that are BAD NEWS.

Fortunately, the effects are reversible. However, we should support high water quality standards to allow such affects to reverse where eutrophication has already occurred, and to prevent it from spreading elsewhere.

Which is why I’m going to link to the fundraiser that started all this:

Protect the ocean from raw sewage

Support if you like.

Sources

Mack, Jeremy. 2015. Lake Scientist. Water Quality. “Eutrophication” April 13, 2015 < http://www.lakescientist.com/lake-facts/water-quality/&gt;

Seaweed Revelations Part 2

I know you were all right on the edges of yours seats waiting to hear about the life cycles of seaweed so I will get right to the point. Here is also where I get to clarify things I learned way long ago but didn’t look at again because I’m not a botanist.

I know many of you are still reeling from yesterday’s revelation that algae are not and have never been a member of the Communist party Plant kingdom. But you’ll have to sit down and clutch your pearls again because I have more news (“news”). Now I must tell you that all plants and many algae display alternating generations. “What is that?” you ask, “Where did I get these pearls I am now clutching??” you exclaim. All will be answered in due time. The phrase ”alternating generations” indicates that the plants or algae alternate haploid and diploid generations. So one generation has double chromosomes (one set doubled, like you’re supposed to) the next has only half/one set of chromosomes (like gametocytes, that is, cells like sperm or eggs, are supposed to). So you have one organism with the appropriate number of chromosomes (2n, with n being one set of a given number) that produces spores to grow into ANOTHER organism with half the chromosomes of its parent (n chromosomes), which in turn produces sperm or eggs to help produce a new, diploid generation. The haploid generation producing the sperm and eggs may be a distinct organism or it may be closely associated/attached to its diploid parent (although subsequent diploid generations will not be). OK, this explanation is all well and good for biologists, but how can everyone else understand it?

First, look at this diagram:

LOOK AT IT.
This will give you an illustration of things to come.

 

Now stick with me for a very bizarre analogy. Imagine your reproductive bits are not an organ. You produced them, they are a part of you (they’re attached to you, anyway), but you can’t control them directly. They are their own entity. Creepy, huh? That is how MANY plants and algae function, they grow their haploid generation on the diploid generation. Now for the REALLY weird part: imagine those reproductive bits DO NOT remain a part of you. Once you have grown them, they live freely. That is how other plants and algae live. To summarize both: the children are like the sexual organs and the grandchildren are new organisms. This system seems confusing, but it does help weed out deleterious genes (haploid generations being more vulnerable to the effects of bad genes) while still allowing for either self-fertilization or non-self-fertilization (plants and algae can effectively mate with themselves or other, unrelated plants and algae). Advantages to self-fertilization would be preventing introduction of bad genes while non-self fertilization means the possibility of BETTER genes being introduced. Basically, all the options are still available, so it’s a win-win situation.

I hope that all makes some (albeit VERY WEIRD) sense. Let me know if it doesn’t. I’d like to do another algae-related thang, but I just had some projects come up so WE SHALL SEE.

 

Source

–. 2010. GRE Subject Test: Biology 5th Ed. Kaplan, New York.

 

Photo credit Pearson Education.

Seaweed Revelations Part 1

Continuing with my topic suggestions, here is one from my sister from another mister who’s doing top-secret research in the North Pole (probably spying on Santa Claus) which you can read about on her blog here–> Snow Kidding

“I want to know more about macro algae… life cycle, what it needs to live, where it grows etc.”

That is not actually a question, Angie-bear, but I will let it slide cause you’re cute.

The term macroalgae encompasses the many species of large, multicellular algae found in marine and freshwater environments. For now I am going to focus on the marine species, but most of the information is applicable to freshwater species.

Now, before I go any further I need to say something important: algae are not plants. Sorry to shatter all y’all’s dreams (assuming you dream of algae-plants), but it’s true, ALGAE ARE NOT PLANTS. Don’t feel bad if you didn’t figure this out before, I only learned this when I took marine biology. Even college-level high school science classes can have gaps (I would say this is a pretty tiny one, anyway) and besides, algae are just not a thing most people think about.

Algae actually belong in the kingdom Protista, along with the animal-like protists (protozoans) and the fungus-like protists (slime molds). Because algae photosynthesize using chlorophyll, we say they are plant-like protists. Besides seaweed, this includes diatoms and dinoflagellates. Seaweed are divided into three main divisions (term for taxonomic rank equivalent to phylum but used in for plants, fungi and protists) that are defined by their photosynthetic accessory pigments. These divisions are chlorophyta (uses chlorophyll a and b), phaeophyta (uses uses chlorophyll a, chlorophyll b and fucoxanthin) and rhodophyta (uses chlorophyll a, chlorophyll b, phycoerythrin and phycocyanin). Algae in these divisions are called green, brown and red algae, respectively. Why? Because, well, they are green, brown and red, respectively.

See?

In general, the structure of macroalgae includes leaf-like blades (for photosynthesis), a gas-filled float (to raise the blades closer to the light) and the stipe (basically a stem, it’s not present in all species) that leads down to the holdfast (which anchors macroalgae to the seafloor). Although many of these structures seem analogous to those in plants, realize that the holdfast is NOT an algal root system. Macroalgae do not uptake nutrients from the seafloor so the holdfast is really just an anchor. Besides that important difference, the leaves and blades of plants and macroalgae are very different on a cellular level. Plant leaves, besides having more complex and complexly arranged tissues (includes vascular system, spongy layer and palisade layer, besides epidermis), have distinct functions for their different sides. The top side of the leaf takes in light and have a waxy cuticle to limit water loss, while the under side only takes in CO2 through the stoma (openings in the leaf). Conversely, macroalgae blades are composed of simple layers of epidermal, cortex and medullar cells with zoospores on theoutside surface. Furthermore, the blades are double-sided so that macroalgae can take in light, nutrients and H3CO from both sides.

Macroalgae also have some life cycle similarities to plants, but I will be getting to that tomorrow. So sit tight, folks.

Sources

-. 2010. GRE Subject Test: Biology 5th Ed. Kaplan, New York.

Yancey, Paul. “Macroalgae adaptations.” Marine Biology. Whitman College. Walla Walla, WA. 5 4 2011. Lecture.

Photo credit

–. “Marine Algae” Marine Education Society of Australasia. Jan 13, 2014 < http://www.mesa.edu.au/marine_algae/default.asp&gt;

–. 2013. “Canadian Aquaculture R & D Review 2011.” Fisheries and Oceans Canada. Jan 13 2014 <http://www.dfo-mpo.gc.ca/science/enviro/aquaculture/rd2011/cimtan-rcamti-eng.html&gt;