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"Roman, Joe"
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Diluting the founder effect: cryptic invasions expand a marine invader's range
Most invasion histories include an estimated arrival time, followed by range expansion. Yet, such linear progression may not tell the entire story. The European green crab (Carcinus maenas) was first recorded in the US in 1817, followed by an episodic expansion of range to the north. Its population has recently exploded in the Canadian Maritimes. Although it has been suggested that this northern expansion is the result of warming sea temperatures or cold-water adaptation, Canadian populations have higher genetic diversity than southern populations, indicating that multiple introductions have occurred in the Maritimes since the 1980s. These new genetic lineages, probably from the northern end of the green crab's native range in Europe, persist in areas that were once thought to be too cold for the original southern invasion front. It is well established that ballast water can contain a wide array of nonindigenous species. Ballast discharge can also deliver genetic variation on a level comparable to that of native populations. Such gene flow not only increases the likelihood of persistence of invasive species, but it can also rapidly expand the range of long-established nonindigenous species.
Journal Article
Eat, poop, die : how animals make our world
\"Reveals how ecosystems are sculpted and sustained by animals eating, pooping, and dying--and how these fundamental functions could help save us from climate catastrophe.\"--Dust jacket
Book
The Whale Pump: Marine Mammals Enhance Primary Productivity in a Coastal Basin
It is well known that microbes, zooplankton, and fish are important sources of recycled nitrogen in coastal waters, yet marine mammals have largely been ignored or dismissed in this cycle. Using field measurements and population data, we find that marine mammals can enhance primary productivity in their feeding areas by concentrating nitrogen near the surface through the release of flocculent fecal plumes. Whales and seals may be responsible for replenishing 2.3×10(4) metric tons of N per year in the Gulf of Maine's euphotic zone, more than the input of all rivers combined. This upward \"whale pump\" played a much larger role before commercial harvest, when marine mammal recycling of nitrogen was likely more than three times atmospheric N input. Even with reduced populations, marine mammals provide an important ecosystem service by sustaining productivity in regions where they occur in high densities.
Journal Article
الحوت : التاريخ الطبيعي والثقافي
الحوت التاريخ الطبيعي والثقافي كتاب لـ جو رومان، عادة ما تكون الإشارة الأولى على وجود الحوت هي زفيره الذي يمكن إيجاز وصفه بأنه عمود من الضباب الرقيق يرى عبر المحيط وبالنسبة لبعضهم، فإن هذه النفخة كانت مثل المدخنة فالمسافرون العرب القدماء كانوا يرون المآذن أو أشرعة السفن البعيدة. وفي حال كان الرذاذا قريباً بما يكفي تنتشر رائحة كريهة ورذاذ مخاطي مالح، ولقذ عزز زفير الحوت الخوف في قلوب البحارة الأوائل : إذ اعتقد النرويجيون أن الحيتان يمكنها إطلاق ما يكفي من الماء لإغراق قارب في حين شعر آخرون بالخوف من استنشاق الهواء الرطب، معتقدين أنه يسبب الدوار ونوبات الإغماء وربما الموت وأن بضع قطيرات صغيرة من أنفاس الحوت السامة يمكنها أن تسبب طفحاً على جلد الإنسان.
Book
Global nutrient transport in a world of giants
The past was a world of giants, with abundant whales in the sea and large animals roaming the land. However, that world came to an end following massive late-Quaternarymegafauna extinctions on land and widespread population reductions in great whale populations over the past few centuries. These losses are likely to have had important consequences for broad-scale nutrient cycling, because recent literature suggests that large animals disproportionately drive nutrient movement. We estimate that the capacity of animals to move nutrients away from concentration patches has decreased to about 8% of the preextinction value on land and about 5%of historic values in oceans. For phosphorus (P), a key nutrient, upward movement in the ocean by marine mammals is about 23% of its former capacity (previously about 340 million kg of P per year). Movements by seabirds and anadromous fish provide important transfer of nutrients from the sea to land, totalling ∼150 million kg of P per year globally in the past, a transfer that has declined to less than 4% of this value as a result of the decimation of seabird colonies and anadromous fish populations. We propose that in the past, marine mammals, seabirds, anadromous fish, and terrestrial animals likely formed an interlinked system recycling nutrients from the ocean depths to the continental interiors, with marine mammals moving nutrients from the deep sea to surface waters, seabirds and anadromous fish moving nutrients from the ocean to land, and large animals moving nutrients away from hotspots into the continental interior.
Journal Article
Whales as marine ecosystem engineers
Baleen and sperm whales, known collectively as the great whales, include the largest animals in the history of life on Earth. With high metabolic demands and large populations, whales probably had a strong influence on marine ecosystems before the advent of industrial whaling: as consumers of fish and invertebrates; as prey to other large-bodied predators; as reservoirs of and vertical and horizontal vectors for nutrients; and as detrital sources of energy and habitat in the deep sea. The decline in great whale numbers, estimated to be at least 66% and perhaps as high as 90%, has likely altered the structure and function of the oceans, but recovery is possible and in many cases is already underway. Future changes in the structure and function of the world's oceans can be expected with the restoration of great whale populations.
Journal Article
Migrating baleen whales transport high-latitude nutrients to tropical and subtropical ecosystems
Baleen whales migrate from productive high-latitude feeding grounds to usually oligotrophic tropical and subtropical reproductive winter grounds, translocating limiting nutrients across ecosystem boundaries in their bodies. Here, we estimate the latitudinal movement of nutrients through carcasses, placentas, and urea for four species of baleen whales that exhibit clear annual migration, relying on spatial data from publicly available databases, present and past populations, and measurements of protein catabolism and other sources of nitrogen from baleen whales and other marine mammals. Migrating gray, humpback, and North Atlantic and southern right whales convey an estimated 3784 tons N yr
−1
and 46,512 tons of biomass yr
−1
to winter grounds, a flux also known as the “great whale conveyor belt”; these numbers might have been three times higher before commercial whaling. We discuss how species recovery might help restore nutrient movement by whales in global oceans and increase the resilience and adaptative capacity of recipient ecosystems.
Baleen whales migrate from high latitude feeding grounds to subtropical reproductive winter grounds, translocating limiting nutrients across ecosystems. This study estimates the latitudinal movement of nutrients from carcasses, placentas and urea for four species of baleen whales that exhibit annual migrations.
Journal Article
Endangered Right Whales Enhance Primary Productivity in the Bay of Fundy
Marine mammals have recently been documented as important facilitators of rapid and efficient nutrient recycling in coastal and offshore waters. Whales enhance phytoplankton nutrition by releasing fecal plumes near the surface after feeding and by migrating from highly productive, high-latitude feeding areas to low-latitude nutrient-poor calving areas. In this study, we measured NH4+ and PO43- release rates from the feces of North Atlantic right whales (Eubalaena glacialis), a highly endangered baleen whale. Samples for this species were primarily collected by locating aggregations of whales in surface-active groups (SAGs), which typically consist of a central female surrounded by males competing for sexual activity. When freshly collected feces were incubated in seawater, high initial rates of N release were generally observed, which decreased to near zero within 24 hours of sampling, a pattern that is consistent with the active role of gut microflora on fecal particles. We estimate that at least 10% of particulate N in whale feces becomes available as NH4+ within 24 hours of defecation. Phosphorous was also abundant in fecal samples: initial release rates of PO43- were higher than for NH4+, yielding low N/P nutrient ratios over the course of our experiments. The rate of PO43- release was thus more than sufficient to preclude the possibility that nitrogenous nutrients supplied by whales would lead to phytoplankton production limited by P availability. Phytoplankton growth experiments indicated that NH4+ released from whale feces enhance productivity, as would be expected, with no evidence that fecal metabolites suppress growth. Although North Atlantic right whales are currently rare (approximately 450 individuals), they once numbered about 14,000 and likely played a substantial role in recycling nutrients in areas where they gathered to feed and mate. Even though the NH4+ released from fresh whale fecal material is a small fraction of total whale fecal nitrogen, and recognizing the fact that the additional nitrogen released in whale urine would be difficult to measure in a field study, the results of this study support the idea that the distinctive isotopic signature of the released NH4+ could be used to provide a conservative estimate of the contribution of the whale pump to primary productivity in coastal regions where whales congregate.
Journal Article
Biodiversity Loss Affects Global Disease Ecology
Changes in the type and prevalence of human diseases have occurred during shifts in human social organization, for example, from hunting and gathering to agriculture and with urbanization during the Industrial Revolution. The recent emergence and reemergence of infectious diseases appears to be driven by globalization and ecological disruption. We propose that habitat destruction and biodiversity loss associated with biotic homogenization can increase the incidence and distribution of infectious diseases affecting humans. The clearest connection between biotic homogenization and infectious disease is the spread of nonindigenous vectors and pathogens. The loss of predators and hosts that dilute pathogen transmission can also increase the incidence of vectorborne illnesses. Other mechanisms include enhanced abiotic conditions for pathogens and vectors and higher host-pathogen encounter rates. Improved understanding of these causal mechanisms can inform decisionmaking on biodiversity conservation as an effective way to protect human health.
Journal Article